AVAILABLE
Functional Diagrams
Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
78M6613
Single-
Phase
AC Power Measu
rement IC
DATA SHEET
DS_6613_018
19-5348; Rev 2; 1/12
DESCRIPTION
The Teridian™ 78M6613 is a highly integrated IC for
simplified implementation of single-phase AC power
measurement into power supplies, smart appliances, and
other applications with embedded AC load monitoring and
control. It is packaged in a small, 5mm x 5mm, 32-pin QFN
package for optimal space savings.
At the measurement interface, the device provides four
analog inputs for interfacing to voltage and current sensors.
Voltages from the sensors are fed to our Single Converter
Technology® that uses a 22-bit delta-sigma ADC,
independent 32-bit compute engine (CE), digital
temperature compensation, and precision voltage
references to provide better than 0.5% power measurement
accuracy over a wide 2000:1 dynamic range.
The integrated MPU core and 32 KB of flash memory
provides a flexible means of configuration, post-processing,
data formatting, and interfacing to any host processor
through the UART interface and/or DIO pins. Complete
application firmware is available and can be preloaded into
the IC during manufacturing test. Alternatively, a complete
array of ICE, development tools, and programming libraries
are available to allow customization for each application.
80515
MPU
TIMERS
A0
A1
XIN
XOUT
VREF
TX
RX
V3P3
GND
DIO 4-8
DIO 14-17, 19
ICE
SERIAL PORT
OSC/PLL
CONVERTER
DIO, PULSE
32-bit
COMPUTE
ENGINE
32KB
FLASH
2KB RAM
VOLTAGE REF
REGULATOR
Earth Ground
Isolated Supply
TERIDIAN
78M6613
32 kHz
LIVE
NEUT
ICE_E
GND
V3P3
TEMP
SENSOR
A2
A3
FEATURES
• < 0.5% Wh Accuracy Over Wide 2000:1
Current Range and Over Temperature
• Voltage Reference < 40ppm/°C
• Four Sensor Inputs—V3P3A Referenced
• 22-Bit Delta-Sigma ADC with Independent
32-Bit Compute Engine (CE)
• 8-Bit MPU (80515), One Clock Cycle per
Instruction with 2KB MPU XRAM
• 32KB Flash with Security
• Integrated In-Circuit Emulator (ICE) Interface
for MPU Debug
• 32kHz Time Base with Hardware Watchdog
Timer
• UART Interface and Up to 10 General-
Purpose 5V Tolerant I/O Pins
• Packaged in a RoHS-Compliant (6/6)
Lead(Pb)-Free, 32-Pin QFN (5mm x 5mm)
• Complete Application Firmware Provides:
o True RMS Calculations for Current,
Voltage, Line Frequency, Real Power,
Reactive Power, Apparent Power, and
Power Factor
o Accumulated Watt-Hours, Kilowatt-Hours
o Intelligent Switch Control at Zero
Crossings
o Digital Temperature Compensation
o Phase Compensation (±15°)
o Quick Calibration Routines
o 46–64Hz Line Frequency Range with
Same Calibration
Teridian is a trademark and Single Converter Technology is a
registered trademark of Maxim Integrated Products, Inc.
78M6613 Data Sheet DS_6613_018
Table of Contents
1 Hardware Description .................................................................................................................... 5
1.1 Hardware Overview ................................................................................................................ 5
1.2 Analog Front End (AFE) .......................................................................................................... 6
1.2.1 Input Multiplexer.......................................................................................................... 6
1.2.2 A/D Converter (ADC) .................................................................................................. 6
1.2.3 FIR Filter ..................................................................................................................... 6
1.2.4 Voltage References ..................................................................................................... 6
1.2.5 Temperature Sensor ................................................................................................... 7
1.2.6 Functional Description ................................................................................................. 7
1.3 Digital Computation Engine (CE) ............................................................................................ 8
1.4 80515 MPU Core .................................................................................................................... 8
1.4.1 UART .......................................................................................................................... 8
1.4.2 Timers and Counters ................................................................................................... 9
1.5 On-Chip Resources ................................................................................................................. 9
1.5.1 Oscillator ..................................................................................................................... 9
1.5.2 PLL and Internal Clocks .............................................................................................. 9
1.5.3 Temperature Sensor ................................................................................................... 9
1.5.4 Flash Memory ............................................................................................................. 9
1.5.5 Digital I/O .................................................................................................................. 10
1.5.6 Hardware Watchdog Timer........................................................................................ 10
1.5.7 Program Security ...................................................................................................... 10
1.5.8 Test Ports.................................................................................................................. 10
2 Functional Description ................................................................................................................ 11
2.1 Theory of Operation .............................................................................................................. 11
2.2 Reset Behavior ..................................................................................................................... 12
2.3 Data Flow ............................................................................................................................. 12
2.4 CE/MPU Communication ...................................................................................................... 13
3 Application Information .............................................................................................................. 14
3.1 Connection of Sensors (CT, Resistive Shunt)........................................................................ 14
3.2 Temperature Measurement ................................................................................................... 15
3.3 Temperature Compensation .................................................................................................. 15
3.4 Connecting 5V Devices ......................................................................................................... 16
3.5 UART (TX/RX) ...................................................................................................................... 16
3.6 Reset Function and Reset Pin Connections........................................................................... 16
3.7 Connecting the Emulator Port Pins ....................................................................................... 18
3.8 Crystal Oscillator................................................................................................................... 19
3.9 Flash Programming .............................................................................................................. 19
3.10 MPU Firmware Library .......................................................................................................... 19
3.11 Measurement Calibration ...................................................................................................... 19
4 Electrical Specifications ............................................................................................................. 20
4.1 Absolute Maximum Ratings .................................................................................................. 20
4.2 Recommended External Components ................................................................................... 21
4.3 Recommended Operating Conditions .................................................................................... 21
4.4 Performance Specifications .................................................................................................. 21
4.4.1 Input Logic Levels ..................................................................................................... 21
