TC7109/A 12-Bit A-Compatible Analog-to-Digital Converters Features: General Description: * Zero Integrator Cycle for Fast Recovery from Input Overloads * Eliminates Cross-Talk in Multiplexed Systems * 12-Bit Plus Sign Integrating A/D Converter with Over Range Indication * Sign Magnitude Coding Format * True Differential Signal Input and Differential Reference Input * Low Noise: 15VP-P Typ. * Input Current: 1pA Typ. * No Zero Adjustment needed * TTL Compatible, Byte Organized Tri-State Outputs * UART Handshake Mode for simple Serial Data Transmissions The TC7109A is a 12-bit plus sign, CMOS low power Analog-to-Digital Converter (ADC). Only eight passive components and a crystal are required to form a complete dual slope integrating ADC. Device Selection Table Part Number (TC7109X)* Package Temperature Range TC7109CKW 44-Pin PQFP 0C to +70C TC7109CLW 44-Pin PLCC 0C to +70C TC7109CPL TC7109IJL 40-Pin PDIP 0C to +70C 40-Pin CERDIP -25C to +85C *The "A" version has a higher IOUT on the digital lines. (c) 2006 Microchip Technology Inc. The improved VOH source current and other TC7109A features make it an attractive per-channel alternative to analog multiplexing for many data acquisition applications. These features include typical input bias current of 1pA, drift of less than 1V/C, input noise typically 15VP-P, and auto-zero. True differential input and reference allow measurement of bridge type transducers, such as load cells, strain gauges and temperature transducers. The TC7109A provides a versatile digital interface. In the Direct mode, Chip Select and HIGH/LOW byte enable control parallel bus interface. In the Handshake mode, the TC7109A will operate with industry standard UARTs in controlling serial data transmission - ideal for remote data logging. Control and monitoring of conversion timing is provided by the RUN/HOLD input and Status output. For applications requiring more resolution, see the TC500, 15-bit plus sign ADC data sheet. The TC7109A has improved over range recovery performance and higher output drive capability than the original TC7109. All new (or existing) designs should specify the TC7109A wherever possible. DS21456C-page 1 TC7109/A Package Type STATUS GND NC 5 4 3 2 1 44 43 42 41 40 REF IN+ POL REF CAP+ OR 6 V+ B12 REF IN+ REF CAP+ REF CAP- REF IN- V+ NC STATUS GND POL OR B12 44 43 42 41 40 39 38 37 36 35 34 REF INREF CAP- 44-Pin PLCC 44-Pin PQFP B11 1 33 IN HI B11 7 39 IN HI B10 2 32 IN LO B10 8 38 IN LO B9 3 31 COMMON B9 9 37 COMMON B8 4 30 INT B8 10 36 INT B7 29 AZ B7 11 28 NC NC 12 33 BUFF 5 TC7109ACKW TC7109CKW NC 6 35 AZ TC7109ACLW TC7109CLW 34 NC B6 7 27 BUFF B6 13 B5 8 26 REF OUT B5 14 32 REF OUT B4 9 25 V- B4 15 31 V- B3 10 24 SEND B3 16 30 SEND B2 11 23 RUN/HOLD B2 17 OSC SEL BUFF OSC OUT OSC IN OSC OUT MODE NC CE/LOAD LBEN HBEN B1 TEST OSC SEL BUFF OSC OUT OSC OUT MODE OSC IN NC CE/LOAD HBEN TEST LBEN B1 29 RUN/HOLD 18 19 20 21 22 23 24 25 26 27 28 12 13 14 15 16 17 18 19 20 21 22 40-Pin PDIP/CERDIP GND 1 40 V+ STATUS 2 39 REF IN- POL 3 38 REF CAP- OR B12 4 37 REF CAP+ 5 36 REF IN+ B11 6 35 IN HI B10 7 B9 8 B8 9 B7 10 B6 11 34 IN LO TC7109A TC7109 33 COMMON 32 INT 31 AZ 30 BUFF B5 12 29 REF OUT B4 13 28 V- B3 14 B2 15 27 SEND B1 16 25 BUFF OSC OUT 26 RUN/HOLD TEST 17 24 OSC SEL LBEN 18 23 OSC OUT HBEN 19 22 OSC IN CE/LOAD 20 21 MODE NC = No internal connection DS21456C-page 2 (c) 2006 Microchip Technology Inc. TC7109/A Typical Application AZ ZI Input 35 High REF IN39 AZ ZI Buffer - INT - 33 DE (+) Input Low 34 AZ DE () ZI INT + DE (+) ZI 17 Low Order Byte Inputs 3 4 5 6 7 8 9 10 11 12 13 14 15 16 18 19 20 Integrator + DE (-) AZ Common R CAZ CINT REF INT CAPBUFF AZ INT 32 38 30 31 High Order Byte Inputs POL OR B12 B11 B10 B9 B8 B7 B6 B5 B4 B3 B2 B1 REF REF CAP+ IN+ 37 36 TEST TC7109A C REF 16 Three-State Outputs Comparator Comp Out LBEN HBEN CE/LOAD 14 Latches AZ 12-Bit Counter Latch DE (-) Clock To Analog Section 10mA - Comp Out AZ INT DE () ZI Conversion Control Logic Oscillator and Clock Circuitry Handshake Logic + 6.2V 29 28 REF VOUT (c) 2006 Microchip Technology Inc. 40 V+ 2 Status 26 22 23 RUN/ HOLD OSC OSC OSC BUFF Mode IN OUT SEL OSC OUT 24 25 21 27 1 Send GND DS21456C-page 3 TC7109/A 1.0 ELECTRICAL CHARACTERISTICS *Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions above those indicated in the operation sections of the specifications is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability. Absolute Maximum Ratings* Positive Supply Voltage (GND to V+) ..................+6.2V Negative Supply Voltage (GND to V-) .....................-9V Analog Input Voltage (Low to High) (Note 1).... V+ to VReference Input Voltage: (Low to High) (Note 1) ............................. V+ to VDigital Input Voltage: (Pins 2-27) (Note 2) ...........................GND - 0.3V Power Dissipation, TA < 70C (Note 3) CERDIP ......................................................2.29W Plastic DIP ..................................................1.23W PLCC ..........................................................1.23W PQFP ..........................................................1.00W Operating Temperature Range Plastic Package (C) ......................... 0C to +70C Ceramic Package (I) .....................-25C to +85C Storage Temperature Range ..............-65C to +150C TC7109/TC7109A ELECTRICAL SPECIFICATIONS Electrical Characteristics: All parameters with V+ = +5V, V- = -5V, GND = 0V, TA = +25C, unless otherwise indicated. Symbol Parameter Min Typ Max Unit Test Conditions -- 0 1 Measurement Cycle Zero Input Reading -00008 00008 +00008 Octal Reading VIN = 0V; Full Scale = 409.6mV Ratio Metric Reading 37778 37778 40008 40008 Octal Reading VIN = VREF VREF = 204.8mV Non-Linearity (Max Deviation from Best Straight Line Fit) -1 0.2 +1 Count Full Scale = 409.6mV to 2.048V Over Full Operating Temperature Range Rollover Error (Difference in Reading for Equal Positive and Inputs near (Full Scale) -1 0.02 +1 Count Full Scale = 409.6mV to 2.048V Over Full Operating Temperature Range CMRR Input Common Mode Rejection Ratio -- 50 -- V/V VCM 1V, VIN = 0V Full Scale = 409.6mV VCMR Common Mode Voltage Range V- +1.5 -- V+ -1.5 V Input High, Input Low and Common Pins eN Noise (P-P Value Not Exceeded 95% of Time) -- 15 -- V VIN = 0V, Full Scale = 409.6mV IIN Leakage Current at Input Analog Overload Recovery Time (TC7109A) NL TCZS Zero Reading Drift -- 1 10 pA VIN, All Packages: +25C -- 20 100 pA C Device: 0C TA +70C -- 100 250 pA I Device: -25C TA +85C -- 0.2 1 V/C VIN = 0V Note 1: Input voltages may exceed supply voltages if input current is limited to 100A. 2: Connecting any digital inputs or outputs to voltages greater than V+ or less than GND may cause destructive device latch-up. Therefore, it is recommended that inputs from sources other than the same power supply should not be applied to the TC7109A before its power supply is established. In multiple supply systems, the supply to the device should be activated first. 