19-1380; Rev 2a; 12/99 Single/Dual/Quad, Low-Cost, SOT23, Low-Power, Rail-to-Rail I/O Op Amps ____________________________Features The MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 family of operational amplifiers combines wide bandwidth and excellent DC accuracy with Rail-to-Rail® operation at the inputs and outputs. These devices require only 650µA per amplifier and operate from either a single supply (+2.4V to +6.5V) or dual supplies (±1.2V to ±3.25V). These unity-gain-stable amplifiers are capable of driving 250Ω loads and have a 5MHz gain-bandwidth product. The MAX4323 and MAX4327 feature a low-power shutdown mode that reduces supply current to 25µA and places the outputs in a high-impedance state. ♦ SOT23 Packages (MAX4322/MAX4323) With their rail-to-rail input common-mode range and output swing, these amplifiers are ideal for low-voltage, single-supply operation. In addition, low offset voltage and high speed make them the ideal signal-conditioning stages for precision, low-voltage data-acquisition systems. The MAX4322/MAX4323 are available in space-saving SOT23 packages. ♦ Drive 250Ω Loads Selector Guide PART BW (MHz) NO. OF AMPS PINPACKAGE MAX4322 5 1 5 SOT23-5, 8 µMAX/SO — MAX4323 5 1 8 µMAX/SO/ 6 SOT23-6 Yes MAX4326 5 2 8 µMAX/SO MAX4327 5 2 10 µMAX, 14 SO MAX4329 5 4 14 SO SHUTDOWN — Yes — ♦ +2.4V to +6.5V Single-Supply Operation ♦ Rail-to-Rail Input Common-Mode Voltage Range ♦ Rail-to-Rail Output Voltage Swing ♦ 5MHz Gain-Bandwidth Product ♦ 650µA Quiescent Current per Amplifier ♦ 700µV Offset Voltage ♦ No Phase Reversal for Overdriven Inputs ♦ 25µA Shutdown Mode (MAX4323/MAX4327) ♦ Unity-Gain Stable for Capacitive Loads up to 500pF Ordering Information PART MAX4322EUK-T -40°C to +85°C MAX4322ESA -40°C to +85°C MAX4322EUA -40°C to +85°C MAX4323ESA -40°C to +85°C MAX4323EUA -40°C to +85°C MAX4323EUT -40°C to +85°C MAX4326EUA -40°C to +85°C MAX4326ESA -40°C to +85°C MAX4327EUB -40°C to +85°C MAX4327ESD -40°C to +85°C MAX4329ESD -40°C to +85°C ________________________Applications TOP MARK 5 SOT23-5 8 SO 8 µMAX 8 SO 8 µMAX 6 SOT23-6 8 µMAX 8 SO 10 µMAX 14 SO 14 SO ACGE — — — — AAEC — — — — — Typical Operating Circuit Battery-Powered Instruments Portable Equipment Data-Acquisition Systems Signal Conditioning +5V MAX187 3 Low-Power, Low-Voltage Applications 6 Pin Configurations appear at end of data sheet. PINPACKAGE TEMP. RANGE SERIAL INTERFACE 8 7 SHDN VDD DOUT AIN SCLK VREF CS GND 1 2 MAX4322 4 5 Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd. ________________________________________________________________ Maxim Integrated Products 1 For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 General Description MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 Single/Dual/Quad, Low-Cost, SOT23, Low-Power, Rail-to-Rail I/O Op Amps ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC-VEE) ..................................................