19-5228; Rev 0; 6/10 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps The MAX9636/MAX9637/MAX9638 are single-supply, CMOS input op amps featuring wide bandwidth at low quiescent current, making them suitable for a broad range of battery-powered applications such as portable medical instruments, portable media players, and smoke detectors. A combination of extremely low input bias currents, low input current noise and low input voltage noise allows interface to high-impedance sources such as photodiode and piezoelectric sensors. These devices are also ideal for general-purpose signal processing functions such as filtering and amplification in a broad range of portable, battery-powered applications. The ICs feature a maximized ratio of gain bandwidth (GBW) to supply current. The devices operate from a single 2.1V to 5.5V supply at a typical quiescent supply current of 36µA. For additional power conservation, the MAX9636 and MAX9638 offer a low-power shutdown mode that reduces supply current to 1µA and places the amplifiers’ outputs into a high-impedance state. The ICs are specified over the automotive operating temperature range (-40°C to +125°C). The single is offered in a space-saving, 6-pin SC70 package, while the dual is offered in tiny, 8-pin SC70 and 10-pin UTQFN packages. Features S Low Input Voltage-Noise Density: 38nV/√Hz S Low Input Current-Noise Density: 50fA/√Hz S Ultra-Low 0.1pA Bias Current S Low 36µA Quiescent Current S 1µA Quiescent Current in Shutdown S Wide 1.5MHz Bandwidth S Single-Supply Operation VDD = 2.1V to 5.5V S Available in Tiny 6-Pin SC70, 8-Pin SC70, and 10-Pin UTQFN Packages S -40°C to +125°C Operating Temperature Range Ordering Information PART TEMP RANGE PIN-PACKAGE MAX9636AXT+ -40NC to +125NC 6 SC70 MAX9637AXA+* -40NC to +125NC 8 SC70 MAX9638AVB+* -40NC to +125NC 10 UTQFN +Denotes a lead(Pb)-free/RoHS-compliant package. T = Tape and reel. *Future product—contact factory for availability. Applications Portable Medical Instruments Piezoelectric Transducer Amplifiers Smoke Detectors Battery-Powered Devices General-Purpose Signal Conditioning Notebooks Portable Media Players ________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX9636/MAX9637/MAX9638 General Description MAX9636/MAX9637/MAX9638 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps ABSOLUTE MAXIMUM RATINGS VDD, SHDN to VSS...................................................-0.3V to +6V IN+, IN-, OUT.....................................GND - 0.3V to VDD + 0.3V Continuous Input Current (any pins)................................ Q20mA Output Short Circuit to VDD or VSS Duration........................... 5s Thermal Limits (Note 1) Multiple Layer PCB Continuous Power Dissipation (TA = +70NC) 6-Pin SC70 (derate 3.1mW/°C above +70NC).............245mW BJA. ......................................................................326.5°C/W BJC .........................................................................115°C/W 8-Pin SC70 (derate 3.1mW/NC above +70NC)..............245mW BJA . ........................................................................326°C/W BJC .........................................................................115NC/W 10-Pin UTQFN (derate 7mW/NC above +70NC).........558.7mW BJA . .....................................................................143.2NC/W BJC. ........................................................................20.1NC/W Operating Temperature Range......................... -40NC to +125NC Junction Temperature .....................................................