4.4.2 Output Logic Levels .................................................................................................. 21
4.4.3 Supply Current .......................................................................................................... 22
4.4.4 Crystal Oscillator ....................................................................................................... 22
4.4.5 VREF ........................................................................................................................ 22
4.4.6 ADC Converter, V3P3 Referenced ............................................................................ 23
4.4.7 Temperature Sensor ................................................................................................. 23
DS_6613_018 78M6613 Data Sheet
4.5 Timing Specifications ............................................................................................................ 24
4.5.1 RAM and Flash Memory ............................................................................................ 24
4.5.2 RESET ...................................................................................................................... 24
4.5.3 Typical Performance Data ......................................................................................... 25
5 Packaging .................................................................................................................................... 26
5.1 Pinout ................................................................................................................................... 26
5.2 Package Outline (QFN 32) .................................................................................................... 27
5.3 Recommended PCB Land Pattern for the QFN-32 Package ................................................. 28
6 Pin Descriptions .......................................................................................................................... 29
6.1 Power/Ground Pins ............................................................................................................... 29
6.2 Analog Pins .......................................................................................................................... 29
6.3 Digital Pins ........................................................................................................................... 30
7 I/O Equivalent Circuits ................................................................................................................ 31
8 Ordering Information................................................................................................................... 32
9 Contact Information .................................................................................................................... 32
Revision History .................................................................................................................................. 33
Figures
Figure 1: IC Functional Block Diagram .................................................................................................... 4
Figure 2: AFE Block Diagram .................................................................................................................. 7
Figure 3: Connecting an External Load to DIO Pins ............................................................................... 10
Figure 4: Voltage. Current, Momentary and Accumulated Energy .......................................................... 11
Figure 5: MPU/CE Data Flow ................................................................................................................ 12
Figure 6: MPU/CE Communication ........................................................................................................ 13
Figure 7: Resistive Voltage Divider........................................................................................................ 14
Figure 8: Resistive Current Shunt .......................................................................................................... 14
Figure 9: Current Transformer ............................................................................................................... 14
Figure 10: Connections for the RX Pin ................................................................................................... 16
Figure 11: 78M6613 External Reset Behavior........................................................................................ 17
Figure 12: MAX810S Connections to the 78M6613 ................................................................................ 17
Figure 13: Reset Generator Based On TL431 Shunt Regulator .............................................................. 18
Figure 14: External Components for the Emulator Interface .................................................................. 18
Figure 15: Wh Accuracy, 10 mA to 20 A at 120 V/60 Hz and Room Temperature Using a 4 mΩ
Current Shunt ....................................................................................................................... 25
Figure 16: Typical Measurement Accuracy over Temperature Relative to 25°C ..................................... 25
Figure 17: 32-Pin QFN Pinout ............................................................................................................... 26
Figure 18: Package Outline (QFN 32).................................................................................................... 27
Figure 19: Recommended PCB Land Pattern Dimensions ..................................................................... 28
Figure 20: I/O Equivalent Circuits .......................................................................................................... 31
Table
Table 1: Inputs Selected in Regular and Alternate Multiplexer Cycles ...................................................... 6
78M6613 Data Sheet DS_6613_018
A0
A1
MUX
XIN
XOUT
VREF
CKADC
CKTEST
CE
32 bit Compute
Engine
MPU
(80515)
CE
CONTROL
RESET
EMULATOR
PORT
CE_BUSY
UART
TX
RX
XFER BUSY
DATA
00-7F
PROG
000-7FF
DATA
0000-FFFF
PROG
0000-7FFF
0000-
7FFF
MPU XRAM
(2KB)
0000-07FF
DIGITAL I/O
2000-20FF
I/O RAM
CE RAM
(0.5KB)
MEMORY SHARE
1000-11FF
RTCLK (32KHz)
MUX_SYNC
CKCE
CKMPU
CK32
4.9152MHz
<4.9152MHz
4.9152MHz
V3P3A
VOLT
REG
32KHz
TMUXOUT
MPU_RSTZ
GNDA
VBIAS
CROSS
CK_GEN
OSC
(32KHz)
CK32
MCK
PLL
VREF
DIV
ADC
MUX
CTRL
STRT
MUX
MUX
CKFIR
4.9152MHz
DIO14
TEST
TEST
MODE
<4.9152MHz
DIO8
SDCK
SDOUT
SDIN
E_RXTX
E_TCLK
E_RST
FLASH
(32KB)
V3P3
FIR
CK_2X
VBIAS
MEMORY
SHARE
E_RXTX
E_TCLK
E_RST (Open Drain)
ICE_E
∆Σ ADC
CONVERTER
+
-
VREF
TEST
MUX
TEMP
A2
A3
V3P3D GNDD
DIO4
DIO5
DIO6
DIO7
DIO19
DIO17
DIO16
DIO15
Figure 1: IC Functional Block Diagram
DS_6613_018 78M6613 Data Sheet
1 Hardware Description
1.1 Hardware Overview
The Teridian 78M6613 single-chip measurement unit integrates all primary functional blocks required to
embed solid-state AC power and energy measurement. Included on chip are:
• An analog front end (AFE)
• An independent digital computation engine (CE)
• An 8051-compatible microprocessor (MPU) which executes one instruction per clock cycle (80515)
• A voltage reference
• A temperature sensor
• RAM and Flash memory
• A variety of I/O pins
Current sensor technologies supported include Current Transformers (CT) and Resistive Shunts.
In a typical application, the 32-bit compute engine (CE) of the 78M6613 sequentially processes the
samples from the voltage inputs on pins A0, A1, A2, A3 and performs calculations to measure active
energy (Wh), reactive energy (VARh), A2h, and V2h for four-quadrant measurement. These
measurements are then accessed by the MPU, processed further and output using the peripheral
interfaces available to the MPU.
In addition to the temperature-trimmed ultra-precision voltage reference, the on-chip digital temperature
compensation mechanism includes a temperature sensor and associated controls for correction of
unwanted temperature effects on measurement. Temperature dependent external components such as
crystal oscillator, current transformers (CTs), and their corresponding signal conditioning circuits can be
characterized and their correction factors can be programmed to produce measurements with
exceptional accuracy over the industrial temperature range, if desired.
A block diagram of the IC is shown in Figure 1. A detailed description of various functional blocks
follows.
78M6613 Data Sheet DS_6613_018
1.2 Analog Front End (AFE)
The AFE of the 78M6613 is comprised of an input multiplexer, a delta-sigma A/D converter and a
voltage reference.
