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19-1343; Rev 3; 9/06 Single/Dual/Quad, +1.8V/10µA, SOT23, Beyond-the-Rails Op Amps General Description The MAX4240–MAX4244 family of micropower op amps operate from a single +1.8V to +5.5V supply or dual ±0.9V to ±2.75V supplies and have Beyond-the-Rails™ inputs and rail-to-rail output capabilities. These amplifiers provide a 90kH z gain-bandwidth product while using only 10µA of supply current per amplifier. The MAX4241/MAX4243 have a low-power shutdown mode that reduces supply current to less than 1µA and forces the output into a high-impedance state. Although the minimum operating voltage is specified at +1.8V, these devices typically operate down to +1.5V. The combination of ultra-low-voltage operation, beyond-the-rails inputs, rail-to-rail outputs, and ultra-low pow er consumption makes these devices ideal for any portable/ two-cell battery-powered system. These amplifiers have an input common-mode range that extends 200mV beyond each rail, and their outputs typically sw ing to within 9mV of the rails with a 100kload. Beyond-the-rails input and rail-to-rail output characteristics allow the full power-supply voltage M Features A X Guaranteed Down to +1.8V Typical Operation to +1.5V 4 2 4 0 ♦ Ultra-Low Power Consumption: 10µA Supply Current per Amplifier M ♦ Beyond-the-Rails Input Common-Mode Range A X 4 2 4 4 ♦ No Phase Reversal for Overdriven Inputs ♦ 200µV Input Offset Voltage ♦ Unity-Gain Stable for Capacitive Loads up to 200pF ♦ 90kHz Gain-Bandwidth Product ♦ Available in Space-Saving 5-Pin SOT23 and ® to be used for signal range. The combination of low input offset voltage, low input bias current, and high open-loop gain makes them suitable for low-power/lowvoltage precision applications. The M AX4240 is of fered in a sp ace-s aving 5-pin SOT23 pack ag e. All sp ecificat ions are guaranteed over the -40°C to +85°C extended temperature range. Applications Two-Cell BatteryPowered Systems Portable/Battery-Powered Electronic Equipment Digital Scales Strain Gauges Sensor Amplifiers Cellular Phones Notebook Computers PDAs PART TEMP RANGE PIN- MAX4240EUK-T -40°C to +85°C 5 SOT23-5 MAX4241EUA -40°C to +85°C 8 µMAX MAX4241ESA -40°C to +85°C 8 SO MAX4242EUA -40°C to +85°C 8 µMAX MAX4242ESA -40°C to +85°C 8 SO TOP ACCS — — — — — MAX4243EUB -40°C to +85°C 10 µMAX MAX4243ESD -40°C to +85°C 14 SO — MAX4244ESD -40°C to +85°C 14 SO — Pin Configurations Selector Guide TOP VIEW PART NO. OF AMPS MAX4240 1 — MAX4241 1 Yes 8-pin µMAX/SO MAX4242 2 — 8-pin µMAX/SO MAX4243 2 Yes MAX4244 4 — SHUTDOWN PIN-PACKAGE 5-pin SOT23 10-pin µMAX, 14-pin SO 14-pin SO Beyond-the-Rails is a trademark and µMAX is a registered trademark of Maxim Integrated Products, Inc. OUT 1 VEE 2 5 VCC MAX4240 IN+ 3 4 IN- SOT23-5 Pin Configurations continued 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 – Beyond-the-Rails Op Amps 4 4 2 4 ABSOLUTE MAXIMUM RATINGS All Other Pins ...................................(VCC + 0.3V) to (VEE - 0.3V) Continuous Power Dissipation (TA = +70°C) 5-pin SOT23 (derate 7.1mW/°C above +70°C).............571mW X 8-pin µMAX (derate 4.1mW/°C above +70°C) ..............330mW A 8-pin SO (derate 5.88mW/°C above +70°C).................471mW M – 0 14-pin SO (derate 8.33mW/°C above +70°C)...............667mW Junction Temperature......................................................+150°C Storage Temperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10s) .................................