+7.5V All Other Pins ...................................(VCC + 0.3V) to (VEE - 0.3V) Output Short-Circuit Duration.....................................Continuous (short to either supply) Continuous Power Dissipation (TA = +70°C) 5-pin SOT23-5 (derate 7.1mW/°C above +70°C) .........571mW 6-pin SOT23 (derate 7.1mW/°C Above + 70°C) ...........571mW 8-pin SO (derate 5.88mW/°C above +70°C).................471mW 8-pin µMAX (derate 4.10mW/°C above +70°C) ............330mW 10-pin µMAX (derate 5.6mW/°C above +70°C) ............444mW 14-pin SO (derate 8.00mW/°C above +70°C)...............640mW Operating Temperature Range MAX432_E__ ....................................................-40°C to +85°C Maximum Junction Temperature .....................................+150°C Storage Temperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10sec) .............................+300°C Stresses beyond 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 beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. DC ELECTRICAL CHARACTERISTICS—TA = +25°C (VCC = +5.0V, VEE = 0, VCM = 0, VOUT = VCC / 2, SHDN = VCC, RL tied to VCC / 2, unless otherwise noted.) PARAMETER TYP MAX MAX432_ESA/MAX4327ESD VCM = VEE, VCC All other packages ±0.7 ±2.0 ±1.2 ±2.50 Input Bias Current VCM = VEE, VCC ±50 ±150 Input Offset Current VCM = VEE, VCC ±1 ±12 Differential Input Resistance -1.5V < VDIFF < 1.5V 500 Common-Mode Input Voltage Range Inferred from CMRR test VEE VEE ≤ VCM ≤ VCC MAX432_ESA/MAX4327ESD 62 94 Common-Mode Rejection Ratio All other packages 60 91 66 Input Offset Voltage CONDITIONS MIN UNITS mV nA nA kΩ VCC V dB Power-Supply Rejection Ratio VCC = 2.4V to 6.5V 100 dB Output Resistance AV = +1V/V 0.1 Ω VOUT = 0.25V to 4.75V, RL = 100kΩ 106 Large-Signal Voltage Gain 2 VOUT = 0.4V to 4.6V, RL = 250Ω 70 86 _______________________________________________________________________________________ dB Single/Dual/Quad, Low-Cost, SOT23, Low-Power, Rail-to-Rail I/O Op Amps MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 DC ELECTRICAL CHARACTERISTICS—TA = +25°C (continued) (VCC = +5V, VEE = 0, VCM = 0, VOUT = VCC / 2, SHDN = VCC, RL tied to VCC / 2, unless otherwise noted.) PARAMETER CONDITIONS MAX4322/ MAX4323 RL = 100kΩ RL = 250Ω Output Voltage Swing MAX4326/ MAX4327/ MAX4329 RL = 100kΩ RL = 250Ω MIN TYP MAX VCC - VOH 12 VOL - VEE 20 VCC - VOH 200 300 VOL - VEE 100 200 VCC - VOH 15 VOL - VEE 25 VCC - VOH 220 350 VOL - VEE 120 250 Output Short-Circuit Current 50 Low SHDN Logic Threshold MAX4323/MAX4327 SHDN Input Current MAX4323/MAX4327 Operating Supply-Voltage Range Inferred from PSRR test High 0.8 Supply Current per Amplifier VCM = VOUT = VCC / 2 Shutdown Supply Current per Amplifier SHDN > 0.8V, MAX4323/MAX4327 2.4 VCC = 2.4V 650 VCC = 5V 725 VCC = 2.4V 25 VCC = 5V 40 mV mA 2.0 ±1 UNITS V ±4 µA 6.5 V 1100 60 µA µA DC