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19-1343; Rev 0; 3/98
Single/Dual/Quad, +1.8V/10A, 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-RailsTM inputs and Rail-to-Rail (R) output capabilities. These amplifiers provide a 90kHz gain-bandwidth product while using only 10A of supply current per amplifier. The MAX4241/MAX4243 have a low-power shutdown mode that reduces supply current to less than 1A 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-therails inputs, rail-to-rail outputs, and ultra-low power 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 swing to within 9mV of the rails with a 100k load. Beyond-the-rails input and rail-to-rail output characteristics allow the full power-supply voltage 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/low-voltage precision applications. The MAX4240 is offered in a space-saving 5-pin SOT23 package. All specifications are guaranteed over the -40C to +85C extended temperature range.
____________________________Features
o Ultra-Low-Voltage Operation: Guaranteed Down to +1.8V Typical Operation to +1.5V o Ultra-Low Power Consumption: 10A Supply Current per Amplifier 1A Shutdown Mode (MAX4241/MAX4243) Up to 200,000 Hours Operation from Two AA Alkaline Cells o Beyond-the-Rails Input Common-Mode Range o Outputs Swing Rail-to-Rail o No Phase Reversal for Overdriven Inputs o 200V Input Offset Voltage o Unity-Gain Stable for Capacitive Loads up to 200pF o 90kHz Gain-Bandwidth Product o Available in Space-Saving 5-Pin SOT23 and 8-Pin MAX Packages
MAX4240-MAX4244
_______________Ordering Information
PART TEMP. RANGE PINPACKAGE 5 SOT23-5 8 MAX 8 SO 8 MAX 8 SO 10 MAX 14 SO 14 SO SOT TOP MARK ACCS -- -- -- -- -- -- --
MAX4240EUK-T -40C to +85C MAX4241EUA MAX4241ESA MAX4242EUA MAX4242ESA MAX4243EUB MAX4243ESD MAX4244ESD -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C
________________________Applications
Two-Cell BatteryPowered Systems Portable/Battery-Powered Electronic Equipment Digital Scales Strain Gauges Sensor Amplifiers Cellular Phones Notebook Computers PDAs
_____________________Selector Guide
PART MAX4240 MAX4241 MAX4242 MAX4243 MAX4244 NO. OF AMPS 1 1 2 2 4 SHUTDOWN -- Yes -- Yes -- PIN-PACKAGE 5-pin SOT23 8-pin MAX/SO 8-pin MAX/SO 10-pin MAX, 14-pin SO 14-pin SO
_________________Pin Configurations
TOP VIEW
OUT 1 5 VCC
VEE 2
MAX4240
IN+ 3
4
IN-
Beyond-the-Rails is a trademark of Maxim Integrated Products. Rail-to-Rail is a registered trademark of Nippon Motorola Ltd.
SOT23-5 Pin Configurations continued at end of data sheet.
________________________________________________________________ Maxim Integrated Products
1
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Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps MAX4240-MAX4244
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC to VEE) ....................................................6V All Other Pins ...................................(VCC + 0.3V) to (VEE - 0.3V) Output Short-Circuit Duration (to VCC or VEE)............Continuous Continuous Power Dissipation (TA = +70C) 5-pin SOT23 (derate 7.1mW/C above +70C).............571mW 8-pin MAX (derate 4.1mW/C above +70C) ..............330mW 8-pin SO (derate 5.88mW/C above +70C).................471mW 10-pin MAX (derate 5.6mW/C above +70C) ............444mW 14-pin SO (derate 8.33mW/C above +70C)...............667mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +160C Lead Temperature (soldering, 10sec) .............................+300C