+300°C Single/Dual/Quad, +1.8V/10µA, SOT23, 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 ELECTRICAL CHARACTERISTICS 4 2 (V = +1.8V to +5.5V, V = 0, V = 0, V = V / 2, R = 100k tied to V / 2, SHDN = V , T = +25°C, unless Supply otherwise Voltage noted.) (V(Note to 1) V ) ....................................................6V 10-pin µMAX (derate 5.6mW/°C above +70°C) ............444mW 4 MIN TYP to +85°C MAX Short-Circuit Duration SYMBOL (to V or V )............Continuous CONDITIONS Operating Temperature Range ...........................-40°C X OutputPARAMETER UNITS A Supply-Voltage Range V Inferred from PSRR test I M Shutdown Supply Current (Note 2) I 1.8 V SHDN = V 5.5 = 1.8V VCC = 5.0V V = 1.8V SHDN = V 10 12 14 1.0 18 1.5 ±0.20 ±0.75 V µA µA CC MAX4241ESA MAX4242ESA/MAX4243ESD/ Input Offset Voltage EE V (V CM ±0.20 ±0.88 ±0.25 ±1.40 ±2 ±6 ±0.5 45 ±1.5 nA M + 0.2 V + 0.2V) MAX4240EUK/MAX424_EUA/ mV MAX4243EUB Input Bias Current Input Offset Current Resistance Input Common-Mode IB (Note 3) IOS (Note 3) - V < 1.0V R IN+ V nA IN- Inferred from the CMRR test V - 0.2 V Voltage Range MAX4241ESA MAX4242ESA/MAX4243ESD/ CC Rejection Ratio MAX4244ESD MAX4240EUK/MAX424_EUA/ MAX4243EUB MAX4241ESA CMRR (Note 4) MAX4242ESA/MAX4243ESD/ MAX4244ESD 72 90 69 90 63 88 74 94 74 94 69 90 CC MAX4240EUK/MAX424_EUA/ MAX4243EUB 2 _______________________________________________________________________________________ dB Single/Dual/Quad, +1.8V/10µA, SOT23, Beyond-the-Rails Op Amps M ELECTRICAL CHARACTERISTICS (continued) A (VCC = +1.8V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC / 2, RL = 100ktied to VCC / 2, SHDN = VCC, TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MAX4241ESA Power-Supply Rejection Ratio Large-Signal Voltage Gain PSRR AVOL 1.8V VCC 5.5V (VEE + 0.2V) VOUT (VCC - 0.2V) MAX4242ESA/MAX4243ES D/ MAX4244ESD MAX4240EUK/MAX424_EU A/ MAX4243EUB RL = 100k VCC = 1.8V RL = 10k RL = 100k VCC = 5.0V RL = 10k VCC = 1.8V Output Voltage Swing High Output Voltage Swing Low V Specified as - V CC V OH Specified as EE - V OL VCC = 5.0V VCC = 1.8V VCC = 5.0V Output Short-Circuit Current IOUT(SC) Output Leakage Current in Shutdown (Notes 2, 5) IOUT(SHDN) MIN TYP 77 85 77 85 75 82 76 66 85 73 86 94 78 85 MAX dB A 8 20 40 65 RL = 100k 10 25 RL = 10k RL = 100k 60 6 95 15 RL = 10k 23 35 RL = 100k 10 20 RL = 10k 40 60 0.7 2.5 SHDN = VEE = 0, VCC = 5.5V 20 X 4 2 4 4 dB RL = 10k Sinking X 4 2 4 0 M RL = 100k Sourcing UNITS mV mV mA 50 nA SHDN Logic Low (Note 2) VIL SHDN Logic High (Note 2) VIH SHDN Input Bias Current (Note 2) IIH, IIL SHDN = VCC = 5.5V or SHDN = VEE = 0 40 Channel-to-Channel Isolation (Note 6) CHISO Specified at DC 80 dB Gain-Bandwidth Product GBW 90 kHz Phase Margin m 68 degrees Gain Margin Gm 18 dB Slew Rate SR 40 V/ms 0.3 x VCC V V 0.7 x VCC 80 _______________________________________________________________________________________ nA – 3 Single/Dual/Quad, +1.8V/10µA, SOT23, Beyond-the-Rails Op Amps ELECTRICAL CHARACTERISTICS (continued) (V 4 2 4 = +1.8V to +5.5V, V = 0, V CC EE otherwise noted.) (Note 1) PARAMETER = 0, V CM = V OUT / 2, R = 100k tied to V CC SYMBOL L , T = +25°C, unless / 2, SHDN = V CC CONDITIONS CC MIN A TYP MAX UNITS Input Voltage-Noise Density en f = 1kHz 70 nV/Hz A M – 0 4 2 4 Input Current-Noise Density in f = 1kHz 0.05 pA/Hz AVCL = +1V/V, no sustained oscillations 200 pF tSHDN 50 µs tENABLE 150 µs X Power-Up Time tON 200 µs A Input Capacitance CIN 3 pF 0.05 % 50 µs X Capacitive-Load Stability Shutdown Time Enable Time from Shutdown Total Harmonic THD M Distortion Settling Time to 0.01% fIN = 1kHz, VCC = 5.0V, VOUT = 2Vp-p, AV = +1V/V tS AV = +1V/V, VCC = 5.0V, VOUT = 2VSTEP ELECTRICAL CHARACTERISTICS (V = +1.8V to +5.5V, V CC = 0, V EE = 0, V CM erwisePARAMETER noted.) (Note 1) SYMBOL Supply-Voltage