ELECTRICAL CHARACTERISTICS—TA = -40°C to +85°C (VCC = +5V, VEE = 0, VCM = 0, VOUT = VCC / 2, SHDN = VCC, RL tied to VCC / 2, unless otherwise noted.) (Note 1) PARAMETER Input Offset Voltage CONDITIONS MIN TYP MAX432_ESA/MAX4327ESD VCM = VEE, VCC All other packages MAX ±3.0 ±6.0 Input Offset Voltage Tempco ±2 UNITS mV µV/°C Input Bias Current VCM = VEE, VCC ±180 nA Input Offset Current VCM = VEE, VCC ±20 nA Common-Mode Input Voltage Range Inferred from CMRR test VEE VCC V VEE ≤ VCM ≤ VCC MAX432_ESA/MAX4327ESD 59 Common-Mode Rejection Ratio All other packages 54 dB _______________________________________________________________________________________ 3 MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 Single/Dual/Quad, Low-Cost, SOT23, Low-Power, Rail-to-Rail I/O Op Amps DC ELECTRICAL CHARACTERISTICS —TA = -40°C to +85°C (continued) (VCC = +5V, VEE = 0, VCM = 0, VOUT = VCC / 2, SHDN = VCC, RL tied to VCC / 2, unless otherwise noted.) (Note 1) PARAMETER CONDITIONS Power-Supply Rejection Ratio VCC = 2.4V to 6.5V Large-Signal Voltage Gain VOUT = 0.4V to 4.6V, RL = 250Ω MAX4322/ MAX4323 Output Voltage Swing MAX4326/ MAX4327/ MAX4329 MIN TYP MAX 62 RL = 250Ω UNITS dB 66 dB VCC - VOH 350 VOL - VEE 250 VCC - VOH 400 VOL - VEE 300 Low 0.8 mV RL = 250Ω SHDN Logic Threshold MAX4323/MAX4327 SHDN Input Current MAX4323/MAX4327 High Operating Supply-Voltage Range 2.0 2.4 V ±5 µA 6.5 V Supply Current per Amplifier VCM = VCC / 2 1.2 mA Shutdown Supply Current per Amplifier SHDN ≤ 0.8V, MAX4323/MAX4327 70 µA MAX UNITS AC ELECTRICAL CHARACTERISTICS (VCC = +5V, VEE = 0, VCM = VOUT = VCC / 2, SHDN = VCC, TA = +25°C unless otherwise noted.) PARAMETER CONDITIONS MIN TYP Gain-Bandwidth Product 5 MHz Phase Margin 64 degrees Gain Margin 12 dB Total Harmonic Distortion f = 10kHz, VOUT = 2Vp-p, AV = +1V/V Slew Rate Settling Time to 0.01% AV = +1V/V, VOUT = 2V step Turn-On Time VCC = 0 to 3V step SHDN Delay MAX4323/MAX4327 0.003 % 2 V/µs 2.0 µs 1 µs Enable 1 Disable 0.2 Input Capacitance µs 3 pF Input Noise Voltage Density f = 1kHz 22 nV/√Hz Input Noise Current Density f = 1kHz 0.4 pA 135 dB 250 pF Amp-Amp Isolation Capacitive Load Stability AV = +1V/V Note 1: All devices are 100% tested at TA = +25°C. All temperature limits are guaranteed by design. 4 _______________________________________________________________________________________ Single/Dual/Quad, Low-Cost, SOT23, Low-Power, Rail-to-Rail I/O Op Amps GAIN AND PHASE vs. FREQUENCY (WITH CLOAD) 60 180 144 144 72 20 36 0 -36 PHASE 72 36 0 0 -36 PHASE -108 AV = +1000 NO LOAD -40 100 1k AV = +1000 RL = ∞ CL = 500pF -20 -144 10k 100k 1M 10M -40 100 -180 100M 1k -144 1M 10M 10 100 1k 10k 110 100 90 80 70 MAX4322/26/29-05 AV = +1 OUTPUT IMPEDANCE (Ω) 120 1M 10M 100M MAX4323/MAX4327 SHUTDOWN SUPPLY CURRENT vs. TEMPERATURE 100 MAX4322/26/29-04 130 100k FREQUENCY (Hz) OUTPUT IMPEDANCE vs. FREQUENCY MAX4326/MAX4327/MAX4329 