19-2424; Rev 1; 12/02 Ultra-Low Offset/Drift, Low-Noise, Precision SOT23 Amplifiers Applications Features ♦ Ultra-Low, 0.1µV Offset Voltage 2.0µV (max) at +25°C 2.5µV (max) at -40°C to +85°C 3.5µV (max) at -40°C to +125°C ♦ Low 10nV/oC Drift ♦ Specified over the -40oC to +125oC Automotive Temperature Range ♦ Low Noise: 1.5µVP-P from DC to 10Hz ♦ 150dB AVOL, 140dB PSRR, 140dB CMRR ♦ High Gain-Bandwidth Product 1MHz (MAX4238) 6.5MHz (MAX4239) ♦ 0.1µA Shutdown Mode Thermocouples ♦ Rail-to-Rail Output (RL = 1kΩ) Strain Gauges ♦ Low 600µA Supply Current Electronic Scales ♦ Ground-Sensing Input Medical Instrumentation ♦ Single 2.7V to 5.5V Supply Voltage Range Instrumentation Amplifiers ♦ Available in a Space-Saving 6-Pin SOT23 Package Ordering Information Typical Application Circuit PART TEMP RANGE PINPACKAGE TOP MARK MAX4238AUT-T -40oC to +125oC 6 SOT23-6 AAZZ MAX4238ASA -40oC to +125oC 8 SO MAX4239AUT-T -40oC to +125oC 6 SOT23-6 MAX4239ASA -40oC to +125oC 8 SO 5V 18kΩ 360Ω STRAIN GUAGE ADC AV = 100 18kΩ — ABAA — AIN MAX4238/ MAX4239 Selector Guide PART MAX4238 MAX4239 Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd. MINIMUM STABLE GAIN 1V/V 10V/V GAIN BANDWIDTH (MHz) 1 6.5 Pin Configurations appear at end of data sheet. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX4238/MAX4239 General Description The MAX4238/MAX4239 are low-noise, low-drift, ultrahigh precision amplifiers that offer near-zero DC offset and drift through the use of patented autocorrelating zeroing techniques. This method constantly measures and compensates the input offset, eliminating drift over time and temperature and the effect of 1/f noise. Both devices feature Rail-to-Rail® outputs, operate from a single 2.7V to 5.5V supply, and consume only 600µA. An active-low shutdown mode decreases supply current to 0.1µA. The MAX4238 is unity-gain stable with a gain-bandwidth product of 1MHz, while the decompensated MAX4239 is stable with AV ≥ 10V/V and a GBWP of 6.5MHz. The MAX4238/MAX4239 are available in 8-pin narrow SO and 6-pin SOT23 packages. MAX4238/MAX4239 Ultra-Low Offset/Drift, Low-Noise, Precision SOT23 Amplifiers ABSOLUTE MAXIMUM RATINGS Power-Supply Voltage (VCC to GND).......................................6V All Other Pins .................................(GND - 0.3V) to (VCC + 0.3V) Output Short-Circuit Duration (OUT shorted to VCC or GND) ...............................Continuous Continuous Power Dissipation (TA = +70°C) 6-Pin Plastic SOT23 (derate 9.1mW/°C above +70°C).727mW 8-Pin Plastic SO (derate 5.88mW/°C above +70°C).....471mW Operating Temperature Range ..........................-40°C to +125°C Junction Temperature ......................................................+150°C Storage Temperature Range..............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+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. ELECTRICAL CHARACTERISTICS (2.7V ≤ V CC ≤ 5.5V, V CM = GND = 0V, V OUT = V CC /2, R L = 10kΩ connected to V CC /2, SHDN = V CC , T A = +25 ° C, unless otherwise noted.) PARAMETER Input Offset Voltage SYMBOL CONDITIONS MIN TYP MAX UNITS 0.1 2 µV VOS (Note 1) 50 nV/1000hr IB (Note 2) 1 pA Input Offset Current IOS (Note 2) 2 pA Input Noise Voltage enP-P Long-Term Offset Drift Input Bias Current Common-Mode Input Voltage Range VCM RS = 100Ω, 0.01Hz to 10Hz 1.5 Inferred from CMRR test GND - 0.1 µVP-P VCC 1.3 V Common-Mode Rejection Ratio CMRR -0.1V ≤ VCM ≤ VCC - 1.3V (Note 1) 120 140 dB