1.2.1 Input Multiplexer
The input multiplexer supports up to four input signals that are applied to pins A0, A1, A2 and A3 of the
device. Additionally, using the alternate mux selection, it has the ability to select the on-chip
temperature sensor. The multiplexer can be operated in two modes:
• During a normal multiplexer cycle, the signals from the A0, A2, A1, and A3 pins are selected.
• During the alternate multiplexer cycle, the temperature signal (TEMP) is selected, along with the
signal sources shown in Table 1.
The alternate mux cycles are usually performed infrequently (e.g. every second) by the MPU. Table 1
details the regular and alternative MUX sequences. Missing samples due to an ALT multiplexer
sequence are filled in by the CE.
Table 1: Inputs Selected in Regular and Alternate Multiplexer Cycles
0 1 2 3 0 1 2 3
A0 A1 A2 A3 TEMP A1 V3P3D A3
In a typical application, A1 and A3 are connected to current sensors that sense the current on each
branch of the line voltage. A0 and A2 are typically connected to voltage sensors through resistor
dividers. The multiplexer control circuit is clocked by CK32, the 32.768 kHz clock from the PLL block,
and launches with each new pass of the CE program.
1.2.2 A/D Converter (ADC)
A single delta-sigma A/D converter digitizes the voltage and current inputs to the 78M6613. The
resolution of the ADC is 22 bits. Conversion time is two cycles of the CK32 clock.
Initiation of each ADC conversion is controlled by the multiplexer control circuit as described previously.
At the end of each ADC conversion, the FIR filter output data is stored into the CE DRAM location.
1.2.3 FIR Filter
The finite impulse response filter is an integral part of the ADC and it is optimized for use with the
multiplexer. The purpose of the FIR filter is to decimate the ADC output to the desired resolution. At the
end of each ADC conversion, the output data is stored into the fixed CE DRAM location determined by
the multiplexer selection.
1.2.4 Voltage References
The device includes an on-chip precision bandgap voltage reference that incorporates auto-zero
techniques. The reference is trimmed to minimize errors caused by component mismatch and drift. The
result is a voltage output with a predictable temperature coefficient.
DS_6613_018 78M6613 Data Sheet
1.2.5 Temperature Sensor
The 78M6613 includes an on-chip temperature sensor implemented as a bandgap reference. It is used
to determine the die temperature. The MPU reads the temperature sensor output during alternate
multiplexer cycles. The primary use of the temperature data is to determine the magnitude of
compensation required to offset the thermal drift in the system (see Section 3.3 Temperature
Compensation).
1.2.6 Functional Description
The AFE functions as a data acquisition system, controlled by the MPU. The input signals (A0, A1, A2,
and A3) are sampled and the ADC counts obtained are stored in CE DRAM where they can be accessed
by the CE and, if necessary, by the MPU. Alternate multiplexer cycles are initiated less frequently by the
MPU to gather access to the slow temperature signal.
A0
A1
MUX
VREF
4.9152 MHz
VBIAS
CROSS
CK32
VREF
MUX
CTRL
MUX
V3P3A
FIR
VBIAS
∆Σ ADC
CONVERTER
+
-
VREF
TEMP
FIR_DONE
FIR_START
A2
A3
Figure 2: AFE Block Diagram
78M6613 Data Sheet DS_6613_018
1.3 Digital Computation Engine (CE)
The CE, a dedicated 32-bit signal processor, performs the precision computations necessary to
accurately measure energy. The CE calculations and processes include:
• Multiplication of each current sample with its associated voltage sample to obtain the energy per
sample (when multiplied with the constant sample time).
• Frequency-insensitive delay cancellation on all channels (to compensate for the delay between
samples caused by the multiplexing scheme).
• 90° phase shifter (for narrowband VARh calculations).
• Monitoring of the input signal frequency (for frequency and phase information).
• Monitoring of the input signal amplitude (for sag detection).
• Scaling of the processed samples based on calibration coefficients.
CE code is provided by Maxim as a part of the application firmware available. The CE is not
programmable by the user. Measurement algorithms in the CE code can be customized by
Maxim upon request.
The CE program resides in Flash memory. Common access to Flash memory by CE and MPU is
controlled by a memory share circuit. Allocated Flash space for the CE program cannot exceed 1024
words (2KB).
The CE DRAM can be accessed by the CE and the MPU. Holding registers are used to convert 8-bit
wide MPU data to/from 32-bit wide CE DRAM data, and wait states are inserted as needed, depending
on the frequency of CKMPU. The CE DRAM contains 128 32-bit words. The MPU can read and write
the CE DRAM as the primary means of data communication between the two processors. CE hardware
issues an interrupt when accumulation is complete.
1.4 80515 MPU Core
The 78M6613 includes an 80515 MPU (8-bit, 8051-compatible) that processes most instructions in one
clock cycle. Using a 5 MHz (4.9152 MHz) clock results in a processing throughput of 5 MIPS. The
80515 architecture eliminates redundant bus states and implements parallel execution of fetch and
execution phases. Normally a machine cycle is aligned with a memory fetch, therefore, most of the
1-byte instructions are performed in a single cycle. This leads to an 8x performance (in average)
improvement (in terms of MIPS) over the Intel 8051 device running at the same clock frequency. Actual
processor clocking speed can be adjusted to the total processing demand of the application
(measurement calculations, memory management and I/O management).
Typical power and energy measurement functions based on the results provided by the internal
32-bit compute engine (CE) are available for the MPU as part of Maxim’s standard library. MPU
Memory Organization, Special Function Registers, Interrupts, Counters, and other controls are
described in the applicable firmware documentation.
1.4.1 UART
The 78M6613 includes a UART that can be programmed to communicate with a variety of external
devices. The UART is a dedicated 2-wire serial interface, which can communicate with an external
device at up to 38,400 bits/s. All UART transfers are programmable for parity enable, parity, 2 stop
bits/1 stop bit and XON/XOFF options for variable communication baud rates from 300 to 38,400 bps.
DS_6613_018 78M6613 Data Sheet
1.4.2 Timers and Counters
The 80515 has two 16-bit timer/counter registers: Timer 0 and Timer 1. These registers can be
configured for counter or timer operations.
In timer mode, the register is incremented every machine cycle, meaning that it counts up after every 12
periods of the MPU clock signal.