CHANNEL SEPARATION vs. FREQUENCY 10 1 0.1 60 60 50 VCC = 6.5V 40 30 VCC = 2.7V 20 10 SHDN = 0V 0 0.01 10k 100k FREQUENCY (Hz) 1M 100 10M SUPPLY CURRENT PER AMPLIFIER vs. TEMPERATURE 850 800 VCC = 2.7V 650 -2.25 500 -3.00 35 50 TEMPERATURE (°C) 65 80 95 5 20 35 50 65 80 TEMPERATURE (°C) INPUT OFFSET VOLTAGE vs. TEMPERATURE INPUT BIAS CURRENT vs. COMMON-MODE VOLTAGE SOT23-5/6 PACKAGE -0.75 550 -40 -25 -10 100M 0 -1.50 20 10M 0.75 600 5 1M 2.25 VOLTAGE (mV) 750 -40 -25 -10 100k FREQUENCY (Hz) 1.50 VCC = 6.5V 700 10k 3.00 MAX4322/26/29-6 900 1k 95 50 40 INPUT BIAS CURRENT (nA) 1k MAX4322/26/29-7 100 MAX4322/26/29-8 50 SUPPLY CURRENT (µA) -100 -180 100M FREQUENCY (Hz) FREQUENCY (Hz) CHANNEL SEPARATION (dB) 100k -60 -80 -108 10k -40 -72 -72 -20 -20 SHUTDOWN SUPPLY CURRENT (mA) 0 GAIN 20 GAIN (dB) GAIN (dB) GAIN PHASE (DEGREES) 108 40 AV = +1 0 108 40 MAX4323-11 180 PSR (dB) 60 POWER-SUPPLY REJECTION vs. FREQUENCY MAX4322/26/29-02 PHASE (DEGREES) MAX4322/26/29-01 MAX4322/26/29-03 GAIN AND PHASE vs. FREQUENCY VCC = 2.7V 30 VCC = 6.5V 20 10 0 -10 -20 -30 SO PACKAGE -40 -50 -40 -25 -10 5 20 35 50 TEMPERATURE (°C) 65 80 95 0 1 2 3 4 5 6 COMMON-MODE VOLTAGE (V) _______________________________________________________________________________________ 5 MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 __________________________________________Typical Operating Characteristics (VCC = +5V, VEE = 0, VCM = VCC / 2, SHDN = VCC, TA = +25°C, unless otherwise noted.) _____________________________Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0, VCM = VCC / 2, SHDN = VCC, TA = +25°C, unless otherwise noted.) 10 0 -10 -20 VCC = 2.7V, VCM = VEE -30 -40 100 5 20 MAX4322/26/29-11 MAX4322/26/29-10 105 95 200 VCC = 6.5V, RL = 500Ω 150 VCC = 2.7V, RL = 500Ω 100 VCM = -0.2V TO 5.2V 90 VCC = 6.5V, RL = 100kΩ 50 35 50 65 80 95 VCC = 2.7V, RL = 100kΩ 0 -40 -25 -10 5 20 35 50 65 80 -40 -25 -10 95 5 20 35 50 65 TEMPERATURE (°C) TEMPERATURE (°C) MAXIMUM OUTPUT VOLTAGE vs. TEMPERATURE LARGE-SIGNAL GAIN vs. OUTPUT VOLTAGE LARGE-SIGNAL GAIN vs. OUTPUT VOLTAGE VCC = 6.5V, RL = 500Ω VCC = 2.7V RL TO VEE 110 RL = 100kΩ 120 95 VCC = 6.5V RL TO VEE 110 RL = 100kΩ 100 GAIN (dB) 200 VCC = 2.7V, RL = 500Ω 100 100 RL = 10kΩ GAIN (dB) 250 120 MAX4322/26/29-12 RL TO VEE 80 MAX4322/26/29-14 TEMPERATURE (°C) 300 VCC - VOUT (mV) VCM = 0 TO 5.0V 80 -40 -25 -10 50 110 RL TO VCC 85 VCC = 6.5V, VCM = VEE -60 150 115 MAX4322/26/29-13 -50 250 VOUT - VEE (mV) VCC = 2.7V, VCM = VCC 120 COMMON-MODE REJECTION (dB) INPUT BIAS CURRENT (nA) VCC = 6.5V, VCM = VCC 30 20 MAX4322/26/29-9 50 40 MINIMUM OUTPUT VOLTAGE vs. TEMPERATURE COMMON-MODE REJECTION vs. TEMPERATURE INPUT BIAS CURRENT vs. TEMPERATURE RL = 2kΩ 90 RL = 500Ω RL = 10kΩ RL = 2kΩ 90 80 80 70 70 RL = 500Ω VCC = 6.5V, RL = 100kΩ (TOP) VCC = 2.7V, RL = 100kΩ (BOTTOM) -40 -25 -10 35 50 65 80 100 200 300 400 500 600 0 