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 -- TA = +25C
(VCC = +1.8V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC / 2, RL = 100k tied to VCC / 2, SHDN = VCC, TA = +25C, unless otherwise noted.) (Note 1) PARAMETER Supply-Voltage Range Supply Current per Amplifier Shutdown Supply Current (Note 2) SYMBOL VCC ICC ICC(SHDN) CONDITIONS Inferred from PSRR test SHDN = VCC SHDN = VEE VCC = 1.8V VCC = 5.0V VCC = 1.8V VCC = 5.0V MAX4241ESA Input Offset Voltage VOS (VEE - 0.2V) VCM (VCC + 0.2V) MAX4242ESA/MAX4243ESD/ MAX4244ESD MAX4240EUK/MAX424_EUA/ MAX4243EUB Input Bias Current Input Offset Current Differential Input Resistance Input Common-Mode Voltage Range IB IOS RIN(DIFF) VCM (Note 3) (Note 3) VIN+ - VIN- < 1.0V VIN+ - VIN- > 2.5V Inferred from the CMRR test MAX4241ESA VCC = 1.8V Common-Mode Rejection Ratio (Note 4) MAX4242ESA/MAX4243ESD/ MAX4244ESD MAX4240EUK/MAX424_EUA/ MAX4243EUB CMRR MAX4241ESA VCC = 5.0V MAX4242ESA/MAX4243ESD/ MAX4244ESD MAX4240EUK/MAX424_EUA/ MAX4243EUB VEE - 0.2 72 72 66 77 77 72 90 90 88 94 94 90 dB MIN 1.8 10 14 1.0 2.0 0.20 0.20 0.25 2 0.5 45 4.4 VCC + 0.2 TYP MAX 5.5 12 18 1.5 3.0 0.75 0.88 1.40 6 1.5 nA nA M k V mV UNITS V A A
2
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Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps
ELECTRICAL CHARACTERISTICS -- TA = +25C (continued)
(VCC = +1.8V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC / 2, RL = 100k tied to VCC / 2, SHDN = VCC, TA = +25C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MAX4241ESA Power-Supply Rejection Ratio PSRR 1.8V VCC 5.5V MAX4242ESA/MAX4243ESD/ MAX4244ESD MAX4240EUK/MAX424_EUA/ MAX4243EUB Large-Signal Voltage Gain (VEE + 0.2V) VOUT (VCC - 0.2V) VCC = 1.8V VCC = 5.0V VCC = 1.8V VCC = 5.0V VCC = 1.8V VCC = 5.0V RL = 100k RL = 10k RL = 100k RL = 10k RL = 100k RL = 10k RL = 100k RL = 10k RL = 100k RL = 10k RL = 100k RL = 10k MIN 80 80 78 80 70 90 82 TYP 85 85 82 85 73 94 85 8 40 10 60 6 23 10 40 0.7 2.5 20 50 20 65 25 95 15 35 20 60 mA mV mV dB dB MAX UNITS
MAX4240-MAX4244
AVOL
Output Voltage Swing High
VOH
Specified as VCC - VOH
Output Voltage Swing Low Output Short-Circuit Current Output Leakage Current in Shutdown (Notes 2, 5) SHDN Logic Low (Note 2) SHDN Logic High (Note 2) SHDN Input Bias Current (Note 2) Channel-to-Channel Isolation (Note 6) Gain-Bandwidth Product Phase Margin Gain Margin Slew Rate
VOL
Specified as VEE - VOL Sourcing Sinking
IOUT(SC)
IOUT(SHDN) SHDN = VEE = 0, VCC = 5.5V
nA
VIL VIH IIH, IIL CHISO GBW m Gm SR SHDN = VCC = 5.5V or SHDN = VEE = 0 Specified at DC 0.7 x VCC 40 80 90 68 18 40
0.3 x VCC
V V
80
nA dB kHz degrees dB V/ms
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3
Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps MAX4240-MAX4244
ELECTRICAL CHARACTERISTICS -- TA = +25C (continued)
(VCC = +1.8V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC / 2, RL = 100k tied to VCC / 2, SHDN = VCC, TA = +25C, unless otherwise noted.) (Note 1) PARAMETER Input Voltage Noise Density Input Current Noise Density Capacitive-Load Stability Shutdown Time Enable Time from Shutdown Power-Up Time Input Capacitance Total Harmonic Distortion Settling Time to 0.01% tSHDN tENABLE tON CIN THD tS fIN = 1kHz, VCC = 5.0V, VOUT = 2Vp-p, AV = +1V/V AV = +1V/V, VCC = 5.0V, VOUT = 2VSTEP SYMBOL en in f = 1kHz f = 1kHz AVCL = +1V/V, no sustained oscillations CONDITIONS MIN TYP 70 0.05 200 50 150 200 3 0.05 50 MAX UNITS nV/Hz pA/Hz pF s s s pF % s
