________________General Description
The MAX4040–MAX4044 family of micropower op amps
operates from a single +2.4V to +5.5V supply or dual
±1.2V to ±2.75V supplies and have rail-to-rail input and
output capabilities. These amplifiers provide a 90kHz
gain-bandwidth product while using only 10µA of supply
current per amplifier. The MAX4041/MAX4043 have a
low-power shutdown mode that reduces supply current
to less than 1µA and forces the output into a high-imped-
ance state. The combination of low-voltage operation,
rail-to-rail inputs and outputs, and ultra-low power con-
sumption makes these devices ideal for any
portable/battery-powered system.
These amplifiers have outputs that typically swing to
within 10mV of the rails with a 100kΩload. Rail-to-rail
input and output characteristics allow the full power-
supply voltage to be used for signal range. The combi-
nation 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 MAX4040 is offered in a space-saving 5-pin SOT23
package. All specifications are guaranteed over the
-40°C to +85°C extended temperature range.
________________________Applications
Battery-Powered Strain Gauges
Systems Sensor Amplifiers
Portable/Battery-Powered Cellular Phones
Electronic Equipment Notebook Computers
Digital Scales PDAs
____________________________Features
♦Single-Supply Operation Down to +2.4V
♦Ultra-Low Power Consumption:
10µA Supply Current per Amplifier
1µA Shutdown Mode (MAX4041/MAX4043)
♦Rail-to-Rail Input Common-Mode Range
♦Outputs Swing Rail-to-Rail
♦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
8-Pin µMAX®Packages
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower Rail-to-Rail I/O Op Amps
________________________________________________________________ Maxim Integrated Products 1
VEE
IN-IN+
15VCC
OUT
MAX4040
SOT23-5
TOP VIEW
2
34
19-1377; Rev 1; 9/05
PART
MAX4040EUK-T
MAX4040EUA
MAX4040ESA -40°C to +85°C
-40°C to +85°C
-40°C to +85°C
TEMP RANGE PIN-
PACKAGE
5 SOT23-5
8 µMAX
8 SO
Ordering Information
Pin Configurations continued at end of data sheet.
NO. OF
AMPS PIN-PACKAGE
MAX4040 15-pin SOT23,
8-pin µMAX/SO
PART
MAX4041 18-pin µMAX/SO
SHUTDOWN
—
Yes
MAX4044 414-pin SO—
µMAX is a registered trademark of Maxim Integrated Products, Inc.
MAX4042EUA
MAX4042ESA -40°C to +85°C
-40°C to +85°C 8 µMAX
8 SO
MAX4044ESD -40°C to +85°C 14 SO
SOT
TOP MARK
ACGF
—
—
—
—
—
Pin Configurations
Selector Guide
MAX4042 28-pin µMAX/SO—
MAX4043 210-pin µMAX/
14-pin SO
Yes
MAX4041ESA
MAX4041EUA -40°C to +85°C
-40°C to +85°C 8 SO
8 µMAX
—
—
MAX4043EUB
MAX4043ESD -40°C to +85°C
-40°C to +85°C 10 µMAX
14 SO
—
—
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.
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
2_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS—TA= +25°C
(VCC = +5.0V, VEE = 0V, VCM = 0V, VOUT = VCC / 2, SHDN = VCC, RL= 100kΩtied to VCC / 2, unless otherwise noted.)
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.
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= +70°C)
5-Pin SOT23 (derate 7.1mW/°C above +70°C).............571mW
8-Pin µMAX (derate 4.1mW/°C above +70°C) ..............330mW
8-Pin SO (derate 5.88mW/°C above +70°C).................471mW
10-Pin µMAX (derate 5.6mW/°C above +70°C) ...........444mW
14-Pin SO (derate 8.33mW/°C above +70°C)..............667mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
14 20VCC = 5.0V
(Note 1)Input Offset Current IOS ±0.5 ±3.0 nA
(Note 1)
VIN+ - VIN-< 1.0V
Differential Input
Resistance RIN(DIFF)
45 MΩ
2.0 5.0
VIN+ - VIN-> 2.5V
SHDN = VEE, MAX4041
and MAX4043 only
Large-Signal
Voltage Gain
Shutdown Supply
Current per Amplifier ICC(SHDN)
1.0
Supply-Voltage Range VCC 2.4 5.5 VInferred from PSRR test
Output Voltage
Swing High
4.4 kΩ
VOH
Inferred from the CMRR test
mV
AVOL dB
PARAMETER SYMBOL MIN TYP MAX UNITS
Supply Current
per Amplifier ICC
10 µA
94
VCC = 2.4V
10
Specified as VCC - VOH
Power-Supply
Rejection Ratio PSRR dB
(VEE + 0.2V) ≤VOUT ≤(VCC - 0.2V)
60 90
74 85
Output Voltage
Swing Low
Input Common-Mode
Voltage Range
RL= 100kΩ
RL= 25kΩ
RL= 100kΩ
RL= 25kΩ
µA
VCM VEE VCC V
2.4V ≤VCC ≤5.5V 75 85
VCC = 2.4V
VOL mV
10
Specified as VEE - VOL
Input Bias Current IB±2 ±10 nA
40 60
RL= 100kΩ
RL= 25kΩ
Output Short-Circuit
Current IOUT(SC) mA
0.7Sourcing
2.5
Channel-to-Channel
Isolation
Sinking
dB
CONDITIONS
80Specified at DC, MAX4042/MAX4043/MAX4044 only
VCC = 5.0V
±0.20 ±2.0
VOS
Input Offset Voltage mV
±0.25 ±2.5
VEE ≤VCM ≤VCC 70 94 dBCMRR
Common-Mode
Rejection Ratio
MAX404_EU_
All other packages
65 94
VEE ≤VCM ≤VCC
MAX4044ESD
MAX404_EU_
All other packages mV±0.20 ±1.50
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS—TA= +25°C (continued)
(VCC = +5.0V, VEE = 0V, VCM = 0V, VOUT = VCC / 2, SHDN = VCC, RL= 100kΩtied to VCC / 2, unless otherwise noted.)
MAX4040–MAX4044
PARAMETER SYMBOL MIN TYP MAX UNITSCONDITIONS
Supply Current
per Amplifier ICC 28
Supply-Voltage Range VCC 2.4 5.5 VInferred from PSRR test
(Note 1)Input Offset Current IOS ±8 nA
Input Voltage Noise Density en70 nV/√Hz
Input Current Noise Density in0.05 pA/√Hz
Capacitive-Load Stability 200 pF
Power-Up Time tON 200 µs
Input Capacitance CIN 3pF
f = 1kHz
f = 1kHz
AVCL = +1V/V, no sustained oscillations
Slew Rate SR 40 V/ms
Total Harmonic Distortion THD 0.05 %
Settling Time to 0.01% tS50 µs
fIN = 1kHz, VOUT = 2Vp-p, AV= +1V/V
AV= +1V/V, VOUT = 2VSTEP
PARAMETER SYMBOL MIN TYP MAX UNITSCONDITIONS
Gain Margin Gm18 dB
Output Leakage Current in
Shutdown IOUT(SHDN)20 100 nA
SHDN = VEE = 0, MAX4041/MAX4043 only
(Note 2)
µA
6.0
SHDN = VEE, MAX4041 and MAX4043 only
Shutdown Supply
Current per Amplifier ICC(SHDN)µA
Shutdown Time tSHDN 50 µsMAX4041 and MAX4043 only
Enable Time from Shutdown tEN 150 µsMAX4041 and MAX4043 only
ELECTRICAL CHARACTERISTICS—TA= TMIN to TMAX
(VCC = +5.0V, VEE = 0V, VCM = 0V, VOUT = VCC / 2, SHDN = VCC, RL= 100kΩtied to VCC / 2, unless otherwise noted.) (Note 3)
Input Offset Voltage Drift TCVOS 2µV/°C
(Note 1)Input Bias Current IB±20 nA
Phase Margin Φm68 degrees
±4.5
SHDN Logic Low VIL 0.3 x VCC VMAX4041/MAX4043 only
SHDN Logic High VIH 0.7 x VCC VMAX4041/MAX4043 only
SHDN Input Bias Current IIH, IIL 40 120 nAMAX4041/MAX4043 only
Gain Bandwidth Product GBW 90 kHz
±5.0VOS
Input Offset Voltage mV
±3.5
VEE ≤VCM ≤VCC
MAX4044ESA
All other packages
MAX404_EU_
20
0
-60 -40 -20 20 40 100
SUPPLY CURRENT PER AMPLIFIER
vs. TEMPERATURE
6
4
2
16
14
18
MAX4040/44-01
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
060
10
8
12
80
VCC = +5.5V
VCC = +2.4V
5
0
-60 -40 -20 020 40 100
MAX4041/MAX4043
SHUTDOWN SUPPLY CURRENT
PER AMPLIFIER vs. TEMPERATURE
1
4
MAX4040/44-01.5
TEMPERATURE (°C)
SHUTDOWN SUPPLY CURRENT (µA)
60
2
3
80
VCC = +5.5V
SHDN = 0
VCC = +2.4V
__________________________________________Typical Operating Characteristics
(VCC = +5.0V, VEE = 0, VCM = VCC / 2, SHDN = VCC, RL= 100kΩto VCC / 2, TA= +25°C, unless otherwise noted.)
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
4_______________________________________________________________________________________
Large-Signal Voltage
Gain
Output Voltage Swing
High VOH
Inferred from the CMRR test
mV
AVOL dB
PARAMETER SYMBOL MIN TYP MAX UNITS
Specified as VCC - VOH, RL= 25kΩ
Common-Mode
Rejection Ratio CMRR dB
(VEE + 0.2V) ≤VOUT ≤(VCC - 0.2V), RL= 25kΩ
125
68
Output Voltage Swing
Low
Input Common-Mode
Voltage Range VCM VEE VCC V
60
VOL mV
Specified as VEE - VOL, RL= 25kΩ75
CONDITIONS
ELECTRICAL CHARACTERISTICS—TA= TMIN to TMAX (continued)
(VCC = +5.0V, VEE = 0V, VCM = 0V, VOUT = VCC / 2, SHDN = VCC, RL= 100kΩtied to VCC / 2, unless otherwise noted.) (Note 3)
Note 1: Input bias current and input offset current are tested with VCC = +5.0V and +0.5V ≤VCM ≤+4.5V.
Note 2: Tested for VEE ≤VOUT ≤VCC. Does not include current through external feedback network.
Note 3: All devices are 100% tested at TA= +25°C. All temperature limits are guaranteed by design.
Power-Supply
Rejection Ratio PSRR dB2.4V ≤VCC ≤5.5V 70
MAX404_EU_
VEE ≤VCM ≤VCC All other packages 65
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
_______________________________________________________________________________________ 5
120
0
-60 -40 -20 20 40 100
OUTPUT SWING HIGH
vs. TEMPERATURE
20
100
80
MAX4040/44-07
TEMPERATURE (°C)
VOLTAGE FROM VCC (mV)
060
60
40
80
VCC = +2.4V, RL = 10kΩ
RL TO VEE
VCC = +5.5V, RL = 20kΩ
VCC = +5.5V, RL = 100kΩ
VCC = +2.4V, RL = 100kΩ
120
0
-60 -40 -20 20 40 100
OUTPUT SWING LOW
vs. TEMPERATURE
20
100
80
MAX4040/44-08
TEMPERATURE (°C)
VOLTAGE FROM VEE (mV)
060
60
40
80
VCC = +2.4V, RL = 10kΩ
VCC = +5.5V, RL = 20kΩ
VCC = +5.5V, RL = 100kΩ
VCC = +2.4V, RL = 100kΩ
RL TO VCC
-80
-100
-60 -40 -20 20 40 100
COMMON-MODE REJECTION
vs. TEMPERATURE
-95
-85
MAX4040/44-09
TEMPERATURE (°C)
COMMON-MODE REJECTION (dB)
060
-90
80
VCC = +2.4V
VCC = +5.5V
0
-4
-60 -40 -20 20 40 100
INPUT BIAS CURRENT
vs. TEMPERATURE
-3
-1
MAX4040/44-04
TEMPERATURE (°C)
INPUT BIAS CURRENT (nA)
060
-2
80
VCM = 0
VCC = +2.4V
VCC = +5.5V
5.0
-5.0
0 0.5 1.5 2.5 3.5 4.5
INPUT BIAS CURRENT vs.
COMMON-MODE VOLTAGE (VCC = 5.5V)
-2.5
2.5
MAX4040/44-06
VCM (V)
IBIAS (nA)
0
5.5
VCC = +5.5V
400
0
-60 -40 -20 20 40 100
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
100
300
MAX4040/44-03
TEMPERATURE (°C)
INPUT OFFSET VOLTAGE (µV)
060
200
80
Typical Operating Characteristics (continued)
(VCC = +5.0V, VEE = 0, VCM = VCC / 2, SHDN = VCC, RL= 100kΩto VCC / 2, TA= +25°C, unless otherwise noted.)
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
6_______________________________________________________________________________________
100
110
0 100 200 300 400
OPEN-LOOP GAIN vs. OUTPUT SWING HIGH
(VCC = +5.5V, RL TIED TO VEE)
50
40
90
80
MAX4040/44-13
∆VOUT (mV)
GAIN (dB)
70
60
RL = 20kΩ
RL = 100kΩ
100
110
0 100 200 300 400
OPEN-LOOP GAIN vs. OUTPUT SWING LOW
(VCC = +5.5V, RL TIED TO VCC)
50
40
90
80
MAX4040/44-12
∆VOUT (mV)
GAIN (dB)
70
60
RL = 100kΩ
RL = 20kΩ
____________________________________Typical Operating Characteristics (continued)
(VCC = +5.0V, VEE = 0, VCM = VCC / 2, SHDN = VCC, RL= 100kΩto VCC / 2, TA= +25°C, unless otherwise noted.)
60
-40
10 100 1k 10k 100k
GAIN AND PHASE vs. FREQUENCY
(NO LOAD)
-20
-30
MAX4040/44-16
FREQUENCY (Hz)
GAIN (dB)
0
-10
20
10
30
40
50
180
-180
-108
-144
PHASE (DEGREES)
-36
-72
36
0
72
108
144
AV = +1000V/V
60
-40
10 100 1k 10k 100k
GAIN AND PHASE vs. FREQUENCY
(CL = 100pF)
-20
-30
MAX4040/44-17
FREQUENCY (Hz)
GAIN (dB)
0
-10
20
10
30
40
50
180
-180
-108
-144
PHASE (DEGREES)
-36
-72
36
0
72
108
144
AV = +1000V/V
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
_______________________________________________________________________________________ 7
____________________________________Typical Operating Characteristics (continued)
(VCC = +5.0V, VEE = 0, VCM = VCC / 2, SHDN = VCC, RL= 100kΩto VCC / 2, TA= +25°C, unless otherwise noted.)
1
0.01
1 100010010
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
0.1
MAX4040/44-19
FREQUENCY (Hz)
THD + NOISE (%)
RL = 10kΩ
RL = 100kΩ
1000
10
0 250 500 1000
LOAD RESISTOR vs.
CAPACITIVE LOAD
MAX4040/44-20
CLOAD (pF)
RLOAD (kΩ)
750
100
10%
OVERSHOOT
REGION OF
MARGINAL STABILITY
REGION OF
STABLE OPERATION
10µs/div
SMALL-SIGNAL TRANSIENT RESPONSE
(NONINVERTING)
MAX4040/44-21
50mV/div
100mV
100mV
IN
OUT
0V
0V
10µs/div
SMALL-SIGNAL TRANSIENT RESPONSE
(INVERTING)
MAX4040/44-22
50mV/div
100mV
100mV
IN
OUT
0V
0V
100µs/div
LARGE-SIGNAL TRANSIENT RESPONSE
(NONINVERTING)
MAX4040/42/44-23
2V/div
4.5V
0.5V
4.5V
IN
0.5V
OUT
100µs/div
LARGE-SIGNAL TRANSIENT RESPONSE
(INVERTING)
MAX4040/42/44-24
2V/div
+2V
-2V
-2V
+2V
IN
OUT
-60
-110
10 1k 10k
100
MAX4042/MAX4043/MAX4044
CROSSTALK vs. FREQUENCY
-100
MAX4040/44-18
FREQUENCY (Hz)
GAIN (dB)
-90
-80
-70
RL = 10kΩ
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
8_______________________________________________________________________________________
_______________Detailed Description
Rail-to-Rail Input Stage
The MAX4040–MAX4044 have rail-to-rail inputs and
rail-to-rail 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 both supply rails. The
crossover region of these two pairs occurs halfway
between VCC and VEE. The input offset voltage is typi-
cally 200µV. Low operating supply voltage, low supply
current, rail-to-rail 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 common-
mode 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.
______________________________________________________________Pin Description
1 —— — —
2 44 4 11 Negative Supply. Tie to ground for
single-supply operation.
VEE
3 —
Amplifier Output. High impedance
when in shutdown mode.
OUT
— — —
4 —— — — Inverting InputIN-
Noninverting InputIN+
510814 4
— —— 5, 7,
8, 10 —No Connection. Not internally con-
nected.
N.C.
— —
Positive SupplyVCC
— — —
—1, 91, 7 1, 13 1, 7 Outputs for Amplifiers A and B. High
impedance when in shutdown mode.
OUTA,
OUTB
Shutdown Input. Drive high, or tie to
VCC for normal operation. Drive to VEE
to place device in shutdown mode.
SHDN
—2, 82, 6 2, 12 2, 6
—3, 73, 5 3, 11 3, 5 Noninverting Inputs to Amplifiers A
and B
INA+,
INB+
—5, 6
Inverting Inputs to Amplifiers A and B
INA-,
INB-
—6, 9 —
— —— — 8, 14 Outputs for Amplifiers C and D
OUTC,
OUTD
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.
SHDNA,
SHDNB
— —— — 9, 13
— —— — 10, 12 Noninverting Inputs to Amplifiers C
and D
INC+,
IND+
Inverting Inputs to Amplifiers C and D
INC-,
IND-
6
4
3
2
7
1, 5
8
—
—
—
—
—
—
—
6
4
3
2
7
1, 5, 8
—
—
—
—
—
—
—
—
MAX4043 MAX4044
PIN
µMAX
MAX4042 SO
MAX4041 FUNCTIONNAME
SOT23-5
MAX4040
SO/µMAX
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
_______________________________________________________________________________________ 9
The MAX4040–MAX4044 family’s inputs are protected
from large differential input voltages by internal 2.2kΩ
series resistors and back-to-back triple-diode stacks
across the inputs (Figure 2). For differential input volt-
ages (much less than 1.8V), input resistance is typically
45MΩ. For differential input voltages greater than 1.8V,
input resistance is around 4.4kΩ, and the input bias
current can be approximated by the following equation:
IBIAS = (VDIFF - 1.8V) / 4.4kΩ
In the region where the differential input voltage
approaches 1.8V, the input resistance decreases expo-
nentially from 45MΩto 4.4kΩas the diode block begins
conducting. Conversely, the bias current increases with
the same curve.
Rail-to-Rail Output Stage
The MAX4040–MAX4044 output stage can drive up to a
25kΩload and still swing to within 60mV of the rails.
Figure 3 shows the output voltage swing of a MAX4040
configured as a unity-gain buffer, powered from a single
+4.0V supply voltage. The output for this setup typically
swings from (VEE + 10mV) to (VCC - 10mV) with a 100kΩ
load.
Applications Information
Power-Supply Considerations
The MAX4040–MAX4044 operate from a single +2.4V to
+5.5V supply (or dual ±1.2V to ±2.75V supplies) and
consume only 10µA of supply current per amplifier. A
high power-supply rejection ratio of 85dB allows the
amplifiers to be powered directly off a decaying battery
voltage, simplifying design and extending battery life.
Power-Up Settling Time
The MAX4040–MAX4044 typically require 200µs 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.
R3
R3 = R1 R2
R1 R2
MAX4040–
MAX4044
VIN
Figure 1b. Minimizing Offset Error Due to Input Bias Current
(Inverting)
2.2kΩ
2.2kΩ
IN-
IN+
Figure 2. Input Protection Circuit
R3
VIN
R3 = R1 R2
R1 R2
MAX4040–
MAX4044
Figure 1a. Minimizing Offset Error Due to Input Bias Current
(Noninverting)
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
10 ______________________________________________________________________________________
Shutdown Mode
The MAX4041 (single) and MAX4043 (dual) feature a
low-power shutdown mode. When the shutdown pin
(SHDN) is pulled low, the supply current drops to 1µA
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 4 shows the
output voltage response to a shutdown pulse. The logic
threshold for SHDN is always referred to VCC / 2 (not to
GND). When using dual supplies, pull SHDN to VEE to
enter shutdown mode.
Load-Driving Capability
The MAX4040–MAX4044 are fully guaranteed over tem-
perature and supply voltage to drive a maximum resis-
tive load of 25kΩto 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 cur-
rent sink when driving the load toward VEE. The magni-
tude of this current source/sink varies with supply
voltage, ambient temperature, and lot-to-lot variations
of the units.
Figures 5a and 5b show the typical current source and
sink capability of the MAX4040–MAX4044 family as a
function of supply voltage and ambient temperature.
The contours on the graph depict the output current
value, based on driving the output voltage to within
50mV, 100mV, and 200mV of either power-supply rail.
1200
0
-60 -40 -20 100
200
400
1000
MAX4040-44 fig05a
TEMPERATURE (°C)
OUTPUT SOURCE CURRENT (µA)
04020
600
800
8060
VCC = 5.5V, VOH = 200mV
VCC = 5.5V, VOH = 100mV
VCC = 2.4V, VOH = 50mV
VCC = 5.5V, VOH = 50mV
VCC = 2.4V,
VOH = 200mV
VCC = 2.4V,
VOH = 100mV
Figure 5a. Output Source Current vs. Temperature
3000
0
-60 -40 -20 100
500
1000
2500
MAX4040-44 fig05b
TEMPERATURE (°C)
OUTPUT SINK CURRENT (µA)
04020
1500
2000
8060
VCC = 5.5V, VOL = 200mV
VCC = 2.4V, VOL = 200mV
VCC = 5.5V,
VOL = 100mV
VCC = 2.4V, VOL = 50mV
VCC = 5.5V, VOL = 50mV
VCC = 2.4V, VOL = 100mV
Figure 5b. Output Sink Current vs. Temperature
1V/div OUT
IN
1V/div
MAX4040-44 fig03
200µs/div
RL = 100kΩ TIED TO VEE
VIN = 4.0V
fIN = 1kHz
Figure 3. Rail-to-Rail Input/Output Voltage Range
MAX4040-44 fig04
200µs/div
5V/div
1V/div
SHDN
OUT
VIN = 2V
RL = 100kΩ TIED TO VEE
Figure 4. Shutdown Enable/Disable Output Voltage
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
______________________________________________________________________________________ 11
For example, a MAX4040 running from a single +2.4V
supply, operating at TA= +25°C, can source 240µA to
within 100mV of VCC and is capable of driving a 9.6kΩ
load resistor to VEE:
The same application can drive a 4.6kΩload resistor
when terminated in VCC / 2 (+1.2V in this case).
Driving Capacitive Loads
The MAX4040–MAX4044 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 capa-
bility should use an isolation resistor between the output
and the capacitive load (Figures 6a–6c). Note that this
alternative results in a loss of gain accuracy because
RISO forms a voltage divider with the load resistor.
Power-Supply Bypassing and Layout
The MAX4040–MAX4044 family operates from either a
single +2.4V to +5.5V supply or dual ±1.2V 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 VCC
and VEE supplies should be bypassed to ground with
separate 100nF capacitors.
Good PC board layout techniques optimize perfor-
mance by decreasing the amount of stray capacitance
at the op amp’s inputs and output. To decrease stray
capacitance, minimize trace lengths by placing exter-
nal components as close as possible to the op amp.
Surface-mount components are an excellent choice.
Using the MAX4040–MAX4044
as Comparators
Although optimized for use as operational amplifiers,
the MAX4040–MAX4044 can also be used as rail-to-rail
I/O comparators. Typical propagation delay depends
on the input overdrive voltage, as shown in Figure 7.
External hysteresis can be used to minimize the risk of
output oscillation. The positive feedback circuit, shown
in Figure 8, 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)
VHI = [(R2 / R1 x VIN) + (R2 / RHYST) x VCC] /
(1 + R1 / R2 + R2 / RHYST)
R = 2.4V - 0.1V
240 A 9.6k to V
LEE
µ=Ω
50mV/div IN
OUT
50mV/div
MAX4040/42/44 fig06b
100µs/div
RISO = NONE, RL = 100kΩ, CL = 700pF
Figure 6b. Pulse Response without Isolating Resistor
50mV/div IN
OUT
50mV/div
MAX4040/42/44 fig06c
100µs/div
RISO = 1kΩ, RL = 100kΩ, CL = 700pF
Figure 6c. Pulse Response with Isolating Resistor
RISO
CL
RL
MAX4040–
MAX4044
AV = RL ≈ 1
RL + RISO
Figure 6a. Using a Resistor to Isolate a Capacitive Load from
the Op Amp
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
12 ______________________________________________________________________________________
The MAX4040–MAX4044 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 com-
parator application, the excursion of the output voltage
is so close to the supply rails that the output stage tran-
sistors will saturate, causing the quiescent current to
increase from the normal 10µA. Typical quiescent cur-
rents increase to 35µA for the output saturating at VCC
and 28µA for the output at VEE.
Using the MAX4040–MAX4044
as Ultra-Low-Power Current Monitors
The MAX4040–MAX4044 are ideal for applications pow-
ered from a battery stack. Figure 9 shows an application
circuit in which the MAX4040 is used for monitoring the
current of a 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 cur-
rent increases, the voltage drop across R1 and R2
increases. Thus, R2 provides a fraction of the load cur-
rent (set by the ratio of R1 and R2) that flows into the
emitter of the PNP transistor. Neglecting PNP base cur-
rent, this current flows into R3, producing a ground-ref-
erenced 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 = 2Ω, R2 = 100kΩ, R3 = 1MΩ.
The circuit consumes less power (but is more suscepti-
ble to noise) with higher values of R1, R2, and R3.
R2
R1
VIN
OUTPUT
INPUT
VOH
VOL
VEE
VCC
VOUT
RHYST
VEE
MAX4040–
MAX4044
HYSTERESIS
VLO
VOH
VHI
Figure 8. Hysteresis Comparator Circuit
R1
ILOAD
R2
VCC
VEE
R3
VOUT
Q1
MAX4040
Figure 9. Current Monitor for a Battery Stack
10,000
10
0203010 100
100
1000
MAX4040-44 fig07
VOD (mV)
tPD (µs)
40 50 60 70 80 90
tPD-; VCC = +5V
tPD+; VCC = +2.4V
tPD-; VCC = +2.4V
tPD+; VCC = +5V
Figure 7. Propagation Delay vs. Input Overdrive
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
______________________________________________________________________________________ 13
_____________________________________________Pin Configurations (continued)
OUT
N.C.VEE
1
2
8
7
N.C.
VCC
IN-
IN+
N.C.
SO/µMAX
TOP VIEW
3
4
6
5
MAX4040
OUT
N.C.VEE
1
2
8
7
SHDN
VCCIN-
IN+
N.C.
SO/µMAX
3
4
6
5
MAX4041
INB-
INB+VEE
1
2
8
7
VCC
OUTBINA-
INA+
OUTA
SO/µMAX
3
4
6
5
MAX4042
14
13
12
11
10
9
8
1
2
3
4
5
6
7
VCC
OUTB
INB-
INB+VEE
INA+
INA-
OUTA
MAX4043
N.C.
SHDNB
N.C.N.C.
SHDNA
N.C.
SO
14
13
12
11
10
9
8
1
2
3
4
5
6
7
OUTD
IND-
IND+
VEE
VCC
INA+
INA-
OUTA
MAX4044
INC+
INC-
OUTCOUTB
INB-
INB+
SO
1
2
3
4
5
10
9
8
7
6
VCC
OUTB
INB-
INB+VEE
INA+
INA-
OUTA
MAX4043
µMAX
SHDNBSHDNA
MAX4040/MAX4041 TRANSISTOR COUNT: 234
MAX4042/MAX4043 TRANSISTOR COUNT: 466
MAX4044 TRANSISTOR COUNT: 932
SUBSTRATE CONNECTED TO VEE
___________________Chip Information
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
14 ______________________________________________________________________________________
SOT-23 5L .EPS
E
1
1
21-0057
PACKAGE OUTLINE, SOT-23, 5L
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.)
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
______________________________________________________________________________________ 15
8LUMAXD.EPS
PACKAGE OUTLINE, 8L uMAX/uSOP
1
1
21-0036 J
REV.DOCUMENT CONTROL NO.APPROVAL
PROPRIETARY INFORMATION
TITLE:
MAX
0.043
0.006
0.014
0.120
0.120
0.198
0.026
0.007
0.037
0.0207 BSC
0.0256 BSC
A2 A1
c
eb
A
L
FRONT VIEW SIDE VIEW
E H
0.6±0.1
0.6±0.1
Ø0.50±0.1
1
TOP VIEW
D
8
A2 0.030
BOTTOM VIEW
16∞
S
b
L
H
E
D
e
c
0∞
0.010
0.116
0.116
0.188
0.016
0.005
8
4X S
INCHES
-
A1
A
MIN
0.002
0.950.75
0.5250 BSC
0.25 0.36
2.95 3.05
2.95 3.05
4.78
0.41
0.65 BSC
5.03
0.66
6∞0∞
0.13 0.18
MAX
MIN
MILLIMETERS
-1.10
0.05 0.15
α
α
DIM
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.)
MAX4040–MAX4044
Single/Dual/Quad, Low-Cost, SOT23,
Micropower, Rail-to-Rail I/O Op Amps
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
©2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.
10LUMAX.EPS
PACKAGE OUTLINE, 10L uMAX/uSOP
1
1
21-0061 I
REV.DOCUMENT CONTROL NO.APPROVAL
PROPRIETARY INFORMATION
TITLE:
TOP VIEW
FRONT VIEW
1
0.498 REF
0.0196 REF
S
6°
SIDE VIEW
α
BOTTOM VIEW
0° 0° 6°
0.037 REF
0.0078
MAX
0.006
0.043
0.118
0.120
0.199
0.0275
0.118
0.0106
0.120
0.0197 BSC
INCHES
1
10
L1
0.0035
0.007
e
c
b
0.187
0.0157
0.114
H
L
E2
DIM
0.116
0.114
0.116
0.002
D2
E1
A1
D1
MIN
-A
0.940 REF
0.500 BSC
0.090
0.177
4.75
2.89
0.40
0.200
0.270
5.05
0.70
3.00
MILLIMETERS
0.05
2.89
2.95
2.95
-
MIN
3.00
3.05
0.15
3.05
MAX
1.10
10
0.6±0.1
0.6±0.1
Ø0.50±0.1
H
4X S
e
D2
D1
b
A2 A
E2
E1 L
L1
c
α
GAGE PLANE
A2 0.030 0.037 0.75 0.95
A1
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.)