MAXIM MAX4321

19-1649; Rev 0; 4/00
Low-Cost, Low-Voltage, Rail-to-Rail,
Input/Output, SOT23 5MHz Op Amp
The MAX4321 operational amplifier (op amp) combines
a 5MHz gain-bandwidth product and excellent DC
accuracy with Rail-to-Rail® operation at both the inputs
and the output. This device requires only 650µA and
operates from either a single +2.4V to +6.5V supply or
dual ±1.2V to ±3.25V supplies, although the MAX4321
typically operates down to +1.8V (±0.9V). The
MAX4321 remains unity-gain stable with capacitive
loads up to 500pF and is capable of driving 250Ω loads
to within 200mV of either rail.
With rail-to-rail input common-mode range and output
swing, the MAX4321 is ideal for low-voltage, single-supply applications. In addition, low ±1.2mV input offset voltage and high 2V/µs slew rate make this device ideal for
signal-conditioning stages for precision, low-voltage dataacquisition systems. The MAX4321 comes in a spacesaving 5-pin SOT23 package and is guaranteed over the
extended (-40°C to +85°C) temperature range.
The MAX4321 is a low-voltage, pin-for-pin compatible
upgrade for the LMC7101 that offers five-times higher
bandwidth, two-times faster slew rate, and about half the
input voltage noise density.
Features
♦ Low-Voltage, Pin-for-Pin Upgrade for LMC7101
♦ Guaranteed +2.4V to +6.5V Single-Supply
Operation
♦ Typically Operates Down to +1.8V
♦ 5MHz Gain-Bandwidth Product
♦ 650µA Quiescent Current
♦ Rail-to-Rail Common-Mode Input Voltage Range
♦ Rail-to-Rail Output Voltage Range
♦ Drives 250Ω Loads
♦ Unity-Gain Stable for Capacitive Loads up to
500pF
♦ No Phase Reversal for Overdriven Inputs
♦ Low-Cost Solution in SOT23-5 Package
Ordering Information
________________________Applications
Battery-Powered Instruments
Portable Equipment
Data-Acquisition Systems
Sensor and Signal Conditioning
PART
TEMP.
RANGE
PINPACKAGE
TOP
MARK
MAX4321EUK-T
-40°C to +85°C
5 SOT23-5
ADOA
Low-Power, Low-Voltage Applications
General-Purpose Low-Voltage Applications
Pin Configuration/
Functional Diagram
Typical Operating Circuit
+5V
TOP VIEW
MAX187
3
6
SERIAL
INTERFACE
8
7
SHDN
VDD
DOUT
AIN
SCLK
VREF
CS
GND
OUT
1
1
5
VEE
4
IN-
2
MAX4321
VCC 2
4
5
IN+ 3
MAX4321
SOT23
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.
MAX4321
General Description
MAX4321
Low-Cost, Low-Voltage, Rail-to-Rail,
Input/Output, SOT23 5MHz Op Amp
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VCC to VEE) ....................................-0.3V to +7V
All Other Pins ..................................(VEE - 0.3V) to (VCC + 0.3V)
Output Short-Circuit Duration.....................................Continuous
(short to either supply)
Continuous Power Dissipation
5-pin SOT23 (derate 7.1mW/°C above +70°C)...........571mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................ +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
(VCC = +5.0V, VEE = 0, VCM = 0, VOUT = VCC/2, RL = ∞ connected to VCC/2, TA = +25°C, unless otherwise noted.)
