OPA241 ® OPA2241 OPA4241 OPA 241 OPA 425 OPA 1 OPA251 424 1 OPA OPA2251 OPA4251 225 1 Single-Supply, MicroPOWER OPERATIONAL AMPLIFIERS OPA241 Family optimized for +5V supply. DESCRIPTION OPA251 Family optimized for ±15V supply. The OPA241 series and OPA251 series are specifically designed for battery powered, portable applications. In addition to very low power consumption (25µA), these amplifiers feature low offset voltage, rail-to-rail output swing, high common-mode rejection, and high open-loop gain. The OPA241 series is optimized for operation at low power supply voltage while the OPA251 series is optimized for high power supplies. Both can operate from either single (+2.7V to +36V) or dual supplies (±1.35V to ±18V). The input common-mode voltage range extends 200mV below the negative supply—ideal for single-supply applications. They are unity-gain stable and can drive large capacitive loads. Special design considerations assure that these products are easy to use. High performance is maintained as the amplifiers swing to their specified limits. Because the initial offset voltage (±250µV max) is so low, user adjustment is usually not required. However, external trim pins are provided for special applications (single versions only). The OPA241 and OPA251 (single versions) are available in standard 8-pin DIP and SO-8 surface-mount packages. The OPA2241 and OPA2251 (dual versions) come in 8-pin DIP and SO-8 surface-mount packages. The OPA4241 and OPA4251 (quad versions) are available in 14-pin DIP and SO-14 surface-mount packages. All are fully specified from –40°C to +85°C and operate from –55°C to +125°C. FEATURES ● ● ● ● ● ● ● ● MicroPOWER: IQ = 25µA SINGLE-SUPPLY OPERATION RAIL-TO-RAIL OUTPUT (within 50mV) WIDE SUPPLY RANGE Single Supply: +2.7V to +36V Dual Supply: ±1.35V to ±18V LOW OFFSET VOLTAGE: ±250µV max HIGH COMMON-MODE REJECTION: 124dB HIGH OPEN-LOOP GAIN: 128dB SINGLE, DUAL, AND QUAD APPLICATIONS ● BATTERY OPERATED INSTRUMENTS ● PORTABLE DEVICES ● MEDICAL INSTRUMENTS ● TEST EQUIPMENT OPA241, OPA251 Offset Trim 1 8 NC Out A 1 –In 2 7 V+ –In A 2 +In 3 6 Output +In A 3 V– 4 5 Offset Trim V– 4 8-Pin DIP, SO-8 OPA4241, OPA4251 OPA2241, OPA2251 V+ Out A 1 14 Out D 7 Out B –In A 2 13 –In D 6 –In B +In A 3 12 +In D 5 +In B V+ 4 11 V– +In B 5 10 +In C 8 A B 8-Pin DIP, SO-8 A B D C –In B 6 9 –In C Out B 7 8 Out C 14-Pin DIP, SO-14 International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 • Twx: 910-952-1111 Internet: http://www.burr-brown.com/ • FAXLine: (800) 548-6133 (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 © 1997 Burr-Brown Corporation PDS-1406B 1 OPA241, 2241, 4241 Printed in U.S.A. October, 1998 OPA251, 2251, 4251 ® SPECIFICATIONS: VS = 2.7V to 5V At TA = +25°C, RL = 100kΩ connected to VS/2, unless otherwise noted. Boldface limits apply over the specified temperature range, TA = –40°C to +85°C. OPA241UA, PA OPA2241UA, PA OPA4241UA, PA PARAMETER CONDITION OFFSET VOLTAGE