In counter mode, the register is incremented when the falling edge is observed at the corresponding
input signal T0 or T1 (T0 and T1 are the timer gating inputs derived from certain DIO pins, see the DIO
Ports section). Since it takes 2 machine cycles to recognize a 1-to-0 event, the maximum input count
rate is 1/2 of the oscillator frequency. There are no restrictions on the duty cycle, however to ensure
proper recognition of 0 or 1 state, an input should be stable for at least 1 machine cycle.
1.5 On-Chip Resources
1.5.1 Oscillator
The 78M6613 oscillator drives a standard 32.768 kHz watch crystal. These crystals are accurate and do
not require a high-current oscillator circuit. The 78M6613 oscillator has been designed specifically to
handle these crystals and is compatible with their high impedance and limited power handling capability.
1.5.2 PLL and Internal Clocks
Timing for the device is derived from the 32.768 kHz oscillator output. On-chip timing functions include
the MPU master clock and the delta-sigma sample clock. In addition, the MPU has two general
counter/timers.
The ADC master clock, CKADC, is generated by an on-chip PLL. It multiplies the oscillator output
frequency (CK32) by 150.
The CE clock frequency is always CK32 * 150, or 4.9152 MHz, where CK32 is the 32 kHz clock. The
MPU clock frequency is scalable from 4.9152 MHz down to 38.4 kHz. The circuit can also generate a 2x
MPU clock for use by the emulator.
1.5.3 Temperature Sensor
The device includes an on-chip temperature sensor for determining the temperature of the bandgap
reference. The primary use of the temperature data is to determine the magnitude of compensation required
to offset the thermal drift in the system (see Section 3.3 Temperature Compensation).
1.5.4 Flash Memory
The 78M6613 includes 32 KB of on-chip Flash memory. The Flash memory primarily contains MPU and
CE program code. It also contains images of the CE DRAM, MPU RAM, and I/O RAM. On power-up,
before enabling the CE, the MPU copies these images to their respective locations. Allocated Flash
space for the CE program cannot exceed 1024 words (2 KB).
MPU RAM: The 78M6613 includes 2KB of static RAM memory on-chip (XRAM) plus 256B of internal
RAM in the MPU core. The 2KB of static RAM are used for data storage during normal MPU operations.
CE DRAM: The CE DRAM is the working data memory of the CE (128 32-bit words). The MPU can read
and write the CE DRAM as the primary means of data communication between the two processors.
78M6613 Data Sheet DS_6613_018
1.5.5 Digital I/O
The device includes up to 10 pins of general purpose digital I/O. When configured as inputs, these pins
are 5V compatible (no current-limiting resistors are needed). On reset or power-up, all DIO pins are
inputs until they are configured for the desired direction under MPU control.
When driving LEDs, relay coils etc., the DIO pins should sink the current into ground (as
shown in Figure 3, right), not source it from V3P3 (as in Figure 3, left).
If more than one input is connected to the same resource, the resources are combined using a logical
OR.
Figure 3: Connecting an External Load to DIO Pins
1.5.6 Hardware Watchdog Timer
In addition to the basic watchdog timer included in the 80515 MPU, an independent, robust, fixed-
duration, watchdog timer (WDT) is included in the device. It uses the crystal oscillator as its time base
and must be refreshed by the MPU firmware at least every 1.5 seconds. When not refreshed on time
the WDT overflows, and the part is reset as if the RESET pin were pulled high, except that the I/O RAM
bits will be maintained. 4096 oscillator cycles (or 125 ms) after the WDT overflow, the MPU will be
launched from program address 0x0000. Asserting ICE_E will deactivate the WDT.
1.5.7 Program Security
When enabled, the security feature limits the ICE to global Flash erase operations only. All other ICE
operations are blocked. This guarantees the security of the user’s MPU and CE program code. Security
is enabled by MPU code that is executed in a 32 cycle preboot interval before the primary boot
sequence begins. Once security is enabled, the only way to disable it is to perform a global erase of the
Flash, followed by a chip reset.
1.5.8 Test Ports
TMUXOUT Pin: One out of 16 digital or 8 analog signals can be selected to be output on the TMUXOUT
pin. The function of the multiplexer is described in the applicable firmware documentation.
Not recommended
78M6613
DIO
LED
V3P3D
3.3V
GNDD
R
Recommended
R
LED
DIO
V3P3D
GNDD
3.3V
78M6613
DS_6613_018 78M6613 Data Sheet
2 Functional Description
2.1 Theory of Operation
The energy delivered by a power source into a load can be expressed as:
∫
=
t
dttItVE
0
)()(
The following formulae apply for wide band mode (true RMS):
• P = ∑ (i(t) * v(t))
• Q = √(S2 – P2)
• S = V * I
• V = √∑v(t)2
• I = √∑i(t)2
For a practical measurement, not only voltage and current amplitudes, but also phase angles and
harmonic content may change constantly. Thus, simple RMS measurements are inherently inaccurate,
and true RMS measurements must be utilized. A modern solid-state electricity Power and Energy
Measurement IC such as the 78M6613 functions by emulating the integral operation above, i.e. it
processes current and voltage samples through an ADC at a constant frequency. As long as the ADC
resolution is high enough and the sample frequency is beyond the harmonic range of interest, the current
and voltage samples, multiplied with the time period of sampling will yield an accurate quantity for the
momentary energy. Summing up the momentary energy quantities over time will result in accumulated
energy.
-500
-400
-300
-200
-100
0
100
200
300
400
500
0 5 10 15 20
Current [A]
Voltage [V]
Energy per Interval [Ws]
Accumulated Energy [Ws]
Figure 4: Voltage. Current, Momentary and Accumulated Energy
Figure 4 shows the shapes of V(t), I(t), the momentary power and the accumulated power, resulting from
50 samples of the voltage and current signals over a period of 20 ms. The application of 240 VAC and
100 A results in an accumulation of 480 Ws (= 0.133 Wh) over the 20 ms period, as indicated by the
Accumulated Power curve. The described sampling method works reliably, even in the presence of
dynamic phase shift and harmonic distortion.
For actual measurement equations, refer to the applicable firmware documentation.
78M6613 Data Sheet DS_6613_018
2.2 Reset Behavior
Reset Mode: When the RESET pin is pulled high all digital activity stops. The oscillator continues to
run. Additionally, all I/O RAM bits are set to their default states.