3: This limit refers to that of the package and will not occur during normal operation. DS21456C-page 4 (c) 2006 Microchip Technology Inc. TC7109/A TC7109/TC7109A ELECTRICAL SPECIFICATIONS (Continued) Electrical Characteristics: All parameters with V+ = +5V, V- = -5V, GND = 0V, TA = +25C, unless otherwise indicated. Symbol Parameter Min Typ Max Unit TCFS Scale Factor Temperature Coefficient -- 1 5 V/C I+ Supply Current (V+ to GND) -- 700 1500 A IS Supply Current (V+ to V-) VREF Reference Out Voltage TCREF Test Conditions VIN = 408.9mV = >77708 Reading, Ext Ref = 0ppm/C VIN = 0V, Crystal Oscillator 3.58MHz Test Circuit -- 700 1500 A Pins 2-21, 25, 26, 27, 29 Open -2.4 -2.8 -3.2 V Referenced to V+, 25k Between V+ and Ref Out Ref Out Temperature Coefficient -- 80 -- ppm/C Output High Voltage IOUT = 700A 3.5 4.3 -- V 25k Between V+ and Ref Out 0C TA +70C Digital VOH VOL TC7109: IOUT = 100A Pins 3 -16, 18, 19, 20 TC7109A: IOUT = 700A Output Low Voltage -- 0.2 0.4 A IOUT = 1.6mA Output Leakage Current -- 0.01 1 A Pins 3 -16 High-Impedance Control I/O Pull-up Current -- 5 -- F Pins 18, 19, 20 VOUT = V+ - 3V Mode Input at GND Control I/O Loading -- -- 50 pF HBEN, Pin 19; LBEN, Pin 18 VIH Input High Voltage 2.5 -- -- V Pins 18 -21, 26, 27 Referenced to GND VIL Input Low Voltage -- -- 1 V Pins 18-21, 26, 27 Referenced to GND Input Pull-up Current -- -- 5 25 -- -- A A Pins 26, 27; VOUT = V+ - 3V Pins 17, 24; VOUT = V+ - 3V tW Input Pull-down Current -- 1 -- A Pins 21, VOUT = GND = +3V Oscillator Output Current, High -- 1 -- mA VOUT - 2.5V Oscillator Output Current, Low -- 1.5 -- mA VOUT - 2.5V Buffered Oscillator Output Current High -- 2 -- mA VOUT - 2.5V Buffered Oscillator Output Current Low -- 5 -- mA VOUT - 2.5V Mode Input Pulse Width 60 -- -- nsec Note 1: Input voltages may exceed supply voltages if input current is limited to 100A. 2: Connecting any digital inputs or outputs to voltages greater than V+ or less than GND may cause destructive device latch-up. Therefore, it is recommended that inputs from sources other than the same power supply should not be applied to the TC7109A before its power supply is established. In multiple supply systems, the supply to the device should be activated first. 3: This limit refers to that of the package and will not occur during normal operation. HANDLING PRECAUTIONS: These devices are CMOS and must be handled correctly to prevent damage. Package and store only in conductive foam, antistatic tubes, or other conducting material. Use proper antistatic handling procedures. Do not connect in circuits under "power-on" conditions, as high transients may cause permanent damage. (c) 2006 Microchip Technology Inc. DS21456C-page 5 TC7109/A 2.0 PIN DESCRIPTIONS The descriptions of the pins are listed in Table 2-1. TABLE 2-1: Pin Number (40-Pin PDIP) PIN FUNCTION TABLE Symbol Description 1 GND 2 STATUS Digital ground, 0V, ground return for all digital logic. 3 POL Polarity - High for positive input. 4 OR Over Range - High if over ranged (Three-State Data bit). Output HIGH during integrate and de-integrate until data is latched. Output LOW when analog section is in auto-zero or zero integrator configuration. 5 B12 Bit 12 (Most Significant bit) (Three-State Data bit). 6 B11 Bit 11 (Three-State Data bit). 7 B10 Bit 10 (Three-State Data bit). 8 B9 Bit 9 (Three-State Data bit). 9 B8 Bit 8 (Three-State Data bit). 10 B7 Bit 7 (Three-State Data bit). 11 B6 Bit 6 (Three-State Data bit). 12 B5 Bit 5 (Three-State Data bit). 13 B4 Bit 4 (Three-State Data bit). 14 B3 Bit 3 (Three-State Data bit). 15 B2 Bit 2 (Three-State Data bit). 16 B1 Bit 1 (Least Significant bit) (Three-State Data bit). 17 TEST Input High - Normal operation. Input LOW - Forces all bit outputs HIGH. Note: This input is used for test purposes only. 18 LBEN Low Byte Enable - with MODE (Pin 21) LOW, and CE/LOAD (Pin 20) LOW, taking this pin LOW activates low order byte outputs, B1-B8. With MODE (Pin 21) HIGH, this pin serves as low byte flag output used in Handshake mode. (See Figure 3-7, Figure , and Figure 3-9.) 19 HBEN High Byte Enable - with MODE (Pin 21) LOW, and CE/LOAD (Pin 20) LOW, taking this pin LOW activates high order byte outputs, B9-B12, POL, OR. With MODE (Pin 21) HIGH, this pin serves as high byte flag output used in Handshake mode. See Figures 3-7, 3-8, and 3-9. 20 CE/LOAD Chip Enable/Load - with MODE (Pin 21) LOW, CE/LOAD serves as a master output enable. When HIGH, B1-B12, POL, OR outputs are disabled. When MODE (Pin 21) is HIGH, a load strobe is used in handshake mode. (See Figure 3-7, Figure , and Figure 3-9.) 21 MODE Input LOW - Direct Output mode where CE/LOAD (Pin 20), HBEN (Pin 19), and LBEN (Pin 18) act as inputs directly controlling byte outputs. Input Pulsed HIGH - Causes immediate entry into Handshake mode and output of data as in Figure 3-9. Input HIGH - enables CE/LOAD (Pin 20), HBEN (Pin 19), and LBEN (Pin 18) as outputs, Handshake mode will be entered and data output as in Figure 3-7 and Figure 3-9 at conversions completion. 22 OSC IN 23 OSC OUT Oscillator Output. 24 OSC SEL Oscillator Select - Input HIGH configures OSC IN, OSC OUT, BUFF OSC OUT as RC oscillator - clock will be same phase and duty cycle as BUFF OSC OUT. Input LOW configures OSC IN, OSC OUT for crystal oscillator - clock frequency will be 1/58 of frequency at BUFF OSC OUT. 25 Oscillator Input. BUFF OSC OUT Buffered Oscillator Output. 26 RUN/HOLD Input HIGH - Conversions continuously performed every 8192 clock pulses. Input LOW - Conversion in progress completed; converter will stop in auto-zero seven counts before integrate. 27 SEND Input - Used in Handshake mode to indicate ability of an external device to accept data. Connect to V+ if not used. 28 V- 29 REF OUT DS21456C-page 6 Analog Negative Supply - Nominally -5V with respect to GND (Pin 1). Reference Voltage Output - Nominally 2.8V down from V+ (Pin 40). (c) 2006 Microchip Technology Inc. TC7109/A TABLE 2-1: PIN FUNCTION TABLE (CONTINUED) Pin Number (40-Pin PDIP) Symbol 30 BUFF Note: Description Buffer Amplifier Output. 31 AZ Auto-Zero Node - Inside foil of CAZ. 32 INT Integrator Output - Outside foil of CINT. 33 COMMON 34 IN LO Analog Common - System is auto-zeroed to COMMON. Differential Input Low Side. 35 IN HI 36 REF IN+ Differential Input High Side. 37 REF CAP+ Reference Capacitor Positive. 38 REF CAP- Reference Capacitor Negative. 39 REF IN- 40 V+ Differential Reference Input Positive. Differential Reference Input Negative. Positive Supply Voltage - Nominally +5V with respect to GND (Pin 1). All Digital levels are positive true. (c) 2006 Microchip Technology Inc. DS21456C-page 7 TC7109/A 3.0 DETAILED DESCRIPTION (All Pin Designations Refer to 40-Pin DIP.) 3.1 Analog Section The Typical Application diagram on page 3 shows a block diagram of the analog section of the TC7109A. The circuit will perform conversions at a rate determined by the clock frequency (8192 clock periods per cycle), when the RUN/HOLD input is left open or connected to V+. Each measurement cycle is divided into four phases, as shown in Figure 3-1. They are: (1) Auto-Zero (AZ), (2) Signal Integrate (INT), (3) Reference De-integrate (DE), and (4) Zero Integrator (ZI). 