100 200 300 400 500 TEMPERATURE (°C) OUTPUT VOLTAGE: FROM VCC (mV) OUTPUT VOLTAGE: FROM VCC (mV) LARGE-SIGNAL GAIN vs. TEMPERATURE LARGE-SIGNAL GAIN vs. OUTPUT VOLTAGE LARGE-SIGNAL GAIN vs. OUTPUT VOLTAGE VCC = 6.5V, RL TO VEE 120 110 100 95 VCC = 6.5V, RL TO VCC 90 RL = 100kΩ RL = 10kΩ 100 RL = 2kΩ 90 RL = 500Ω 80 85 600 RL = 2kΩ 90 RL = 500Ω 80 70 70 80 VCC = 6.5V RL TO VCC 110 100 GAIN (dB) 105 120 RL = 10kΩ VCC = 2.7V, RL TO VEE 110 RL = 100kΩ VCC = 2.7V RL TO VCC GAIN (dB) RL = 500Ω VOUT(p-p) = VCC - 1V 115 VCC = 2.7V, RL TO VCC 75 60 60 -40 -25 -10 5 20 35 50 TEMPERATURE (°C) 6 60 0 95 MAX4322/26/29-16 120 20 MAX4322/26/29-15 125 5 MAX4322/26/29-17 60 0 GAIN (dB) MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 Single/Dual/Quad, Low-Cost, SOT23, Low-Power, Rail-to-Rail I/O Op Amps 65 80 95 0 100 200 300 400 500 OUTPUT VOLTAGE: FROM VEE (mV) 600 0 100 200 300 400 500 OUTPUT VOLTAGE: FROM VEE (mV) _______________________________________________________________________________________ 600 Single/Dual/Quad, Low-Cost, SOT23, Low-Power, Rail-to-Rail I/O Op Amps (VCC = +5V, VEE = 0, VCM = VCC / 2, SHDN = VCC, TA = +25°C, unless otherwise noted.) VCC = 2.7V, RL TO VCC 90 85 VOUT(p-p) = VCC - 600mV RL = 100kΩ 80 75 5 20 35 50 65 80 1.5 0.025 0.020 0.015 1.4 0.010 1.3 95 0.005 0 -40 -25 -10 5 20 35 50 65 80 TEMPERATURE (°C) TOTAL HARMONIC DISTORTION AND NOISE vs. PEAK-TO-PEAK SIGNAL AMPLITUDE SMALL-SIGNAL TRANSIENT RESPONSE (NONINVERTING) MAX4322/26/29-21 TEMPERATURE (°C) RL = 2kΩ RL = 250Ω RL = 10kΩ 1k 10k FREQUENCY (Hz) IN AV = -1 OUT RL = 100kΩ 100 100k SMALL-SIGNAL TRANSIENT RESPONSE (INVERTING) VOLTAGE (50mV/div) 0.01 10 95 AV = +1 VOLTAGE (50mV/div) AV = +1 10kHz SINE WAVE RL TO VCC / 2 500kHz LOWPASS FILTER IN OUT 0.001 4.2 4.4 4.6 4.8 5.0 TIME (200ns/div) TIME (200ns/div) PEAK-TO-PEAK SIGNAL AMPLITUDE (V) AV = +1 MAX4322/26/29-26 LARGE-SIGNAL TRANSIENT RESPONSE (INVERTING) LARGE-SIGNAL TRANSIENT RESPONSE (NONINVERTING) MAX4322/26/29-24 AV = -1 IN IN VOLTAGE (2V/div) 4.0 VOLTAGE (2V/div) THD + NOISE (%) 1.6 1.2 -40 -25 -10 0.1 0.030 1.7 MAX4322/26/29-23 VCC = 2.7V, RL TO VEE 95 AV = +1 2Vp-p SIGNAL 500kHz LOWPASS FILTER RL = 10kΩ TO VCC / 2 0.035 THD + NOISE (%) 100 1.8 MAX4322/26/29-22 GAIN (dB) 105 0.040 MAX4322/26/29-19 VCC = 6.5V, RL TO VCC 115 110 1.9 MINIMUM OPERATING VOLTAGE (V) VCC = 6.5V, RL TO VEE 120 MAX4322/26/29-18 125 TOTAL HARMONIC DISTORTION AND NOISE vs. FREQUENCY MINIMUM OPERATING VOLTAGE vs. TEMPERATURE MAX4322/26/29-20 LARGE-SIGNAL GAIN vs. TEMPERATURE OUT OUT TIME (2µs/div) TIME (2µs/div) _______________________________________________________________________________________ 7 MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 _____________________________Typical Operating Characteristics (continued) MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 Single/Dual/Quad, Low-Cost, SOT23, Low-Power, Rail-to-Rail I/O Op Amps Pin Description PIN MAX4322 MAX4323 SOT23-5 SO/µMAX SOT23-6 SO/µMAX MAX4326 MAX4327 µMAX SO FUNCTION 1 6 1 6 — — — — OUT Output 2 4 2 4 4 4 4 11 VEE Negative Supply. Ground for single-supply operation. 