Once initiated, the reset mode will persist until the reset timer times out. This will occur in 4096 CK32
clock cycles (32768 Hz clock cycles from PLL block) after RESET goes low, at which time the MPU will
begin executing its preboot and boot sequences from address 00.
2.3 Data Flow
The data flow between CE and MPU is shown in Figure 5. In a typical application, the 32-bit compute
engine (CE) sequentially processes the samples from the voltage inputs on pins A0, A1, A2, and A3,
performing calculations to measure active power (Wh), reactive power (VARh), A2h, and V2h for
four-quadrant measurements. These measurements are then accessed by the MPU, processed further
and output using the peripheral devices available to the MPU.
Figure 5: MPU/CE Data Flow
CE
MPU
Pre
-
Processor
Post
-
Processor
IRQ
Processed
Measurement
Data
I/O RAM (Configuration RAM)
Samples
Data
DS_6613_018 78M6613 Data Sheet
2.4 CE/MPU Communication
Figure 6 shows the functional relationship between CE and MPU. The CE is controlled by the MPU via
shared registers in the I/O RAM and by registers in the CE DRAM. The CE outputs two interrupt signals
to the MPU to indicate when the CE is actively processing data and when the CE is updating data to the
output region of the CE DRAM.
MPU
CE
INTERRUPTS
DIO
SERIAL
(UART)
SAMPLES
ADC
CE_BUSY
XFER_BUSY
Mux Ctrl.
DATA
CONTROL
I/O RAM (CONFIGURATION RAM)
Figure 6: MPU/CE Communication
78M6613 Data Sheet DS_6613_018
3 Application Information
3.1 Connection of Sensors (CT, Resistive Shunt)
Figure 7, Figure 8, and Figure 9 show how resistive voltage dividers, resistive current shunts, and
current transformers are connected to the voltage and current inputs of the 78M6613.
Figure 7: Resistive Voltage Divider
Figure 8: Resistive Current Shunt
Figure 9: Current Transformer
DS_6613_018 78M6613 Data Sheet
3.2 Temperature Measurement
Measurement of absolute temperature uses the on-chip temperature sensor while applying the following
formula:
n
n
n
T
S
NTN
T+
−
=))((
In the above formula, T is the temperature in °C, N(T) is the ADC count at temperature T, Nn is the ADC
count at 25°C, Sn is the sensitivity in LSB/°C and Tn is +25°C.
Example: At 25°C a temperature sensor value of 518,203,584 (Nn) is read by the ADC by a 78M6613 in
the 32-pin QFN package. At an unknown temperature T the value 449,648,000 is read at (N(T)). The
absolute temperature is then determined by dividing both Nn and N(T) by 512 to account for the 9-bit
shift of the ADC value and then inserting the results into the above formula, using –2220 for LSB/°C:
CCT °=+
−⋅
=3.8525
)2220( 512
4518,203,58-0449,648,00
3.3 Temperature Compensation
Temperature Coefficients: The internal voltage reference is calibrated during device manufacture.
The temperature coefficients TC1 and TC2 are given as constants that represent typical component
behavior (in µV/°C and µV/°C2, respectively).
Since TC1 and TC2 are given in µV/°C and µV/°C2, respectively, the value of the VREF voltage
(1.195V) has to be taken into account when transitioning to PPM/°C and PPM/°C2. This means
that PPMC = 26.84*TC1/1.195, and PPMC2 = 1374*TC2/1.195).
Temperature Compensation: The CE provides the bandgap temperature to the MPU, which then may
digitally compensate the power outputs for the temperature dependence of VREF.
The MPU, not the CE, is entirely in charge of providing temperature compensation. The MPU applies
the following formula to determine any gain adjustments. In this formula TEMP_X is the deviation from
nominal or calibration temperature expressed in multiples of 0.1°C:
23
2
14 2
2_
2
_
16385_ PPMCXTEMPPPMCXTEMP
ADJGAIN ⋅
+
⋅
+=
In a power and energy measurement unit, the 78M6613 is not the only component contributing to
temperature dependency. A whole range of components (e.g. current transformers, resistor
dividers, power sources, filter capacitors) will contribute temperature effects. Since the output of
the on-chip temperature sensor is accessible to the MPU, temperature-compensation
mechanisms with great flexibility are possible (e.g. system-wide temperature correction over the
entire unit rather than local to the chip).
78M6613 Data Sheet DS_6613_018
3.4 Connecting 5V Devices
All digital input pins of the 78M6613 are compatible with external 5V devices. I/O pins configured as
inputs do not require current-limiting resistors when they are connected to external 5V devices.
3.5 UART (TX/RX)
The RX pin should be pulled down by a 10 kΩ resistor and optionally protected by a 100 pF ceramic
capacitor, as shown in Figure 10.
Figure 10: Connections for the RX Pin
3.6 Reset Function and Reset Pin Connections
The 78M6613 requires an external reset circuit to drive the RESET input pin. The reset is used to
prevent the 78M6613 from operating at supply voltages outside the recommended operating conditions.
Reset ensures the device is set to a known set of initial conditions and that it begins executing
instructions from a predetermined starting address.
The reset can be forced by applying a high level to the RESET pin. The reset input is internally filtered
(low-pass filter) in order to eliminate spurious reset conditions that can be triggered in a noisy
environment. For this reason the RESET pin must be asserted (high) for at least 1μs in order to initiate a
reset sequence.
The external reset circuitry should be designed in order to hold the RESET pin high (active) whenever
V3P3D is below normal operating level. Refer to Section 4.3, Recommended Operating Conditions.
Figure 11 shows the behavior of the external reset circuitry.
TX
RX
10k
Ω
100pF
RX
TX
TX
RX
78M6613
10k
Ω
100pF
RX
TX
Optional
DS_6613_018 78M6613 Data Sheet
0.0V
V3P3
RESET
> 1 µs
> 1 µs
3.3V Supply Voltage (V3P3D/V3P3A)
Max
Min
Typ
Time
Figure 11: 78M6613 External Reset Behavior
The RESET signal can be generated in a number of different ways. For example, a voltage supervisory
device such as Maxim’s MAX810S can be used to implement the reset/supply voltage supervisory
function as shown in Figure 12.
Vcc
GND
RST
V3P3
GND
RESET
78M6613
MAX810S
Figure 12: MAX810S Connections to the 78M6613
78M6613 Data Sheet DS_6613_018
An alternate solution using discrete components can be used. Figure 13 shows an implementation using
a shunt regulator and two transistors.