3.1.1 AUTO-ZERO PHASE The buffer and the integrator inputs are disconnected from input high and input low and connected to analog common. The reference capacitor is charged to the reference voltage. A feedback loop is closed around the system to charge the auto-zero capacitor, CAZ, to compensate for offset voltage in the buffer amplifier, integrator, and comparator. Since the comparator is included in the loop, the AZ accuracy is limited only by the noise of the system. The offset referred to the input is less than 10V. 3.1.2 SIGNAL INTEGRATE PHASE The buffer and integrator inputs are removed from common and connected to input high and input low. The auto-zero loop is opened. The auto-zero capacitor is placed in series in the loop to provide an equal and opposite compensating offset voltage. The differential voltage between input high and input low is integrated for a fixed time of 2048 clock periods. At the end of this phase, the polarity of the integrated signal is determined. If the input signal has no return to the converter's power supply, input low can be tied to analog common to establish the correct Common mode voltage. 3.1.3 DE-INTEGRATE PHASE Input high is connected across the previously charged reference capacitor and input low is internally connected to analog common. Circuitry within the chip ensures the capacitor will be connected with the correct polarity to cause the integrator output to return to the zero crossing (established by auto-zero), with a fixed slope. The time, represented by the number of clock periods counted for the output to return to zero, is proportional to the input signal. DS21456C-page 8 3.1.4 ZERO INTEGRATOR PHASE The ZI phase only occurs when an input over range condition exists. The function of the ZI phase is to eliminate residual charge on the integrator capacitor after an over range measurement. Unless removed, the residual charge will be transferred to the auto-zero capacitor and cause an error in the succeeding conversion. The ZI phase virtually eliminates hysteresis, or "crosstalk" in multiplexed systems. An over range input on one channel will not cause an error on the next channel measured. This feature is especially useful in thermocouple measurements, where unused (or broken thermocouple) inputs are pulled to the positive supply rail. During ZI, the reference capacitor is charged to the reference voltage. The signal inputs are disconnected from the buffer and integrator. The comparator output is connected to the buffer input, causing the integrator output to be driven rapidly to 0V (Figure 3-1). The ZI phase only occurs following an over range and lasts for a maximum of 1024 clock periods. 3.1.5 DIFFERENTIAL INPUT The TC7109A has been optimized for operation with analog common near digital ground. With +5V and -5V power supplies, a full 4V full scale integrator swing maximizes the analog section's performance. A typical CMRR of 86dB is achieved for input differential voltages anywhere within the typical Common mode range of 1V below the positive supply, to 1.5V above the negative supply. However, for optimum performance, the IN HI and IN LO inputs should not come within 2V of either supply rail. Since the integrator also swings with the Common mode voltage, care must be exercised to ensure the integrator output does not saturate. A worst-case condition is near a full scale negative differential input voltage with a large positive Common mode voltage. The negative input signal drives the integrator positive when most of its swing has been used up by the positive Common mode voltage. In such cases, the integrator swing can be reduced to less than the recommended 4V full scale value, with some loss of accuracy. The integrator output can swing to within 0.3V of either supply without loss of linearity. (c) 2006 Microchip Technology Inc. TC7109/A 3.1.6 DIFFERENTIAL REFERENCE The reference voltage can be generated anywhere within the power supply voltage of the converter. Rollover voltage is the main source of Common mode error, caused by the reference capacitor losing or gaining charge, due to stray capacity on its nodes. With a large Common mode voltage, the reference capacitor can gain charge (increase voltage) when called upon to de-integrate a positive signal and lose charge (decrease voltage) when called upon to de-integrate a negative input signal. This difference in reference for (+) or (-) input voltages will cause a rollover error. This error can be held to less than 0.5 count, worst-case, by using a large reference capacitor in comparison to the stray capacitance. To minimize rollover error from these sources, keep the reference Common mode voltage near or at analog common. 3.2 Digital Section The digital section is shown in Figure 3-2 and includes the clock oscillator and scaling circuit, a 12-bit binary counter with output latches and TTL compatible threestate output drivers, UART handshake logic, polarity, over range, and control logic. Logic levels are referred to as LOW or HIGH. Inputs driven from TTL gates should have 3k to 5k pull-up resistors added for maximum noise immunity. For minimum power consumption, all inputs should swing from GND (LOW) to V+ (HIGH). 3.2.1 STATUS OUTPUT During a conversion cycle, the Status output goes high at the beginning of signal integrate and goes low onehalf clock period after new data from the conversion has been stored in the output latches (see Figure 3-1). The signal may be used as a "data valid" flag to drive interrupts, or for monitoring the status of the converter. (Data will not change while status is low.) 3.2.2 3.2.3 RUN/HOLD INPUT With the RUN/HOLD input high, or open, the circuit operates normally as a dual slope ADC, as shown in Figure 3-1. Conversion cycles operate continuously with the output latches updated after zero crossing in the De-integrate mode. An internal pull-up resistor is provided to ensure a HIGH level with an open input. The RUN/HOLD input may be used to shorten conversion time. If RUN/HOLD goes LOW any time after zero crossing in the De-integrate mode, the circuit will jump to auto-zero and eliminate that portion of time normally spent in de-integrate. If RUN/HOLD stays or goes LOW, the conversion will complete with minimum time in de-integrate. It will stay in auto-zero for the minimum time and wait in auto-zero for a HIGH at the RUN/HOLD input. As shown in Figure 3-3, the Status output will go HIGH, 7 clock periods after RUN/HOLD is changed to HIGH, and the converter will begin the integrate phase of the next conversion. The RUN/HOLD input allows controlled conversion interface. The converter may be held at Idle in autozero with RUN/HOLD LOW. The conversion is started when RUN/HOLD goes HIGH, and the new data is valid when the Status output goes LOW (or is transferred to the UART; see "Handshake Mode"). RUN/ HOLD may now go LOW, terminating de-integrate and ensuring a minimum auto-zero time before stopping to wait for the next conversion. Conversion time can be minimized by ensuring RUN/HOLD goes LOW during de-integrate, after zero crossing, and goes HIGH after the hold point is reached. The required activity on the RUN/HOLD input can be provided by connecting it to the buffered oscillator output. In this mode, the input value measured determines the conversion time. MODE INPUT The Output mode of the converter is controlled by the MODE input. The converter is in its "Direct" Output mode, when the MODE input is LOW or left open. The output data is directly accessible under the control of