Input Offset Voltage TA = –40°C to +85°C vs Temperature vs Power Supply TA = –40°C to +85°C Channel Separation (dual, quad) TA = –40°C to +85°C VS = 2.7V to 36V VS = 2.7V to 36V dVOS/dT PSRR POWER SUPPLY Specified Voltage Range Operating Voltage Range Quiescent Current (per amplifier) TA = –40°C to +85°C TEMPERATURE RANGE Specified Range Operating Range Storage Range Thermal Resistance 8-Pin DIP SO-8 Surface Mount 14-Pin DIP SO-14 Surface Mount 3 30 30 ✻ ±0.1 en in 1 45 40 VCM CMRR VCM = –0.2V to (V+) –0.8V VCM = 0V to (V+) –0.8V –0.2 80 80 AOL RL = 100kΩ, VO = (V–)+100mV to (V+)–100mV RL = 100kΩ, VO = (V–)+100mV to (V+)–100mV RL = 10kΩ, VO = (V–)+200mV to (V+)–200mV RL = 10kΩ, VO = (V–)+200mV to (V+)–200mV GBW SR VO 100 100 100 100 VS = 5V, G = 1 VIN • G = VS RL = 100kΩ to VS /2, AOL ≥ 70dB RL = 100kΩ to VS /2, AOL ≥ 100dB RL = 100kΩ to VS /2, AOL ≥ 100dB RL = 10kΩ to VS /2, AOL ≥ 100dB RL = 10kΩ to VS /2, AOL ≥ 100dB MAX ±100 ±130 ±0.6 IOS TA = –40°C to +85°C TA = –40°C to +85°C Short-Circuit Current Single Versions Dual, Quad Versions Capacitive Load Drive ±250 TYP(1) ±400 –4 TA = –40°C to +85°C OUTPUT Voltage Output Swing from Rail(3) MIN ±100 ±0.4 IB INPUT IMPEDANCE Differential Common-Mode FREQUENCY RESPONSE Gain-Bandwidth Product Slew Rate Overload Recovery Time MAX ✻ ✻ ✻ 0.3 NOISE Input Voltage Noise, f = 0.1Hz to 10Hz Input Voltage Noise Density, f = 1kHz Current Noise Density, f = 1kHz OPEN-LOOP GAIN Open-Loop Voltage Gain TA = –40°C to +85°C TYP(1) ±50 VOS INPUT BIAS CURRENT Input Bias Current(2) TA = –40°C to +85°C Input Offset Current TA = –40°C to +85°C INPUT VOLTAGE RANGE Common-Mode Voltage Range Common-Mode Rejection Ratio TA = –40°C to +85°C MIN OPA251UA, PA OPA2251UA, PA OPA4251UA, PA ✻ –20 –25 ±2 ±2 UNITS µV µV µV/°C µV/V µV/V µV/V nA nA nA nA ✻ ✻ ✻ ✻ µVp-p nV/√Hz fA/√Hz 106 ✻ V dB dB 107 || 2 109 || 4 ✻ ✻ Ω || pF Ω || pF 120 ✻ 120 ✻ dB dB dB dB 35 0.01 60 ✻ ✻ ✻ kHz V/µs µs ✻ ✻ mV mV mV mV mV (V+) –0.8 50 75 100 100 100 200 200 ✻ ISC CLOAD VS IQ ✻ ✻ ✻ –24/+4 –30/+4 See Typical Curve ✻ +2.7 to +5 TA = –40°C to +85°C IO = 0 IO = 0 +2.7 ±25 –40 –55 –55 +36 ±30 ±36 ✻ +85 +125 +125 ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ θJA 100 150 80 100 mA mA ✻ ✻ ✻ ✻ V V µA µA °C °C °C °C/W °C/W °C/W °C/W ✻ Specifications the same as OPA241UA, PA. NOTES: (1) VS = +5V. (2) The negative sign indicates input bias current flows out of the input terminals. (3) Output voltage swings are measured between the output and power supply rails. The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems. ® OPA241, 2241, 4241 OPA251, 2251, 4251 2 SPECIFICATIONS: VS = ±15V At TA = +25°C, RL = 100kΩ connected to ground, unless otherwise noted. Boldface limits apply over the specified temperature range, TA = –40°C to +85°C. OPA241UA, PA OPA2241UA, PA OPA4241UA, PA PARAMETER OFFSET VOLTAGE Input Offset Voltage TA = –40°C to +85°C vs Temperature vs Power Supply TA = –40°C to +85°C Channel Separation (dual, quad) CONDITION dVOS/dT PSRR NOISE Input Voltage Noise, f = 0.1Hz to 10Hz Input Voltage Noise Density, f = 1kHz Current Noise Density, f = 1kHz TA = –40°C to +85°C VS = ±1.35V to ±18V VS = ±1.35V to ±18V OUTPUT Voltage Output Swing from Rail(2) POWER SUPPLY Specified Voltage Range Operating Voltage Range Quiescent Current (per amplifier) TA = –40°C to +85°C TEMPERATURE RANGE Specified Range Operating Range Storage Range Thermal Resistance 8-Pin DIP SO-8 Surface Mount 14-Pin DIP SO-14 Surface Mount TYP ±50 ✻ ✻ ✻ ±0.1 en in ✻ ✻ ✻ 1 45 40 (V–) –0.2 100 100 ✻ ✻ AOL GBW SR VO ✻ RL = 100kΩ, VO = –14.75V to +14.75V RL = 100kΩ, VO = –14.75V to +14.75V RL = 20kΩ, VO = –14.7V to +14.7V RL = 20kΩ, VO = –14.7V to +14.7V 100 100 100 100 ✻ G=1 VIN • G = VS RL = 100kΩ, AOL ≥ 70dB RL = 100kΩ, AOL ≥ 100dB RL = 100kΩ, AOL ≥ 100dB RL = 20kΩ, AOL ≥ 100dB RL = 20kΩ, AOL ≥ 100dB µV µV µV/°C µV/V µV/V µV/V 30 30 IOS ✻ ±250 3 –4 VCM = –15.2V to 14.2V VCM = –15V to 14.2V UNITS ±300 ✻ VCM CMRR MAX ±100 ±0.5 IB TA = –40°C to +85°C TA = –40°C to +85°C Short-Circuit Current Single Versions Dual Versions Capacitive Load Drive MIN 0.3 TA = –40°C to +85°C FREQUENCY RESPONSE Gain-Bandwidth Product Slew Rate Overload Recovery Time MAX ✻ INPUT IMPEDANCE Differential Common-Mode OPEN-LOOP GAIN Open-Loop Voltage Gain TA = –40°C to +85°C TYP ±100 ±150 ±0.6 ✻ VOS INPUT BIAS CURRENT Input Bias Current(1) TA = –40°C to +85°C Input Offset Current TA = –40°C to +85°C INPUT VOLTAGE RANGE Common-Mode Voltage Range Common-Mode Rejection Ratio TA = –40°C to +85°C MIN OPA251UA, PA OPA2251UA, PA OPA4251UA, PA –20 –25 ±2 ±2 nA nA nA nA µVp-p nV/√Hz fA/√Hz 124 (V+) –0.8 V dB dB 107 || 2 109 || 4 Ω || pF Ω || pF 128 dB dB dB dB 128 ✻ ✻ ✻ 35 0.01 60 ✻ ✻ 50 75 ✻ 100 ✻ ✻ ✻ –21/+4 –50/+4 See Typical Curve mA mA ±15 ±45 ±38 V V µA µA +85 +125 +125 °C °C °C kHz V/µs µs 250 250 300 300 mV mV mV mV mV ISC CLOAD VS IQ TA = –40°C to +85°C IO = 0 IO = 0 ✻ ✻ ✻ ±1.35 ✻ ✻ ✻ ✻ ✻ ✻ ✻ ±27 –40 –55 –55 θJA ✻ ✻ ✻ ✻ 100 150 80 100 ±18 °C/W °C/W °C/W °C/W ✻ Specifications the same as OPA251UA, PA. NOTES: (1) The negative sign indicates input bias current flows out of the input terminals. (2) Output voltage swings are measured between the output and power supply rails. 3 OPA241, 2241, 4241 OPA251, 2251, 4251 ® ABSOLUTE MAXIMUM RATINGS(1) ELECTROSTATIC DISCHARGE SENSITIVITY Supply Voltage, V+ to V– .................................................................... 36V Input Voltage(2) .................................................. (V–) –0.5V to (V+) +0.5V Output Short Circuit to Ground(3) ............................................ Continuous Operating Temperature .................................................. –55°C to +125°C Storage Temperature ..................................................... –55°C to +125°C Junction Temperature ...................................................................... 150°C Lead Temperature (soldering, 10s) ................................................. 