MAXIM MAX4488AUT-T

19-2137; Rev 0; 8/01
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
The MAX4475–MAX4478/MAX4488/MAX4489 wideband, low-noise, low-distortion operational amplifiers
offer Rail-to-Rail® outputs and single-supply operation
down to 2.7V. They draw 2.2mA of quiescent supply
current per amplifier while featuring ultra-low distortion
(0.0002% THD + N), as well as low input voltage noise
density (4.5nV/√Hz) and low input current noise density
(0.5fA/√Hz). These features make the devices an ideal
choice for applications that require low distortion and/or
low noise.
For power conservation, the MAX4475/MAX4488 offer a
low-power shutdown mode that reduces supply current
to 0.01µA and places the amplifiers’ outputs into a highimpedance state. These amplifiers have outputs which
swing rail-to-rail and their input common-mode voltage
range includes ground. The MAX4475–MAX4478 are
unity-gain stable with a gain-bandwidth product of
10MHz. The MAX4488/MAX4489 are internally compensated for gains of +5V/V or greater with a gain-bandwidth product of 42MHz. The single MAX4475/
MAX4476/MAX4488 are available in space-saving,
6-pin SOT23 packages.
Applications
ADC Buffers
DAC Output Amplifiers
Low-Noise Microphone/Preamplifiers
Digital Scales
Strain Gauges/Sensor Amplifiers
Medical Instrumentation
Typical Operating Characteristic
25
MAX4475 toc20
VIN EQUIVALENT INPUT NOISE VOLTAGE (nV/√Hz)
INPUT VOLTAGE NOISE DENSITY
vs. FREQUENCY
20
Features
♦ Low Input Voltage Noise Density: 4.5nV/√Hz
♦ Low Input Current Noise Density: 0.5fA/√Hz
♦ Low Distortion: 0.0002% THD + N (1kΩ load)
♦ Single-Supply Operation from +2.7V to +5.5V
♦ Input Common-Mode Voltage Range Includes
Ground
♦ Rail-to-Rail Output Swings with a 1kΩ Load
♦ 10MHz GBW Product, Unity-Gain Stable
(MAX4475–MAX4478)
♦ 42MHz GBW Product, Stable with AV ≥ +5V/V
(MAX4488/MAX4489)
♦ Excellent DC Characteristics
VOS = 70µV
IBIAS = 1pA
Large-Signal Voltage Gain = 120dB
♦ Low-Power Shutdown Mode:
Reduces Supply Current to 0.01µA
Places Output in High-Impedance State
♦ Available in Space-Saving SOT23, µMAX, and
TSSOP Packages
Ordering Information
TEMP. RANGE
PINPACKAGE
TOP
MARK
MAX4475AUT-T
-40°C to +125°C
6 SOT23-6
AAZV
MAX4475AUA
-40°C to +125°C
8 µMAX
—
MAX4475ASA
-40°C to +125°C
8 SO
—
MAX4476AUT-T
-40°C to +125°C
6 SOT23-6
PART
AAZX
Ordering Information continued at end of data sheet.
Pin Configurations and Typical Operating Circuit appear at
end of data sheet.
Selector Guide
15
10
PART
GAIN BW
(MHz)
STABLE
GAIN
(V/V)
NO. OF
AMPS
SHDN
5
MAX4475
10
1
1
Yes
MAX4476
10
1
1
—
MAX4477
10
1
2
—
MAX4478
10
1
4
—
0
10
100
1k
10k
100k
FREQUENCY (Hz)
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
MAX4488
42
5
1
Yes
MAX4489
42
5
2
—
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
1
MAX4475–MAX4478/MAX4488/MAX4489
General Description
MAX4475–MAX4478/MAX4488/MAX4489
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
ABSOLUTE MAXIMUM RATINGS
Power Supply Voltage (VDD to VSS) ......................-0.3V to +6.0V
Analog Input Voltage (IN_+, IN_-)....(VSS - 0.3V) to (VDD + 0.3V)
SHDN Input Voltage....................................(VSS - 0.3V) to +6.0V
Output Short-Circuit Duration to Either Supply ..........Continuous
Continuous Power Dissipation (TA = +70°C)
6-Pin SOT23 (derate 9.1mW/°C above +70°C)...........727mW
8-Pin µMAX (derate 4.5mW/°C above +70°C) ............362mW
8-Pin SO (derate 5.88mW/°C above +70°C)...............471mW
14-Pin SO (derate 8.33mW/°C above +70°C)..............667mW
14-Pin TSSOP (derate 9.1mW/°C above +70°C) .........727mW
Operating Temperature Range .........................-40°C to +125°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
(VDD = +5V, VSS = 0, VCM = 0, VOUT = VDD/2, RL tied to VDD/2, SHDN = VDD, TA = -40°C to +125°C, unless otherwise noted. Typical
values are at TA = +25°C) (Notes 1, 2)
PARAMETER
Supply Voltage Range
Quiescent Supply Current Per
Amplifier