the chip and byte enable inputs (this input is provided with a pull-down resistor to ensure a LOW level when the pin is left open). When the MODE input is pulsed high, the converter enters the UART Handshake mode and outputs the data in 2 bytes, then returns to "Direct" mode. When the MODE input is kept HIGH, the converter will output data in the Handshake mode at the end of every conversion cycle. With MODE = 0 (direct bus transfer), the send input should be tied to V+. (See "Handshake Mode".) (c) 2006 Microchip Technology Inc. DS21456C-page 9 TC7109/A ZI Integrator Saturates AZ Integrator Output for Over Range Input Zero Integrator Phase forces Integrator Output to 0V No Zero Crossing Zero Crossing Occurs Zero Crossing Detected Integrator Output for Normal Input AZ Phase I INT Phase II DE Phase III AZ Internal Clock Internal Latch Status Output 2048 Fixed Counts 2048 Min. Counts Number of Counts to Zero Crossing Proportional to VIN FIGURE 3-1: 4096 Counts Max After Zero Crossing, Analog section will be in Auto-Zero Configuration Conversion Timing (RUN/HOLD) Pin High TEST High Order Byte Outputs B B B POL OR 12 11 10 17 3 4 5 6 7 B 9 8 B 8 Low Order Byte Outputs B B B B 6 5 4 3 B 7 B 2 B 1 9 10 11 12 13 14 15 16 18 19 14 Three-State Outputs 20 LBEN HBEN CE/LOAD 14 Latches 12-Bit Counter Latch Clock To Analog Section COMP OUT AZ INT DE () ZI Conversion Control Logic 2 STATUS FIGURE 3-2: DS21456C-page 10 Oscillator and Clock Circuitry 26 22 23 24 25 Handshake Logic 21 RUN/ OSC OSC OSC BUFF MODE IN OUT SEL OSC HOLD OUT 27 1 SEND GND Digital Section (c) 2006 Microchip Technology Inc. TC7109/A Determinated at Zero Crossing Detection Auto-Zero Phase I Min 1790 Counts Max 2041 Counts Static in Hold State INT Phase II Integrator Output 7 Counts Internal Clock Internal Latch Status Output RUN/HOLD Input * *Note: RUN/HOLD input is ignored until end of auto-zero phase. FIGURE 3-3: 3.2.4 TC7109A RUN/HOLD Operation TABLE 3-1: DIRECT MODE The data outputs (bits 1 through 8, low order bytes; bits 9 through 12, polarity and over range high order bytes) are accessible under control of the byte and chip enable terminals as inputs, with the MODE pin at a LOW level. These three inputs are all active LOW. Internal pull-up resistors are provided for an inactive HIGH level when left open. When chip enable is LOW, a byte enable input LOW will allow the outputs of the byte to become active. A variety of parallel data accessing techniques may be used, as shown in the "Interfacing" section. (See Figure 3-4 and Table 3-1.) The access of data should be synchronized with the conversion cycle by monitoring the Status output. This prevents accessing data while it is being updated and eliminates the acquisition of erroneous data. tCEA CE/LOAD As Input tBEA HBEN As Input LBEN As Input tDAB High Byte Data tDAB Data Valid Data Valid tDAC Low Byte Data tDHC Data Valid Symbol TC7109A DIRECT MODE TIMING REQUIREMENTS Description Min Typ Max Units tBEA Byte Enable Width 200 500 -- nsec tDAB Data Access Time from Byte Enable -- 150 300 nsec tDHB Data Hold Time from Byte Enable -- 150 300 nsec tCEA Chip Enable Width 300 500 tDAC Data Access Time from Chip Enable -- 200 400 tDHC Data Hold Time from Chip Enable -- 200 400 3.2.5 nsec nsec nsec HANDSHAKE MODE An alternative means of interfacing the TC7109A to digital systems is provided when the Handshake Output mode of the TC7109A becomes active in controlling the flow of data, instead of passively responding to chip and byte enable inputs. This mode allows a direct interface between the TC7109A and industry standard UARTs with no external logic required. The TC7109A provides all the control and flag signals necessary to sequence the two bytes of data into the UART and initiate their transmission in serial form when triggered into the Handshake mode. The cost of designing remote data acquisition stations is reduced using serial data transmission to minimize the number of lines to the central controlling processor. = High-Impedance FIGURE 3-4: Output Timing TC7109A Direct Mode (c) 2006 Microchip Technology Inc. DS21456C-page 11 TC7109/A The MODE input controls the Handshake mode. When the MODE input is held HIGH, the TC7109A enters the Handshake mode after new data has been stored in the output latches at the end of every conversion performed (see Figure 3-7 and Figure ). Entry into the Handshake mode may be triggered on demand by the MODE input. At any time during the conversion cycle, the LOW-to-HIGH transition of a short pulse at the MODE input will cause immediate entry into the Handshake mode. If this pulse occurs while new data is being stored, the entry into Handshake mode is delayed until the data is stable. The MODE input is ignored in the Handshake mode, and until the converter completes the output cycle and clears the Handshake mode, data updating will be inhibited (see Figure 3-9). When the MODE input is HIGH, or when the converter enters the Handshake mode, the chip and byte enable inputs become TTL compatible outputs, which provide the output cycle control signals (see Figure 3-7, Figure and Figure 3-9). The SEND input is used by the converter as an indication of the ability of the receiving device (such as a UART) to accept data in the Handshake mode. The sequence of the output cycle with SEND held HIGH is shown in Figure 3-7. The Handshake mode (internal MODE HIGH) is entered after the data latch pulse (the CE/LOAD, LBEN and HBEN terminals are active as outputs, since MODE remains HIGH). The HIGH level at the SEND input is sensed on the same HIGH-to-LOW internal clock edge. On the next LOW-to-HIGH internal clock edge, the high order byte (bits 9 through 12, POL, and OR) outputs are enabled and the CE/LOAD and the HBEN outputs assume a LOW level. The CE/LOAD output remains LOW for one full internal clock period only; the data outputs remain active for 1-1/2 internal clock periods; and the high byte enable remains LOW for 2 clock periods. The CE/LOAD output LOW level, or LOW-to-HIGH edge, may be used as a synchronizing signal to ensure valid data, and the byte enable as an output may be used as a byte identification flag. With SEND remaining HIGH, the converter completes the output cycle using CE/LOAD and LBEN, while the low order byte outputs (bits 1 through 8) are activated. When both bytes are sent, the Handshake mode is terminated. The typical UART interfacing timing is shown in Figure . The SEND input is used to delay portions of the sequence, or handshake, to ensure correct data transfer. This timing diagram shows an industry standard HD6403 or CDP1854 CMOS UART to interface to serial data channels. The SEND input to the TC7109A is driven by the TBRE (Transmitter Buffer Register Empty) output of the UART, and the CE/LOAD input of the TC7109A drives the TBRL (Transmitter Buffer Register Load) input to the UART. The eight transmitter buffer register inputs accept the parallel data outputs. With the UART transmitter buffer register empty, the DS21456C-page 12 SEND input will be HIGH when the Handshake mode is entered, after new data is stored. The high order byte outputs become active and the CE/LOAD and HBEN inputs will go LOW after SEND is sensed. When CE/ LOAD goes HIGH at the end