Figure 13: Reset Generator Based On TL431 Shunt Regulator
As long as V3P3 is below the 2.79V threshold set by the voltage divider of R1 and R2, U1 will not
conduct current, the base of Q2 will be at the same potential as its emitter, so Q1 will be turned off. With
no current flowing in the collector of Q2, the base of Q1 will be low, Q1 will be turned off, and RESET will
track V3P3. When the V3P3 rises above 2.79V, the TL431 starts to conduct, the base of Q2 is be pulled
low, turning on Q2. This drives the base of Q1 high, turning Q1 on and pulling RESET low. The inherent
turn-on and turn-off delays of the TL4313 provide the ~1µs delay required to ensure proper resetting of
the 78M6613.
3.7 Connecting the Emulator Port Pins
It is important to bring out the ICE_E pin to the programming interface in order to create a way
for reprogramming parts that have the Flash SECURE bit (SFR 0xB2[6]) set. Providing access to
ICE_E ensures that the part can be reset between erase and program cycles, which will enable
programming devices to reprogram the part. The reset required is implemented with a watchdog timer
reset (i.e. the hardware WDT must be enabled).
Figure 14: External Components for the Emulator Interface
E_RST
E_RXTX
E_TCLK
62
Ω
62
Ω
62
Ω
1000pF
ICE_E
V3P3
E_RST
78M6613
62
Ω
62
Ω
62
Ω
ICE_E
300
Ω
DS_6613_018 78M6613 Data Sheet
3.8 Crystal Oscillator
The oscillator of the 78M6613 drives a standard 32.768 kHz watch crystal. The oscillator has been
designed specifically to handle these crystals and is compatible with their high impedance and limited
power handling capability. Good layouts will have XIN and XOUT shielded from each other.
Since the oscillator is self-biasing, an external resistor must not be connected across the crystal.
3.9 Flash Programming
Operational or test code can be programmed into the Flash memory using either an in-circuit emulator or
the Flash Programmer Module (TFP-2) available from Maxim. The Flash programming procedure uses
the E_RST, E_RXTX, and E_TCLK pins.
3.10 MPU Firmware Library
Any application-specific MPU functions mentioned above are available from Maxim as a standard ANSI
C library and as ANSI “C” source code. The code is pre-programmed in Demonstration and Evaluation
Kits for the 78M6613 IC and can be pre-programmed into engineering IC samples for system evaluation.
The application code allows for quick and efficient evaluation of the IC without having to write firmware
or having to purchase an in-circuit emulator (ICE). A Software Licensing Agreement (SLA) can be
signed to receive either the source Flash HEX file for use in a production environment or (partial) source
code and SDK documentation for modification.
3.11 Measurement Calibration
Once the 78M6613 Power and Energy Measurement device has been installed in a measurement
system, it is typically calibrated for tolerances of the current sensors, voltage dividers and signal
conditioning components. The device can be calibrated using a single gain and a single phase
adjustment factors accessible to the CE. The gain adjustment is used to compensate for tolerances of
components used for signal conditioning, especially the resistive components. Phase adjustment is
provided to compensate for phase shifts introduced by certain types of current sensors.
Due to the flexibility of the MPU firmware, any calibration method, such as calibration based on energy,
or current and voltage can be implemented. It is also possible to implement segment-wise calibration
(depending on current range). Maxim software supports a “quick cal” method.
78M6613 Data Sheet DS_6613_018
4 Electrical Specifications
4.1 Absolute Maximum Ratings
Supplies and Ground Pins:
V3P3
-0.5 V to 4.6 V
GNDD, GNDA -0.5 V to +0.5 V
Analog Output Pins:
VREF -10 mA to +10 mA,
-0.5 V to V3P3+0.5 V
Analog Input Pins:
A0, A1, A2, A3 -10 mA to +10 mA
-0.5 V to V3P3+0.5 V
XIN, XOUT -10 mA to +10 mA
-0.5 V to 3.0 V
All Other Pins:
Configured as Digital Inputs -10 mA to +10 mA,
-0.5 to 6 V
Configured as Digital Outputs -15 mA to +15 mA,
-0.5 V to V3P3D+0.5 V
All other pins -0.5 V to V3P3D+0.5 V
Operating junction temperature (peak, 100 ms) +140 °C
Operating junction temperature (continuous)
+125 °C
Storage temperature -45 °C to +165 °C
Soldering temperature (10 second duration) +250 °C
ESD stress on all pins ±4 kV
Stresses beyond Absolute Maximum Ratings may cause permanent damage to the device. These are
stress ratings only and functional operation at these or any other conditions beyond those indicated
under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated
conditions for extended periods may affect device reliability. All voltages are with respect to GND.
DS_6613_018 78M6613 Data Sheet
4.2 Recommended External Components
Name
From
To
Function
Value
Unit
C1 V3P3A GNDA Bypass capacitor for 3.3V supply. ≥0.1±10% µF
CSYS V3P3D GNDD Bypass capacitor for V3P3D. ≥0.1±10% µF
XTAL XIN XOUT
32.768 kHz crystal – electrically similar to
ECS .327-12.5-17X or Vishay XT26T, load
capacitance 12.5 pF.
32.768 kHz
CXS
†
XIN GND Load capacitor for crystal (exact value
depends on crystal specifications and
parasitic capacitance of board).
27±10% pF
CXL † XOUT GND 27±10% pF
† Depending on trace capacitance, higher or lower values for CXS and CXL must be used. Capacitance from
XIN to GND and XOUT to GND (combining pin, trace and crystal capacitance) should be 35 pF to 37 pF.