PARAMETER
Supply Voltage Range
SYMBOL
CONDITIONS
VCC - VEE
Supply Current
MIN
TYP
2.4
VCM = VOUT = VCC/2
VCC = +2.4V
650
VCC = +6.5V
725
MAX
UNITS
6.5
V
µA
Input Offset Voltage
VOS
VCM = VEE or VCC
±1.2
±3.5
mV
Input Bias Current
IBIAS
VCM = VEE or VCC
±50
±150
nA
IOFFSET
VCM = VEE or VCC
±4
±25
nA
500
Input Offset Current
Differential Input
Resistance
RIN
-1.5V < VDIFF <+1.5V
Common-Mode Input Voltage
Range
VCM
Inferred from CMRR test
VEE
kΩ
VCC
V
Common-Mode Rejection
Ratio
CMRR
VEE ≤ VCM ≤ VCC
60
91
dB
Power-Supply Rejection Ratio
PSRR
2.4V < VCC < 6.5V
66
100
dB
Output Resistance
ROUT
AV = +1V/V
0.1
Ω
VOUT = 0.25V to 4.75V, RL = 100kΩ
103
VOUT = 0.40V to 4.60V, RL = 600Ω
100
Large-Signal Voltage Gain
AV
VOUT = 0.40V to 4.60V, RL = 250Ω
RL = 100kΩ
Output Voltage Swing
VOUT
RL = 600Ω
RL = 250Ω
Output Short-Circuit Current
2
70
dB
86
VCC - VOH
VOL - VEE
25
VCC - VOH
135
VOL - VEE
60
VCC - VOH
200
300
VOL - VEE
100
200
20
50
_______________________________________________________________________________________
mV
mA
Low-Cost, Low-Voltage, Rail-to-Rail,
Input/Output, SOT23 5MHz Op Amp
(VCC = +5.0V, VEE = 0, VCM = 0, VOUT = VCC/2, RL = ∞ connected to VCC/2, TA = -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER
Supply Voltage Range
SYMBOL
CONDITIONS
VCC - VEE
MIN
Supply Current
ICC
VCM = VOUT = VCC/2
Input Offset Voltage
VOS
VCM = VEE or VCC
Input Offset Voltage
Temperature Coefficient
Input Bias Current
Input Offset Current
Common-Mode Input Voltage
Range
TYP
2.4
MAX
UNITS
6.5
V
1200
µA
±6
mV
µV/°C
±2
IBIAS
VCM = VEE or VCC
±180
nA
IOFFSET
VCM = VEE or VCC
±50
nA
VCC
V
VCM
Inferred from CMRR test
VEE
Common-Mode Rejection Ratio
CMRR
VEE ≤ VCM ≤ VCC
54
dB
Power-Supply Rejection Ratio
PSRR
2.4V < VCC < 6.5V
62
dB
Large-Signal Voltage Gain
Output Voltage Swing
AV
VOUT
VOUT = 0.40V to 4.60V, RL = 250Ω
R = 250Ω
66
dB
VCC - VOH
350
VOL - VEE
250
mV
AC ELECTRICAL CHARACTERISTICS
(VCC = +5.0V, VEE = 0, VCM = 0, VOUT = VCC/2, RL = 250Ω connected to VCC/2, TA = +25°C, unless otherwise noted.)
PARAMETER
Gain-Bandwidth Product
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
5
MHz
Phase Margin
64
degrees
Gain Margin
12
dB
0.003
%
VOUT = 1V step
2
V/µs
VOUT = 2V step, AV = +1V/V
2
µs
Total Harmonic Distortion
and Noise
Slew Rate
GBP
THD+N
SR
Settling Time to 0.01%
tSETTLE
Turn-On Time
tON
Input Capacitance
CIN
10kHz tone, VOUT = 2Vpp,
AV = +1V/V
VCC = 0 to 3V step
1
µs
3
pF
Input Noise Voltage Density
f = 1kHz
22
nV/√ Hz
Input Noise Current Density
f = 1kHz
0.4
pA/√Hz
Note 1: All devices are 100% production tested at TA = +25°C. All temperature limits are guaranteed by design and characterization.
_______________________________________________________________________________________
3
MAX4321
DC ELECTRICAL CHARACTERISTICS
Low-Cost, Low-Voltage, Rail-to-Rail,
Input/Output, SOT23 5MHz Op Amp
MAX4321
Typical Operating Characteristics
(VCC = +5V, VEE = 0, VCM = VCC/2, TA = +25°C, unless otherwise noted.)