of one clock period, the high order byte data is clocked into the UART transmitter buffer register. The UART TBRE output will go LOW, which halts the output cycle with the HBEN output LOW, and the high order byte outputs active. When the UART has transferred the data to the transmitter register and cleared the transmitter buffer register, the TBRE returns HIGH. The high order byte outputs are disabled on the next TC7109A internal clock HIGH-toLOW edge, and one-half internal clock later, the HBEN output returns HIGH. The CE/LOAD and LBEN outputs go LOW at the same time as the low order byte outputs become active. When the CE/LOAD returns HIGH at the end of one clock period, the low order data is clocked into the UART transmitter buffer register, and TBRE again goes LOW. The next TC7109A internal clock HIGH-to-LOW edge will sense when TBRE returns to a HIGH, disabling the data inputs. One-half internal clock later, the Handshake mode is cleared, and the CE/LOAD, HBEN and LBEN terminals return HIGH and stay active, if MODE still remains HIGH. Handshake output sequences may be performed on demand by triggering the converter into Handshake mode with a LOW-to-HIGH edge on the MODE input. A handshake output sequence triggered is shown in Figure 3-9. The SEND input is LOW when the converter enters Handshake mode. The whole output sequence is controlled by the SEND input, and the sequence for the first (high order) byte is similar to the sequence for the second byte. Figure 3-9 also shows that the output sequence can take longer than a conversion cycle. New data will not be latched when the Handshake mode is still in progress and is, therefore, lost. 3.3 Oscillator The oscillator may be over driven, or may be operated as an RC or crystal oscillator. The OSCILLATOR SELECT input optimizes the internal configuration of the oscillator for RC or crystal operation. The OSCILLATOR SELECT input is provided with a pull-up resistor. When the OSCILLATOR SELECT input is HIGH or left open, the oscillator is configured for RC operation. The internal clock will be the same frequency and phase as the signal at the BUFFERED OSCILLATOR OUTPUT. Connect the resistor and capacitor as in Figure . The circuit will oscillate at a frequency given by f = 0.45/RC. A 100k resistor is recommended for useful ranges of frequency. The capacitor value should be chosen such that 2048 clock periods are close to an integral multiple of the 60Hz period for optimum 60Hz line rejection. (c) 2006 Microchip Technology Inc. TC7109/A Clock V+ 24 22 23 25 OSC SEL OSC IN OSC OUT R Buffered OSC OUT / 58 FOSC = 0.45/RC FIGURE 3-5: With OSCILLATOR SELECT input LOW, two on-chip capacitors and a feedback device are added to the oscillator. In this configuration, the oscillator will operate with most crystals in the 1MHz to 5MHz range, with no external components (Figure ). The OSCILLATOR SELECT input LOW inserts a fixed 458 divider circuit between the BUFFERED OSCILLATOR OUTPUT and the internal clock. A 3.58MHz TV crystal gives a division ratio, providing an integration time given by: EQUATION 3-1: 58 3.58 MHz = 33.18 msec 23 25 OSC OUT Buffered OSC OUT Crystal GND TC7109A RC Oscillator t = (2048 clock periods) 22 OSC OSC SEL IN C V+ or Open 24 FIGURE 3-6: Crystal Oscillator The error is less than 1% from two 60Hz periods, or 33.33msec, which will give better than 40dB, 60Hz rejection. The converter will operate reliably at conversion rates up to 30 per second, corresponding to a clock frequency of 245.8kHz. When the oscillator is to be over driven, the OSCILLATOR OUTPUT should be left open, and the over driving signal should be applied at the OSCILLATOR INPUT. The internal clock will be of the same duty cycle, frequency and phase as the input signal. When the OSCILLATOR SELECT is at GND, the clock will be 1/58 of the input frequency. Zero Crossing Occurs Zero Crossing Detected Integrator Output Internal Clock Internal Latch Status Output Mode Input Internal Mode UART Norm Send Sensed Send Sensed Terminates UART Mode Mode Low, not in Handshake Mode Disables Outputs Send Input CE/LOAD CE/LOAD, HBEN, LBEN HBEN High Byte Data Data Valid LBEN Mode High Activates CE/LOAD, HBEN, LBEN Low Byte Data Data Invalid = Don't Care FIGURE 3-7: = Three-State High-Impendance = Three-State will Pull-up TC7109A Handshake with Send Input Held Positive (c) 2006 Microchip Technology Inc. DS21456C-page 13 TC7109/A Zero Crossing Occurs Zero Crossing Detected Integrator Output Internal Clock Internal Latch Status Output Mode Input Internal Mode UART Norm Send Sensed Send Sensed Send Sensed Terminates UART Mode Send Input (UART TBRE) CE/LOAD Output (UART TBRL) HBEN High Byte Data Data Valid LBEN Low Byte Data Data Valid = Three-State High-Impedance = Don't Care FIGURE 3-8: TC7109A Handshake - Typical UART Interface Timing Zero Crossing Occurs Zero Crossing Detected Positive Transiton causes Entry into UART Mode Status Output unchanged in UART Mode Latch Pulse inhibited in UART Mode Internal Clock Internal Latch Status Output Mode Input Internal Mode DE Phase III UART Norm Send Sensed Send Sensed Send Sensed Terminates UART Mode Send Input CE/LOAD as Output HBEN High Byte Data Data Valid LBEN Low Byte Data Data Valid = Don't Care FIGURE 3-9: DS21456C-page 14 = Three-State High-Impedance = Three-State with Pull-up TC7109A Handshake Triggered by Mode Input (c) 2006 Microchip Technology Inc. TC7109/A 3.4 Test Input The counter and its outputs may be tested easily. When the TEST input is connected to GND, the internal clock is disabled and the counter outputs are all forced into the HIGH state. When the input returns to the 1/2 (V+ - GND) voltage or to V+ and one clock is input, the counter outputs will all be clocked to the LOW state. this very linear region over the input voltage range, but small enough that undue leakage requirements are not placed on the PC board. For 2.048V full scale, a 100k resistor is recommended and for 409.6mV full scale, a 20k resistor is recommended. RINT may be selected for other values of full scale by: EQUATION 3-3: The counter output latches are enabled when the TEST input is taken to a level halfway between V+ and GND, allowing the counter contents to be examined any time. 3.5 Component Value Selection The integrator output swing for full scale should be as large as possible. For example, with 5V supplies and COMMON connected to GND, the nominal integrator output swing at full scale is 4V. Since the integrator output can go to 0.3V from either supply without significantly effecting linearity, a 4V integrator output swing allows 0.7V for variations in output swing, due to component value and oscillator tolerances. With 5V supplies and a Common mode voltage range of 1V required, the component values should be selected to provide 3V integrator output swing. Noise and rollover errors will be slightly worse than in the 4V case. For large Common mode voltage ranges, the integrator output swing must be reduced further. This will increase both noise and rollover errors. To improve performance, 6V supplies may be used. 3.5.1 INTEGRATING CAPACITOR The integrating capacitor, CINT, should be selected to give the maximum integrator output voltage swing that will not