ELECTRICAL CHARACTERISTICS -- TA = TMIN to TMAX
(VCC = +1.8V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC / 2, RL = 100k tied to VCC / 2, SHDN = VCC, TA = TMIN to TMAX, unless otherwise noted.) (Note 1) PARAMETER Supply-Voltage Range Supply Current per Amplifier Shutdown Supply Current (Note 2) SYMBOL VCC ICC ICC(SHDN) CONDITIONS Inferred from PSRR test SHDN = VCC SHDN = VEE VCC = 1.8V VCC = 5.0V VCC = 1.8V VCC = 5.0V MAX4241ESA Input Offset Voltage VOS (VEE - 0.2V) VCM (VCC + 0.2V) MAX4242ESA/MAX4243ESD/ MAX4244ESD MAX4240EUK/MAX424_EUA/ MAX4243EUB Input Offset Voltage Drift Input Bias Current Input Offset Current Input Common-Mode Voltage Range TCVOS IB IOS VCM (Note 3) (Note 3) Inferred from the CMRR test -0.2 2 15 7 VCC + 0.2 MIN 1.8 TYP MAX 5.5 14 19 2.0 3.5 1.2 1.3 2.0 V/C nA nA V mV UNITS V A A
4
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Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps
ELECTRICAL CHARACTERISTICS -- TA = TMIN to TMAX (continued)
(VCC = +1.8V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC / 2, RL = 100k tied to VCC / 2, SHDN = VCC, TA = TMIN to TMAX, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MAX4241ESA VCC = 1.8V Common-Mode Rejection Ratio (Note 4) MAX4242ESA/MAX4243ESD/ MAX4244ESD MAX4240EUK/MAX424_EUA/ MAX4243EUB CMRR MAX4241ESA VCC = 5.0V MAX4242ESA/MAX4243ESD/ MAX4244ESD MAX4240EUK/MAX424_EUA/ MAX4243EUB MAX4241ESA Power-Supply Rejection Ratio PSRR 1.8V VCC 5.5V MAX4242ESA/MAX4243ESD/ MAX4244ESD MAX4240EUK/MAX424_EUA/ MAX4243EUB (VEE + 0.2V) VOUT (VCC - 0.2V) VCC = 1.8V VCC = 5.0V VCC = 1.8V VCC = 5.0V VCC = 1.8V VCC = 5.0V Output Leakage Current in Shutdown (Notes 2, 5) SHDN Logic Low (Note 2) RL = 100k RL = 10k RL = 100k RL = 10k RL = 100k RL = 10k RL = 100k RL = 10k RL = 100k RL = 10k RL = 100k RL = 10k MIN 68 68 64 74 74 70 76 76 74 76 66 84 76 25 95 30 145 20 50 25 75 100 nA dB dB dB dB dB TYP MAX UNITS
MAX4240-MAX4244
Large-Signal Voltage Gain
AVOL
Output Voltage Swing High
VOH
Specified as VCC - VOH
Output Voltage Swing Low
VOL
Specified as VEE - VOL
IOUT(SHDN) SHDN = VEE = 0, VCC = 5.5V
VIL
0.3 x VCC
V
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5
Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps MAX4240-MAX4244
ELECTRICAL CHARACTERISTICS -- TA = TMIN to TMAX (continued)
(VCC = +1.8V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC / 2, RL = 100k tied to VCC / 2, SHDN = VCC, TA = TMIN to TMAX, unless otherwise noted.) (Note 1) PARAMETER SHDN Logic High (Note 2) SHDN Input Bias Current (Note 2) SYMBOL VIH IIH, IIL SHDN = VCC = 5.5V or SHDN = VEE = 0 CONDITIONS MIN 0.7 x VCC 120 TYP MAX UNITS V nA
Note 1: The MAX4240EUK, MAX4241EUA, MAX4242EUA, and MAX4243EUB specifications are 100% tested at TA = +25C. All temperature limits are guaranteed by design. Note 2: Shutdown mode applies to the MAX4241/MAX4243 only. Note 3: Input bias current and input offset current are tested with VCC = +5.0V and 0 VCM 5.0V. Note 4: Tested over the specified input common-mode range. Note 5: Tested for 0 VOUT VCC. Does not include current through external feedback network. Note 6: Channel-to-channel isolation specification applies to the MAX4242/MAX4243/MAX4244 only.
__________________________________________Typical Operating Characteristics
(VCC = +5.0V, VEE = 0, VCM = VCC / 2, V SHDN = VCC, RL = 100k to VCC / 2, TA = +25C, unless otherwise noted.)
SUPPLY CURRENT PER AMPLIFIER vs. TEMPERATURE
MAX4240/44-01
SHUTDOWN SUPPLY CURRENT PER AMPLIFIER vs. TEMPERATURE
MAX4240/44-02
MINIMUM OPERATING VOLTAGE vs. TEMPERATURE
1.7 1.6 1.5 VCC (V) PSRR 80dB
MAX4240/44-03
20 18 16 SUPPLY CURRENT (A) 14 12 10 8 6 4 2 0 -60 -40 -20 0 20 40 60 80 VCC = +1.8V VCC = +5.5V
5 SHUTDOWN SUPPLY CURRENT (A)
1.8
4
3 VCC = +5.5V 2 VCC = +1.8V 1
1.4 1.3 1.2 1.1
0 100 -60 -40 -20 0 20 40 60 80 100 TEMPERATURE (C) TEMPERATURE (C)
1.0 -60 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
INPUT OFFSET VOLTAGE vs. TEMPERATURE
MAX4240/44-04
INPUT BIAS CURRENT vs. TEMPERATURE
VCM = 0 VCC = +1.8V INPUT BIAS CURRENT (nA) -1 IBIAS (nA)
MAX4240/44-05
INPUT BIAS CURRENT vs. COMMON-MODE VOLTAGE (VCC = 1.8V)
VCC = +1.8V 2.5
MAX4240/44-06a
400
0
5.0
INPUT OFFSET VOLTAGE (V)
300
200
-2
VCC = +5.5V
0
100
-3
-2.5
0 -60 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
-4 -60 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
-5.0 -0.2 0.2 0.6 1.0 VCM (V) 1.4 1.8
6
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Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps
____________________________________Typical Operating Characteristics (continued)
(VCC = +5.0V, VEE = 0, VCM = VCC / 2, V SHDN = VCC, RL = 100k to VCC / 2, TA = +25C, unless otherwise noted.)
MAX4240-MAX4244
INPUT BIAS CURRENT vs. COMMON-MODE VOLTAGE (VCC = 5.5V)
MAX4240/44-06b
OUTPUT SWING HIGH vs. TEMPERATURE
MAX4240/44-07
OUTPUT SWING LOW vs. TEMPERATURE
RL TO VCC 100 VOLTAGE FROM VEE (mV) 80 60 VCC = +5.5V, RL = 20k 40 VCC = +1.8V, RL = 10k 20 0 80 100 -60 VCC = +5.5V, RL = 100k VCC = +1.8V, RL = 100k -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
MAX4240/44-08
5.0 VCC = +5.5V 2.5 IBIAS (nA)
120 RL TO VEE 100 VOLTAGE FROM VCC (mV) 80 60 40 20 VCC = +5.5V, RL = 100k VCC = +1.8V, RL = 100k -60 -40 -20 0 20 40 60 VCC = +1.8V, RL = 10k
120
0
VCC = +5.5V, RL = 20k
-2.5
-5.0 -0.5 0.5 1.5 2.5 VCM (V) 3.5 4.5 5.5
0
TEMPERATURE (C)
COMMON-MODE REJECTION vs. TEMPERATURE
MAX4240/44-09
OPEN-LOOP GAIN vs. OUTPUT SWING LOW (VCC = +1.8V, RL TIED TO VEE)
MAX4240/44-10
OPEN-LOOP GAIN vs. OUTPUT SWING HIGH (VCC = +1.8V, RL TIED TO VEE)
RL = 100k
MAX4240/44-11
-80 COMMON-MODE REJECTION (dB)
100 90 RL = 100k 80 GAIN (dB) 70 60 50 40 RL = 10k
100 90 80 GAIN (dB) 70 60 50 40 30
-85
RL = 10k
-90
VCC = +1.8V
-95
VCC = +5.5V
-100 -60 -40 -20 0 20 40 60 80 100 TEMPERATURE (C)
30 0 100 200 300 400 500 VOUT (mV)
0
100
200
300
400
500
VOUT (mV)
OPEN-LOOP GAIN vs. OUTPUT SWING LOW (VCC = +5.5V, RL TIED TO VEE)
MAX4240/44-12
OPEN-LOOP GAIN vs. OUTPUT SWING HIGH (VCC = +5.5V, RL TIED TO VEE)
MAX4240/44-13
OPEN-LOOP GAIN vs. TEMPERATURE
105 100 VCC = +5.5V, RL = 20k TO VEE
MAX4240/44-14
110 100 90 GAIN (dB) 80 70 60 50 40 0 100 200 VOUT (mV) 300 RL = 100k RL = 20k
110 100 90 GAIN (dB) 80 70 60 50 40 RL = 20k RL = 100k
110
GAIN (dB)
95 90 85 80 75 70 VCC = +1.8V, RL = 10k TO VEE VCC = +5.5V, RL = 20k TO VCC
VCC = +1.8V, RL = 10k TO VCC -60 -40 -20 0 20 40 60 80 100
400
0
100
200 VOUT (mV)
300
400
TEMPERATURE (C)
_______________________________________________________________________________________
7
Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps MAX4240-MAX4244
____________________________________Typical Operating Characteristics (continued)
(VCC = +5.0V, VEE = 0, VCM = VCC / 2, V SHDN = VCC, RL = 100k to VCC / 2, TA = +25C, unless otherwise noted.)
OPEN-LOOP GAIN vs. TEMPERATURE
MAX4240/44-15
GAIN AND PHASE vs. FREQUENCY (CL = 0pF)
60 50 40 30
110 105 100 GAIN (dB) 95 90 85 80 75 70 -60 -40 -20 0 20 40 60 80 VCC = +5.5V, RL TO VEE VCC = +5.5V, RL TO VCC VCC = +1.8V, RL TO VEE VCC = +1.8V, RL TO VCC
MAX4240/44-16
GAIN AND PHASE vs. FREQUENCY (CL = 100pF)
180 144 108 PHASE (DEGREES) 72 36 0 -36 -72 -108 -144 -180 60 50 40 30 GAIN (dB) 20 10 0 -10 -20 -30 -40 10 100 1k 10k 100k FREQUENCY (Hz)
MAX4240/44-17
180 144 108 PHASE (DEGREES) 72 36 0 -36 -72 -108 -144 -180
AV = +1000V/V
AV = +1000V/V
GAIN (dB) 100
20 10 0 -10 -20 -30 -40 10 100 1k 10k 100k
TEMPERATURE (C)
FREQUENCY (Hz)
MAX4242/MAX4243/MAX4244 CROSSTALK vs. FREQUENCY
MAX4240/44-18
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
MAX4240/44-19
LOAD RESISTOR vs. CAPACITIVE LOAD
10% OVERSHOOT REGION OF MARGINAL STABILITY 100
MAX4240/44-20
-60 RL = 10k -70
1
1000
THD + NOISE (%)
GAIN (dB)
-80
0.1
-90
RLOAD (k)
-100 RL = 100k RL = 10k -110 10 100 1k FREQUENCY (Hz) 10k 0.01 1 10 100 1000 FREQUENCY (Hz) 10 0
REGION OF STABLE OPERATION
250
500 CLOAD (pF)
750
1000
SMALL-SIGNAL TRANSIENT RESPONSE (NONINVERTING)
MAX4240/44-21
SMALL-SIGNAL TRANSIENT RESPONSE (INVERTING)
MAX4240/44-22
100mV IN 0V 50mV/div 100mV OUT 0V OUT 50mV/div IN
100mV
0V
100mV
0V
10s/div
10s/div
8
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Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps
____________________________________Typical Operating Characteristics (continued)
(VCC = +5.0V, VEE = 0, VCM = VCC / 2, V SHDN = VCC, RL = 100k to VCC / 2, TA = +25C, unless otherwise noted.)
LARGE-SIGNAL TRANSIENT RESPONSE (NONINVERTING)
MAX4240/44-23
MAX4240-MAX4244
LARGE-SIGNAL TRANSIENT RESPONSE (INVERTING)
MAX4240/44-24
4.5V IN 0.5V 2V/div 4.5V OUT 0.5V OUT 2V/div IN
+2V
-2V
+2V
-2V 100s/div
100s/div
______________________________________________________________Pin Description
PIN MAX4240 1 2 3 4 5 -- -- -- -- -- -- -- -- -- MAX4241 6 4 3 2 7 1, 5 8 -- -- -- -- -- -- -- MAX4242 -- 4 -- -- 8 -- -- 1, 7 2, 6 3, 5 -- -- -- -- MAX4243 MAX SO -- 4 -- -- 10 -- -- 1, 9 2, 8 3, 7 5, 6 -- -- -- -- 4 -- -- 14 5, 7, 8, 10 -- 1, 13 2, 12 3, 11 6, 9 -- -- -- MAX4244 -- 11 -- -- 4 -- -- 1, 7 2, 6 3, 5 -- 8, 14 9, 13 10, 12 NAME FUNCTION Amplifier Output. High impedance when in shutdown mode. Negative Supply. Tie to ground for singlesupply operation. Noninverting Input Inverting Input Positive Supply No Connection. Not internally connected. Shutdown Input. Drive high, or tie to VCC for normal operation. Drive to VEE to place device in shutdown mode. Outputs for Amplifiers A and B. High impedance when in shutdown mode. Inverting Inputs to Amplifiers A and B Noninverting Inputs to Amplifiers A and B Shutdown Inputs for Amplifiers A and B. Drive high, or tie to VCC for normal operation. Drive to VEE to place device in shutdown mode. Outputs for Amplifiers C and D Inverting Inputs to Amplifiers C and D Noninverting Inputs to Amplifiers C and D
OUT VEE IN+ INVCC N.C. SHDN OUTA, OUTB INA-, INBINA+, INB+ SHDNA, SHDNB OUTC, OUTD INC-, INDINC+, IND+
_______________________________________________________________________________________
9
Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps MAX4240-MAX4244
_______________Detailed Description
Beyond-the-Rails Input Stage
The MAX4240-MAX4244 have Beyond-the-RailsTM inputs and Rail-to-Rail(R) output stages that are specifically designed for low-voltage, single-supply operation. The input stage consists of separate NPN and PNP differential stages, which operate together to provide a common-mode range extending to 200mV beyond both supply rails. The crossover region of these two pairs occurs halfway between VCC and VEE. The input offset voltage is typically 200V. Low operating supply voltage, low supply current, beyond-the-rails common-mode input range, and rail-to-rail outputs make this family of operational amplifiers an excellent choice for precision or general-purpose, low-voltage battery-powered systems. Since the input stage consists of NPN and PNP pairs, the input bias current changes polarity as the commonmode voltage passes through the crossover region. Match the effective impedance seen by each input to 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
VIN R3
MAX4240 MAX4241 MAX4242 MAX4243 MAX4244
R3 = R1
R2
R1
R2
Figure 1a. Minimizing Offset Error Due to Input Bias Current (Noninverting)
R3
MAX4240 MAX4241 MAX4242 MAX4243 MAX4244
R3 = R1 VIN
R2
R1
R2
Figure 1b. Minimizing Offset Error Due to Input Bias Current (Inverting)
IN+ 2.2k
IN2.2k
Figure 2. Input Protection Circuit
10 ______________________________________________________________________________________
Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps
In the region where the differential input voltage approaches 1.8V, the input resistance decreases exponentially from 45M to 4.4k as the diode block begins conducting. Conversely, the bias current increases with the same curve.
MAX4240-MAX4244
MAX4240-44 fig03
1V/div
RL = 100k TIED TO VEE VIN = 2.0V 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 (VEE + 6mV) to (VCC - 8mV) with a 100k load.
1V/div
IN
__________Applications Information
Power-Supply Considerations
The MAX4240-MAX4244 operate from a single +1.8V to +5.5V supply (or dual 0.9V to 2.75V supplies) and consume only 10A of supply current per amplifier. A high power-supply rejection ratio of 90dB 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 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 time from a MAX4240/MAX4241, assuming nominal conditions for both normal and shutdown modes. Although the amplifiers are fully guaranteed over temperature 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.
100 TA = +85C 90 PSRR (dB)
200s/div
Figure 3. Rail-to-Rail Input/Output Voltage Range
80 TA = -40C 70 TA = +25C 60 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 200s to power up after VCC is stable. During this start-up time, the output is indeterminant. The application circuit should allow for this initial delay.
MAX4240-44 fig05
12 10 SUPPLY CURRENT (A) 8 TA = +85C 6 4 TA = +25C 2 0 1.0 1.2 1.4 1.6 1.8 TA = -40C
Shutdown Mode
The MAX4241 (single) and MAX4243 (dual) feature a low-power shutdown mode. When the shutdown pin (SHDN) is pulled low, the supply current drops to 1A per amplifier, the amplifier is disabled, and the outputs 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 place 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
2.0
SUPPLY VOLTAGE (V)
Figure 5. Supply Current vs. Supply Voltage
11
______________________________________________________________________________________
MAX4240-44 fig04
Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps MAX4240-MAX4244
Table 1. MAX4240/MAX4241 Characteristics with Typical Battery Systems
BATTERY TYPE RECHARGEABLE VFRESH (V) 3.0 2.4 3.5 2.4 VEND-OF-LIFE (V) 1.8 1.8 2.7 1.8 CAPACITY, AA SIZE (mA-h) 2000 750 1000 1000 MAX4240/MAX4241 OPERATING TIME IN NORMAL MODE (Hours) 200,000 75,000 100,000 100,000 MAX4241 OPERATING TIME IN SHUTDOWN MODE (Hours) 2 x 106 0.75 x 106 106 106
Alkaline (2 Cells) NickelCadmium (2 Cells) Lithium-Ion (1 Cell) Nickel-MetalHydride (2 Cells)
No Yes Yes Yes
MAX4240-44 fig06
SHDN 5V/div
OUTPUT SOURCE CURRENT (A)
VIN = 2V RL = 100k TIED TO VEE
VCC = 5.5V, VOH = 200mV 1000 800 600 400 200 0 VCC = 1.8V, VOH = 100mV VCC = 5.5V, VOH = 50mV VCC = 1.8V, VOH = 50mV -60 -40 -20 0 20 40 60 80 VCC = 1.8V, VOH = 200mV
VCC = 5.5V, VOH = 100mV
OUT
1V/div
200s/div
100
TEMPERATURE (C)
Figure 6. Shutdown Enable/Disable Output Voltage
Figure 7a. Output Source Current vs. Temperature
The MAX4240-MAX4244 are fully guaranteed over temperature and supply voltage to drive a maximum resistive load of 10k to 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 supply 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 temperature. The contours on the graph depict the output current
12
OUTPUT SINK CURRENT (A)
Load-Driving Capability
2500 2000 1500 1000 500 0 -60 -40
VCC = 5.5V, VOL = 200mV VCC = 1.8V, VOL = 200mV VCC = 5.5V, VOL = 100mV
VCC = 1.8V, VOL = 100mV VCC = 5.5V, VOL = 50mV VCC = 1.8V, VOL = 50mV -20 0 20 40 60 80 100 TEMPERATURE (C)
Figure 7b. Output Sink Current vs. Temperature
______________________________________________________________________________________
MAX4240-44 fig07b
GND). When using dual supplies, pull SHDN to VEE to enter shutdown mode.
3000
MAX4240-44 fig07a
1200
Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps
value, based on driving the output voltage to within 50mV, 100mV, and 200mV of either power-supply rail. For example, a MAX4241 running from a single +1.8V supply, operating at TA = +25C, can source 240A to within 100mV of VCC and is capable of driving a 7k load resistor to VEE: RL = 1.8V - 0.1V = 7k to VEE 240A and VEE supplies should be bypassed to ground with separate 100nF capacitors. Good PC board layout techniques optimize performance by decreasing the amount of stray capacitance at the op amp's inputs and output. To decrease stray capacitance, minimize trace lengths by placing external components as close as possible to the op amp. Surface-mount components are an excellent choice.
MAX4240-MAX4244
The same application can drive a 3.3k load resistor when terminated in VCC / 2 (+0.9V in this case).
Driving Capacitive Loads
The MAX4240-MAX4244 are unity-gain stable for loads up to 200pF (see Load Resistor vs. Capacitive Load graph in Typical Operating Characteristics). Applications that require greater capacitive drive capability should use an isolation resistor between the output and the capacitive load (Figure 8). Note that this alternative results in a loss of gain accuracy because RISO forms a voltage divider with the load resistor.
RISO
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-supply operation, bypass the power supply with a 100nF capacitor to VEE (in this case GND). For dual-supply operation, both the V CC
MAX4240 MAX4241 MAX4242 MAX4243 MAX4244
RL
CL
AV =
RL 1 RL + RISO
Figure 8a Using a Resistor to Isolate a Capacitive Load from the Op Amp
MAX4240-44 fig08b
MAX4240-44 fig08c
50mV/div
IN
50mV/div
IN
50mV/div
OUT
50mV/div
OUT
100s/div RISO = NONE, RL = 100k, CL = 700pF
100s/div RISO = 1k, RL = 100k, CL = 700pF
Figure 8b. Pulse Response without Isolating Resistor
Figure 8c. Pulse Response with Isolating Resistor
13
______________________________________________________________________________________
Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps MAX4240-MAX4244
Using the MAX4240-MAX4244 as Comparators
Although optimized for use as operational amplifiers, the MAX4240-MAX4244 can also be used as rail-to-rail I/O comparators. Typical propagation delay depends on the input overdrive voltage, as shown in Figure 9. External hysteresis can be used to minimize the risk of output oscillation. The positive feedback circuit, shown in Figure 10, causes the input threshold to change when the output voltage changes state. The two thresholds create a hysteresis band that can be calculated by the following equations: VHYST = VHI - VLO VLO = VIN x R2 / (R1 + (R1 x R2 / RHYST) + R2) V HI = [(R2 / R1 x V IN ) + (R2 / R HYST ) x V CC ] / (1 + R1 / R2 + R2 / RHYST) The MAX4240-MAX4244 contain special circuitry to boost internal drive currents to the amplifier output stage. This maximizes the output voltage 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 10A. Typical quiescent currents increase to 35A for the output saturating at VCC and 28A for the output at VEE.
Using the MAX4240-MAX4244 as Ultra-Low-Power Current Monitors
The MAX4240-MAX4244 are ideal for applications 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. The voltage on the load side of the battery stack is equal to the voltage at the emitter of Q1, due to the feedback loop containing the op amp. As the load current increases, the voltage drop 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.
MAX4240-44 fig09
10,000
INPUT VOH
VHI VLO
HYSTERESIS
VOH OUTPUT VOL
1000 tPD (s)
tPD+; VCC = +5V tPD-; VCC = +5V
VIN 100 tPD+; VCC = +1.8V tPD-; VCC = +1.8V 10 0 10 20 30 40 50 60 70 80 VOD (mV) 90 100 R2 R1
RHYST VCC VOUT
VEE
VEE
MAX4240 MAX4241 MAX4242 MAX4243 MAX4244
Figure 9. Propagation Delay vs. Input Overdrive
14
Figure 10. Hysteresis Comparator Circuit
______________________________________________________________________________________
Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps
___________________Chip Information
ILOAD R1 VCC R2
MAX4240-MAX4244
MAX4240/MAX4241 TRANSISTOR COUNT: 234 MAX4242/MAX4243 TRANSISTOR COUNT: 466 MAX4244 TRANSISTOR COUNT: 932 SUBSTRATE CONNECTED TO VEE
Q1 VOUT
R3
MAX4240
VEE
Figure 11. Current Monitor for a 2-Cell Battery Stack
_____________________________________________Pin Configurations (continued)
TOP VIEW
N.C. 1 IN- 2
8 7
SHDN VCC OUT N.C.
OUTA 1 INA- 2
8 7
VCC OUTB INB-
OUTA 1 INAINA+ 2 3 4 5
10 VCC 9 OUTB INBINB+ SHDNB
MAX4241
IN+ 3 6 5 VEE 4
MAX4242
INA+ 3 6 5 VEE 4 INB+
MAX4243
8 7 6
VEE SHDNA
SO/MAX
SO/MAX
MAX
OUTA 1 INAINA+ 2 3
14 VCC 13 OUTB 12 INB-
OUTA 1 INAINA+ 2 3
14 OUTD 13 IND12 IND+
VEE 4 N.C. 5 SHDNA 6 N.C. 7
MAX4243
11 INB+ 10 N.C. 9 8 SHDNB N.C.
VCC 4 INB+ 5 INB- 6 OUTB 7
MAX4244
11 VEE 10 INC+ 9 8 INCOUTC
SO
SO
______________________________________________________________________________________
15
Single/Dual/Quad, +1.8V/10A, SOT23, Beyond-the-Rails Op Amps MAX4240-MAX4244
__________________________________________________Tape-and-Reel Information
E D P0 P2 W B0
F
D1
t
NOTE: DIMENSIONS ARE IN MM. AND FOLLOW EIA481-1 STANDARD.
P A0
K0
A0 B0 D D1
3.200 3.099 1.499 0.991
0.102 0.102 +0.102 +0.000 +0.254 +0.000
E F K0 P
1.753 3.505 1.397 3.988
0.102 0.051 0.102 0.102
P0 P010 P2 t W
3.988 40.005 2.007 0.254 8.001
0.102 0.203 0.051 0.127 +0.305 -0.102
5 SOT23-5
________________________________________________________Package Information
SOT5L.EPS
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 (c) 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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