Power-Supply Rejection Ratio PSRR 2.7V ≤ VCC ≤ 5.5V (Note 1) 120 140 dB Large-Signal Voltage Gain AVOL 0.05V ≤ VOUT ≤ VCC - 0.05V (Note 1) RL = 10kΩ 125 150 0.1V ≤ VOUT ≤ VCC - 0.1V (Note 1) RL = 1kΩ 125 145 RL = 10kΩ Output Voltage Swing VOH/VOL RL = 1kΩ dB VCC - VOH VOL 4 10 35 50 VOL 35 50 To either supply Output Leakage Current 0 ≤ VOUT ≤ VCC, SHDN = GND (Note 2) Gain-Bandwidth Product Minimum Stable Closed-Loop Gain 2 GBWP 40 0.01 VCC = 5V, CL = 100pF, VOUT = 2V step MAX4238 0.35 MAX4239 1.6 RL = 10kΩ, CL = 100pF, measured at f = 100kHz MAX4238 1 MAX4239 6.5 RL = 10kΩ, CL = 100pF, phase margin = 60o 10 VCC - VOH Output Short-Circuit Current Slew Rate 4 MAX4238 1 MAX4239 10 _______________________________________________________________________________________ mV mA 1 µA V/µs MHz V/V Ultra-Low Offset/Drift, Low-Noise, Precision SOT23 Amplifiers (2.7V ≤ V CC ≤ 5.5V, V CM = GND = 0V, V OUT = V CC /2, R L = 10kΩ connected to V CC /2, SHDN = V CC , T A = +25 ° C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS RL = 10kΩ, CL = 100pF, phase margin = 60o Maximum Closed-Loop Gain Settling Time -1V step AV = 10 (Note 4) Overload Recovery Time Startup Time AV = 10 MIN MAX4238 1000 MAX4239 6700 0.1% (10 bit) 0.5 0.025% (12 bit) 1.0 0.006% (14 bit) 0.0015% (16 1.7 2.3 0.1% (10 bit) 3.3 0.025% (12 bit) 4.1 0.006% (14 bit) 0.0015% (16 4.9 5.7 0.1% (10 bit) 1.8 0.025% (12 bit) 2.6 0.006% (14 bit) 3.4 0.0015% (16 Supply Voltage Range VCC Supply Current ICC Shutdown Logic High VIH Shutdown Logic Low VIL Shutdown Input Current TYP Inferred by PSRR test MAX V/V ms ms ms 4.3 2.7 5.5 SHDN = VCC, no load, VCC = 5.5V 600 850 SHDN = GND, VCC = 5.5V 0.1 1 2.2 0V ≤ V SHDN ≤ VCC UNITS V µA V 0.1 0.8 V 1 µA _______________________________________________________________________________________ 3 MAX4238/MAX4239 ELECTRICAL CHARACTERISTICS (continued) MAX4238/MAX4239 Ultra-Low Offset/Drift, Low-Noise, Precision SOT23 Amplifiers ELECTRICAL CHARACTERISTICS (2.7V ≤ VCC ≤ 5.5V, VCM = GND = 0V, VOUT = VCC/2, RL = 10kΩ connected to VCC/2, SHDN = VCC, TA = -40°C to +125°C, unless otherwise noted.) (Note 5) PARAMETER Input Offset Voltage Input Offset Drift Common-Mode Input Voltage Range Common-Mode Rejection Ratio Power-Supply Rejection Ratio Large-Signal Voltage Gain SYMBOL CONDITIONS VOS (Note 1) TCVOS (Note 1) VCM CMRR PSRR 10 GND 0.05 2.7V ≤ VCC ≤ 5.5V (Note 1) 120 RL = 10kΩ, TA = -40°C to +85°C 0.1V ≤ VOUT ≤ VCC - 0.1V TA = -40°C to +125°C (Note 1) 125 VOH/VOL RL = 1kΩ Supply Voltage Range VCC Supply Current ICC Shutdown Logic High VIH Shutdown Logic Low VIL µV nV/°C VCC 1.4 V dB dB dB 95 0.1V ≤ VOUT ≤ VCC - 0.1V, TA = -40°C to +85°C 120 0.2V ≤ VOUT ≤ VCC - 0.2V, TA = -40°C to +125°C 80 dB VCC - VOH 20 VOL 20 VCC - VOH 100 Inferred by PSRR test UNITS 90 mV 100 VOL 0V ≤ VOUT ≤ VCC, SHDN = GND (Note Output Leakage Current Shutdown Input Current 3.5 115 RL = 10kΩ MAX TA = -40°C to +125°C GND - 0.05V ≤ TA = -40°C to +85°C VCM ≤ VCC 1.4V (Note 1) TA = -40°C to +125°C AVOL TYP 2.5 Inferred from CMRR test RL = 1kΩ (Note 1) Output Voltage Swing MIN TA = -40°C to +85°C 2.7 SHDN = VCC, no load, VCC = 5.5V 2 µA 5.5 V 900 SHDN = GND, VCC = 5.5V 2 2.2 0V ≤ V SHDN ≤ VCC µA V 0.7 V 2 µA Note 1: Guaranteed by design. Thermocouple and leakage effects preclude measurement of this parameter during production testing. Devices are screened during production testing to eliminate defective units. Note 2: IN+ and IN- are gates to CMOS transistors with typical input bias current of 1pA. CMOS leakage is so small that it is impractical to test and guarantee in production. Devices are screened during production testing to eliminate defective units. Note 3: Leakage does not include leakage through feedback resistors. Note 4: Overload recovery time is the time required for the device to recover from saturation when the output has been driven to either rail. Note 5: Specifications are 100% tested at TA = +25°C, unless otherwise noted. Limits over temperature are guaranteed by design. 4 _______________________________________________________________________________________ Ultra-Low Offset/Drift, Low-Noise, Precision SOT23 Amplifiers 30 20 TA = +25°C 0 -1.5 -1.2 -0.9 -0.6 -0.3 0 TA = +25°C TA = -40°C 0 -0.4 0.3 0.6 0.9 1.2 1.5 2.7 3.4 4.1 4.8 5.5 0.9 0 1.8 2.7 3.6 COMMON-MODE VOLTAGE (V) OUTPUT HIGH VOLTAGE vs. OUTPUT SOURCE CURRENT OUTPUT LOW VOLTAGE vs. OUTPUT SINK CURRENT MAX4238 GAIN AND PHASE vs. FREQUENCY (TA = +25°C) 0.20 VCC = 2.7V 0.15 VCC = 5V 0.10 MAX4238/39 toc05 0.25 0.35 0.30 OUTPUT LOW VOLTAGE (V) MAX4238/39 toc04 VOH = VCC - VOUT 0.05 0.25 VCC = 2.7V 0.20 VCC = 5V 0.15 0.10 0.05 0 0 15 0 20 5 VCC = 5V AV = 1000V/V CL = 100pF RL = 10kΩ 10k 100k 0.1k 20 1k 1M 10M MAX4238/39 toc08 80 60 40 20 0 -20 -40 -60 -80 -100 -120 -140 -160 -180 VCC = 5V AV = 1000V/V CL = 100pF RL = 10kΩ 0.1k 1k 10k 100k FREQUENCY (Hz) 10k 100k 1M 10M FREQUENCY (Hz) MAX4238 GAIN AND PHASE vs. FREQUENCY (TA = +125°C) GAIN AND PHASE (dB/DEGREES) MAX4238/39 toc07 MAX4238 GAIN AND PHASE vs. FREQUENCY (TA = -40°C) FREQUENCY (Hz) 15 SINK CURRENT (mA) SOURCE CURRENT (mA) 1k 10 VCC = 5V AV = 1000V/V CL = 100pF RL = 10kΩ 1M 10M MAX4239 GAIN AND PHASE vs. FREQUENCY (TA = +25°C) 80 60 40 20 0 -20 -40 -60 -80 -100 -120 -140 -160 -180 MAX4238/39 toc09 10 GAIN AND PHASE (dB/DEGREES) 5 0 80 60 40 20 0 -20 -40 -60 -80 -100 -120 -140 -160 -180 MAX4238/39 toc06 SUPPLY VOLTAGE (V) GAIN AND PHASE (dB/DEGREES) OFFSET VOLTAGE (µV) 0.30 0.1k TA = +125°C 0.2 -0.2 -0.4 0 GAIN AND PHASE (dB/DEGREES) TA = -40°C -0.2 10 OUTPUT HIGH VOLTAGE (V) 0.2 MAX4238/39 toc03 TA = +125°C OFFSET VOLTAGE (µV) 40 0.4 MAX4238/39 toc02 0.4 MAX4238/39 toc01 PERCENTAGE OF UNITS (%) 50 80 60 40 20 0 -20 -40 -60 -80 -100 -120 -140 -160 -180 OFFSET VOLTAGE vs. COMMON-MODE VOLTAGE OFFSET VOLTAGE vs. SUPPLY VOLTAGE OFFSET VOLTAGE (µV) INPUT OFFSET DISTRIBUTION VCC = 5V AV = 1000V/V CL = 100pF RL = 10kΩ 0.1k 1k 10k 100k 1M 10M FREQUENCY (Hz) _______________________________________________________________________________________ 5 MAX4238/MAX4239 Typical Operating Characteristics (VCC = 5V, VCM = 0V, RL = 10kΩ connected to VCC/2, SHDN = VCC, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = 5V, VCM = 0V, RL = 10kΩ connected to VCC/2, SHDN = VCC, TA = +25°C, unless otherwise noted.) VCC = 5V AV = 1000V/V CL = 100pF RL = 10kΩ 1k 10k 100k 1M 10M SUPPLY CURRENT vs. SUPPLY VOLTAGE TA = +125°C 500 VCC = 5V AV = 1000V/V CL = 100pF RL = 10kΩ 0.1k 1k MAx4238/39 toc12 600 SUPPLY CURRENT (µA) MAX4238/39 toc11 80 60 40 20 0 -20 -40 -60 -80 -100 -120 -140 -160 -180 TA = -40°C 400 TA = +25°C 300 200 100 0 10k 100k 1M 0 10M 1 2 3 5 FREQUENCY (Hz) SUPPLY VOLTAGE (V) POWER-SUPPLY REJECTION RATIO vs. FREQUENCY COMMON-MODE REJECTION RATIO vs. FREQUENCY MAX4238 LARGE-SIGNAL TRANSIENT RESPONSE -20 -40 -20 -40 -80 IN 1V/div -60 CMRR (dB) -60 MAX4238/39 toc15 0 MAX4238/39 toc13 0 -80 -100 -100 -120 -120 -140 -140 OUT 1V/div -160 -160 0.01 0.1 1 10 100 1000 0.01 0.1 1 10 100 1000 FREQUENCY (kHz) FREQUENCY (kHz) MAX4238 SMALL-SIGNAL TRANSIENT RESPONSE MAX4239 SMALL-SIGNAL TRANSIENT RESPONSE MAX4238/39 toc16 MAX4238/39 toc17 10µs/div AV = 1V/V RL = 2kΩ CL = 100pF OVERVOLTAGE RECOVERY TIME MAX4238/39 toc18 IN 50mV/div IN 50mV/div 0 IN 50mV/div OUT 50mV/div OUT 1V/div OUT 500mV/div 0 10µs/div 10µs/div AV = 1V/V RL = 2kΩ CL = 100pF 6 4 FREQUENCY (Hz) MAX4238/39 toc14 0.1k MAX4239 GAIN AND PHASE vs. FREQUENCY (TA = +125°C) GAIN AND PHASE (dB/DEGREES) 80 60 40 20 0 -20 -40 -60 -80 -100 -120 -140 -160 -180 MAX4238/39 toc10 GAIN AND PHASE (dB/DEGREES) MAX4239 GAIN AND PHASE vs. FREQUENCY (TA = -40°C) PSRR (dB) MAX4238/MAX4239 Ultra-Low Offset/Drift, Low-Noise, Precision SOT23 Amplifiers AV = 10V/V RL = 2kΩ CL = 100pF 400µs/div AV = 100V/V RL = 10kΩ VCC = 2.5V VEE = -2.5V _______________________________________________________________________________________ Ultra-Low Offset/Drift, Low-Noise, Precision SOT23 Amplifiers SHUTDOWN WAVEFORM DC TO 10Hz NOISE MAX4238/39 toc20 MAX4238/39 toc19 SHDN 2V/div 2µV/div OUT 1V/div OUT 10µs/div 1s/div RL = 10kΩ CL = 100pF VCC = 2.5V VEE = -2.5V Pin Description PIN NAME FUNCTION SOT23 SO 1 6 OUT Amplifier Output 2 4 GND Ground 3 3 IN+ Noninverting Input 4 2 IN- Inverting Input 5 1 SHDN 6 7 VCC Positive Power Supply N.C. No Connection. Not internally connected. — 5, 8 Shutdown Input. Active low shutdown, connect to VCC for normal operation. Detailed Description The MAX4238/MAX4239 are high-precision amplifiers that have less than 2.5µV of input-referred offset and low 1/f noise. These characteristics are achieved through a patented autozeroing technique that samples and cancels the input offset and noise of the amplifier. The pseudorandom clock frequency varies from 10kHz to 15kHz, reducing intermodulation distortion present in chopper-stabilized amplifiers. Offset Error Sources To achieve very low offset, several sources of error common to autozero-type amplifiers need to be considered. The first contributor is the settling of the sampling capacitor. This type of error is independent of inputsource impedance, or the size of the external gain-setting resistors. Maxim uses a patented design technique to avoid large changes in the voltage on the sampling capacitor to reduce settling time errors. The second error contributor, which is present in both autozero and chopper-type amplifiers, is the charge injection from the switches. The charge injection appears as current spikes at the input, and combined with the impedance seen at the amplifier’s input, contributes to input offset voltage. Minimize this feedthrough by reducing the size of the gain-setting resistors and the input-source impedance. A capacitor in parallel with the feedback resistor reduces the amount of clock feedthrough to the output by limiting the closed-loop bandwidth of the device. The design of the MAX4238/MAX4239 minimizes the effects of settling and charge injection to allow specification of an input offset voltage of 0.1µV (typ) and less than 2.5µV over temperature (-40°C to +85°C). 1/f Noise 1/f noise, inherent in all semiconductor devices, is inversely proportional to frequency. 1/f noise increases 3dB/octave and dominates amplifier noise at lower frequencies. This noise appears as a constantly changing voltage in series with any signal being measured. The MAX4238/MAX4239 treat 1/f noise as a slow varying offset error, inherently canceling the 1/f noise. _______________________________________________________________________________________ 7 MAX4238/MAX4239 Typical Operating Characteristics (continued) (VCC = 5V, VCM = 0V, RL = 10kΩ connected to VCC/2, SHDN = VCC, TA = +25°C, unless otherwise noted.) MAX4238/MAX4239 Ultra-Low Offset/Drift, Low-Noise, Precision SOT23 Amplifiers Output Overload Recovery Autozeroing amplifiers typically require a substantial amount of time to recover from an output overload. This is due to the time it takes for the null amplifier to correct the main amplifier to a valid output. The MAX4238/ MAX4239 require only 3.3ms to recover from an output overload (see Electrical Characteristics and Typical Operating Characteristics). Shutdown The MAX4238/MAX4239 feature a low-power (0.1µA) shutdown mode. When SHDN is pulled low, the clock stops and the device output enters a high-impedance state. Connect SHDN to VCC for normal operation. Pin Configurations TOP VIEW MAX4238/ MAX4239 MAX4238/ MAX4239 SHDN 1 8 N.C. IN- 2 7 VCC 3 6 OUT GND 4 5 N.C. IN+ OUT 1 6 VCC GND 2 5 SHDN IN+ 3 4 IN- SO SOT23 Applications Information Minimum and Maximum Gain Configurations The MAX4238 is a unity-gain stable amplifier with a gainbandwidth product (GBWP) of 1MHz. The MAX4239 is decompensated for a GBWP of 6.5MHz and is stable with a gain of 10V/V. Unlike conventional operational amplifiers, the MAX4238/MAX4239 have a maximum gain specification. To maintain stability, set the gain of the MAX4238 between AV = 1000V/V to 1V/V, and set the gain of the MAX4239 between AV = 6700V/V and 10V/V. Chip Information TRANSISTOR COUNT: 821 PROCESS: BiCMOS ADC Buffer Amplifier The low offset, fast settling time, and 1/f noise cancellation of the MAX4238/MAX4239 make these devices ideal for ADC buffers. The MAX4238/MAX4239 are well suited for low-speed, high-accuracy applications such as strain gauges (see Typical Application Circuit). Error Budget Example When using the MAX4238/MAX4239 as an ADC buffer, the temperature drift should be taken into account when determining the maximum input signal. With a typical offset drift of 10nV/°C, the drift over a 10°C range is 100nV. Setting this equal to 1/2LSB in a 16-bit system yields a full-scale range of 13mV. With a single 2.7V supply, an acceptable closed-loop gain is AV = 200. This provides sufficient gain while maintaining headroom. 8 _______________________________________________________________________________________ Ultra-Low Offset/Drift, Low-Noise, Precision SOT23 Amplifiers 6LSOT.EPS _______________________________________________________________________________________ 9 MAX4238/MAX4239 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) DIM A A1 B C e E H L N E H INCHES MILLIMETERS MAX MIN 0.069 0.053 0.010 0.004 0.014 0.019 0.007 0.010 0.050 BSC 0.150 0.157 0.228 0.244 0.016 0.050 MAX MIN 1.35 1.75 0.10 0.25 0.35 0.49 0.25 0.19 1.27 BSC 3.80 4.00 5.80 6.20 0.40 SOICN .EPS MAX4238/MAX4239 Ultra-Low Offset/Drift, Low-Noise, Precision SOT23 Amplifiers 1.27 VARIATIONS: 1 INCHES TOP VIEW DIM D D D MIN 0.189 0.337 0.386 MAX 0.197 0.344 0.394 MILLIMETERS MIN 4.80 8.55 9.80 MAX 5.00 8.75 10.00 N MS012 8 AA 14 AB 16 AC D A B e C 0 -8 A1 L FRONT VIEW SIDE VIEW PROPRIETARY INFORMATION TITLE: PACKAGE OUTLINE, .150" SOIC APPROVAL DOCUMENT CONTROL NO. 21-0041 REV. B 1 1 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. 10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.