Range VCC / 2, SHDN = V CC Inferred from PSRR test ICC I SHDN = VCC SHDN = V VOS EE (VEE - 0.2V) VCM (VCC + 0.2V) Input Offset Voltage Drift L CONDITIONS CC(SHDN) Input Offset Voltage / 2, R = 100ktied to V CC ,T =T CC MIN A to T MIN TYP 1.8 , unless othMAX MAX 5.5 UNITS V 14 VCC = 1.8V Supply Current per Amplifier Shutdown Supply Current (Note 2) =V OUT VCC = 5.0V 19 VCC = 1.8V 2.0 VCC = 5.0V MAX4241ESA ±1.2 3.5 MAX4242ESA/MAX4243ES D/ MAX4244ESD MAX4240EUK/MAX424_EU A/ MAX4243EUB ±1.3 µA µA mV ±2.0 2 TCVOS µV/°C Input Bias Current IB (Note 3) ±15 nA Input Offset Current IOS (Note 3) ±7 nA Input Common-Mode Voltage Range VCM Inferred from the CMRR test 4 -0.2 _______________________________________________________________________________________ VCC + 0.2 V Single/Dual/Quad, +1.8V/10µA, SOT23, Beyond-the-Rails Op Amps M ELECTRICAL CHARACTERISTICS A X (VCC = +1.8V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC / 2, RL = 100ktied to VCC / 2, SHDN = VCC, TA = TMIN to TMAX, unless otherwise noted.) (Note 1) PARAMETER UNITS SYMBOL CONDITIONS MAX4241ESA MAX4242ESA/MAX4243ES D/ MAX4244ESD MAX4240EUK/MAX424_EU A/ MAX4243EUB MAX4241ESA VCC = 1.8V Common-Mode Rejection (Note 4) Ratio CMRR MAX4242ESA/MAX4243ES D/ MAX4244ESD MAX4240EUK/MAX424_EU A/ MAX4243EUB MAX4241ESA VCC = 5.0V Power-Supply PSRR 1.8V VCC 5.5V Rejection Ratio Large-Signal Voltage Gain AVOL (VEE + 0.2V) VOUT (VCC - 0.2V) MAX4242ESA/MAX4243ES D/ MAX4244ESD MAX4240EUK/MAX424_EU A/ MAX4243EUB RL = 100k VCC = 1.8V VCC = 5.0V Output Voltage Swing High VCC = 1.8V Specified as VOH CC OH -V VCC = 5.0V Output Voltage Swing Low VOL Specified as EE - VOL VCC = 1.8V VCC = 5.0V Output Leakage Current in Shutdown (Notes 2, 5) SHDN Logic Low (Note 2) IOUT(SHDN) VIL MIN SHDN = VEE = 0, VCC = 5.5V TYP 4 2 4 0 MAX 65 65 61 M 71 A X dB 71 4 2 4 4 67 73 73 dB 71 72 RL = 10k 62 RL = 100k 80 RL = 10k 72 dB RL = 100k 25 RL = 10k 95 RL = 100k 30 RL = 10k 145 RL = 100k 20 RL = 10k 50 RL = 100k 25 RL = 10k 75 100 0.3 x VCC _______________________________________________________________________________________ mV – mV nA V 5 Beyond-the-Rails Op Amps 4 4 2 4 X ELECTRICAL CHARACTERISTICS (continued) (VCC = +1.8V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC / 2, RL = 100ktied to VCC / 2, SHDN = VCC, TA = TMIN to MAX, unless othT erwise noted.) (Note 1) PARAMETER SYMBOL SHDN Logic High (Note 2) CONDITIONS MIN VIH TYP MAX UNITS V 0.7 x VCC Single/Dual/Quad, +1.8V/10µA, SOT23, A SHDN Input Bias IIH, IIL SHDN = VCC = 5.5V or SHDN = VEE = 0 M Current (Note 2) – 0 Note 1: The MAX4240EUK, MAX4241EUA, MAX4242EUA, and MAX4243EUB specifications are 100% tested at T temperature limits are guaranteed by design. 4 120 nA = +25°C. All 2 Note 3: Input bias current and input offset current are tested with VCC = +0.5V and +0.5V VCM +4.5V. Note 4: Tested over the specified input common-mode range. Note 5: Tested for 0 V V . Does not include current through external feedback network. X Note 6: Channel-to-channel isolation specification applies to the MAX4242/MAX4243/MAX4244 only. A __________________________________________Typical Operating M Characteristics (VCC = +5.0V, VEE = 0, VCM = VCC / 2, VSHDN = VCC, RL = 100kto VCC / 2, TA = +25°C, unless otherwise noted.) SUPPLY CURRENT PER AMPLIFIER vs. TEMPERATURE OPERATING VOLTAGE TEMPERATURE 1 20 16 CC V CC = +1.8V -4 2 442X 5 -4 4 ) 24X 4 42X T R R U Y )L U SN 3 A 14 N 12 R V 310 C P P U S 6 SHUTDOWN SUPPLY CURRENT PER AMPLIFIER vs. TEMPERATURE 1.8 PSRR 80dB 4 C V 1.4 = +1.8V 2 1.1 0 0 -60 60 400 6 - 1.6 CC U S MINIMUM vs. -40 80 -20 0 20 40 60 100 TEMPERATURE (°C) 80 O T 200 F F O T -60 -40 -20 0 20 40 1.0 80 60 100 -60 TEMPERATURE (°C) vs. TEMPERATURE INPUT CC OFFSET VOLTAGE vs. 300 100 V V =0 0 -4 4 a V = +1.8V 24 2.5 A ( nS IB I -2.5 IN -4 0 -60 -40 -20 0 20 40 60 TEMPERATURE (°C) 80 100 -5.0 -60 -40 -20 0 20 40 60 80 10 0 -0.2 0.2 TEMPERATURE (°C) 0.6 1.0 VC (V) M 6 20 40 TEMPERATURE (°C) M = +1.8V -20 COMMON-MODE VOLTAGE (V INPUT BIAS CURRENT 5.0 = 1.8V) 0 INPUT BIAS CURRENT 50 /440 X 0/4A ) X A A (T N E R C -2 A U P N -3 -40 _______________________________________________________________________________________ 1.4 1.8 Single/Dual/Quad, +1.8V/10µA, SOT23, Beyond-the-Rails Op Amps M ____________________________________Typical Operating Characteristics (continued) A X (VCC = +5.0V, VEE = 0, VCM = VCC / 2, VSHDN = VCC, RL = 100kto VCC / 2, TA = +25°C, unless otherwise noted.) 5.0 8 INPUT BIAS CURRENT vs. COMMON-MODE VOLTAGE (V = 5.5V) LOW TEMPERATURE 120 0b OUTPUT SWING HIGH vs. TEMPERATURE 44 -24 X 100 4A )V m ( C 80 C M O R 60 O 60 T O V CC 2.5 V A B L EE V = +1.8V, R = 10k 7 44 MA M 120 L M E 80 CC CC -5.0 0.5 1.5 80 100 2.5 3.5 4.5 5.5 -60 VCM (V) 100 11 A )B (X A N -85 O 100k T E R ( -90 M N O M -95 C 0 20 40 60 4 2 4 4 L 0 100 80 -60 -40 -20 0 20 40 TEMPERATURE (°C) (VCC = +1.8V, RL TIED TOEE V ) CC EEOPEN-LOOP GAIN vs. OUTPUT 100 LOW 10 SWING / 0 4 2 4X A 90 R = L OPEN-LOOP GAIN vs. 0 4 4 R = 100k2 90 80 80 L V dB 70 B A (I G A = +1.8V CC R = 10k d I G 50 50 40 40 -100 30 -60 400 4 -20 CC TEMPERATURE (°C) COMMON-MODE REJECTION 09-4 OUTPUT SWING HIGH 110 20 = +1.8V, R = 100k -40 L V = +5.5V, R = 100k 0 -0.5 60 A X L V = +5.5V, R = 100k V CC 100 F G T O V = +5.5V, R = 20k 20 4 2 4 0 OUTPUT SWING vs. -40 -20 500 0 20 40 60 80 100 0 (V = +5.5V, R TIED TO V ) TEMPERATURE TEMPERATURE (°C) (V 142 /41 LOW OPEN-LOOP GAIN vs. OUTPUT SWING 4 100 X OPEN-LOOP R =GAIN 100k 44 X 90 R = 20k B 80 (N I 100 200 300 30 500 400 0 = +5.5V, R TIED TO V ) VOUT (mV) 3 110 /44 L OPEN-LOOP GAIN vs. OUTPUT SWING HIGH 4 105 X M V V M 100 )B (N R = 20kB 100 vs. VOUT (mV) / = +5.5V, R = 20kTO CC L CC V CC= +1.8V, LR = 10kTO V G5070 300 95 ( IN 60 G5070 200 EE G 85 80 V (mV) TEMPERATURE (°C) V (mV) VCC = +1.8V, RL = 10kTO VCC 40 40 0 80 100 100 200 300 400 0 100 200 300 70 400 -60 -40 -20 0 20 OUT _______________________________________________________________________________________ 7 40 60 Beyond-the-Rails Op Amps Typical Operating Characteristics (continued) 4 4 (VCC = +5.0V, VEE = 0, VCM = VCC/2, VSHDN = VCC, RL = 100k to VCC/2, TA = +25°C unless otherwise noted.) 2 4 OPEN-LOOP GAIN GAIN AND PHASE vs. FREQUENCY Single/Dual/Quad, +1.8V/10µA, SOT23, GAIN AND PHASE vs. FREQUENCY L X 110 A 100 0 95 ( )B 4N 2 A G VC = +5.5V, RL C TO V M EE C vs. TEMPERATURE 90 VC =100pF) +1.8V, RL C TO V 85 EE VC = +1.8V, RL CC C TO V 80 75 A 70 M 0 20 40 60 80 40 108 30 72 20 36 36 E -10 -72 -20 -108 D ( R G ) 10 BG 0 )H ( N-10 E A A -20 -30 -144 -30 -180 -40 0 -36 1 0 10 0 1k 10k (C = 0 -36 -72 -108 FREQUENCY (Hz) TOTAL HARMONIC DISTORTION PLUS NOISE )SP ( E A 10 0 1 10k k FREQUENCY (Hz) 100k VOLTAGE NOISE vs. FREQUENCY 1000 / X 840 2 D R G -180 10 X A 4 ) A 0 ct 4 vs. FREQUENCY ) -80 d N G -90 A E -144 100k A -70 50 72 100 MAX4242/MAX4243/MAX4244 CROSSTALK vs. FREQUENCY RL = 10k 144 MAX4240/44-17 180 AV = +1000V/V 144 30 TEMPERATURE (°C) -60 60 108 -40 -60 -40 -20 180 40 540 2X ( 20 )d A 10 N 0 VC = +5.5V, RLTO VCC 4 X AV = +1000V/V 50 105 M – MAX4240/44-16 60 -49 0 2 1 )% E IO N +T 0.1 D 100 O -100 RL = 100k -110 10 100 1k 0.0 1 1 10k FREQUENCY (Hz) 10 1 100 0 FREQUENCY (Hz) 1000 MAX4240/44-2 2 10% OVERSHOOT 100mV A IN REGION OF MARGINAL STABILITY 0.1 1000 SMALL-SIGNAL TRANSIENT RESPONSE (NONINVERTING) LOAD RESISTOR vs. CAPACITIVE LOAD ) (D O R RL = 10k zH V ( Y I N D E I N E G T 1 FREQUENCY (Hz) SMALL-SIGNAL TRANSIENT RESPONSE (INVERTING) MAX4240/44-2 3 100mV IN 0V 0mV/div 0V 50mV/div 100mV 04/ 04X A REGION OF STABLE OPERATION OUT 100mV OUT 0V 0V 10 0 250 C 500 (pF) 75 0 1000 1 0 10s/div 10s/div LOAD 8 _______________________________________________________________________________________ Beyond-the-Rails Op Amps M Typical Operating Characteristics (continued) (V CC = +5.0V, V = 0, V EE A = V /2, V = V , R = 100k to V +1.8V/10µA, /2, T = +25°C unless otherwise noted.) Single/Dual/Quad, SOT23, CM CC SHDN CC L CC A X 4 2 4 0 M A X 4 2 4 4 Pin Description – _______________________________________________________________________________________ 9 Beyond-the-Rails Op Amps _______________Detailed Description 4 2 4 Beyond-the-Rails Input Stage The MAX4240–MAX4244 have Beyond-the-Rails inputs and rail-to-rai l output stages that are specifically designed for low-voltage, single-supply operation. The X input stage consists of separate NPN and PNP differenA tial stages, which operate together to provide a comM mon-mode range extending to 200mV beyond b oth MAX4240 MAX4241 MAX4242 MAX4243 MAX4244 Single/Dual/Quad, +1.8V/10µA, SOT23, – CC EE 0 voltage is typically 200µV. Low operating supply voltage, 4 low supply current, beyond-the-rails common-mode input range, and rail-to-rail outputs make this family of 4 operational amplifiers an excellent choice for precision or general-purpose, low-voltage battery-powered systems. X Since the input stage consists of NPN and PNP pairs, Athe input bias current changes polarity as the commone passes impedance through theseen crossover Match voltag the effective by eachregion. input to M mode reduce the offset error caused by input bias currents flowing through external source impedances (Figures 1a and 1b). The combination of high source impedance plus input capacitance (amplifier input capacitance plus stray capacitance) creates a parasitic pole that produces an underdamped signal response. Reducing input capacitance or placing a small capacitor across the feedback resistor improves response in this case. The MAX4240–MAX4244 family’s inputs are protected from large differential input voltages by internal 2.2k series resistors and back-to-back triple-diode stacks across the inputs (Figure 2). For differential input voltages (much less than 1.8V), input resistance is typically 45M. For differential input voltages greater than 1.8V, input resistance is around 4.4k, and the input bias current can be approximated by the following equation: IBIAS = (VDIFF - 1.8V) / 4.4k R3 R3 = R1 R2 R1 R2 V Figure 1a. Minimizing Offset Error Due to Input Bias Current (Noninverting) MAX4240 MAX4241 MAX4242 MAX4243 R3 R3 = R1 R2 VIN R1 R2 Figure 1b. Minimizing Offset Error Due to Input Bias Current (Inverting) IN+ 2.2k MAX4244 IN2.2k Figure 2. Input Protection Circuit 10 ______________________________________________________________________________________ Single/Dual/Quad, +1.8V/10µA, SOT23, Beyond-the-Rails Op Amps M In the region w here t he d if ferent ial input voltag e approaches 1.8V, the input resistance decreases exponentially from 45Mto 4.4k as the diode block begins conducting. Conversely, the bias current increases with the same curve. MAX4240-44 fig03 A X RILN= 1 20.00kTIED TO VEE 1V/div fIN = 1kHz OUT Rail-to-Rail Output Stage The MAX4240–MAX4244 output stage can drive up to a 10k load and still swing to within 40mV of the rails. Figure 3 shows the output voltage swing of a MAX4240 configured as a unity-gain buffer, powered from a single +2V supply voltage. The output for this setup typically swings from (V + 6mV) to (V - 8mV) with a 100k load. __________Applications Information 1V/div IN 200s/div Figure 3. Rail-to-Rail Input/Output Voltage Range Power-Supply Considerations 4 fg 40 24 M 100 A high pow er-supply rejection ratio of 85dB allows the amplifiers to be powered directly off a decaying battery voltage, simplifying design and extending battery life. The MAX4240–MAX4244 are ideally suited for use with perature for operation down to a +1.8V single supply, even lower-voltage operation is possible in practice. Figures 4 and 5 show the PSRR and supply current as a function of supply voltage and temperature. 90 S ) d R R T = -40°C 70 A 1.0 1.2 1.4 1.6 1.8 2.0 SUPPLY VOLTAGE (V) Figure 4. Power-Supply Rejection Ratio vs. Supply Voltage Power-Up Settling Time The MAX4240–MAX4244 typically require 200µs to power up after V is stable. During this start-up time, 12 ) Shutdown Mode (SHDN) is pulled low, the supply current drops to 1µA enter a high-impedance state. Pulling SHDN high or leaving it floating enables the amplifier. Take care to ensure that parasitic leakage current at the SHDN pin does not inadvertently p lace the part into shutdown mode when SHDN is left floating. Figure 6 shows the output voltage response to a shutdown pulse. The logic threshold for SHDN is always referred to VCC / 2 (not to M A X The MAX4240–MAX4244 operate from a single +1.8V most battery-powered systems. Table 1 lists a variety of typical battery types showing voltage when fresh, voltage at end-of-life, capacity, and approximate operating tim e from a MAX4240/MAX4241, assuming nom inal conditions for both normal and shutdown modes. Although the amplifiers are fully guaranteed over tem- 4 2 4 0 R U C Y L S g 4 f4 0 2 4 X M 8 T = +85°C 4 T = -40°C T = +25°C 2 0 Figure 5. Supply Current vs. Supply Voltage ______________________________________________________________________________________ 11 4 2 4 4 Beyond-the-Rails Op Amps 4 4 2 4 Table 1. MAX4240/MAX4241 Characteristics with Typical Battery Systems BATTERY TYPE RECHARGEABLE VFRESH (V) VEND-OF-LIFE (V) CAPACITY, AA SIZE (mA-h) X A M – 0 4 2 4 MAX4240/MAX4241 OPERATING TIME IN NORMAL MODE (Hours) Alkaline (2 Cells) No 3.0 1.8 2000 Single/Dual/Quad, +1.8V/10µA, SOT23, Nickel- MAX4241 OPERATING TIME IN SHUTDOWN MODE (Hours) 200,000 2 x 106 Yes 2.4 1.8 750 75,000 0.75 x 106 Lithium-Ion (1 Cell) Yes 3.5 2.7 1000 100,000 106 Nickel-MetalHydride (2 Cells) Yes 2.4 1.8 1000 100,000 106 Cadmium (2 Cells) X MAX4240-44 fig06 A 1200 VIN = 2V RL = 100kTIED TO VEE M VC = 5.5V, O = 200mV V H ) 4 C A SHDN 5V/div OUT A 1000 T N S800 R U C E 400 C 600 U O O200 T U T U 1V/div = 1.8V, VO = 200mV VC = 5.5V, O = 100mV C V H H = 1.8V, V C VC = 100mV O H V a4 0 i4 - = 50mV VC = 5.5V, C VOH = 50mV V = 1.8V, V C C 0 200s/div -60 -40 -20 Figure 6. Shutdown Enable/Disable Output Voltage GND). When using dual supplies, pull SHDN to V enter shutdown mode. OH 40 60 80 20 TEMPERATURE (°C) 100 Figure 7a. Output Source Current vs. Temperature EE to 3000 V Load-Driving Capability The MAX4240–MAX4244 are fully guaranteed over temperature and supply voltage to drive a maximum resistive load of 10kto VCC / 2, although heavier loads can be driven in many applications. The rail-to-rail output stage of the amplifier can be modeled as a current source when driving the load toward VCC, and as a current sink when driving the load toward VEE. The magnitude of this current source/sink varies with sup ply voltage, ambient temperature, and lot-to-lot variations of the units. Figures 7a and 7b show the typical current source and sink capability of the MAX4240–MAX4244 family as a function of supply voltage and ambient tem perature. The contours on the graph depict the output current 12 0 ) 2500 = 5.5V, V CC = 200mV OL 4 X 2M VC = 1.8V, O = L 200mV C V = 5.5V, VO = 100mV L O = 100mV 500 T N E R 0 U C N1500 S T U P U VC = 5.5V, C VOL b0 i4 - VC = 1.8V, C VOL = 50mV = 50mV VC = 1.8V, C VOL -60 -40 -20 0 20 40 60 80 100 V TEMPERATURE (°C) Figure 7b. Output Sink Current vs. Temperature ______________________________________________________________________________________ Single/Dual/Quad, +1.8V/10µA, SOT23, Beyond-the-Rails Op Amps M value, based on driving the output voltage to within and VEE supplies should be bypassed to ground with 50mV, 100mV, and 200mV of either power-supply rail. separate 100nF capacitors. For example, a MAX4241 running from a single +1.8V Good PC board lay out techniques optimiz e perforsupply, operating at TA = +25°C, can source 240µA to mance by decreasing the amount of stray capacitance within 100mV of V and is capable of driving a 7kat the op amp’s inputs and output. To decrease stray load resistor to VEE: RL = 1.8V - 0.1V A X 4 2 4 0 capacitance, minimize trace lengths by placing external components as close as possible to the op amp. Surface-mount components are an excellent choice. 7kto V EE 240 M The same application can drive a 3.3k load resistor when terminated in VCC / 2 (+0.9V in this case). A X Driving Capacitive Loads The MAX4240–MAX4244 are unity-gain stable for loads up to 200pF (see Load Resistor vs. Capacitive Load R graph in Typical Operating Characteristics). Applications that require greater capacitive drive capability should use an isolation resistor between the output and results in a loss of gain accuracy because R voltage divider with the load resistor. 4 2 4 4 R forms a CL MAX4241 MAX4242 MAX4243 MAX4244 Power-Supply Bypassing and Layout The MAX4240–MAX4244 family operates from either a single +1.8V to +5.5V supply or dual ±0.9V to ±2.75V supplies . For single-supp ly operation, bypass the power supply with a 100nF capacitor to V (in this case GND). For dual-supply operation, both the V R A = L 1 ISO Figure 8a Using a Resistor to Isolate a Capacitive Load from the Op Amp MAX4240-44 fig08c MAX4240-44 fig08b 50mV/div IN 50mV/div IN 50mV/div OUT 50mV/div OUT 100s/div RISO = NONE, RL = 100k, CL = 700pF Figure 8b. Pulse Response without Isolating Resistor – 100s/div RISO = 1k, RL = 100k, CL = 700pF Figure 8c. Pulse Response with Isolating Resistor ______________________________________________________________________________________ 13 Beyond-the-Rails Op Amps Using the MAX4240–MAX4244 4 as Comparators 4 Although optimized for use as operational amplifiers, 2 the MAX4240–MAX4244 can also be used as rail-to-rail 4 I/O comparators. Typical propagation delay depends Using the MAX4240–MAX4244 as Ultra-Low-Power Current Monitors The MAX4240–MAX4244 are ideal for app lications powered from a 2-cell battery stack. Figure 11 shows an application circuit in which the MAX4240 is used for monitoring the current of a 2-cell battery stack. In this circuit, a current load is applied, and the voltage drop at the battery terminal is sensed. Single/Dual/Quad, +1.8V/10µA, SOT23, X on the input overdrive voltage, as shown in Figure 9. External hysteresis be used to minimize the risk of A output oscillation. Thecan positive feedback circuit, shown in Figure 10, causes the input threshold to change M – when the output voltage changes state. The two thresholds create a hysteresis band that can be calculated by 0 the following equations: 4 V =V -V 2 V = V x R2 / (R1 + (R1 x R2 / R ) + R2) 4 V = [(R2 / R1 x V ) + (R2 / R ) x V ]/ X (1 + R1 / R2 + R2 / R ) A The MAX4240–MAX4244 contain special circuitry to boost drive currents to thevoltage amplifier output stage. internal This maximizes the output range over which the amplifiers are linear. In an open-loop comparator application, the excursion of the output voltage is so close to the supply rails that the output stage transistors will saturate, causing the quiescent current to increase from the normal 10µA. Typical quiescent currents increase to 35µA for the output saturating at V and 28µA for the output at VEE. The voltage on the load side of the b attery stack is equal to the voltage at the em itter of Q1, due to the feedback loop containing the op amp. As the load current increases, the voltage d rop across R1 and R2 increases. Thus, R2 provides a fraction of the load current (set by the ratio of R1 and R2) that flows into the emitter of the PNP transistor. Neglecting PNP base current, this current flows into R3, producing a ground-referenced voltage proportional to the load current. Scale R1 to give a voltage drop large enough in comparison to VOS of the op amp, in order to minimize errors. The output voltage of the application can be calculated using the following equation: VOUT = [ILOAD x (R1 / R2)] x R3 For a 1V output and a current load of 50mA, the choice of resistors can be R1 = 2, R2 = 100k, R3 = 1M. The circuit consumes less power (but is more susceptible to noise) with higher values of R1, R2, and R3. INPUT VOH 10,000 HYSTERESIS VHI VLO M VOH t +; V = +5V PD 1000 OUTPUT C C VOL ) t -; V = +5V P D t D 9g f4 02 X C C 100 VIN RHYS T R1 tP +; C = D V C +1.8V VCC t -; V PD VOUT = +1.8V CC 10 0 10 20 30 40 50 60 70 80 90 100 R2 VE MAX4240 MAX4241 E VO (mV) D VEE Figure 9. Propagation Delay vs. Input Overdrive 14 Figure 10. Hysteresis Comparator Circuit ______________________________________________________________________________________ MAX4242 MAX4243 MAX4244 Beyond-the-Rails Op Amps M ___________________Chip Information A X MAX4240/MAX4241 TRANSISTOR COUNT: 234 MAX4242/MAX4243 R1 4 2 4 0 TRANSISTOR COUNT: 466 MAX4244 TRANSISTOR COUNT: 932 R2 M SUBSTRATE CONNECTED TO VEE Single/Dual/Quad, +1.8V/10µA, SOT23, Q1 A X VOU T R3 4 2 4 4 MAX4240 I VEE V Figure 11. Current Monitor for a 2-Cell Battery Stack _____________________________________________Pin Configurations (continued) TOP VIEW N.C. 1 8 SHDN OUTA 1 8 VCC IN- 2 7 VCC INA- 2 7 OUTB IN+ 3 6 OUT INA+ 3 6 INB- VEE 4 5 N.C. VEE 4 5 INB+ MAX4241 OUTA 1 10 V INA- 2 MAX4242 MAX4243 INA+ 3 6 SHDNB MA X SO/MAX 14 V CC INA- 2 13 INA+ 3 OUTA 1 14 OUTD OUTB INA- 2 13 IND- 12 INB- INA+ 3 12 IND+ 11 INB+ VCC 4 11 VEE 10 N.C. INB+ 5 10 INC+ SHDNA 6 9 SHDNB INB- 6 9 INC- N.C. 7 8 N.C. OUTB 7 8 OUTC VEE 4 MAX4243 N.C. 5 SO 8 INB7 INB+ SHDNA 5 OUTA 1 – 9 OUTB VEE 4 SO/MAX CC MAX4244 SO ______________________________________________________________________________________ 15 Beyond-the-Rails Op Amps Tape-and-Reel Information 4 4 2 4 0 2 X A M – 0 4 2 4 X A F Single/Dual/Quad, +1.8V/10µA, SOT23, K0 A0 E 1.753 0.102 P0 W B0 3.099 0.102 F 3.505 0.051 P010 D 1.499 +0.102 +0.000 K0 1.397 0.102 P22.007 3.988 0.102 t 0.051 t 0.254 W 8.001 0E +0.254 M P NOTE: DIMENSIONS ARE IN MM. AND FOLLOW EIA481-1 STANDARD. D1 0.991 P D 0.000 0.102 3.988 0 40.005 0.102 0.203 0.127 -0.102 +0.305 Package 5 5 -2 Information O (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.) S E L 3 SO Revision History Pages changed at Rev 3: 1, 8, 9, 16 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 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2006 Maxim Integrated Products is a registered trademark of Maxim Integrated Products. Inc.