saturate the integrator to within 0.3V from either supply. A 3.5V to 4V integrator output swing is nominal for the TC7109A, with 5V supplies and analog common connected to GND. For 7-1/2 conversions per second (61.72kHz internal clock frequency), nominal values CINT and CAZ are 0.15F and 0.33F, respectively. These values should be changed if different clock frequencies are used to maintain the integrator output voltage swing. The value of CINT is given by: EQUATION 3-2: CINT = (2048 Clock Period) (20 A) Integrator Output Voltage Swings The integrating capacitor must have low dielectric absorption to prevent rollover errors. Polypropylene capacitors give undetectable errors, at reasonable cost, up to +85C. 3.5.2 INTEGRATING RESISTOR The integrator and buffer amplifiers have a class A output stage with 100A of quiescent current. They supply 20A of drive current with negligible non-linearity. The integrating resistor should be large enough to remain in (c) 2006 Microchip Technology Inc. Full Scale Voltage RINT = 3.5.3 20 A AUTO-ZERO CAPACITOR As the auto-zero capacitor is made large, the system noise is reduced. Since the TC7109A incorporates a zero integrator cycle, the size of the auto-zero capacitor does not affect overload recovery. The optimal value of the auto-zero capacitor is between 2 and 4 times CINT. A typical value for CAZ is 0.33F. The inner foil of CAZ should be connected to Pin 31 and the outer foil to the RC summing junction. The inner foil of CINT should be connected to the RC summing junction and the outer foil to Pin 32, for best rejection of stray pickups. 3.5.4 REFERENCE CAPACITOR A 1F capacitor is recommended for most circuits. However, where a large Common mode voltage exists, a larger value is required to prevent rollover error (e.g., the reference low is not analog common), and a 409.6mV scale is used. The rollover error will be held to 0.5 count with a 10F capacitor. 3.5.5 REFERENCE VOLTAGE To generate full scale output of 4096 counts, the analog input required is VIN = 2VREF. For 409.6mV full scale, use a reference of 204.8mV. In many applications, where the ADC is connected to a transducer, a scale factor will exist between the input voltage and the digital reading. For instance, in a measuring system, the designer might like to have a full scale reading when the voltage for the transducer is 700mV. Instead of dividing the input down to 409.6mV, the designer should use the input voltage directly and select VREF = 350mV. Suitable values for integrating resistor and capacitor would be 34k and 0.15F. This makes the system slightly quieter and also avoids a divider network on the input. Another advantage of this system occurs when temperature and weight measurements, with an offset or tare, are desired for non-zero input. The offset may be introduced by connecting the voltage output of the transducer between common and analog high, and the offset voltage between common and analog low, observing polarities carefully. In processor based systems using the TC7109A, it may be more desirable to use software and perform this type of scaling or tare subtraction digitally. DS21456C-page 15 TC7109/A 3.5.6 REFERENCE SOURCES A major factor in the absolute accuracy of the ADC is the stability of the reference voltage. The 12-bit resolution of the TC7109A is one part in 4096, or 244 ppm. Thus, for the on-board reference temperature coefficient of 70ppm/C, a temperature difference of 3C will introduce a one-bit absolute error. Where the ambient temperature is not controlled, or where high accuracy absolute measurements are being made, it is recommended that an external high quality reference be used. A reference output (Pin 29) is provided, which may be used with a resistive divider to generate a suitable reference voltage (20mA may be sunk without significant variation in output voltage). A pull-up bias device is provided, which sources about 10A. The output voltage is nominally 2.8V below V+. When using the on-board reference, REF OUT (Pin 29) should be connected to REF IN- (pin 39), and REF IN+ should be connected to the wiper of a precision potentiometer between REF OUT and V+. The test circuit shows the circuit for a 204.8mV reference, generated by a 2k precision potentiometer in series with a 24k fixed resistor. DS21456C-page 16 (c) 2006 Microchip Technology Inc. TC7109/A 4.0 INTERFACING 4.1 Direct Mode Combinations of chip enable and byte enable control signals, which may be used when interfacing the TC7109A to parallel data lines, are shown in Figure . The CE/LOAD input may be tied low, allowing either byte to be controlled by its own enable (see Figure (A)). Figure (B) shows the HBEN and LBEN as flag inputs, and CE/LOAD as a master enable, which could be the READ strobe available from most microprocessors. Figure (C) shows a configuration where the two byte enables are connected together. The CE/LOAD is a chip enable, and the HBEN and LBEN may be used as a second chip enable, or connected to ground. The 14 data outputs will be enabled at the same time. In the direct MODE, SEND should be tied to V+. Figure shows interfacing several TC7109A's to a bus, ganging the HBEN and LBEN signals to several converters together, and using the CE/LOAD input to select the desired converter. A. B. GND MODE CE/LOAD B9 - B12 POL, OR Analog In MODE LBEN Control FIGURE 4-1: Direct interfacing to most microcontroller busses is easily accomplished through the three-state output of the TC7109A. Figure 4-8 is a typical connection diagram. To ensure requirements for setup and hold times, minimum pulse widths, and the drive limitations on long busses are met, it is necessary to carefully consider the system timing in this type of interface. This type of interface is used when the memory peripheral address density is low, providing simple address decoding. Interrupt handling can be simplified by using an interface to reduce the component count. C. Chip Select GND CE/LOAD B1 - B12 POL, OR 6 MODE 14 Analog In B1 - B8 Analog In RUN/HOLD Convert HBEN LBEN CE/LOAD B9 - B12 POL, OR 6 TC7109A TC7109A 8 RUN/HOLD HBEN The RUN/HOLD input is also used to initiate conversions under software control. Chip Select 1 GND TC7109A B1 - B8 Figure through Figure give practical circuits utilizing the parallel three-state output capabilities of the TC7109A. Figure shows parallel interface to the 8748/ 49 systems via an 8255 PPI, where the TC7109A data outputs are active at all times. This interface can be used in a read-after-update sequence, as shown in Figure . The data is accessed by the high-to-low transition of the Status driving an interrupt to the microcontroller. 