300°C This integrated circuit can be damaged by ESD. Burr-Brown recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. NOTES: (1) Stresses above these ratings may cause permanent damage. (2) Input terminals are diode-clamped to the power supply rails. Input signals that can swing more that 0.5V beyond the supply rails should be currentlimited to 5mA or less. (3) One amplifier per package. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. PACKAGE/ORDERING INFORMATION SPECIFIED VOLTAGE OPERATING VOLTAGE RANGE PACKAGE PACKAGE DRAWING NUMBER(1) SPECIFICATION TEMPERATURE RANGE Single OPA241PA OPA241UA 2.7V to 5V 2.7V to 5V 2.7V to 36V 2.7V to 36V 8-Pin DIP SO-8 Surface Mount 006 182 –40°C to +85°C –40°C to +85°C Dual OPA2241PA OPA2241UA 2.7V to 5V 2.7V to 5V 2.7V to 36V 2.7V to 36V 8-Pin DIP SO-8 Surface Mount 006 182 –40°C to +85°C –40°C to +85°C Quad OPA4241PA OPA4241UA 2.7V to 5V 2.7V to 5V 2.7V to 36V 2.7V to 36V 14-Pin DIP SO-14 Surface Mount 010 235 –40°C to +85°C –40°C to +85°C Single OPA251PA OPA251UA ±15V ±15V 2.7V to 36V 2.7V to 36V 8-Pin DIP SO-8 Surface Mount 006 182 –40°C to +85°C –40°C to +85°C Dual OPA2251PA OPA2251UA ±15V ±15V 2.7V to 36V 2.7V to 36V 8-Pin DIP SO-8 Surface Mount 006 182 –40°C to +85°C –40°C to +85°C Quad OPA4251PA OPA4251UA ±15V ±15V 2.7V to 36V 2.7V to 36V 14-Pin DIP SO-14 Surface Mount 010 235 –40°C to +85°C –40°C to +85°C PRODUCT OPA241 SERIES OPA251 SERIES NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. ® OPA241, 2241, 4241 OPA251, 2251, 4251 4 TYPICAL PERFORMANCE CURVES At TA = +25°C, and RL = 100kΩ connected to VS/2 (ground for VS = ±15V), unless otherwise noted. Curves apply to OPA241 and OPA251 unless specified. POWER SUPPLY and COMMON-MODE REJECTION RATIO vs FREQUENCY 180 140 160 120 140 G 100 120 80 Φ 100 60 80 40 60 20 40 VS = ±15V VS = +5V 0 –20 0.01 0.1 140 20 1 10 100 1k 10k Power Supply Rejection Ratio (dB) 160 Phase (°) Voltage Gain (dB) OPEN-LOOP GAIN/PHASE vs FREQUENCY 0 100k VS = ±15V VS = ±5V 120 CMRR 100 80 +PSRR 60 –PSRR 40 20 0 0.1 1 10 100 1k 10k Frequency (Hz) Frequency (Hz) CHANNEL SEPARATION vs FREQUENCY INPUT VOLTAGE AND CURRENT NOISE SPECTRAL DENSITY vs FREQUENCY 140 100k 1k 1k 120 110 Dual and quad devices. G = 1, all channels. Quad measured channel A to D or B to C—other combinations yield improved rejection. 100 90 80 70 Current Noise 100 Voltage Noise 10 10 100 1k 10k 10 0.1 100k 1 10 Frequency (Hz) 100 1k 10k Frequency (Hz) QUIESCENT CURRENT vs SUPPLY VOLTAGE QUIESCENT CURRENT vs TEMPERATURE 30 40 Per Amplifier Per Amplifier Quiescent Current (µA) Quiescent Current (µA) 100 28 26 24 22 35 VS = ±15V 30 25 VS = +5V 20 15 0 5 10 15 20 25 30 35 40 –75 Total Supply Voltage (V) –50 –25 0 25 50 75 100 125 Temperature (°C) 5 OPA241, 2241, 4241 OPA251, 2251, 4251 ® Current Noise (fA/√Hz) Voltage Noise (nV/÷Hz) Channel Separation (dB) 130 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, and RL = 100kΩ connected to VS/2 (ground for VS = ±15V), unless otherwise noted. Curves apply to OPA241 and OPA251 unless specified. INPUT BIAS CURRENT vs INPUT COMMON-MODE VOLTAGE INPUT BIAS CURRENT vs TEMPERATURE –5 –6 Input Bias Current (nA) Input Bias Current (nA) IB –4 IB –2 IOS 0 –4 –3 –2 –1 IOS 0 2 0 –75 –50 –25 0 25 50 75 100 5 10 125 15 20 25 30 Common-Mode Voltage (V) Temperature (°C) COMMON-MODE REJECTION vs TEMPERATURE SHORT-CIRCUIT CURRENT vs TEMPERATURE 50 140 Short-Circuit Current (mA) Common-Mode Rejection (dB) VS = ±15V 45 –ISC 40 VS = +5V 35 30 25 VS = +5V 20 Single Versions Dual, Quad Versions 15 10 VS = ±15V +ISC, VS = +5V, ±15V (all versions) 5 VS = ±15V 120 VS = +2.7V, +5V 100 80 60 40 VCM = (V–) –0.2V to (V+) –0.8V VCM = (V–) –0.1V to (V+) –0.8V VCM = (V–) to (V+) –0.8V 20 0 0 –75 –50 –25 0 25 50 75 100 –75 125 –50 –25 Temperature (°C) 0 25 50 75 100 125 Temperature (°C) OPEN-LOOP GAIN AND POWER SUPPLY REJECTION vs TEMPERATURE OUTPUT VOLTAGE SWING vs OUTPUT CURRENT (V+) 140 T = +25°C RL = 20kΩ, 100kΩ AOL, PSR (dB) 130 RL = 100kΩ 120 RL = 10kΩ 110 AOL, VS = ±15V AOL, VS = +5V Output Voltage Swing (V) (V+) –0.1V T = –55°C T = +125°C (V+) –0.2V (V+) –0.3V (V–) +0.3V T = +125°C (V–) +0.2V T = +25°C, –55°C (V–) +0.1V PSRR (V–) 100 –75 –50 –25 0 25 50 75 100 0.1 125 ® OPA241, 2241, 4241 OPA251, 2251, 4251 ±1 Output Current (mA) Temperature (°C) 6 ±10 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, and RL = 100kΩ connected to VS/2 (ground for VS = ±15V), unless otherwise noted. Curves apply to OPA241 and OPA251 unless specified. OPEN-LOOP GAIN vs OUTPUT VOLTAGE SWING MAXIMUM OUTPUT VOLTAGE vs FREQUENCY 140 30 Open-Loop Gain (dB) Maximum Output Voltage (Vp-p) RL = 20kΩ VS = ±15V RL = 100kΩ 130 VS = +5V 120 VS = +2.7V 110 RL = 10kΩ 100 90 80 400 10 VS = +5V 5 VS = 2.7V 300 200 100 0 100 1k 10k Output Voltage Swing from Rail (mV) Frequency (Hz) OPA241 SERIES OFFSET VOLTAGE PRODUCTION DISTRIBUTION OPA241 SERIES OFFSET VOLTAGE DRIFT PRODUCTION DISTRIBUTION 100k 20 Typical production distribution of packaged units. Singles, duals, and quads included. VS = +5V VS = +5V 18 Percent of Amplifiers (%) Percent of Amplifiers (%) 20 15 10 30 25 20 0 500 Maximum output voltage without slew rate-induced distortion. VS = ±15V 25 15 10 5 Typical production distribution of packaged units. Singles, duals, and quads included. 16 14 12 10 8 6 4 2 0 –225 –200 –175 –150 –125 –100 –75 –50 –25 0 25 50 75 100 125 150 175 200 225 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 Offset Voltage (µV/°C) Offset Voltage (µV) OPA251 SERIES OFFSET VOLTAGE PRODUCTION DISTRIBUTION OPA251 SERIES OFFSET VOLTAGE DRIFT PRODUCTION DISTRIBUTION 30 18 20 16 15 10 5 14 VS = ±15V Typical production distribution of packaged units. Singles, duals, and quads included. 