MIC7122 Micrel MIC7122 Rail-to-Rail Dual Op Amp General Description Features The MIC7122 is a dual high-performance CMOS operational amplifier featuring rail-to-rail inputs and outputs. The input common-mode range extends beyond the rails by 300mV, and the output voltage swings to within 150V of both rails when driving a 100k load. The amplifiers operate from 2.2V to 15V and are fully specified at 2.2V, 5V, and 15V. Gain bandwidth and slew rate are 750kHz and 0.7V/s, respectively at 2.2V supply. The MIC7122 is available in the MM8TM 8-lead MSOP package. * * * * * * Small footprint MSOP-8 package 350A supply current per op amp at 2.2V supply Guaranteed 2.2V, 5V, and 15V performance 750kHz gain-bandwidth product at 2.2V supply 0.01% total harmonic distortion at 1kHz (15V, 2k) Drives 200pF at 5V and greater supply voltages Applications * Battery-powered instrumentation * PCMCIA, USB peripherals * Portable computers and PDAs Ordering Information Part Number Standard MIC7122BMM Pb-free Temperature Range Package MIC7122YMM -40C to +85C MSOP-8 Pin Configuration OUT A 1 8 V+ 1 IN A- 2 7 OUT B 2 IN A+ 3 6 V- 4 5 8 7 A INB- 6 3 B INB+ 4 5 MSOP-8 (MM) Pin Description Pin Number Pin Name Pin Function 1/7 OUTA / OUTB 2/6 INA- / INB- Inverting Inputs 3/5 INA+ / INB+ Noninverting Inputs 4 V- Negative Supply: Negative supply for split supply application or ground for single supply applications. 8 V+ Positive Supply Amplifier Outputs MM8 is a trademark of Micrel, Inc. Micrel, Inc. * 2180 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 474-1000 * http://www.micrel.com June 2005 1 MIC7122 MIC7122 Micrel Absolute Maximum Ratings (Note 1) Operating Ratings (Note 2) Supply Voltage (VV+ - VV-) ........................................ 16.5V Differential Input Voltage (VIN+ - VIN-) ....................... 10V I/O Pin Voltage (VIN, VOUT), Note 3 ............................................. VV+ + 0.3V to VV- - 0.3V Junction Temperature (TJ) ...................................... +150C Storage Temperature ............................... -65C to +150C Lead Temperature (soldering, 10 sec.) ..................... 260C ESD, Note 6 .............................................................. 1000V Supply Voltage (VV+ - VV-) .............................. 2.2V to 15V Junction Temperature (TJ) ......................... -40C to +85C Max. Power Dissipation ............................................ Note 4 Package Thermal Resistance, Note 5 MSOP-8 (JA) .................................................... 200C/W DC Electrical Characteristics (2.2V) VV+ = +2.2V, VV- = 0V, VCM = VOUT = VV+/2; RL = 1M; TJ = 25C, bold values indicate -40C TJ +85C; Note 7; unless noted Symbol Parameter VOS Condition Min Typ Max Units Input Offset Voltage 0.5 9 mV TCVOS Input Offset Voltage Average Drift 3.0 IB Input Bias Current 1.0 64 10 500 pA pA IOS Input Offset Current 0.5 32 5 250 pA pA RIN Input Resistance >1 T CMRR Common-Mode Rejection Ratio -0.3V VCM 2.5V, Note 9 45 65 dB PSRR Power Supply Rejection Ratio VV+ = VV- = 1.1V to 2.5V, VOUT = VCM = 0 60 85 dB CIN Common-Mode Input Capacitance 3 pF VO Output Swing V/C output high, RL = 100k, specified as VV+ - VOUT 0.15 1 1 mV mV output low, RL = 100k 0.15 1 1 mV mV output high, RL = 2k specified as VV+ - VOUT 8 33 50 mV mV output low, RL = 2k 8 33 50 mV mV output high, RL = 600 specified as VV+ - VOUT 26 110 165 mV mV output low, RL = 600 26 110 165 mV mV ISC Output Short Circuit Current sinking or sourcing, Note 8 IS Supply Current both amplifiers 20 50 0.7 mA 1.6 mA AC Electrical Characteristics (2.2V) VV+ = 2.2V, VV- = 0V, VCM = VOUT = VV+/2; RL = 1M; TJ = 25C, bold values indicate -40C TJ +85C; Note 7; unless noted Symbol Parameter SR Slew Rate 0.7 V/s GBW Gain-Bandwidth Product 750 kHz m Phase Margin CL = 0pF 80 CL = 200pF 40 10 dB 90 dB Gm Min Gain Margin Interamplifier Isolation MIC7122 Condition Note 12 2 Typ Max Units June 2005 MIC7122 Micrel DC Electrical Characteristics (5V) VV+ = +5.0V, VV- = 0V, VCM = 1.5V, VOUT = VV+/2; RL = 1M; TJ = 25C, bold values indicate -40C TJ +85C; Note 7; unless noted Symbol Parameter VOS Condition Min Typ Max Units Input Offset Voltage 0.5 9 mV TCVOS Input Offset Voltage Average Drift 3.0 IB Input Bias Current 1.0 64 10 500 pA pA IOS Input Offset Current 0.5 32 5 250 pA pA RIN Input Resistance >1 T CMRR Common-Mode Rejection Ratio -0.3V VCM 5.3V, Note 9 55 75 dB PSRR Power Supply Rejection Ratio VV+ = VV- = 2.5V to 7.5V, VOUT = VCM = 0 55 100 dB CIN Common-Mode Input Capacitance 3 pF VOUT Output Swing V/C output high, RL = 100k specified as VV+ - VOUT 0.3 1.0 1.5 mV mV output low, RL = 100k 0.3 1.0 1.5 mV mV output high, RL = 2k specified as VV+ - VOUT 13 50 75 mV mV output low, RL = 2k 13 50 75 mV mV output high, RL = 600 specified as VV+ - VOUT 40 165 250 mV mV output low, RL = 600 40 165 250 mV mV ISC Output Short Circuit Current sinking or sourcing, Note 8 IS Supply Current both amplifiers 40 140 0.8 mA 1.8 mA AC Electrical Characteristics (5V) VV+ = 5V, VV- = 0V, VCM = 1.5V, VOUT = VV+/2; RL = 1M; TJ = 25C, bold values indicate -40C TJ +85C; Note 7; unless noted Symbol Parameter Condition Min THD Total Harmonic Distortion f = 1kHz, AV = -2, RL = 2k, VOUT = 4.0 VPP SR Typ Max Units 0.05 % Slew Rate 0.6 V/s GBW Gain-Bandwidth Product 465 kHz m Phase Margin CL = 0pF 85 CL = 200pF 40 10 dB 90 dB Gm Gain Margin Interamplifier Isolation June 2005 Note 12 3 MIC7122 MIC7122 Micrel DC Electrical Characteristics (15V) VV+ = +15V, VV- = 0V, VCM = 1.5V, VOUT = VV+/2; RL = 1M; TJ = 25C, bold values indicate -40C TJ +85C; Note 7; unless noted Symbol Parameter VOS Condition Min Typ Max Units Input Offset Voltage 0.5 9 mV TCVOS Input Offset Voltage Average Drift 3.0 IB Input Bias Current 1.0 64 10 500 pA pA IOS Input Offset Current 0.5 32 5 250 pA pA RIN Input Resistance >1 T CMRR Common-Mode Rejection Ratio -0.3V VCM 15.3V, Note 9 60 85 dB PSRR Power Supply Rejection Ratio 55 100 dB AV Large Signal Voltage Gain VV+ = VV- = 2.5V to 7.5V, VOUT = VCM = 0 sourcing or sinking, RL = 2k, Note 10 340 V/mV 300 V/mV 3 pF sourcing or sinking, RL = 600, Note 10 CIN Common-Mode Input Capacitance VOUT Output Swing V/C output high, RL = 100k specified as VV+ - VOUT 0.8 2 3 mV mV output low, RL = 100k 0.8 2 3 mV mV output high, RL = 2k specified as VV+ - VOUT 40 80 120 mV mV output low, RL = 2k 40 80 120 mV mV output high, RL = 600 specified as VV+ - VOUT 130 270 400 mV mV output low, RL = 600 130 270 400 mV mV ISC Output Short Circuit Current sinking or sourcing, Notes 8 IS Supply Current both amplifiers 50 250 0.9 mA 2.0 mA AC Electrical Characteristics (15V) VV+ = 15V, VV- = 0V, VCM = 1.5V, VOUT = VV+/2; RL = 1M; TJ = 25C, bold values indicate -40C TJ +85C; Note 7; unless noted Symbol Parameter Condition Min Typ Max Units THD Total Harmonic Distortion f = 1kHz, AV = -2, RL = 2k, VOUT = 8.5 VPP 0.01 % SR Slew Rate V+ = 15V, Note 11 0.5 V/s GBW Gain-Bandwidth Product 420 kHz m Phase Margin CL = 0pF 85 CL = 500pF 40 10 dB Gm Gain Margin en Input-Referred Voltage Noise f = 1kHz, VCM = 1V 37 nV/ Hz in Input-Referred Current Noise f = 1kHz 1.5 fA/ Hz Interamplifier Isolation Note 12 90 dB MIC7122 4 June 2005 MIC7122 Micrel Note 1. Exceeding the absolute maximum rating may damage the device. Note 2. The device is not guaranteed to function outside its operating rating. Note 3. I/O Pin Voltage is any external voltage to which an input or output is referenced. Note 4. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(max); the junction-to-ambient thermal resistance, JA; and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using: PD = (TJ(max) - TA) / JA. Exceeding the maximum allowable power dissipation will result in excessive die temperature. Note 5. Thermal resistance, JA, applies to a part soldered on a printed-circuit board. Note 6. Devices are ESD protected; however, handling precautions are recommended. Human body model, 1.5k in series with 100pF. Note 7. All limits guaranteed by testing or statistical analysis. Note 8. Continuous short circuit may exceed absolute maximum TJ under some conditions. Note 9. CMRR is determined as follows: The maximum VOS over the VCM range is divided by the magnitude of the VCM range. The measurement points are: VCM = VV- - 0.3V, (VV+ - VV-)/2, and VV+ + 0.3V. Note 10. RL connected to 7.5V. Sourcing: 7.5V VOUT 12.5V. Sinking: 2.5V VOUT 7.5V. Note 11. Device connected as a voltage follower with a 10V step input. The value is the positive or negative slew rate, whichever is slower. Note 12. Referenced to input. June 2005 5 MIC7122 MIC7122 Micrel voltage drop (VDROP) and the output (load) current (IOUT). Total on-chip power dissipation is: PD = PS + PO PD = VS IS + VDROP IOUT where: PD = total on-chip power PS = supply power dissipation PO = output power dissipation VS = VV+ - VV- IS = power supply current VDROP = VV+ - VOUT (sourcing current) VDROP = VOUT - VV- (sinking current) Application Information Input Common-Mode Voltage The MIC7122 tolerates input overdrive by at least 300mV beyond either rail without producing phase inversion. If the absolute maximum input voltage is exceeded, the input current should be limited to 5mA maximum to prevent reducing reliability. A 10k series input resistor, used as a current limiter, will protect the input structure from voltages as large as 50V above the supply or below ground. See Figure 1. RIN VOUT VIN 10k The above addresses only steady state (dc) conditions. For non-dc conditions the user must estimate power dissipation based on rms value of the signal. The task is one of determining the allowable on-chip power dissipation for operation at a given ambient temperature and power supply voltage. From this determination, one may calculate the maximum allowable power dissipation and, after subtracting PS, determine the maximum allowable load current, which in turn can be used to determine the miniumum load impedance that may safely be driven. The calculation is summarized below. Figure 1. Input Current-Limit Protection Output Voltage Swing Sink and source output resistances of the MIC7122 are equal. Maximum output voltage swing is determined by the load and the approximate output resistance. The output resistance is: V ROUT = DROP ILOAD VDROP is the voltage dropped within the amplifier output stage. VDROP and ILOAD can be determined from the VO (output swing) portion of the appropriate Electrical Characteristics table. ILOAD is equal to the typical output high voltage minus V+/2 and divided by RLOAD. For example, using the Electrical Characteristics DC (5V) table, the typical output high voltage drops 13mV using a 2k load (connected to V+/ 2), which produces an ILOAD of: PD(max) = Driving Capacitive Loads Driving a capacitive load introduces phase-lag into the output signal, and this in turn reduces op-amp system phase