+150NC Lead Temperature (soldering 10s)..................................+300NC Soldering Temperature (reflow).......................................+260NC Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. 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 (VDD = 3.3V, VSS = 0V, VIN+ = VIN- = VCM = VDD/2, RL = 10kI to VDD/2, SHDN = VDD, TA = -40NC to +125NC. Typical values are at TA = +25NC, unless otherwise noted.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS VDD + 0.1 V DC CHARACTERISTICS Input Voltage Range VIN+, VIN- Input Offset Voltage VOS Input Offset Voltage Drift TCVOS Guaranteed by CMRR VSS 0.1 TA = +25NC 0.01 TA = -40NC to +125NC 3.5 (Note 3) 7 TA = +25NC Input Bias Current (Note 3) Common-Mode Rejection Ratio IB CMRR ±50 ±800 VSS < VCM < (VDD - 1.4V) TA = +25NC 72 TA = -40NC to +125NC 68 77 VOUT = 0.25V from rails 104 124 VOUT = 0.4V from rails, RL = 600I Short to VDD 100 120 Output Voltage Low VOL VOUT Output Voltage High VOH VDD - VOUT Short to VSS dB 10 mA 40 RL = 10kI 0.014 0.03 RL = 600I RL = 10kI 0.044 0.08 0.019 0.04 RL = 600I 0.057 0.1 0.01 1 SHDN = VSS, VOUT = 0V to VDD pA dB 58 ISC FV/NC 86 (VSS - 0.1V) < VCM < (VDD + 0.1V) Output Short-Circuit Current mV ±0.8 TA = -40NC to +125NC AOL 2 ±0.1 TA = -40NC to +85NC Open-Loop Gain Output Leakage in Shutdown (MAX9636, MAX9638 Only) 2.2 V V FA 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps (VDD = 3.3V, VSS = 0V, VIN+ = VIN- = VCM = VDD/2, RL = 10kI to VDD/2, SHDN = VDD, TA = -40NC to +125NC. Typical values are at TA = +25NC, unless otherwise noted.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS AC CHARACTERISTICS Input Voltage Noise Density eN Input Voltage Noise Input Current Noise Density Input Capacitance Gain Bandwidth Slew Rate Capacitive Loading Distortion IN f = 1kHz 38 nV/√Hz 0.1Hz ≤ f ≤ 10Hz 5 FVP-P f = 1kHz 50 fA/√Hz CIN 2 pF GBW 1.5 MHz SR CLOAD THD Settling Time 0.9 V/Fs No sustained oscillations 300 pF f = 10kHz, VO = 2VP-P, AV = 1V/V -68 f = 10kHz, VO = 2VP-P, AV = 1V/V, VDD = 5.5V -74 To 0.1%, VOUT = 2V step, AV = 1V/V 11.5 dB Fs POWER-SUPPLY CHARACTERISTICS Power-Supply Range Power-Supply Rejection Ratio Quiescent Current Shutdown Supply Current (MAX9636, MAX9638 Only) VDD PSRR Guaranteed by PSRR VIN+ = VIN- = VSS, VDD - VSS = 2.1V to 5.5V IDD Per amplifier IDD_SHDN VSHDN P VIL 2.1 TA = +25NC 72 TA = -40NC to +125NC 69 TA = +25NC VIL Over the power-supply range Shutdown Input High (MAX9636, MAX9638 Only) VIH Over the power-supply range ISHDN 100 36 TA = -40NC to +125NC Shutdown Input Low (MAX9636, MAX9638 Only) Shutdown Input Bias Current (MAX9636, MAX9638 Only) 5.5 V dB 55 60 FA 1 FA 0.5 V 1.4 V (Note 3) 1 100 nA Turn-On Time (MAX9636, MAX9638 Only) tON VSHDN = 0V to 3V 60 Fs Power-Up Time tUP VDD = 0V to 3.3V 18 Fs Note 2: All devices are 100% production tested at TA = +25NC. Temperature limits are guaranteed by design. Note 3: Parameter is guaranteed by design. 3 MAX9636/MAX9637/MAX9638 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VDD = 3.3V, VSS = 0V, VIN+ = VIN- = VCM = VDD/2, RL = 10kI to VDD/2, SHDN = VDD, TA = -40NC to +125NC. Typical values are at TA = +25NC, unless otherwise noted.) OFFSET VOLTAGE THERMAL COEFFICIENT HYSTOGRAM 12 10 8 6 35 4 20 15 10 0 0 TA = +25°C 150 100 TA = +85°C 50 TA = +125°C 0 COMMON-MODE VOLTAGE (V) INPUT OFFSET VOLTAGE vs. SUPPLY VOLTAGE VCM = VDD/2 INPUT BIAS CURRENT vs. COMMON-MODE VOLTAGE OUTPUT VOLTAGE LOW vs. SINK CURRENT VDD = 2.1V TA = +85°C -200 -600 1 2 3 4 5 6 -0.5 0 OUTPUT VOLTAGE LOW vs. SINK CURRENT VDD = 3.3V OUTPUT VOLTAGE LOW vs. SINK CURRENT VDD = 5V TA = +85°C 150 TA = +25°C 100 TA = 0°C 50 350 TA = +125°C 300 OUTPUT VOLTAGE LOW (mV) MAX9636 toc07 TA = +125°C 250 200 TA = +25°C 150 100 TA = 0°C 2 4 6 8 SINK CURRENT (mA) 10 12 200 TA = +25°C 150 100 TA = 0°C TA = -40°C 2 0 4 6 5 10 15 SINK CURRENT (mA) 20 10 12 OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT VDD = 2.1V, VOH = VDD - VOUT 1200 1000 TA = +125°C 800 TA = +85°C 600 400 TA = +25°C TA = 0°C TA = -40°C 0 0 8 200 TA = -40°C 0 0 250 SINK CURRENT (mA) TA = +85°C 50 TA = -40°C 300 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 COMMON-MODE VOLTAGE (V) 200 TA = +85°C 350 0 SUPPLY VOLTAGE (V) 250 400 50 OUTPUT VOLTAGE HIGH (mV) 200 TA = +125°C 450 TA = +125°C MAX9636 toc06 MAX9636 toc05 0 500 -400 TA = +125°C 220 TA = +25°C 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 MAX9636 toc09 TA = +85°C 200 0 -0.5 OUTPUT VOLTAGE LOW (mV) TA = +25°C 280 240 400 INPUT BIAS CURRENT (pA) TA = 0°C 260 600 MAX9636 toc04 340 0 TA = 0°C 200 OFFSET VOLTAGE THERMAL COEFFICIENT (µV/°C) 360 0 250 OFFSET VOLTAGE (mV) TA = -40°C 300 300 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 380 320 350 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 400 OFFSET VOLTAGE (µV) 25 TA = -40°C 400 5 2 4 30 450 OFFSET VOLTAGE (µV) 14 500 MAX9636 toc02 16 40 MAX9636 toc08 PERCENT OCCURANCE (%) 18 PERCENT OCCURANCE (%) MAX9636 toc01 20 INPUT OFFSET VOLTAGE vs. COMMON-MODE VOLTAGE MAX9636 toc03 OFFSET VOLTAGE HISTOGRAM OUTPUT VOLTAGE LOW (mV) MAX9636/MAX9637/MAX9638 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps 25 0 1 2 3 4 5 6 7 SOURCE CURRENT (mA) 8 9 10 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps TA = +85°C 600 TA = +25°C 400 0 5 10 15 20 25 5 GAIN 80 135 90 90 60 45 40 0 20 -45 PHASE 0 -90 -20 -135 -40 -60 0.001 0.01 0.1 1 10 100 PHASE (DEG) OPEN-LOOP GAIN (dB) 100 COMMON-MODE REJECTION RATIO (dB) 120 100 -180 1000 10,000 50 40 30 20 10 70 60 50 40 30 20 10 1 10 100 FREQUENCY (kHz) 1000 10,000 4.0 MAX9636 toc12 4.5 5.0 5.5 6.0 98 96 94 92 90 88 86 84 82 80 0.01 0.1 1 10 100 -50 1000 10,000 -25 0 25 50 75 100 125 TEMPERATURE (°C) INPUT VOLTAGE NOISE vs. FREQUENCY MAX9636 toc17 100 98 96 94 92 90 88 86 84 300 250 200 150 100 50 82 0 80 0 3.5 100 0 DC POWER-SUPPLY REJECTION RATIO (dB) 60 0.1 3.0 DC COMMON-MODE REJECTION RATIO vs. TEMPERATURE DC POWER-SUPPLY REJECTION RATIO vs. TEMPERATURE 70 0.01 2.5 FREQUENCY (kHz) MAX9636 toc16 POWER-SUPPLY REJECTION RATIO (dB) 80 2.0 COMMON-MODE REJECTION RATIO vs. FREQUENCY 80 POWER-SUPPLY REJECTION RATIO vs. FREQUENCY 90 TA = -40°C SUPPLY VOLTAGE (V) FREQUENCY (kHz) 100 TA = 0°C SOURCE CURRENT (mA) MAX9636 toc14 OPEN-LOOP GAIN AND PHASE vs. FREQUENCY 180 TA = +25°C 31 10 15 20 25 30 35 40 45 50 SOURCE CURRENT (mA) 140 33 25 0 35 MAX9636 toc13 35 27 0 30 37 29 TA = -40°C TA = 0°C TA = -40°C 0 400 200 TA = 0°C 200 TA = +25°C 39 MAX9636 toc18 800 600 DC COMMON-MODE REJECTION RATIO (dB) 1000 TA = +85°C 800 TA = +85°C 41 SUPPLY CURRENT (µA) TA = +125°C 1200 TA = +125°C 43 INPUT VOLTAGE NOISE (nV/√Hz) 1400 TA = +125°C 1000 SUPPLY CURRENT vs. SUPPLY VOLTAGE 45 MAX9636 toc11 1600 OUTPUT VOLTAGE HIGH (mV) 1800 OUTPUT VOLTAGE HIGH (mV) 1200 MAX9636 toc10 2000 OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT VDD = 5V, VOH = VDD - VOUT MAX9636 toc15 OUTPUT VOLTAGE HIGH vs. SOURCE CURRENT VDD = 3.3V, VOH = VDD - VOUT -50 -25 0 25 50 75 TEMPERATURE (°C) 100 125 0.01 0.1 1 10 100 FREQUENCY (kHz) 5 MAX9636/MAX9637/MAX9638 Typical Operating Characteristics (continued) (VDD = 3.3V, VSS = 0V, VIN+ = VIN- = VCM = VDD/2, RL = 10kI to VDD/2, SHDN = VDD, TA = -40NC to +125NC. Typical values are at TA = +25NC, unless otherwise noted.) Typical Operating Characteristics (continued) (VDD = 3.3V, VSS = 0V, VIN+ = VIN- = VCM = VDD/2, RL = 10kI to VDD/2, SHDN = VDD, TA = -40NC to +125NC. Typical values are at TA = +25NC, unless otherwise noted.) 0.1Hz TO 10Hz VOLTAGE vs. TIME INPUT CURRENT NOISE vs. FREQUENCY MAX9636 toc20 MAX9636 toc19 INPUT CURRENT NOISE (fA/√Hz) 140 120 5µVP-P NOISE 100 80 2µV/div 60 40 20 0 0.1 0.01 1 10 10s/div 100 FREQUENCY (kHz) TOTAL HARMONIC DISTORTION vs. FREQUENCY VDD = 5.5V, AO = 1V/V, VOUT = 2VP-P, RL = 10kI to VDD/2 TOTAL HARMONIC DISTORTION vs. INPUT VOLTAGE AMPLITUDE VDD = 5.5V, AO = 1V/V -20 -30 -40 -50 -60 -70 -80 0 MAX9636 toc22 -10 TOTAL HARMONIC DISTORTION (dB) MAX9636 toc21 0 TOTAL HARMONIC DISTORTION (dB) MAX9636/MAX9637/MAX9638 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps -20 -40 -60 -80 -100 -120 -90 0 1 2 3 4 5 0.01 6 0.1 1 100 FREQUENCY (kHz) SMALL-SIGNAL TRANSIENT RESPONSE LARGE-SIGNAL TRANSIENT RESPONSE MAX9636 toc24 MAX9636 toc23 VIN 2V/div VIN 100mV/div VOUT 20mV/div VOUT 500mV/div 1µs/div 6 10 INPUT VOLTAGE AMPLITUDE (VP-P) 2µs/div 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps STABILITY vs. CAPACITIVE AND RESISTIVE LOAD RISO IN SERIES WITH CLOAD PERCENT OVERSHOOT vs. RESISTIVE LOAD 20 15 10 CLOAD = 50pF 5 90 80 70 60 50 STABLE 40 30 20 0 UNSTABLE 10 -5 0 10 100 1000 10,000 100,000 1,000,000 100 1000 10,000 RESISTIVE LOAD (I) CAPACITIVE LOAD (pF) STABILITY vs. CAPACITIVE AND RESISTIVE LOAD RP IN PARALLEL WITH CL POWER-UP TIME 90 80 VDD 2V/div 70 60 STABLE 100,000 MAX9636 toc28 MAX9636 toc27 100 RESISTIVE LOAD (kI) MAX9636 toc26 CLOAD = 100pF CLOAD = 300pF RESISTIVE LOAD (I) PERCENT OVERSHOOT (%) 25 100 MAX9636 toc25 30 UNSTABLE 50 40 VOUT 500mV/div 30 20 10 0 100 1000 10,000 40µs/div CAPACITIVE LOAD (pF) TURN-ON TIME MAX9636 toc29 SHDN 2V/div VOUT 500mV/div 100µs/div 7 MAX9636/MAX9637/MAX9638 Typical Operating Characteristics (continued) (VDD = 3.3V, VSS = 0V, VIN+ = VIN- = VCM = VDD/2, RL = 10kI to VDD/2, SHDN = VDD, TA = -40NC to +125NC. Typical values are at TA = +25NC, unless otherwise noted.) 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps MAX9636/MAX9637/MAX9638 Pin Configurations TOP VIEW IN+ 1 + MAX9636 VSS 2 IN- 3 6 VDD 5 SHDN OUTA 1 INAINA+ OUT 4 + 8 VDD 2 7 OUTB 3 6 INB- VSS 4 5 INB+ MAX9637 SC70 SC70 SHDNB SHDNA 7 OUTA 8 INA- 9 OUTB 10 6 MAX9638 + 1 2 VDD INB+ 5 VSS 4 INA+ 3 INB- UTQFN Pin Description 8 MAX9636 (6 SC70) MAX9637 (8 SC70) MAX9638 (10 UTQFN) NAME FUNCTION 1 — — IN+ — 3 4 INA+ Positive Input Positive Input A — 5 2 INB+ Positive Input B 2 4 5 VSS Negative Power Supply. Bypass with a 0.1FF capacitor to ground. Negative Input 3 — — IN- — 2 9 INA- Negative Input A — 6 3 INB- Negative Input B 4 — — OUT Output — 1 8 OUTA Output A — 7 10 OUTB Output B — — 6 SHDNA Active-Low Shutdown A — — 7 SHDNB Active-Low Shutdown B 5 — — 6 8 1 SHDN VDD Active-Low Shutdown Positive Power Supply. Bypass with a 0.1FF capacitor to ground. 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps The MAX9636/MAX9637/MAX9638 are single-supply, CMOS input op amps. They feature wide bandwidth at low quiescent current, making them suitable for a broad range of battery-powered applications such as portable medical instruments, portable media players, and smoke detectors. A combination of extremely low input bias currents, low input current noise, and low input voltage noise allows interface to high-impedance sources such as photodiode and piezoelectric sensors. These devices are also ideal for general-purpose signal processing functions such as filtering and amplification in a broad range of portable, battery-powered applications. The devices’ operational common-mode range extends 0.1V beyond the supply rails, allowing for a wide variety of single-supply applications. The ICs also feature low quiescent current and a shutdown mode that greatly reduces quiescent current while the device is not operational. This makes the device suitable for portable applications where power consumption must be minimized. Rail-to-Rail Input Stage The operational amplifiers have parallel-connected nand p-channel differential input stages that combine to accept a common-mode range extending 100mV beyond the supply rails. The n-channel stage is active for common-mode input voltages typically greater than (VDD - 1.2V), and the p-channel stage is active for common-mode input voltages typically less than (VDD - 1.4V). A small transition region exists, typically VDD - 1.4 to VDD - 1.2V, during which both pairs are on. Rail-to-Rail Output Stage The maximum output voltage swing is load dependent. However, it is guaranteed to be within 100mV of the positive rail even with 3mA of load current. To maximize the output current sourcing capability, these parts do not come with built-in short-circuit protection. If loads heavier than 600ω must be driven, then ensure that the maximum allowable power dissipation is not exceeded (see the Absolute Maximum Ratings section). Low Input Bias Current This op-amp family features ultra-low 0.1pA (typ) input bias current and guaranteed maximum current of Q50pA over -40NC to +85NC when the input common-mode voltage is at midrail. For the -40NC to +85NC temperature range, the variation in the input bias current is small with changes in the input voltage due to very high input impedance (in the order of 100GI). Power-Up Time The ICs typically require a power-up time of 18µs. Supply settling time depends on the supply voltage, the value of the bypass capacitor, the output impedance of the incoming supply, and any lead resistance or inductance between components. Op amp settling time depends primarily on the output voltage and is slew-rate limited. The output settles in approximately 11.5µs for VDD = 3V and VOUT = VDD/2V (see the Power-Up Time graph in the Typical Operating Characteristics section). 9 MAX9636/MAX9637/MAX9638 Detailed Description MAX9636/MAX9637/MAX9638 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps High-Impedance Sensor Front-Ends Driving Capacitive Loads The ICs have a high tolerance for capacitive loads. In unity-gain configuration, the op amps can typically drive up to 300pF pure capacitive load. Increasing the gain enhances the amplifier’s ability to drive greater capacitive loads. In unity-gain configurations, capacitive load drive can be improved by inserting a small (5I to 30I) isolation resistor, RISO, in series with the output, as shown in Figure 1. This significantly reduces ringing while maintaining DC performance for purely capacitive loads. However, if the load also has a resistive component then a voltage-divider is created, introducing a direct current (DC) error at the output. The error introduced is proportional to the ratio RISO/RL, which is usually negligible in most cases. Applications that cannot tolerate this slight DC error can use an alternative approach of providing stability by placing a suitable resistance in parallel with the capacitive load as shown in Figure 2 (see the Typical Operating Characteristics section for graphs of the stable operating region for various capacitive loads vs. resistive loads). While this approach of adding a resistor parallel to the load does not introduce DC error, it nevertheless reduces the output swing proportionally. The ICs interface to both current-output sensors, such as photodiodes (Figure 3), and high-impedance voltage sources, such as piezoelectric sensors. For currentoutput sensors, a transimpedance amplifier is the most noise-efficient method for converting the input signal to a voltage. High-value feedback resistors are commonly chosen to create large gains, while feedback capacitors help stabilize the amplifier by cancelling any poles introduced in the feedback function by the highly capacitive sensor or cabling. A combination of low-current noise and low-voltage noise is important for these applications. Take care to calibrate out photodiode dark current if DC accuracy is important. The high bandwidth and slew rate also allows AC signal processing in certain medical photodiode sensor applications such as pulse oximetry. For voltage-output sensors, a noninverting amplifier is typically used to buffer and/or apply a small gain to the input voltage signal. Due to the extremely high impedance of the sensor output, a low input bias current with minimal temperature variation is very important for these applications. MAX9636/ MAX9637/ MAX9638 + - RISO RL MAX9636/ MAX9637/ MAX9638 CL VDD PHOTODIODE IN- MAX9636 IN+ REF Figure 3. MAX9636 in a Sensor Preamp Configuration RL CL Figure 2. Using a Parallel Resistor to Degenerate the Effect of the Capacitive Load and Increase Stability Figure 1. Using a Series Resistor to Isolate the Capacitive Load from the Op Amp 10 RP + RL AV = ≈ 1V/V RL + RISO OUT SIGNAL CONDITIONING/ FILTERS MAX1286 ADC 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps U Using shielding techniques to guard against parasitic leakage paths. For example, put a trace connected to the noninverting input around the inverting input. U Minimizing the amount of stray capacitance connected to op amp’s inputs to improve stability. To achieve this, minimize trace lengths and resistor leads by placing external components as close as possible to the package. U Use separate analog and digital power supplies. Applications Information Shutdown Operation The MAX9636/MAX9638 feature an active-low shutdown mode that sends the inputs and output into high impedance and substantially lowers the quiescent current. Active-Low Input The shutdown active-low (VIL) and high (VIH) threshold voltages are designed for ease of integration with digital controls, such as microcontroller outputs. These thresholds are independent of supply, eliminating the need for external pulldown circuitry. Output During Shutdown The MAX9638 output is in a high-impedance state while SHDN is low. The device structure limits the output leakage current in this state to 0.01µA when the output is between 0V to VDD. ADC Driver The MAX9636/MAX9637/MAX9638 are low-power amplifiers ideal for driving high to medium-resolution ADCs. Figure 3 shows how the MAX9636 is connected to a photodiode, with the amplifier output connected to additional signal conditioning/filtering, or directly to the ADC. The MAX1286–MAX1289 family of low-power, 12-bit ADCs are ideal for connecting to the MAX9636/MAX9637/MAX9638. The MAX1286–MAX1289 ADCs offer sample rates up to 150ksps, with 3V and 5V supplies, as well as 1- and 2-channel options. These ADCs dissipate just 15µA when sampling at 10ksps and 0.2µA in shutdown. Offered in tiny 8-pin SOT23 and 3mm x 3mm TDFN packages, the MAX1286–MAX1289 ADCs are an ideal fit to pair with the MAX9636/MAX9637/MAX9638 amplifiers in portable applications. Similarly, the MAX1086–MAX1089 is a family of 10-bit pin-compatible low-power ADCs with the same 3V/5V, 1- and 2-channel options. Table 1 details the amplifier and ADC pairings for single- and dual-channel applications. Chip Information PROCESS: BiCMOS Table 1. Recommended Amplifiers/ADCs CHANNELS AMPLIFIER 1 ADC 3V, 10 BIT 3V, 12 BIT 5V, 10 BIT 5V, 12 BIT MAX9636 MAX1089 MAX1289 MAX1088 MAX1288 2 MAX9637 MAX1087 MAX1287 MAX1086 MAX1286 2 MAX9638 MAX1087 MAX1287 MAX1086 MAX1286 11 MAX9636/MAX9637/MAX9638 For best performance, follow standard high-impedance layout techniques, which include the following: Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 6 SC70 X6SN+1 21-0077 8 SC70 X8CN+1 21-0460 10 UTQFN V101A1CN+1 21-0028 SC70, 6L.EPS MAX9636/MAX9637/MAX9638 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps 12 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. 13 MAX9636/MAX9637/MAX9638 Package Information (continued) Package Information (continued) For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. ULTRA TQFN.EPS MAX9636/MAX9637/MAX9638 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps 14 TABLE 1 TABLE 2 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. TABLE 1 TABLE 2 15 MAX9636/MAX9637/MAX9638 Package Information (continued) MAX9636/MAX9637/MAX9738 3V/5V Low-Power, Low-Noise, CMOS, Rail-to-Rail I/O Op Amps Revision History REVISION NUMBER REVISION DATE 0 6/10 DESCRIPTION Initial release PAGES CHANGED — 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. 16 © 2010 Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.