GAIN AND PHASE vs. FREQUENCY
(WITH CLOAD)
MAX4321-02
60
180
0
0
-36
PHASE
20
36
0
0
-108
AV = +1000
NO LOAD
1k
-144
10k
100k
1M
-40
100
-180
100M
10M
1k
1
0.1
0.01
1k
10k
100k
1M
10M
10M
10
1k
10k
100k
1M
10M 100M
SUPPLY CURRENT vs. TEMPERATURE
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
MAX4321-05
3.00
1.50
VCC = 6.5V
750
700
2.25
VCC = 2.7V
650
0.75
0
-0.75
600
-1.50
550
-2.25
-3.00
-40 -25 -10
5
20
35
50
65
80
-40 -25 -10
95
5
20
35
50
65
80
FREQUENCY (Hz)
TEMPERATURE (°C)
TEMPERATURE (°C)
INPUT BIAS CURRENT
vs. COMMON-MODE VOLTAGE
INPUT BIAS CURRENT
vs. TEMPERATURE
COMMON-MODE REJECTION
vs. TEMPERATURE
10
0
-10
-20
20
0
-10
-20
-40
-50
-50
-60
3
4
5
COMMON-MODE VOLTAGE (V)
6
VCC = 2.7V, VCM = VEE
-30
-40
2
VCC = 2.7V, VCM = VCC
10
-30
1
VCC = 6.5V, VCM = VCC
30
120
COMMON-MODE REJECTION (dB)
VCC = 6.5V
20
40
INPUT BIAS CURRENT (nA)
VCC = 2.7V
30
50
MAX4321-07
40
0
100
FREQUENCY (Hz)
800
100M
50
INPUT BIAS CURRENT (nA)
1M
500
100
4
100k
-100
FREQUENCY (Hz)
850
SUPPLY CURRENT (µA)
10
-80
-144
MAX4321-08
OUTPUT IMPEDANCE (Ω)
AV = +1
-60
-180
100M
900
MAX4321-04
100
-40
-108
10k
FREQUENCY (Hz)
OUTPUT IMPEDANCE
vs. FREQUENCY
-72
AV = +1000
RL = ∞
CL = 500pF
-20
-20
95
MAX4321-09
-40
100
-36
PHASE
-72
-20
72
PSR (dB)
36
GAIN
VOLTAGE (mV)
20
GAIN (dB)
72
PHASE (DEGREES)
GAIN (dB)
GAIN
108
40
108
40
AV = +1
0
144
144
MAX4321-06
180
PHASE (DEGREES)
MAX4321-01
60
POWER-SUPPLY REJECTION
vs. FREQUENCY
MAX4321-03
GAIN AND PHASE vs. FREQUENCY
115
110
VCM = 0 TO 5.0V
105
100
95
VCM = -0.2V TO 5.2V
90
85
VCC = 6.5V, VCM = VEE
80
-40 -25 -10
5
20
35
50
TEMPERATURE (°C)
65
80
95
-40 -25 -10
5
20
35
50
TEMPERATURE (°C)
_______________________________________________________________________________________
65
80
95
Low-Cost, Low-Voltage, Rail-to-Rail,
Input/Output, SOT23 5MHz Op Amp
MAXIMUM OUTPUT VOLTAGE
vs. TEMPERATURE
250
150
VCC = 2.7V, RL = 500Ω
100
VCC = 6.5V, RL = 100kΩ
RL = 100kΩ
100
200
VCC = 2.7V, RL = 500Ω
150
RL = 10kΩ
RL = 2kΩ
90
RL = 500Ω
80
100
50
VCC = 2.7V
RL TO VEE
110
VCC = 6.5V, RL = 500Ω
GAIN (dB)
VCC - VOUT (mV)
VOUT - VEE (mV)
RL TO VEE
VCC = 6.5V, RL = 500Ω
120
MAX4321-11
RL TO VCC
200
300
MAX4321-10
250
LARGE-SIGNAL GAIN
vs. OUTPUT VOLTAGE
MAX4321-12
MINIMUM OUTPUT VOLTAGE
vs. TEMPERATURE
VCC = 6.5V, RL = 100kΩ (TOP)
50
70
VCC = 2.7V, RL = 100kΩ (BOTTOM)
-40 -25 -10
20
35
50
65
0
80
5
20
35
65
80
95
0
100
200
300
500
400
TEMPERATURE (°C)
OUTPUT VOLTAGE: FROM VCC (mV)
LARGE-SIGNAL GAIN
vs. OUTPUT VOLTAGE
LARGE-SIGNAL GAIN
vs. OUTPUT VOLTAGE
LARGE-SIGNAL GAIN
vs. OUTPUT VOLTAGE
RL = 100kΩ
VCC = 2.7V
RL TO VCC
110
RL = 100kΩ
100
GAIN (dB)
RL = 2kΩ