4.3 Recommended Operating Conditions
Parameter Condition Min Typ Max Unit
3.3V Supply Voltage (V3P3) Normal Operation 3.0 3.3 3.6 V
Operating Temperature -40 +85 ºC
4.4 Performance Specifications
4.4.1 Input Logic Levels
Parameter
Condition
Min
Typ
Max
Unit
Digital high-level input voltage, V
IH
2 V
Digital low-level input voltage, VIL 0.8 V
Input pull-up current, IIL
E_RXTX,
E_RST, CKTEST
Other digital inputs
VIN=0V, ICE_E=1
10
10
-1
0
100
100
1
µA
µA
µA
Input pull down current, IIH
ICE_E
Other digital inputs
VIN=V3P3
10
-1
0
100
1
µA
µA
4.4.2 Output Logic Levels
Parameter
Condition
Min
Typ
Max
Unit
Digital high-level output voltage VOH
ILOAD = 1 mA V3P3
–0.4 V
ILOAD = 15 mA V3P3-
0.61 V
Digital low-level output voltage VOL ILOAD = 1 mA 0 0.4 V
ILOAD = 15 mA 0.8
1
V
1 Guaranteed by design; not production tested.
78M6613 Data Sheet DS_6613_018
4.4.3 Supply Current
Parameter
Condition
Min
Typ
Max
Unit
V3P3A + V3P3D current
Normal Operation,
V3P3=3.3V,
ICE Disabled
8.1 10.3 mA
V3P3A + V3P3D current vs.
MPU clock frequency Same conditions as above 0.5 mA/
MHz
V3P3A + V3PD current,
Write Flash
Normal Operation as above,
except write Flash at maximum
rate, ADC & CE Disabled
9.1 10 mA
4.4.4 Crystal Oscillator
Parameter Condition Min Typ Max Unit
Maximum Output Power to Crystal Crystal connected 1 µW
XIN to XOUT Capacitance 3 pF
Capacitance to GND
XIN
XOUT
5
5
pF
pF
4.4.5 VREF
Unless otherwise specified, VREF_DIS=0
Parameter Condition Min Typ Max Unit
VREF output voltage, VNOM(25) Ta = 22ºC 1.193 1.195 1.197 V
VREF
chop step 50 mV
VREF output impedance VREF_CAL =1,
ILOAD = 10 µA, -10 µA 2.5 kΩ
VNOM definition*
2)22(1)22()22()(
2
TCTTCTVREFTVNOM −+−+=
V
VREF temperature coefficients
TC1
TC2
124.4 - 2.435*TRIMT
-0.265 + 0.00106*TRIMT
µV/ºC
µ
V/°C
2
VREF aging ±25 ppm/
year
VREF(T) deviation from VNOM(T)
62
10
)()( 6
VNOM
TVNOMTVREF −
Ta = -40ºC to +85ºC -401 +401 ppm/º
C
* This relationship describes the nominal behavior of VREF at different temperatures.
DS_6613_018 78M6613 Data Sheet
4.4.6 ADC Converter, V3P3 Referenced
VREF_DIS=0, LSB values do not include the 9-bit left shift at CE input.
Parameter Condition Min Typ Max Unit
Recommended Input Range
(Vin-V3P3A) -250 250 mV
peak
Voltage to Current Crosstalk:
)cos(
*106
VcrosstalkVin
Vin
Vcrosstalk ∠−∠
Vin = 200 mV peak,
65 Hz, on A0
Vcrosstalk = largest
measurement on A1 or
A3
-101 101 μV/V
THD (First 10 harmonics)
250 mV-pk
20 mV-pk
Vin=65 Hz,
64 kpts FFT, Blackman-
Harris window
-75
-90
dB
dB
Input Impedance Vin=65 Hz 40 90 kΩ
Temperature coefficient of Input
Impedance Vin=65 Hz 1.7 Ω/°C
LSB size FIR_LEN=0
FIR_LEN=1 357
151 nV/LSB
Digital Full Scale FIR_LEN=0
FIR_LEN=1 +884736
+2097152
LSB
ADC Gain Error vs
%Power Supply Variation
3.3/33100
/35710
6
APV
VnVNout
INPK
∆
∆
Vin=200 mV pk, 65 Hz
V3P3=3.0V, 3.6V 50 ppm/%
Input Offset (Vin-V3P3A) -10 10 mV
4.4.7 Temperature Sensor
Parameter Condition Min Typ Max Unit
Nominal Sensitivity (Sn) FIR_LEN=0
FIR_LEN=1 -669
-1585 LSB/ºC
Nominal (Nn) † FIR_LEN=0
FIR_LEN=1 +429301
+1017558 LSB
Temperature Error
+
−
−=
n
n
n
T
S
NTN
TERR ))((
TA = -40ºC to +85ºC
Tn = 25°C -101 +101 ºC
† Nn is measured at Tn during calibration and is stored in MPU or CE for use in temperature calculations.
1 Guaranteed by design; not production tested.
78M6613 Data Sheet DS_6613_018
4.5 Timing Specifications
4.5.1 RAM and Flash Memory
Parameter Condition Min Typ Max Unit
CE DRAM wait states
CKMPU = 4.9152 MHz 5 Cycles
CKMPU = 1.25 MHz 2 Cycles
CKMPU = 614 kHz 1 Cycles
Flash write cycles
-40 °C to +85 °C
20,000
Cycles
Flash data retention 25 °C 100 Years
Flash data retention 85 °C 10 Years
Flash byte writes between page or
mass erase operations
2 Cycles
4.5.2 RESET
Parameter
Condition
Min
Typ
Max
Unit
Reset pulse fall time 1 µs
Reset pulse width 5 µ
s
DS_6613_018 78M6613 Data Sheet
4.5.3 Typical Performance Data
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.01 0.1 110
Accuracy (%)
Current (A)
Wh Accuracy (%)
Wh Accuracy (%)
Figure 15: Wh Accuracy, 10 mA to 20 A at 120 V/60 Hz and Room Temperature Using a 4 mΩ
Current Shunt
Relative Accuracy over Temperature
-30
-20
-10
0
10
20
30
40
-60 -40 -20 020 40 60 80 100
Temperature [°C]
Accuracy [PPM/°C]
Figure 16: Typical Measurement Accuracy over Temperature Relative to 25°C
78M6613 Data Sheet DS_6613_018
5 Packaging
5.1 Pinout
V3P3A
GNDA
RESET
RX
DIO8
DIO7
DIO6
DIO5
32 31 30 29 28 27 26 25
A1 124 ICE_E
A3 223 GNDD
A2 322 DIO4
A0 421 DIO19
VREF 520 DIO16
XIN 619 DIO15
TEST 718 DIO14
XOUT 8 17 DIO17
910 11 12 13 14 15 16
CKTEST
V3P3D
N/C
E_TCLK
E_RST
E_RXTX
TMUXOUT
TX
Figure 17: 32-Pin QFN Pinout
DS_6613_018 78M6613 Data Sheet
5.2 Package Outline (QFN 32)
NOTE: Controlling dimensions are in mm.