3 — 3 — — — — — IN+ Noninverting Input 4 — 4 — — — — — IN- Inverting Input 5 7 6 7 8 10 14 4 VCC Positive Supply — 1, 5, 8 — 1, 5 — — 5, 7, 8, 10 — N.C. No Connection — — 5 8 — — — SHDN Shutdown Control. Tie high or leave floating to enable amplifier. — — — — 1, 7 1, 9 1, 13 1, 7 OUT1, OUT2 Outputs for amps 1 and 2 — 2 — 2 2, 6 2, 8 2, 12 2, 6 IN1-, IN2- Inverting Inputs for amps 1 and 2 — 3 — 3 3, 5 3, 7 3, 11 3, 5 IN1+, IN2+ Noninverting Inputs for amps 1 and 2 — — — — — 5, 6 5, 9 — SHDN1, SHDN2 Shutdown Control for amps 1 and 2. Tie high or leave floating to enable amplifier. — — — — — — — 8, 14 OUT3, OUT4 Outputs for amps 3 and 4 — — — — — — — 9, 13 IN3-, IN4- Inverting Inputs for amps 3 and 4 — — — — — — — 10, 12 IN3+, IN4+ __________ Applications Information Rail-to-Rail Input Stage Devices in the MAX4322/MAX4323/MAX4326/MAX4327/ MAX4329 family of high-speed amplifiers have rail-torail input and output stages designed for low-voltage, single-supply operation. The input stage consists of separate NPN and PNP differential stages, which combine to provide an input common-mode range extending to the supply rails. The PNP stage is active for input voltages close to the negative rail, and the NPN stage is active for input voltages near the positive rail. The input offset voltage is typically below 250µV. The 8 NAME MAX4329 Noninverting Inputs for amps 3 and 4 switchover transition region, which occurs near VCC / 2, has been extended to minimize the slight degradation in CMRR caused by the mismatch of the input pairs. Their low offset voltage, high bandwidth, and rail-to-rail common-mode range make these op amps excellent choices for precision, low-voltage, data-acquisition systems. Since the input stage switches between the NPN and PNP pairs, the input bias current changes polarity as the input voltage passes through the transition region. To reduce the offset error caused by input bias currents flowing through external source impedances, match the effective impedance seen by each input (Figures 1a, 1b). High source impedances, together _______________________________________________________________________________________ Single/Dual/Quad, Low-Cost, SOT23, Low-Power, Rail-to-Rail I/O Op Amps IBIAS = VDIFF - 1.8V 2kΩ Rail-to-Rail Output Stage The minimum output voltage will be within millivolts of ground for single-supply operation where the load is referenced to ground (VEE). Figure 3 shows the input voltage range and output voltage swing of a MAX4322 connected as a voltage follower. With a +3V supply and the load tied to ground, the output swings from 0.00V to 2.90V. The maximum output voltage swing depends