80
100
RL = 2kΩ
90
RL = 500Ω
80
600
RL = 10kΩ
RL = 10kΩ
RL = 10kΩ
90
VCC = 6.5V
RL TO VCC
110
GAIN (dB)
100
120
MAX4321-14
120
RL = 100kΩ
GAIN (dB)
50
TEMPERATURE (°C)
VCC = 6.5V
RL TO VEE
110
60
-40 -25 -10
95
MAX4321-13
120
5
MAX4321-15
VCC = 2.7V, RL = 100kΩ
0
RL = 2kΩ
90
RL = 500Ω
80
RL = 500Ω
70
70
60
60
200
300
500
400
600
100
200
300
500
400
600
0
100
200
300
400
500
OUTPUT VOLTAGE: FROM VCC (mV)
OUTPUT VOLTAGE: FROM VEE (mV)
OUTPUT VOLTAGE: FROM VEE (mV)
LARGE-SIGNAL GAIN
vs. TEMPERATURE
LARGE-SIGNAL GAIN
vs. TEMPERATURE
MINIMUM OPERATING VOLTAGE
vs. TEMPERATURE
125
VCC = 6.5V, RL TO VEE
120
VCC = 6.5V, RL TO VCC
115
VCC = 2.7V,
RL TO VEE
105
110
GAIN (dB)
110
100
95
VCC = 6.5V, RL TO VCC
90
105
100
95
VCC = 2.7V, RL TO VCC
90
85
85
80
VCC = 2.7V, RL TO VEE
80
VCC = 2.7V, RL TO VCC
75
VOUT(p-p) = VCC - 600mV
RL = 100kΩ
5
20
35
50
TEMPERATURE (°C)
65
80
95
1.8
1.7
1.6
1.5
1.4
1.3
1.2
75
-40 -25 -10
1.9
600
MAX4321-18
VCC = 6.5V,
RL TO VEE
MINIMUM OPERATING VOLTAGE (V)
RL = 500Ω
VOUT(p-p) = VCC - 1V
115
GAIN (dB)
60
0
MAX4321-17
120
100
MAX4321-16
0
125
70
-40 -25 -10
5
20
35
50
TEMPERATURE (°C)
65
80
95
-40 -25 -10
5
20
35
50
65
80
95
TEMPERATURE (°C)
_______________________________________________________________________________________
5
MAX4321
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0, VCM = VCC/2, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0, VCM = VCC/2, TA = +25°C, unless otherwise noted.)
0.025
0.020
0.015
MAX4321-20
AV = +1
10kHz SINE WAVE
RL TO VCC / 2
500kHz LOWPASS
FILTER
0.01
SMALL-SIGNAL TRANSIENT
RESPONSE (NONINVERTING)
AV = +1
IN
VOLTAGE
50mV/div
RL = 2kΩ
RL = 250Ω
0.010
OUT
RL = 10kΩ
0.005
RL = 100kΩ
0.001
0
1k
10k
FREQUENCY (Hz)
4.0
100k
4.4
4.6
4.8
200ns/div
5.0
LARGE-SIGNAL TRANSIENT
RESPONSE (INVERTING)
LARGE-SIGNAL TRANSIENT
RESPONSE (NONINVERTING)
MAX4321-22
SMALL-SIGNAL TRANSIENT
RESPONSE (INVERTING)
AV = -1
4.2
PEAK-TO-PEAK SIGNAL AMPLITUDE (V)
AV = +1
IN
IN
IN
VOLTAGE
2V/div
OUT
AV = -1
VOLTAGE
2V/div
100
MAX4321-23
10
MAX4321-24
THD + NOISE (%)
0.030
THD + NOISE (%)
AV = +1
2Vp-p SIGNAL
500kHz LOWPASS FILTER
RL = 10kΩ TO VCC / 2
0.035
0.1
MAX4321-19
0.040
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. PEAK-TO-PEAK SIGNAL AMPLITUDE
MAX4321-21
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
VOLTAGE
50mV/div
MAX4321
Low-Cost, Low-Voltage, Rail-to-Rail,
Input/Output, SOT23 5MHz Op Amp
OUT
OUT
2µs/div
200ns/div
2µs/div
Pin Description
6
PIN
NAME
1
OUT
Output
FUNCTION
2
VCC
Positive Supply
3
IN+
Noninverting Input
4
5
INVEE
Inverting Input
Negative Supply. Connect to ground for single-supply operation.
_______________________________________________________________________________________
Low-Cost, Low-Voltage, Rail-to-Rail,
Input/Output, SOT23 5MHz Op Amp
Rail-to-Rail Input Stage
The MAX4321 high-speed amplifier has rail-to-rail input
and output stages designed for low-voltage, singlesupply 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 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. Its low offset
voltage, high bandwidth, and rail-to-rail common-mode
range makes this op amp an excellent choice 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 cur-
rents flowing through external source impedances,
match the effective impedance seen by each input
(Figures 1a, 1b). High source impedances, together
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 MAX4321’s inputs are protected from large differential input voltages by 1kΩ series resistors and back-toback 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:
IBIAS =
R3
R3
MAX4321
MAX4321
R1
R3 = R1
VDIFF - 1.8V
2kΩ
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
_______________________________________________________________________________________
7
MAX4321
__________ Applications Information
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 MAX4321
connected as a voltage follower. With a +3V supply
and the 100kΩ load tied to ground, the output swings
from 0.02V to 2.97V. The maximum output voltage
swing depends on the load but will be within 300mV of
a +5V supply, even with the maximum load (250Ω to
ground).
LOAD CAPACITIVE (pF)
VOLTAGE
1V/div
IN
Driving a capacitive load can cause instability in most
high-speed op amps, especially those with low quiescent current. The MAX4321 has a high tolerance for
capacitive loads. It is 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.
10,000
VCC = 3V
AV = +1
OUT
UNSTABLE
REGION
1000
RL TO VEE
VOUT = VCC / 2
RL = 100kΩ
2µs/div
Figure 3. Rail-to-Rail Input /Output Voltage Range
100
100
1k
10k
RESISTIVE LOAD (Ω)
100k
Figure 4. Capacitive-Load Stability
AV = +1
CL = 500pF
IN
AV = +1
CL = 1000pF
RS = 39Ω
VOLTAGE
50mV/div
IN
VOLTAGE
50mV/div
MAX4321
Low-Cost, Low-Voltage, Rail-to-Rail,
Input/Output, SOT23 5MHz Op Amp
OUT
OUT
400ns/div
Figure 5. Small-Signal Transient Response with Capacitive
Load
8
400ns/div
Figure 6. Transient Response to Capacitive Load with Isolation
Resistor
_______________________________________________________________________________________
Low-Cost, Low-Voltage, Rail-to-Rail,
Input/Output, SOT23 5MHz Op Amp
Power Supplies and Layout
The MAX4321 operates from single +2.4V to +6.5V or
dual ±1.2V to ±3.25V supplies, though it typically operates down to +1.8V (±0.9V). 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.
Package Information
TRANSISTOR COUNT: 84
VCC
MAX4321
0V TO 2.7V
STEP FOR
POWER-UP
TEST 2k
RS
VOUT
CL
MAX4321
2k
Figure 7. Capacitive-Load-Driving Circuit
10k
Figure 8. Power-Up Test Circuit
VCC
1V/div
VOLTAGE
1V/div
VCC
SUPPLY-CURRENT
10Ω MONITORING POINT
OUT
ICC
500µA/div
5µs/div
5µs/div
Figure 9. Power-Up Output Voltage
Figure 10. Power-Up Supply Current
_______________________________________________________________________________________
9
MAX4321
Power-Up
The MAX4321 typically settles 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.
Low-Cost, Low-Voltage, Rail-to-Rail,
Input/Output, SOT23 5MHz Op Amp
SOT5L.EPS
MAX4321
Package Information
10
______________________________________________________________________________________
Low-Cost, Low-Voltage, Rail-to-Rail,
Input/Output, SOT23 5MHz Op Amp
______________________________________________________________________________________
MAX4321
NOTES
11
MAX4321
Low-Cost, Low-Voltage, Rail-to-Rail,
Input/Output, SOT23 5MHz Op Amp
NOTES
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
© 2000 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.