8 RUN/HOLD Convert GND or Chip Select 2 HBEN LBEN Convert Byte Flags Direct Mode Chip and Byte Enable Combination (c) 2006 Microchip Technology Inc. DS21456C-page 17 TC7109/A Converter Select Converter Select GND Converter Select GND MODE CE/LOAD MODE B9 - B12 POL, OR MODE 6 RUN/HOLD Analog In HBEN B1 - B8 8 Analog In RUN/HOLD +5V LBEN 6 TC7109A B1 - B8 8 CE/LOAD B9 - B12 POL, OR 6 TC7109A B1 - B8 HBEN CE/LOAD B9 - B12 POL, OR TC7109A Analog In GND RUN/HOLD +5V LBEN HBEN 8 +5V LBEN Byte Select Flags FIGURE 4-2: Three-Stating Several TC7109As to a Small Bus Address Bus Control Bus Data Bus GND Analog In MODE CE/LOAD B9 - B12 POL, OR RUN/HOLD TC7109A B1 - B8 STATUS HBEN 6 +5V 8 See Text RD WR D7 - D0 A0 - A1 CS PA5 - PA0 PD8255A (Mode 0) PB7 - PB0 PD8748H/49H PC5 LBEN GND FIGURE 4-3: DS21456C-page 18 Full Time Parallel Interface to PD8748H/494 Microcontrollers (c) 2006 Microchip Technology Inc. TC7109/A Address Bus Control Bus Data Bus GND Analog In MODE CE/LOAD B9 - B12 POL, OR RD WR D7 - D0 A0 - A1 CS 6 PA5 - PA0 PC6 RUN/HOLD TC7109A B1 - B8 HBEN LBEN GND FIGURE 4-4: PB7 - PB0 8 STBA STATUS 1mF PD8748H/49H PD8255A PC6 PC4 INTRA INTR 10kW +5V (See Text) Full Time Parallel Interface to PD8748H/494 Microcontrollers Address Bus Control Bus Data Bus Analog In B9 - B12 POL, OR 6 B1 - B8 8 TC7109A CE/LOAD SEND FIGURE 4-5: RD WR D7 - D0 A0 - A1 CS STBA IBFA PA7 - PA0 PD8255A (Mode 1) PC4 PD8748H/49H PC5 RUN/HOLD PC6 PC MODE PC7 PC3 INTR TC7109A Handshake Interface to PD8748H/494 Microcontrollers (c) 2006 Microchip Technology Inc. DS21456C-page 19 TC7109/A 4.2 Handshake Mode Conversions may be obtained on command under software control by driving the RUN/HOLD input to the TC7109A by a bit of the 8255. Another peripheral device may be serviced by the unused port of the 8255. The Handshake mode provides an interface to a wide variety of external devices. The byte enables may be used as byte identification flags, or as load enables, and external latches may be clocked by the rising edge of CE/LOAD. A handshake interface to Intel(R) microprocessors using an 8255 PPI is shown in Figure . The handshake operation with the 8255 is controlled by inverting its Input Buffer Full (IBF) flag to drive the SEND input to the TC7109A, and using the CE/LOAD to drive the 8255 strobe. The internal control register of the PPI should be set in MODE 1 for the port used. If the 8255 IBF flag is LOW and the TC7109A is in Handshake mode, the next word will be strobed into the port. The strobe will cause IBF to go HIGH (SEND goes LOW), which will keep the enabled byte outputs active. The PPI will generate an interrupt which, when executed, will result in the data being read. The IBF will be reset LOW when the byte is read, causing the TC7109A to sequence into the next byte. The MODE input to the TC7109A is connected to the control line on the PPI. The Handshake mode is particularly useful for directly interfacing to industry standard UARTs (such as Intersil HD-6402), providing a means of serially transmitting converted data with minimum component count. A typical UART connection is shown in Figure . In this circuit, any word received by the UART causes the UART DR (Data Ready) output to go HIGH. The MODE input to the TC7109A goes HIGH, triggering the TC7109A into Handshake mode. The high order byte is output to the UART and when the UART has transferred the data to the Transmitter register, TBRE (SEND) goes HIGH again, LBEN will go HIGH, driving the UART DRR (Data Ready Reset), which will signal the end of the transfer of data from the TC7109A to the UART. An extension of the typical connection to several TC7109A's with one UART is shown in Figure 4-7. In this circuit, the word received by the UART (available at the RBR outputs when DR is HIGH) is used to select which converter will handshake with the UART. Up to eight TC7109A's may interface with one UART, with no external components. Up to 256 converters may be accessed on one serial line with additional components. The data from every conversion will be sequenced in two bytes in the system, if this output is left HIGH, or tied HIGH separately. (The data access must take less time than a conversion.) The output sequence can be obtained on demand if this output is made to go from LOW to HIGH and the interrupt may be used to reset the MODE bit. 15 Q3 CD4060B RESET CLK 11 10 1 V +5V TRC RRC 3 GND 4 RRD GND +5V EPE CLS1 CLS2 5-12 RBR1-8 SBS 40 V+ GND 1 25 17 39 2 +5V 38 19 37 36 35 HD-640R GND PI 13 PE CMOS UART 34 +5V CRL 14 FE GND 15 OE 16 SFD 20 *TBR1-8 TRE DRR RR1 Serial Input 25 TRO Serial Output DR TBRL TBRE MR 26-33 6 8 3-8 8 9-16 24 17 18 18 19 21 23 20 22 27 21 GND 40 39 REF IN38 BUFF OSC OUT REF CAP37 REF CAP+ STATUS REF IN+ 36 35 IN HI HBEN 34 IN LO TC7109A COM 33 32 B9 - B12, INT POL, OR 31 AZ 30 BUFF B1 - B8 29 REF OUT TEST 28 VLBEN 26 RUN/HOLD MODE 24 OSC SEL CE/LOAD 23 OSC OUT SEND OSC IN 22 +5V - GND 1F External Reference 1M + + 0.01F Input - Analog GND CINT CAZ 0.15F 0.33F RINT 20k 0.2VREF 100k 1VREF -5V +5V or Open GND 3.58MHz Crystal *Note: For lowest power consumption, TBR1-TBR8 inputs should have 100k pull-up resistors to +5V. Send any word to UART to transmit latest result. FIGURE 4-6: DS21456C-page 20 TC7109 Typical UART Interface (c) 2006 Microchip Technology Inc. TC7109/A Serial Output 6402 CMOS UART TBRE TBRL DRR Serial Input RBR1 - RBR8 2 SFD 3 TBR1 - TBR8 GND 8-Bit Data Bus MODE CE/ SEND LOAD B9 - B12 POL, OR MODE CE/ SEND LOAD B9 - B12 POL, OR 6 TC7109A B1 - B8 HBEN 4 5 6 7 10 9 +5V RUN/HOLD HBEN 3 XTAL2 8 TC7109A +5V LBEN T0 RESET P20 - P27 SS INT +5V 2 GND EA 40 1 17 21-24, 35-38 8 PD8748H/49H CMOS Microcomputer Other I/O P14 - P17 31-34 5 WR P13 PSEN 11 ALE +5V 25 PROG +5V 26 VDD +5V 39 T1 +5V 40 VCC P12 P11 P10 26 30 29 2 28 18 27 19 3-8 6 DB0 - DB7 GND 20 GND FIGURE 4-8: B1 - B8 B1 - B8 6 8 RUN/HOLD HBEN +5V LBEN Handshake Interface for Multiplexed Converters 2 XTAL1 1 TC7109A LBEN FIGURE 4-7: GND Analog In 8 RUN/HOLD +5V 6 Analog In Analog In MODE CE/ SEND LOAD B9 - B12 POL, OR RD 12-19 8 9-16 8 8 20 39 REF IN38 REF CAPGND REF CAP+ 37 TEST 36 REF IN+ 35 IN HI 34 HI LO 33 COM TC7109A 32 INT 31 AZ 30 BUFF RUN/HOLD 29 REF OUT STATUS 28 VLBEN 27 SEND HBEN 25 BUFF OSC OUT B9 - B12, 24 OSC SEL POL, OR 23 OSC OUT 22 B1 - B8 OSC IN 21 CE/LOAD MODE - V+ External Reference 1F 1M + + 0.01F CINT - Input Analog GND CAZ 0.15F 0.33F RINT -5V 20k 0.2 VREF 10 k 1 VREF GND 3.58MHz Crystal Connection Diagram (c) 2006 Microchip Technology Inc. DS21456C-page 21 TC7109/A INTEGRATING CONVERTER FEATURES The output of integrating ADCs represents the integral, or average, of an input voltage over a fixed period of time. Compared with techniques in which the input is sampled and held, the integrating converter averages the effects of noise. A second important characteristic is that time is used to quantize the answer, resulting in extremely small non-linearity errors and no missing output codes. The integrating converter also has very good rejection of frequencies whose periods are an integral multiple of the measurement period. This feature can be used to advantage in reducing line frequency noise (Figure ). 