Figure 18: Package Outline (QFN 32)
2.5
5
2.5
5
TOP VIEW
1
2
3
0.85 NOM.
/
0.9MAX.
0.00 / 0.005
0.20 REF.
SEATING
PLANE
SIDE VIEW
0.2 MIN.
0.35 / 0.45
1.5 / 1.6
3.0 / 3.2
0.18 / 0.3
BOTTOM VIEW
1
2
3
0.5
0.5
3.0 / 3.2
1.5 / 1.6
0.35 / 0.45
CHAMFERED
0.30
78M6613 Data Sheet DS_6613_018
5.3 Recommended PCB Land Pattern for the QFN-32 Package
e
Ad G
x
x
e
y
y
A
d
G
Symbol
Description
Min
Typ
Max
e Lead pitch 0.50
mm
x 0.28 mm 0.28 mm
y
0.69 mm
d
See Note 1
3.00 mm
A 3.78 mm
G 3.93 mm
Note 1: Do not place unmasked vias in region denoted by dimension “d”.
Note 2: Soldering of bottom internal pad not required for proper operation of either commercial or
industrial temperature rated versions.
Figure 19: Recommended PCB Land Pattern Dimensions
DS_6613_018 78M6613 Data Sheet
6 Pin Descriptions
6.1 Power/Ground Pins
Name Type Circuit Description
GNDA
GNDD P – These pins should be connected directly to the ground plane.
V3P3A
V3P3D
P – A 3.3V power supply should be connected to these pins.
6.2 Analog Pins
Name Type Circuit Description
A0, A1,
A2, A3 I 5
Sense Inputs: These pins are voltage inputs to the internal A/D
converter. Typically, they are connected to either the outputs of
current sensors or the outputs of resistor dividers (voltage sensors).
Unused pins must be connected to V3P3.
VREF O 8 Voltage Reference for the ADC. This pin is left unconnected. Never
use as an external reference.
XIN
XOUT I 7
Crystal Inputs. A 32 kHz crystal should be connected across these
pins. Typically, a 27 pF capacitor is also connected from each pin to
GND. It is important to minimize the capacitance between these
pins. See the crystal manufacturer datasheet for details.
Pin types: P = Power, O = Output, I = Input, I/O = Input/Output
The circuit number denotes the equivalent circuit, as specified under “I/O Equivalent Circuits”.
78M6613 Data Sheet DS_6613_018
6.3 Digital Pins
Name Type Circuit Description
DIO4
DIO5
DIO6
DIO7
DIO8
DIO14
DIO15
DIO16
DIO17
DIO19
I/O 3, 4 DIO pins. If unused, these pins must be configured as DIOs and
set to outputs by the firmware.
E_RXTX,
E_RST I/O 1, 4 Emulator port pins (when ICE_E pulled high) .
E_TCLK O 4
ICE_E I 2
ICE enable. When zero, E_RST, E_TCLK, and E_RXTX are disabled.
For production units, this pin should be pulled to GND to disable the
emulator port. This pin should be brought out to the programming
interface in order to create a way for reprogramming parts that have
the SECURE bit set.
CKTEST
O
4
Clock PLL output.
TMUXOUT O 4 Digital output test multiplexer.
RESET I 3
This input pin resets the chip into a known state. For normal operation,
this pin should be pulled low. To force the device into reset state, it should be
pulled high. Refer to Section 3.6 for RESET pin connections, use, and
relevant external circuitry.
RX I 3 UART input. If unused, this pin must be terminated to V3P3 or
GND.
TX O 4 UART output.
TEST I 7 Enables Production Test.
Must be grounded in normal operation.
Pin types: P = Power, O = Output, I = Input, I/O = Input/Output
The circuit number denotes the equivalent circuit, as specified on the following page.
DS_6613_018 78M6613 Data Sheet
7 I/O Equivalent Circuits
Figure 20: I/O Equivalent Circuits
Digital Input Equivalent Circuit
Type 1:
Standard Digital Input or
pin configured as DIO Input
with Internal Pull-Up
GND
110K
V3P3
CMOS
Input
V3P3
Digital
Input
Pin
CMOS
Output
GND
V3P3
GND
V3P3
Digital Output Equivalent Circuit
Type 4:
Standard Digital Output or
pin configured as DIO Output
Digital
Output
Pin To
MUX
GND
V3P3
Analog Input Equivalent Circuit
Type 5:
ADC Input
Analog
Input
Pin
VREF Equivalent Circuit
Type 8:
VREF
from
internal
reference
GND
V3P3
VREF
Pin
Oscillator Equivalent Circuit
Type 7:
Oscillator I/O
To
Oscillator
GND
Oscillator
Pin
Digital Input
Type 2:
Pin configured as DIO Input
with Internal Pull-Down
GND
110K
GND
CMOS
Input
V3P3
Digital
Input
Pin
Digital Input Type 3:
Standard Digital Input or
pin configured as DIO Input
GND
CMOS
Input
V3P3
Digital
Input
Pin
Comparator Input Equivalent Circuit
Type 6:
Comparator Input
GND
V3P3
To
Comparator
Comparator
Input
Pin
78M6613 Data Sheet DS_6613_018
8 Ordering Information
Part Package Option Ordering Number IC Marking
78M6613 32-pin QFN
(Lead(Pb)-Free)
Bulk 78M6613-IM/F
78M6613-IM
Tape & Reel 78M6613-IMR/F
*Programmed, Bulk
78M6613-IM/F/P
*Programmed, Tape & Reel
78M6613-IMR/F/P
*Contact the factory for more information on programmed part options.
9 Contact Information
For more information about Maxim products or to check the availability of the 78M6613, contact
technical support at www.maxim-ic.com/support.
DS_6613_018 78M6613 Data Sheet
Revision History
REVISION
NUMBER
REVISION
DATE
DESCRIPTION PAGES
CHANGED
1.0 11/10 First publication.
1.1 3/11 In Section 6.3, corrected the description of the RESET
pin. 30
2 1/12 Added Maxim logo. 1
33
Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.
Maxim reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical
Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
© 2012 Maxim Integrated The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc.