Maxim MAX4327EUB Single/dual/quad, low-cost, sot23, low-power, rail-to-rail i/o op amp Datasheet

19-1380; Rev 2a; 12/99
Single/Dual/Quad, Low-Cost, SOT23,
Low-Power, Rail-to-Rail I/O Op Amps
____________________________Features
The MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
family of operational amplifiers combines wide bandwidth
and excellent DC accuracy with Rail-to-Rail® operation at
the inputs and outputs. These devices require only 650µA
per amplifier and operate from either a single supply
(+2.4V to +6.5V) or dual supplies (±1.2V to ±3.25V). These
unity-gain-stable amplifiers are capable of driving 250Ω
loads and have a 5MHz gain-bandwidth product. The
MAX4323 and MAX4327 feature a low-power shutdown
mode that reduces supply current to 25µA and places the
outputs in a high-impedance state.
♦ SOT23 Packages (MAX4322/MAX4323)
With their rail-to-rail input common-mode range and
output swing, these amplifiers are ideal for low-voltage,
single-supply operation. In addition, low offset voltage
and high speed make them the ideal signal-conditioning stages for precision, low-voltage data-acquisition
systems. The MAX4322/MAX4323 are available in
space-saving SOT23 packages.
♦ Drive 250Ω Loads
Selector Guide
PART
BW
(MHz)
NO. OF
AMPS
PINPACKAGE
MAX4322
5
1
5 SOT23-5,
8 µMAX/SO
—
MAX4323
5
1
8 µMAX/SO/
6 SOT23-6
Yes
MAX4326
5
2
8 µMAX/SO
MAX4327
5
2
10 µMAX, 14 SO
MAX4329
5
4
14 SO
SHUTDOWN
—
Yes
—
♦ +2.4V to +6.5V Single-Supply Operation
♦ Rail-to-Rail Input Common-Mode Voltage Range
♦ Rail-to-Rail Output Voltage Swing
♦ 5MHz Gain-Bandwidth Product
♦ 650µA Quiescent Current per Amplifier
♦ 700µV Offset Voltage
♦ No Phase Reversal for Overdriven Inputs
♦ 25µA Shutdown Mode (MAX4323/MAX4327)
♦ Unity-Gain Stable for Capacitive Loads
up to 500pF
Ordering Information
PART
MAX4322EUK-T -40°C to +85°C
MAX4322ESA -40°C to +85°C
MAX4322EUA -40°C to +85°C
MAX4323ESA -40°C to +85°C
MAX4323EUA -40°C to +85°C
MAX4323EUT -40°C to +85°C
MAX4326EUA -40°C to +85°C
MAX4326ESA -40°C to +85°C
MAX4327EUB -40°C to +85°C
MAX4327ESD -40°C to +85°C
MAX4329ESD -40°C to +85°C
________________________Applications
TOP
MARK
5 SOT23-5
8 SO
8 µMAX
8 SO
8 µMAX
6 SOT23-6
8 µMAX
8 SO
10 µMAX
14 SO
14 SO
ACGE
—
—
—
—
AAEC
—
—
—
—
—
Typical Operating Circuit
Battery-Powered Instruments
Portable Equipment
Data-Acquisition Systems
Signal Conditioning
+5V
MAX187
3
Low-Power, Low-Voltage Applications
6
Pin Configurations appear at end of data sheet.
PINPACKAGE
TEMP. RANGE
SERIAL
INTERFACE
8
7
SHDN
VDD
DOUT
AIN
SCLK
VREF
CS
GND
1
2
MAX4322
4
5
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
________________________________________________________________ Maxim Integrated Products
1
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
General Description
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
Single/Dual/Quad, Low-Cost, SOT23,
Low-Power, Rail-to-Rail I/O Op Amps
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC-VEE) ..................................................+7.5V
All Other Pins ...................................(VCC + 0.3V) to (VEE - 0.3V)
Output Short-Circuit Duration.....................................Continuous
(short to either supply)
Continuous Power Dissipation (TA = +70°C)
5-pin SOT23-5 (derate 7.1mW/°C above +70°C) .........571mW
6-pin SOT23 (derate 7.1mW/°C Above + 70°C) ...........571mW
8-pin SO (derate 5.88mW/°C above +70°C).................471mW
8-pin µMAX (derate 4.10mW/°C above +70°C) ............330mW
10-pin µMAX (derate 5.6mW/°C above +70°C) ............444mW
14-pin SO (derate 8.00mW/°C above +70°C)...............640mW
Operating Temperature Range
MAX432_E__ ....................................................-40°C to +85°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS—TA = +25°C
(VCC = +5.0V, VEE = 0, VCM = 0, VOUT = VCC / 2, SHDN = VCC, RL tied to VCC / 2, unless otherwise noted.)
PARAMETER
TYP
MAX
MAX432_ESA/MAX4327ESD
VCM =
VEE, VCC All other packages
±0.7
±2.0
±1.2
±2.50
Input Bias Current
VCM = VEE, VCC
±50
±150
Input Offset Current
VCM = VEE, VCC
±1
±12
Differential Input Resistance
-1.5V < VDIFF < 1.5V
500
Common-Mode Input
Voltage Range
Inferred from CMRR test
VEE
VEE ≤
VCM ≤
VCC
MAX432_ESA/MAX4327ESD
62
94
Common-Mode Rejection Ratio
All other packages
60
91
66
Input Offset Voltage
CONDITIONS
MIN
UNITS
mV
nA
nA
kΩ
VCC
V
dB
Power-Supply Rejection Ratio
VCC = 2.4V to 6.5V
100
dB
Output Resistance
AV = +1V/V
0.1
Ω
VOUT = 0.25V to 4.75V, RL = 100kΩ
106
Large-Signal Voltage Gain
2
VOUT = 0.4V to 4.6V, RL = 250Ω
70
86
_______________________________________________________________________________________
dB
Single/Dual/Quad, Low-Cost, SOT23,
Low-Power, Rail-to-Rail I/O Op Amps
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
DC ELECTRICAL CHARACTERISTICS—TA = +25°C (continued)
(VCC = +5V, VEE = 0, VCM = 0, VOUT = VCC / 2, SHDN = VCC, RL tied to VCC / 2, unless otherwise noted.)
PARAMETER
CONDITIONS
MAX4322/
MAX4323
RL = 100kΩ
RL = 250Ω
Output Voltage Swing
MAX4326/
MAX4327/
MAX4329
RL = 100kΩ
RL = 250Ω
MIN
TYP
MAX
VCC - VOH
12
VOL - VEE
20
VCC - VOH
200
300
VOL - VEE
100
200
VCC - VOH
15
VOL - VEE
25
VCC - VOH
220
350
VOL - VEE
120
250
Output Short-Circuit Current
50
Low
SHDN Logic Threshold
MAX4323/MAX4327
SHDN Input Current
MAX4323/MAX4327
Operating Supply-Voltage Range
Inferred from PSRR test
High
0.8
Supply Current per Amplifier
VCM = VOUT = VCC / 2
Shutdown Supply Current
per Amplifier
SHDN > 0.8V, MAX4323/MAX4327
2.4
VCC = 2.4V
650
VCC = 5V
725
VCC = 2.4V
25
VCC = 5V
40
mV
mA
2.0
±1
UNITS
V
±4
µA
6.5
V
1100
60
µA
µA
DC ELECTRICAL CHARACTERISTICS—TA = -40°C to +85°C
(VCC = +5V, VEE = 0, VCM = 0, VOUT = VCC / 2, SHDN = VCC, RL tied to VCC / 2, unless otherwise noted.) (Note 1)
PARAMETER
Input Offset Voltage
CONDITIONS
MIN
TYP
MAX432_ESA/MAX4327ESD
VCM =
VEE, VCC All other packages
MAX
±3.0
±6.0
Input Offset Voltage Tempco
±2
UNITS
mV
µV/°C
Input Bias Current
VCM = VEE, VCC
±180
nA
Input Offset Current
VCM = VEE, VCC
±20
nA
Common-Mode Input
Voltage Range
Inferred from CMRR test
VEE
VCC
V
VEE ≤
VCM ≤
VCC
MAX432_ESA/MAX4327ESD
59
Common-Mode Rejection Ratio
All other packages
54
dB
_______________________________________________________________________________________
3
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
Single/Dual/Quad, Low-Cost, SOT23,
Low-Power, Rail-to-Rail I/O Op Amps
DC ELECTRICAL CHARACTERISTICS —TA = -40°C to +85°C (continued)
(VCC = +5V, VEE = 0, VCM = 0, VOUT = VCC / 2, SHDN = VCC, RL tied to VCC / 2, unless otherwise noted.) (Note 1)
PARAMETER
CONDITIONS
Power-Supply Rejection Ratio
VCC = 2.4V to 6.5V
Large-Signal Voltage Gain
VOUT = 0.4V to 4.6V, RL = 250Ω
MAX4322/
MAX4323
Output Voltage Swing
MAX4326/
MAX4327/
MAX4329
MIN
TYP
MAX
62
RL = 250Ω
UNITS
dB
66
dB
VCC - VOH
350
VOL - VEE
250
VCC - VOH
400
VOL - VEE
300
Low
0.8
mV
RL = 250Ω
SHDN Logic Threshold
MAX4323/MAX4327
SHDN Input Current
MAX4323/MAX4327
High
Operating Supply-Voltage Range
2.0
2.4
V
±5
µA
6.5
V
Supply Current per Amplifier
VCM = VCC / 2
1.2
mA
Shutdown Supply Current
per Amplifier
SHDN ≤ 0.8V, MAX4323/MAX4327
70
µA
MAX
UNITS
AC ELECTRICAL CHARACTERISTICS
(VCC = +5V, VEE = 0, VCM = VOUT = VCC / 2, SHDN = VCC, TA = +25°C unless otherwise noted.)
PARAMETER
CONDITIONS
MIN
TYP
Gain-Bandwidth Product
5
MHz
Phase Margin
64
degrees
Gain Margin
12
dB
Total Harmonic Distortion
f = 10kHz, VOUT = 2Vp-p, AV = +1V/V
Slew Rate
Settling Time to 0.01%
AV = +1V/V, VOUT = 2V step
Turn-On Time
VCC = 0 to 3V step
SHDN Delay
MAX4323/MAX4327
0.003
%
2
V/µs
2.0
µs
1
µs
Enable
1
Disable
0.2
Input Capacitance
µs
3
pF
Input Noise Voltage Density
f = 1kHz
22
nV/√Hz
Input Noise Current Density
f = 1kHz
0.4
pA
135
dB
250
pF
Amp-Amp Isolation
Capacitive Load Stability
AV = +1V/V
Note 1: All devices are 100% tested at TA = +25°C. All temperature limits are guaranteed by design.
4
_______________________________________________________________________________________
Single/Dual/Quad, Low-Cost, SOT23,
Low-Power, Rail-to-Rail I/O Op Amps
GAIN AND PHASE vs. FREQUENCY
(WITH CLOAD)
60
180
144
144
72
20
36
0
-36
PHASE
72
36
0
0
-36
PHASE
-108
AV = +1000
NO LOAD
-40
100
1k
AV = +1000
RL = ∞
CL = 500pF
-20
-144
10k
100k
1M
10M
-40
100
-180
100M
1k
-144
1M
10M
10
100
1k
10k
110
100
90
80
70
MAX4322/26/29-05
AV = +1
OUTPUT IMPEDANCE (Ω)
120
1M
10M
100M
MAX4323/MAX4327
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
100
MAX4322/26/29-04
130
100k
FREQUENCY (Hz)
OUTPUT IMPEDANCE
vs. FREQUENCY
MAX4326/MAX4327/MAX4329
CHANNEL SEPARATION vs. FREQUENCY
10
1
0.1
60
60
50
VCC = 6.5V
40
30
VCC = 2.7V
20
10
SHDN = 0V
0
0.01
10k
100k
FREQUENCY (Hz)
1M
100
10M
SUPPLY CURRENT PER AMPLIFIER
vs. TEMPERATURE
850
800
VCC = 2.7V
650
-2.25
500
-3.00
35
50
TEMPERATURE (°C)
65
80
95
5
20
35
50
65
80
TEMPERATURE (°C)
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
INPUT BIAS CURRENT
vs. COMMON-MODE VOLTAGE
SOT23-5/6
PACKAGE
-0.75
550
-40 -25 -10
100M
0
-1.50
20
10M
0.75
600
5
1M
2.25
VOLTAGE (mV)
750
-40 -25 -10
100k
FREQUENCY (Hz)
1.50
VCC = 6.5V
700
10k
3.00
MAX4322/26/29-6
900
1k
95
50
40
INPUT BIAS CURRENT (nA)
1k
MAX4322/26/29-7
100
MAX4322/26/29-8
50
SUPPLY CURRENT (µA)
-100
-180
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
CHANNEL SEPARATION (dB)
100k
-60
-80
-108
10k
-40
-72
-72
-20
-20
SHUTDOWN SUPPLY CURRENT (mA)
0
GAIN
20
GAIN (dB)
GAIN (dB)
GAIN
PHASE (DEGREES)
108
40
AV = +1
0
108
40
MAX4323-11
180
PSR (dB)
60
POWER-SUPPLY REJECTION
vs. FREQUENCY
MAX4322/26/29-02
PHASE (DEGREES)
MAX4322/26/29-01
MAX4322/26/29-03
GAIN AND PHASE vs. FREQUENCY
VCC = 2.7V
30
VCC = 6.5V
20
10
0
-10
-20
-30
SO PACKAGE
-40
-50
-40 -25 -10
5
20
35
50
TEMPERATURE (°C)
65
80
95
0
1
2
3
4
5
6
COMMON-MODE VOLTAGE (V)
_______________________________________________________________________________________
5
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
__________________________________________Typical Operating Characteristics
(VCC = +5V, VEE = 0, VCM = VCC / 2, SHDN = VCC, TA = +25°C, unless otherwise noted.)
_____________________________Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0, VCM = VCC / 2, SHDN = VCC, TA = +25°C, unless otherwise noted.)
10
0
-10
-20
VCC = 2.7V, VCM = VEE
-30
-40
100
5
20
MAX4322/26/29-11
MAX4322/26/29-10
105
95
200
VCC = 6.5V, RL = 500Ω
150
VCC = 2.7V, RL = 500Ω
100
VCM = -0.2V TO 5.2V
90
VCC = 6.5V, RL = 100kΩ
50
35
50
65
80
95
VCC = 2.7V, RL = 100kΩ
0
-40 -25 -10
5
20
35
50
65
80
-40 -25 -10
95
5
20
35
50
65
TEMPERATURE (°C)
TEMPERATURE (°C)
MAXIMUM OUTPUT VOLTAGE
vs. TEMPERATURE
LARGE-SIGNAL GAIN
vs. OUTPUT VOLTAGE
LARGE-SIGNAL GAIN
vs. OUTPUT VOLTAGE
VCC = 6.5V, RL = 500Ω
VCC = 2.7V
RL TO VEE
110
RL = 100kΩ
120
95
VCC = 6.5V
RL TO VEE
110
RL = 100kΩ
100
GAIN (dB)
200
VCC = 2.7V, RL = 500Ω
100
100
RL = 10kΩ
GAIN (dB)
250
120
MAX4322/26/29-12
RL TO VEE
80
MAX4322/26/29-14
TEMPERATURE (°C)
300
VCC - VOUT (mV)
VCM = 0 TO 5.0V
80
-40 -25 -10
50
110
RL TO VCC
85
VCC = 6.5V, VCM = VEE
-60
150
115
MAX4322/26/29-13
-50
250
VOUT - VEE (mV)
VCC = 2.7V, VCM = VCC
120
COMMON-MODE REJECTION (dB)
INPUT BIAS CURRENT (nA)
VCC = 6.5V, VCM = VCC
30
20
MAX4322/26/29-9
50
40
MINIMUM OUTPUT VOLTAGE
vs. TEMPERATURE
COMMON-MODE REJECTION
vs. TEMPERATURE
INPUT BIAS CURRENT
vs. TEMPERATURE
RL = 2kΩ
90
RL = 500Ω
RL = 10kΩ
RL = 2kΩ
90
80
80
70
70
RL = 500Ω
VCC = 6.5V, RL = 100kΩ (TOP)
VCC = 2.7V, RL = 100kΩ (BOTTOM)
-40 -25 -10
35
50
65
80
100
200
300
400
500
600
0
100
200
300
400
500
TEMPERATURE (°C)
OUTPUT VOLTAGE: FROM VCC (mV)
OUTPUT VOLTAGE: FROM VCC (mV)
LARGE-SIGNAL GAIN
vs. TEMPERATURE
LARGE-SIGNAL GAIN
vs. OUTPUT VOLTAGE
LARGE-SIGNAL GAIN
vs. OUTPUT VOLTAGE
VCC = 6.5V,
RL TO VEE
120
110
100
95
VCC = 6.5V, RL TO VCC
90
RL = 100kΩ
RL = 10kΩ
100
RL = 2kΩ
90
RL = 500Ω
80
85
600
RL = 2kΩ
90
RL = 500Ω
80
70
70
80
VCC = 6.5V
RL TO VCC
110
100
GAIN (dB)
105
120
RL = 10kΩ
VCC = 2.7V,
RL TO VEE
110
RL = 100kΩ
VCC = 2.7V
RL TO VCC
GAIN (dB)
RL = 500Ω
VOUT(p-p) = VCC - 1V
115
VCC = 2.7V, RL TO VCC
75
60
60
-40 -25 -10
5
20
35
50
TEMPERATURE (°C)
6
60
0
95
MAX4322/26/29-16
120
20
MAX4322/26/29-15
125
5
MAX4322/26/29-17
60
0
GAIN (dB)
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
Single/Dual/Quad, Low-Cost, SOT23,
Low-Power, Rail-to-Rail I/O Op Amps
65
80
95
0
100
200
300
400
500
OUTPUT VOLTAGE: FROM VEE (mV)
600
0
100
200
300
400
500
OUTPUT VOLTAGE: FROM VEE (mV)
_______________________________________________________________________________________
600
Single/Dual/Quad, Low-Cost, SOT23,
Low-Power, Rail-to-Rail I/O Op Amps
(VCC = +5V, VEE = 0, VCM = VCC / 2, SHDN = VCC, TA = +25°C, unless otherwise noted.)
VCC = 2.7V, RL TO VCC
90
85
VOUT(p-p) = VCC - 600mV
RL = 100kΩ
80
75
5
20
35
50
65
80
1.5
0.025
0.020
0.015
1.4
0.010
1.3
95
0.005
0
-40 -25 -10
5
20
35
50
65
80
TEMPERATURE (°C)
TOTAL HARMONIC DISTORTION AND NOISE
vs. PEAK-TO-PEAK SIGNAL AMPLITUDE
SMALL-SIGNAL TRANSIENT
RESPONSE (NONINVERTING)
MAX4322/26/29-21
TEMPERATURE (°C)
RL = 2kΩ
RL = 250Ω
RL = 10kΩ
1k
10k
FREQUENCY (Hz)
IN
AV = -1
OUT
RL = 100kΩ
100
100k
SMALL-SIGNAL TRANSIENT
RESPONSE (INVERTING)
VOLTAGE (50mV/div)
0.01
10
95
AV = +1
VOLTAGE (50mV/div)
AV = +1
10kHz SINE WAVE
RL TO VCC / 2
500kHz LOWPASS FILTER
IN
OUT
0.001
4.2
4.4
4.6
4.8
5.0
TIME (200ns/div)
TIME (200ns/div)
PEAK-TO-PEAK SIGNAL AMPLITUDE (V)
AV = +1
MAX4322/26/29-26
LARGE-SIGNAL TRANSIENT
RESPONSE (INVERTING)
LARGE-SIGNAL TRANSIENT
RESPONSE (NONINVERTING)
MAX4322/26/29-24
AV = -1
IN
IN
VOLTAGE (2V/div)
4.0
VOLTAGE (2V/div)
THD + NOISE (%)
1.6
1.2
-40 -25 -10
0.1
0.030
1.7
MAX4322/26/29-23
VCC = 2.7V, RL TO VEE
95
AV = +1
2Vp-p SIGNAL
500kHz LOWPASS FILTER
RL = 10kΩ TO VCC / 2
0.035
THD + NOISE (%)
100
1.8
MAX4322/26/29-22
GAIN (dB)
105
0.040
MAX4322/26/29-19
VCC = 6.5V, RL TO VCC
115
110
1.9
MINIMUM OPERATING VOLTAGE (V)
VCC = 6.5V, RL TO VEE
120
MAX4322/26/29-18
125
TOTAL HARMONIC DISTORTION
AND NOISE vs. FREQUENCY
MINIMUM OPERATING VOLTAGE
vs. TEMPERATURE
MAX4322/26/29-20
LARGE-SIGNAL GAIN
vs. TEMPERATURE
OUT
OUT
TIME (2µs/div)
TIME (2µs/div)
_______________________________________________________________________________________
7
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
_____________________________Typical Operating Characteristics (continued)
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
Single/Dual/Quad, Low-Cost, SOT23,
Low-Power, Rail-to-Rail I/O Op Amps
Pin Description
PIN
MAX4322
MAX4323
SOT23-5 SO/µMAX SOT23-6 SO/µMAX
MAX4326
MAX4327
µMAX
SO
FUNCTION
1
6
1
6
—
—
—
—
OUT
Output
2
4
2
4
4
4
4
11
VEE
Negative Supply. Ground for
single-supply operation.
3
—
3
—
—
—
—
—
IN+
Noninverting Input
4
—
4
—
—
—
—
—
IN-
Inverting Input
5
7
6
7
8
10
14
4
VCC
Positive Supply
—
1, 5, 8
—
1, 5
—
—
5, 7, 8,
10
—
N.C.
No Connection
—
—
5
8
—
—
—
SHDN
Shutdown Control. Tie high or
leave floating to enable
amplifier.
—
—
—
—
1, 7
1, 9
1, 13
1, 7
OUT1,
OUT2
Outputs for amps 1 and 2
—
2
—
2
2, 6
2, 8
2, 12
2, 6
IN1-, IN2-
Inverting Inputs for amps 1
and 2
—
3
—
3
3, 5
3, 7
3, 11
3, 5
IN1+, IN2+
Noninverting Inputs for amps
1 and 2
—
—
—
—
—
5, 6
5, 9
—
SHDN1,
SHDN2
Shutdown Control for amps 1
and 2. Tie high or leave floating to enable amplifier.
—
—
—
—
—
—
—
8, 14
OUT3,
OUT4
Outputs for amps 3 and 4
—
—
—
—
—
—
—
9, 13
IN3-, IN4-
Inverting Inputs for amps 3
and 4
—
—
—
—
—
—
—
10, 12
IN3+, IN4+
__________ Applications Information
Rail-to-Rail Input Stage
Devices in the MAX4322/MAX4323/MAX4326/MAX4327/
MAX4329 family of high-speed amplifiers have rail-torail input and output stages designed for low-voltage,
single-supply operation. The input stage consists of
separate NPN and PNP differential stages, which combine to provide an input common-mode range extending to the supply rails. The PNP stage is active for input
voltages close to the negative rail, and the NPN stage
is active for input voltages near the positive rail. The
input offset voltage is typically below 250µV. The
8
NAME
MAX4329
Noninverting Inputs for amps
3 and 4
switchover transition region, which occurs near VCC / 2,
has been extended to minimize the slight degradation in
CMRR caused by the mismatch of the input pairs. Their
low offset voltage, high bandwidth, and rail-to-rail common-mode range make these op amps excellent choices
for precision, low-voltage, data-acquisition systems.
Since the input stage switches between the NPN and
PNP pairs, the input bias current changes polarity as
the input voltage passes through the transition region.
To reduce the offset error caused by input bias currents flowing through external source impedances,
match the effective impedance seen by each input
(Figures 1a, 1b). High source impedances, together
_______________________________________________________________________________________
Single/Dual/Quad, Low-Cost, SOT23,
Low-Power, Rail-to-Rail I/O Op Amps
IBIAS =
VDIFF - 1.8V
2kΩ
Rail-to-Rail Output Stage
The minimum output voltage will be within millivolts of
ground for single-supply operation where the load is
referenced to ground (VEE). Figure 3 shows the input
voltage range and output voltage swing of a MAX4322
connected as a voltage follower. With a +3V supply
and the load tied to ground, the output swings from
0.00V to 2.90V. The maximum output voltage swing
depends on the load, but will be within 350mV of a +5V
supply, even with the maximum load (500Ω to ground).
Driving a capacitive load can cause instability in most
high-speed op amps, especially those with low quiescent current. The MAX4322/MAX4323/MAX4326/
MAX4327/MAX4329 have a high tolerance for capacitive loads. They are stable with capacitive loads up to
500pF. Figure 4 gives the stable operating region for
capacitive loads. Figures 5 and 6 show the response
with capacitive loads and the results of adding an isolation resistor in series with the output (Figure 7). The
resistor improves the circuit’s phase margin by isolating the load capacitor from the op amp’s output.
R3
R3
MAX4322/MAX4323
MAX4326/MAX4327
MAX4329
MAX4322/MAX4323
MAX4326/MAX4327
MAX4329
R1
R3 = R1
R2
R2
R1
R3 = R1
Figure 1a. Reducing Offset Error Due to Bias Current
(Noninverting)
R2
R2
Figure 1b. Reducing Offset Error Due to Bias Current
(Inverting)
1k
1k
Figure 2. Input Protection Circuit
_______________________________________________________________________________________
9
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
with the input capacitance, can create a parasitic pole
that produces an underdamped signal response.
Reducing the input impedance or placing a small (2pF
to 10pF) capacitor across the feedback resistor
improves the response.
The MAX4322/MAX4323/MAX4326/MAX4327/MAX4329’s
inputs are protected from large differential input voltages by 1kΩ series resistors and back-to-back triple
diodes across the inputs (Figure 2). For differential input
voltages less than 1.8V the input resistance is typically
500kΩ. For differential input voltages greater than 1.8V
the input resistance is approximately 2kΩ, and the input
bias current is determined by the following equation:
Power-Up and Shutdown Mode
Power Supplies and Layout
The MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
amplifiers typically settle within 1µs after power-up.
Using the test circuit of Figure 8, Figures 9 and 10 show
the output voltage and supply current on power-up.
The MAX4323 and MAX4327 have a shutdown option.
When the shutdown pin (SHDN) is pulled low, the supply current drops below 25µA per amplifier and the
amplifiers are disabled with the outputs in a highimpedance state. Pulling SHDN high or leaving it floating enables the amplifier. In the dual-amplifier
MAX4327, the shutdown functions operate independently. Figures 11 and 12 show the output voltage and
supply current responses of the MAX4323 to a shutdown pulse.
The MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
operate from a single +2.4V to +6.5V power supply, or
from dual supplies of ±1.2V to ±3.25V. For single-supply
operation, bypass the power supply with a 0.1µF
ceramic capacitor in parallel with at least 1µF. For dual
supplies, bypass each supply to ground.
Good layout improves performance by decreasing the
amount of stray capacitance at the op amp’s inputs
and outputs. To decrease stray capacitance, minimize
trace lengths and resistor leads by placing external
components close to the op amp’s pins.
10,000
VCC = 3V
AV = +1
CAPACITIVE LOAD (pF)
VOLTAGE (1V/div)
IN
OUT
UNSTABLE
REGION
1000
RL TO VEE
VOUT = VCC/2
100
TIME (2µs/div)
100
1k
10k
100k
RESISTIVE LOAD (Ω)
Figure 3. Rail-to-Rail Input /Output Voltage Range
Figure 4. Capacitive-Load Stability
AV = +1
CL = 500pF
IN
IN
OUT
OUT
TIME (400ns/div)
Figure 5. Small-Signal Transient Response with
Capacitive Load
10
AV = +1
CL = 1000pF
RS = 39Ω
VOLTAGE (50mV/div)
VOLTAGE (50mV/div)
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
Single/Dual/Quad, Low-Cost, SOT23,
Low-Power, Rail-to-Rail I/O Op Amps
TIME (400ns/div)
Figure 6. Transient Response to Capacitive Load with
Isolation Resistor
______________________________________________________________________________________
Single/Dual/Quad, Low-Cost, SOT23,
Low-Power, Rail-to-Rail I/O Op Amps
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
VCC
MAX4322/MAX4323
MAX4326/MAX4327
MAX4329
0V TO 2.7V
STEP FOR
POWER-UP
TEST 2k
RS
VOUT
CL
MAX4322/MAX4323
MAX4326/MAX4327
MAX4329
Figure 7. Capacitive-Load-Driving Circuit
VCC
SUPPLY-CURRENT
10Ω MONITORING POINT
2k
10k
Figure 8. Power-Up Test Circuit
VOLTAGE (1V/div)
VCC
(1V/div)
OUT
ICC
(500µA/div)
TIME (5µs/div)
TIME (5µs/div)
Figure 9. Power-Up Output Voltage
Figure 10. Power-Up Supply Current
VCC = 2.7V
VCC = 2.7V
RL = 10kΩ
SHDN
(1V/div)
SHDN
(1V/div)
OUT
(0.5V/div)
ICC
(500µA/div)
TIME (2µs/div)
Figure 11. Shutdown Output Voltage
TIME (2µs/div)
Figure 12. Shutdown Enable/Disable Supply Current
______________________________________________________________________________________
11
MAX4322/MAX4323/MAX4326/MAX4327/MAX4329
Single/Dual/Quad, Low-Cost, SOT23,
Low-Power, Rail-to-Rail I/O Op Amps
___________________________________________________________Pin Configurations
TOP VIEW
OUT 1
VEE 2
5
OUT 1
VCC
MAX4322
IN+ 3
VEE 2
IN+ 3
IN-
4
IN1- 2
MAX4326
8
VCC
7
OUT2
IN1+ 3
6
IN2-
VEE 4
5
IN2+
SO/µMAX
VCC
5
SHDN
8
N.C.
N.C. 1
7
VCC
IN1- 2
IN1+ 3
6
OUT
VEE 4
5
N.C.
N.C. 1
IN1- 2
IN-
4
OUT1 1
14 VCC
IN1- 2
13 OUT2
IN1+ 3
12 IN2-
VEE 4
MAX4327
N.C. 5
MAX4322
8
SHDN
7
VCC
IN1+ 3
6
OUT
VEE 4
5
N.C.
OUT1 1
IN1IN1+
3
OUT1 1
14 OUT4
OUT2
IN1- 2
13 IN4-
IN2-
IN1+ 3
12 IN4+
10 VCC
2
9
MAX4327
8
11 IN2+
VEE
4
7
IN2+
VCC 4
10 N.C.
SHDN1
5
6
SHDN2
IN2+ 5
SHDN1 6
9
SHDN2
N.C. 7
8
N.C.
SO
µMAX
MAX4323
SO
SO/µMAX
SOT23-6
SOT23-5
OUT1 1
MAX4323
6
MAX4329
11 VEE
10 IN3+
IN2- 6
9
IN3-
OUT2 7
8
OUT3
SO
Chip Information
MAX4322 TRANSISTOR COUNT: 170
MAX4323 TRANSISTOR COUNT: 170
MAX4326 TRANSISTOR COUNT: 340
MAX4327 TRANSISTOR COUNT: 340
MAX4329 TRANSISTOR COUNT: 680
SUBSTRATE CONNECTED TO VEE
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.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 1999 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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