12 10 8 6 4 2 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 0 –225 –200 –175 –150 –125 –100 –75 –50 –25 0 25 50 75 100 125 150 175 200 225 Percent of Amplifiers (%) 25 Typical production distribution of packaged units. Singles, duals, and quads included. Percent of Amplifiers (%) VS = ±15V Offset Voltage (µV) Offset Voltage Drift (µV/°C) 7 OPA241, 2241, 4241 OPA251, 2251, 4251 ® TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, and RL = 100kΩ connected to VS/2 (ground for VS ±15V), unless otherwise noted. Curves apply to OPA241 and OPA251 unless specified. QUIESCENT CURRENT PRODUCT DISTRIBUTION QUIESCENT CURRENT PRODUCTION DISTRIBUTION 25 35 Typical production distribution of packaged units. Singles, duals, and quads included. Per Amplifier Percent of Amplifiers (%) 20 VS = ±15V Typical production distribution of packaged units. Singles, duals, and quads included. 30 15 10 5 25 20 15 10 Per Amplifier 5 0 Quiescent Current (µA) Quiescent Current (µA) OPA241 SMALL-SIGNAL STEP RESPONSE VS = +5V, G = +1, RL = 100kΩ, CL = 100pF 0.5V/div 50mV/div OPA241 LARGE-SIGNAL STEP RESPONSE VS = +5V, G + 1, RL = 100kΩ, CL = 100pF 200µs/div 200µs/div OPA251 SMALL-SIGNAL STEP RESPONSE VS = ±15V, G = +1, RL = 100kΩ, CL = 500pF OPA251 LARGE-SIGNAL STEP RESPONSE VS = ±15V, G = +1, RL = 100kΩ, CL = 500pF 2V/div 2ms/div 200µs/div ® OPA241, 2241, 4241 OPA251, 2251, 4251 8 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 21.5 22 22.5 23 23.5 24 24.5 25 25.5 26 26.5 27 27.5 28 28.5 29 29.5 30 0 50mV/div Percent of Amplifiers (%) VS = +5V APPLICATIONS INFORMATION Figures 2 and 3 show the regions where the OPA241 series and OPA251 series have the potential for instability. As shown, the unity gain configuration with low supplies is the most susceptible to the effects of capacitive load. With VS = +5V, G = +1, and IOUT = 0, operation remains stable with load capacitance up to approximately 200pF. Increasing supply voltage, output current, and/or gain significantly improves capacitive load drive. For example, increasing the supplies to ±15V and gain to 10 allows approximately 2700pF to be driven. One method of improving capacitive load drive in the unity gain configuration is to insert a resistor inside the feedback loop as shown in Figure 4. This reduces ringing with large capacitive loads while maintaining dc accuracy. For example, with VS = ±1.35V and RS = 5kΩ, the OPA241 series and OPA251 series perform well with capacitive loads in excess of 1000pF. Without the series resistor, capacitive load drive is typically 200pF for these conditions. However, this method will result in a slight reduction of output voltage swing. The OPA241 and OPA251 series are unity-gain stable and suitable for a wide range of general purpose applications. Power supply pins should be bypassed with 0.01µF ceramic capacitors. OPERATING VOLTAGE The OPA241 series is laser-trimmed for low offset voltage and drift at low supply voltage (VS = +5V). The OPA251 series is trimmed for ±15V operation. Both products operate over the full voltage range (+2.7V to +36V or ±1.35V to ±18V) with some compromises in offset voltage and drift performance. However, all other parameters have similar performance. Key parameters are guaranteed over the specified temperature range, –40°C to +85°C. Most behavior remains unchanged throughout the full operating voltage range. Parameters which vary significantly with operating voltage or temperature are shown in typical performance curves. OFFSET VOLTAGE TRIM As mentioned previously, offset voltage of the OPA241 series is laser-trimmed at +5V. The OPA251 series is trimmed at ±15V. Because the initial offset is so low, user adjustment is usually not required. However, the OPA241 and OPA251 (single op amp versions) provide offset voltage trim connections on pins 1 and 5. Offset voltage can be adjusted by connecting a potentiometer as shown in Figure 1. This adjustment should be used only to null the offset of the op amp, not to adjust system offset or offset produced by the signal source. Nulling offset could degrade the offset drift behavior of the op amp. While it is not possible to predict the exact change in drift, the effect is usually small. V+ 100k Capacitive Load (pF) VS = +2.7V VS = +5V Operation above selected gain curve not recommended 10k G = 10 1k G = –1 Sinking Sourcing G = +1 100 –1 –0.1 –0.01 0 0.01 0.1 1 Output Current (mA) FIGURE 2. Stability—Capacitive Load versus Output Current for Low Supply Voltage. OPA241 and OPA251 (single op amps) only. 0.01µF Use offset adjust pins only to null offset voltage of op amp—see text. 7 2 6 3 OPA241 100k 5 VS = ±15V 1 100kΩ Capacitive Load (pF) 0.01µF 4 Operation above selected gain curve not recommended Trim Range: ±2mV (V–) = 0V for single-supply operation. V– FIGURE 1. OPA241 and OPA251 Offset Voltage Trim Circuit. 10k G = 10 G = –1 1k G = +1 Sinking Sourcing 100 CAPACITIVE LOAD AND STABILITY The OPA241 series and OPA251 series can drive a wide range of capacitive loads. However, all op amps under certain conditions may be unstable. Op amp configuration, gain, and load value are just a few of the factors to consider when determining stability. –1 –0.1 –0.01 0 0.01 0.1 1 Output Current (mA) FIGURE 3. Stability—Capacitive Load versus Output Current for ±15V Supplies. 9 OPA241, 2241, 4241 OPA251, 2251, 4251 ® RS 5kΩ OPA241 VOUT VIN CL FIGURE 4. Series Resistor in Unity Gain Configuration Improves Capacitive Load Drive. RH 10Ω To Load R5 383kΩ IH High-Side Current Sense R3 38.3kΩ R1 38.3kΩ V+ –In A1 +In OPA241 V+ for A1, A2 R4 20kΩ R2 19.1kΩ Out VO = 10 • IH • RH V– + 2.7V to ±15V R2 and R4 divide down the common-mode input to A1. R8 100kΩ V– for A1, A2 V+ –In A2 +In OPA241 V– R7 9.09kΩ R6 10kΩ RL 10Ω Out VO = 10 • IL • RL Low-Side Current Sense Common-mode range of A2 extends to V– for low-side sensing. Optional for IB Cancellation (R7 = R6 II R8) To Load IL NOTE: Low and high-side sensing circuits can be used independently. FIGURE 5. Low and High-Side Battery Current Sensing. ® OPA241, 2241, 4241 OPA251, 2251, 4251 10