on the load, but will be within 350mV of a +5V supply, even with the maximum load (500Ω to ground). Driving a capacitive load can cause instability in most high-speed op amps, especially those with low quiescent current. The MAX4322/MAX4323/MAX4326/ MAX4327/MAX4329 have a high tolerance for capacitive loads. They are stable with capacitive loads up to 500pF. Figure 4 gives the stable operating region for capacitive loads. Figures 5 and 6 show the response with capacitive loads and the results of adding an isolation resistor in series with the output (Figure 7). The resistor improves the circuit’s phase margin by isolating the load capacitor from the op amp’s output. R3 R3 MAX4322/MAX4323 MAX4326/MAX4327 MAX4329 MAX4322/MAX4323 MAX4326/MAX4327 MAX4329 R1 R3 = R1 R2 R2 R1 R3 = R1 Figure 1a. Reducing Offset Error Due to Bias Current (Noninverting) R2 R2 Figure 1b. Reducing Offset Error Due to Bias Current (Inverting) 1k 1k Figure 2. Input Protection Circuit _______________________________________________________________________________________ 9 MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 with the input capacitance, can create a parasitic pole that produces an underdamped signal response. Reducing the input impedance or placing a small (2pF to 10pF) capacitor across the feedback resistor improves the response. The MAX4322/MAX4323/MAX4326/MAX4327/MAX4329’s inputs are protected from large differential input voltages by 1kΩ series resistors and back-to-back triple diodes across the inputs (Figure 2). For differential input voltages less than 1.8V the input resistance is typically 500kΩ. For differential input voltages greater than 1.8V the input resistance is approximately 2kΩ, and the input bias current is determined by the following equation: Power-Up and Shutdown Mode Power Supplies and Layout The MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 amplifiers typically settle within 1µs after power-up. Using the test circuit of Figure 8, Figures 9 and 10 show the output voltage and supply current on power-up. The MAX4323 and MAX4327 have a shutdown option. When the shutdown pin (SHDN) is pulled low, the supply current drops below 25µA per amplifier and the amplifiers are disabled with the outputs in a highimpedance state. Pulling SHDN high or leaving it floating enables the amplifier. In the dual-amplifier MAX4327, the shutdown functions operate independently. Figures 11 and 12 show the output voltage and supply current responses of the MAX4323 to a shutdown pulse. The MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 operate from a single +2.4V to +6.5V power supply, or from dual supplies of ±1.2V to ±3.25V. For single-supply operation, bypass the power supply with a 0.1µF ceramic capacitor in parallel with at least 1µF. For dual supplies, bypass each supply to ground. Good layout improves performance by