30 Normal Mode Rejection Plan 5.0 t = Measurement Period 20 10 0 0.1/t 1/t Input Frequency 10/t FIGURE 5-1: Normal Mode Rejection of Dual Slope Converter as a Function of Frequency DS21456C-page 22 (c) 2006 Microchip Technology Inc. TC7109/A 6.0 PACKAGING INFORMATION 6.1 Package Marking Information Package marking data not available at this time. 6.2 Taping Form Component Taping Orientation for 44-Pin PQFP Devices User Direction of Feed Pin 1 W P Standard Reel Component Orientation for 713 Suffix Device Carrier Tape, Number of Components Per Reel and Reel Size Package 44-Pin PQFP Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size 24 mm 16 mm 500 13 in Note: Drawing does not represent total number of pins. Component Taping Orientation for 44-Pin PLCC Devices User Direction of Feed Pin 1 W P Standard Reel Component Orientation for 713 Suffix Device Carrier Tape, Number of Components Per Reel and Reel Size Package 44-Pin PLCC Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size 32 mm 24 mm 500 13 in Note: Drawing does not represent total number of pins. (c) 2006 Microchip Technology Inc. DS21456C-page 23 TC7109/A 6.3 Package Dimensions 40-Pin PDIP (Wide) Pin1 .555 (14.10) .530 (13.46) 2.065 (52.45) 2.027 (51.49) .610 (15.49) .590 (14.99) .200 (5.08) .140 (3.56) .040 (1.02) .020 (0.51) .150 (3.81) .115 (2.92) .110 (2.79) .090 (2.29) .070 (1.78) .045 (1.14) .015 (0.38) .008 (0.20) 3 Min. .700 (17.78) .610 (15.50) .022 (0.56) .015 (0.38) Dimensions: inches (mm) 40-Pin CERDIP (Wide) Pin 1 .540 (13.72) .510 (12.95) .030 (0.76) Min. .098 (2.49) Max. 2.070 (52.58) 2.030 (51.56) .620 (15.75) .590 (15.00) .060 (1.52) .020 (0.51) .210 (5.33) .170 (4.32) .150 (3.81) MIN. .200 (5.08) .125 (3.18) .110 (2.79) .090 (2.29) .065 (1.65) .045 (1.14) .020 (0.51) .016 (0.41) .015 (0.38) .008 (0.20) 3 Min. .700 (17.78) .620 (15.75) Dimensions: inches (mm) DS21456C-page 24 (c) 2006 Microchip Technology Inc. TC7109/A 6.3 Package Dimensions (Continued) 44-Pin PQFP 7 Max. .009 (0.23) .005 (0.13) Pin 1 .018 (0.45) .012 (0.30) .041 (1.03) .026 (0.65) .398 (10.10) .390 (9.90) .557 (14.15) .537 (13.65) .031 (0.80) TYP. .010 (0.25) Typ. .398 (10.10) .390 (9.90) .083 (2.10) .075 (1.90) .557 (14.15) .537 (13.65) .096 (2.45) Max. Dimensions: inches (mm) W P Standard Reel Component Orientation for 713 Suffix Device Carrier Tape, Number of Components Per Reel and Reel Size Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size 32 mm 24 mm 500 13 in 44-Pin PLCC Note: Drawing does not represent total number of pins. Dimensions: inches (mm) (c) 2006 Microchip Technology Inc. DS21456C-page 25 TC7109/A NOTES: DS21456C-page 26 (c) 2006 Microchip Technology Inc. TC7109/A THE MICROCHIP WEB SITE CUSTOMER SUPPORT Microchip provides online support via our WWW site at www.microchip.com. This web site is used as a means to make files and information easily available to customers. Accessible by using your favorite Internet browser, the web site contains the following information: Users of Microchip products can receive assistance through several channels: * Product Support - Data sheets and errata, application notes and sample programs, design resources, user's guides and hardware support documents, latest software releases and archived software * General Technical Support - Frequently Asked Questions (FAQ), technical support requests, online discussion groups, Microchip consultant program member listing * Business of Microchip - Product selector and ordering guides, latest Microchip press releases, listing of seminars and events, listings of Microchip sales offices, distributors and factory representatives * * * * * Distributor or Representative Local Sales Office Field Application Engineer (FAE) Technical Support Development Systems Information Line Customers should contact their distributor, representative or field application engineer (FAE) for support. Local sales offices are also available to help customers. A listing of sales offices and locations is included in the back of this document. Technical support is available through the web site at: http://support.microchip.com CUSTOMER CHANGE NOTIFICATION SERVICE Microchip's customer notification service helps keep customers current on Microchip products. Subscribers will receive e-mail notification whenever there are changes, updates, revisions or errata related to a specified product family or development tool of interest. To register, access the Microchip web site at www.microchip.com, click on Customer Change Notification and follow the registration instructions. (c) 2006 Microchip Technology Inc. DS21456C-page 27 TC7109/A READER RESPONSE It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation can better serve you, please FAX your comments to the Technical Publications Manager at (480) 792-4150. Please list the following information, and use this outline to provide us with your comments about this document. To: Technical Publications Manager RE: Reader Response Total Pages Sent ________ From: Name Company Address City / State / ZIP / Country Telephone: (_______) _________ - _________ FAX: (______) _________ - _________ Application (optional): Would you like a reply? Device: TC7109/A Y N Literature Number: DS21456C Questions: 1. What are the best features of this document? 2. How does this document meet your hardware and software development needs? 3. Do you find the organization of this document easy to follow? If not, why? 4. What additions to the document do you think would enhance the structure and subject? 5. What deletions from the document could be made without affecting the overall usefulness? 6. Is there any incorrect or misleading information (what and where)? 7. How would you improve this document? DS21456C-page 28 (c) 2006 Microchip Technology Inc. Note the following details of the code protection feature on Microchip devices: * Microchip products meet the specification contained in their particular Microchip Data Sheet. * Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. * There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip's Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. * Microchip is willing to work with the customer who is concerned about the integrity of their code. * Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as "unbreakable." Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break Microchip's code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act. Information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. 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Trademarks The Microchip name and logo, the Microchip logo, Accuron, dsPIC, KEELOQ, microID, MPLAB, PIC, PICmicro, PICSTART, PRO MATE, PowerSmart, rfPIC, and SmartShunt are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. AmpLab, FilterLab, Migratable Memory, MXDEV, MXLAB, SEEVAL, SmartSensor and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. Analog-for-the-Digital Age, Application Maestro, dsPICDEM, dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, Linear Active Thermistor, Mindi, MiWi, MPASM, MPLIB, MPLINK, PICkit, PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal, PowerInfo, PowerMate, PowerTool, REAL ICE, rfLAB, rfPICDEM, Select Mode, Smart Serial, SmartTel, Total Endurance, UNI/O, WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. (c) 2006, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. Microchip received ISO/TS-16949:2002 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona, Gresham, Oregon and Mountain View, California. The Company's quality system processes and procedures are for its PICmicro(R) 8-bit MCUs, KEELOQ(R) code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip's quality system for the design and manufacture of development systems is ISO 9001:2000 certified. (c) 2006 Microchip Technology Inc. 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