margin. The application that is least forgiving of reduced phase margin is a unity gain amplifier. The MIC7122 can typically drive a 200pF capacitive load connected directly to the output when configured as a unity-gain amplifier and powered with a 2.2V supply. At 15V operation the circuit typically drives 500pF. Using Large-Value Feedback Resistors A large-value feedback resistor (> 500k) can reduce the phase margin of a system. This occurs when the feedback resistor acts in conjunction with input capacitance to create phase lag in the feedback signal. Input capacitance is usually a combination of input circuit components and other parasitic capacitance, such as amplifier input capacitance and stray printed circuit board capacitance. Figure 2 illustrates a method of compensating phase lag caused by using a large-value feedback resistor. Feedback capacitor CFB introduces sufficient phase lead to overcome the phase lag caused by feedback resistor RFB and input Because of output stage symmetry, the corresponding typical output low voltage (13mV) also equals VDROP. Then: 0.013V = 10.5 0.001244A Power Dissipation The MIC7122 output drive capability requires considering power dissipation. If the load impedance is low, it is possible to damage the device by exceeding the 125C junction temperature rating. On-chip power consists of two components: supply power and output stage power. Supply power (PS) is the product of the supply voltage (VS = VV+ - VV-) and supply current (IS). Output stage power (PO) is the product of the output stage MIC7122 JA JA(MSOP-8) = 200C/W 5.0V - 0.013V - 2.5V = 1.244mA 2k ROUT = TJ(max) - TA 6 June 2005 MIC7122 Micrel capacitance CIN. The value of CFB is determined by first estimating CIN and then applying the following formula: RIN x CIN RFB x CFB V+ 12 VIN 0V to V+ MIC7122 VOUT 0V to V+ CFB RFB VOUT = VIN RIN VIN Figure 4. Voltage Follower/Buffer VOUT VS 0.5V to Q1 VCEO(sus) V+ Figure 2. Cancelling Feedback Phase Lag 12 VIN 0V to 2V Since a significant percentage of CIN may be caused by board layout, it is important to note that the correct value of CFB may change when changing from a breadboard to the final circuit layout. Typical Circuits Some single-supply, rail-to-rail applications for which the MIC7122 is well suited are shown in the circuit diagrams of Figures 3 through 7. VOUT 0V to V+ Load CIN MIC7122 IOUT Q1 VCEO = 40V 2N3904 IC(max) = 200mA { RS 10 12W Change Q1 and RS for higher current and/or different gain. IOUT = VIN = 100mA/V as shown RS Figure 5. Voltage-Controlled Current Sink V+ R4 12 VIN 0V to MIC7122 V+ AV 100k V+ C1 0.001F VOUT 0V to V+ 12 MIC7122 VOUT R2 V+ 0V 910k R1 100k V+ R2 R4 100k 100k Figure 3a. Noninverting Amplifier R3 100k Figure 6. Square Wave Oscillator 100 V+ VOUT (V) CIN A V = 1+ R1 R2 33k 330k V+ R2 10 R1 12 MIC7122 COUT RL 0 0 VIN (V) VOUT 0V 100 V+ Figure 3b. Noninverting Amplifier Behavior R3 330k R2 C1 1F 330k = = -10 R4 A V = - R1 33k 330k Figure 7. AC-Coupled Inverting Amplifier June 2005 7 MIC7122 MIC7122 Micrel Package Information 0.199 (5.05) 0.187 (4.74) 0.122 (3.10) 0.112 (2.84) DIMENSIONS: INCH (MM) 0.120 (3.05) 0.116 (2.95) 0.036 (0.90) 0.032 (0.81) 0.043 (1.09) 0.038 (0.97) 0.007 (0.18) 0.005 (0.13) 0.012 (0.30) R 0.008 (0.20) 0.004 (0.10) 0.012 (0.03) 0.0256 (0.65) TYP 5 MAX 0 MIN 0.012 (0.03) R 0.039 (0.99) 0.035 (0.89) 0.021 (0.53) MM8TM 8-Lead MSOP (MM) MICREL INC. 2180 FORTUNE DRIVE TEL + 1 (408) 944-0800 FAX SAN JOSE, CA 95131 + 1 (408) 474-1000 WEB USA http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. (c) 2005 Micrel Incorporated MIC7122 8 June 2005