decreasing the amount of stray capacitance at the op amp’s inputs and outputs. To decrease stray capacitance, minimize trace lengths and resistor leads by placing external components close to the op amp’s pins. 10,000 VCC = 3V AV = +1 CAPACITIVE LOAD (pF) VOLTAGE (1V/div) IN OUT UNSTABLE REGION 1000 RL TO VEE VOUT = VCC/2 100 TIME (2µs/div) 100 1k 10k 100k RESISTIVE LOAD (Ω) Figure 3. Rail-to-Rail Input /Output Voltage Range Figure 4. Capacitive-Load Stability AV = +1 CL = 500pF IN IN OUT OUT TIME (400ns/div) Figure 5. Small-Signal Transient Response with Capacitive Load 10 AV = +1 CL = 1000pF RS = 39Ω VOLTAGE (50mV/div) VOLTAGE (50mV/div) MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 Single/Dual/Quad, Low-Cost, SOT23, Low-Power, Rail-to-Rail I/O Op Amps TIME (400ns/div) Figure 6. Transient Response to Capacitive Load with Isolation Resistor ______________________________________________________________________________________ Single/Dual/Quad, Low-Cost, SOT23, Low-Power, Rail-to-Rail I/O Op Amps MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 VCC MAX4322/MAX4323 MAX4326/MAX4327 MAX4329 0V TO 2.7V STEP FOR POWER-UP TEST 2k RS VOUT CL MAX4322/MAX4323 MAX4326/MAX4327 MAX4329 Figure 7. Capacitive-Load-Driving Circuit VCC SUPPLY-CURRENT 10Ω MONITORING POINT 2k 10k Figure 8. Power-Up Test Circuit VOLTAGE (1V/div) VCC (1V/div) OUT ICC (500µA/div) TIME (5µs/div) TIME (5µs/div) Figure 9. Power-Up Output Voltage Figure 10. Power-Up Supply Current VCC = 2.7V VCC = 2.7V RL = 10kΩ SHDN (1V/div) SHDN (1V/div) OUT (0.5V/div) ICC (500µA/div) TIME (2µs/div) Figure 11. Shutdown Output Voltage TIME (2µs/div) Figure 12. Shutdown Enable/Disable Supply Current ______________________________________________________________________________________ 11 MAX4322/MAX4323/MAX4326/MAX4327/MAX4329 Single/Dual/Quad, Low-Cost, SOT23, Low-Power, Rail-to-Rail I/O Op Amps ___________________________________________________________Pin Configurations TOP VIEW OUT 1 VEE 2 5 OUT 1 VCC MAX4322 IN+ 3 VEE 2 IN+ 3 IN- 4 IN1- 2 MAX4326 8 VCC 7 OUT2 IN1+ 3 6 IN2- VEE 4 5 IN2+ SO/µMAX VCC 5 SHDN 8 N.C. N.C. 1 7 VCC IN1- 2 IN1+ 3 6 OUT VEE 4 5 N.C. N.C. 1 IN1- 2 IN- 4 OUT1 1 14 VCC IN1- 2 13 OUT2 IN1+ 3 12 IN2- VEE 4 MAX4327 N.C. 5 MAX4322 8 SHDN 7 VCC IN1+ 3 6 OUT VEE 4 5 N.C. OUT1 1 IN1IN1+ 3 OUT1 1 14 OUT4 OUT2 IN1- 2 13 IN4- IN2- IN1+ 3 12 IN4+ 10 VCC 2 9 MAX4327 8 11 IN2+ VEE 4 7 IN2+ VCC 4 10 N.C. SHDN1 5 6 SHDN2 IN2+ 5 SHDN1 6 9 SHDN2 N.C. 7 8 N.C. SO µMAX MAX4323 SO SO/µMAX SOT23-6 SOT23-5 OUT1 1 MAX4323 6 MAX4329 11 VEE 10 IN3+ IN2- 6 9 IN3- OUT2 7 8 OUT3 SO Chip Information MAX4322 TRANSISTOR COUNT: 170 MAX4323 TRANSISTOR COUNT: 170 MAX4326 TRANSISTOR COUNT: 340 MAX4327 TRANSISTOR COUNT: 340 MAX4329 TRANSISTOR COUNT: 680 SUBSTRATE CONNECTED TO VEE 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. 12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.