Input Offset Voltage
Input Offset Voltage Tempco
Input Bias Current
SYMBOL
VDD
ID
VOS
CONDITIONS
(Note 3)
2.5
4.4
1.0
±350
TA = -40°C to +125°C
IOS
(Note 4)
Input Common-Mode Voltage
Range
VCM
AVOL
V
±70
RIN
PSRR
5.5
0.01
Differential Input Resistance
2
VDD = 5V
UNITS
TA = +25°C
Input Offset Current
Large-Signal Voltage Gain
2.2
MAX
Shutdown mode (SHDN = VSS) (Note 2)
(Note 4)
Power-Supply Rejection Ratio
VDD = 3V
±750
TCVOS
CMRR
TYP
2.7
Normal mode
IB
Common-Mode Rejection Ratio
MIN
(VSS - 0.2V) ≤
VCM ≤ (VDD 1.6V)
(VSS - 0.1V) ≤
VCM ≤ (VDD 1.7V)
±6
µV/°C
±150
pA
±1
±150
pA
GΩ
-0.2
VDD - 1.6
TA = -40°C to +125°C
-0.1
VDD - 1.7
90
µV
±1
TA = +25°C
TA = +25°C
µA
±0.3
1000
Guaranteed by
CMRR Test
mA
V
115
dB
TA = -40°C to +125°C
90
VDD = 2.7 to 5.5V
90
120
RL = 10kΩ to VDD/2;
VOUT = 100mV to (VDD - 125mV)
90
120
RL = 1kΩ to VDD/2;
VOUT = 200mV to (VDD - 250mV)
85
110
RL = 500Ω to VDD/2;
VOUT = 350mV to (VDD - 500mV)
85
110
_______________________________________________________________________________________
dB
dB
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
(VDD = +5V, VSS = 0, VCM = 0, VOUT = VDD/2, RL tied to VDD/2, SHDN = VDD, TA = -40°C to +125°C, unless otherwise noted. Typical
values are at TA = +25°C) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
|VIN+ - VIN-| ≥ 10mV
RL = 10kΩ to VDD/2
Output Voltage Swing
Output Short-Circuit Current
Output Leakage Current
VOUT
ILEAK
VIL
SHDN Logic High
VIH
SHDN Input Current
TYP
MAX
VDD - VOH
10
45
VOL - VSS
10
40
|VIN+ - VIN-| ≥ 10mV,
RL = 1kΩ to VDD/2
VDD - VOH
80
200
VOL - VSS
50
150
|VIN+ - VIN-| ≥ 10mV,
RL = 500Ω to VDD/2
VDD - VOH
100
300
VOL - VSS
80
250
ISC
SHDN Logic Low
Input Capacitance
MIN
48
Shutdown mode (SHDN = VSS),
VOUT = VSS to VDD
±0.001
SHDN = VSS to VDD
mV
mA
±1.0
µA
0.3 x VDD
V
0.7 x VDD
V
0.01
CIN
UNITS
1
10
µA
pF
AC ELECTRICAL CHARACTERISTICS
(VDD = +5V, VSS = 0, VCM = 0, VOUT = VDD/2, RL tied to VDD/2, SHDN = VDD, TA = +25°C.)
PARAMETER
Gain-Bandwidth Product
Slew Rate
SYMBOL
GBWP
SR
Full-Power Bandwidth (Note 5)
Peak-to-Peak Input Noise Voltage
Input Voltage Noise Density
Input Current Noise Density
Total Harmonic Distortion Plus
Noise (Note 6)
en(p-p)
en
in
THD+N
CONDITIONS
MIN
TYP
MAX4475–MAX4478
AV = +1V/V
10
MAX4488/MAX4489
AV = +5V/V
42
MAX4475–MAX4478
AV = +1V/V
3
MAX4488/MAX4489
AV = +5V/V
10
MAX4475–MAX4478
AV = +1V/V
0.4
MAX4488/MAX4489
AV = +5V/V
1.25
f = 0.1Hz to 10Hz
260
f = 10Hz
21
f = 1kHz
4.5
f = 30kHz
3.5
f = 1kHz
0.5
VOUT = 2Vp-p,
AV = +1V/V,
(MAX4475–MAX4478)
RL = 10kΩ to GND
VOUT = 2Vp-p,
AV = +1V/V,
(MAX4475–MAX4478)
RL = 1kΩ to GND
VOUT = 2Vp-p,
AV = +5V/V,
MAX4488/MAX4489
RL = 10kΩ to GND
f = 1kHz
0.0002
f = 20kHz
0.0007
f = 1kHz
0.0002
f = 20kHz
0.001
f = 1kHz
0.0004
f = 20kHz
0.0006
MAX
UNITS
MHz
V/µs
MHz
nVp-p
nV/√Hz
fA/√Hz
%
_______________________________________________________________________________________
3
MAX4475–MAX4478/MAX4488/MAX4489
DC ELECTRICAL CHARACTERISTICS (continued)
AC ELECTRICAL CHARACTERISTICS (continued)
(VDD = +5V, VSS = 0, VCM = 0, VOUT = VDD/2, RL tied to VDD/2, SHDN = VDD, TA = +25°C.)
PARAMETER
Total Harmonic Distortion Plus
Noise (Note 6)
SYMBOL
THD+N
Capacitive Load Stability
CONDITIONS
VOUT = 2Vp-p,
AV = +5V/V,
MAX4488/MAX4489
RL = 1kΩ to GND
MIN
GM
Phase Margin
ΦM
Settling Time
Delay Time to Shutdown
tSH
Enable Delay Time from Shutdown
tEN
Power-Up Delay Time
TYP
MAX
f = 1kHz
0.0005
f = 20kHz
0.008
UNITS
%
No sustained oscillations
Gain Margin
200
pF
12
dB
MAX4475–MAX4478, AV = +1V/V
70
MAX4488/MAX4489, AV = +5V/V
80
To 0.01%, VOUT = 2V step
2
µs
1.5
µs
VOUT = 2.5V, VOUT settles to 0.1%
10
µs
VDD = 0 to 5V step, VOUT stable to 0.1%
13
µs
degrees
All devices are 100% tested at TA = +25°C. Limits over temperature are guaranteed by design.
SHDN is available on the MAX4475/MAX4488 only.
Guaranteed by the PSRR test.
Guaranteed by design.
Full-power bandwidth for unity-gain stable devices (MAX4475–MAX4478) is measured in a closed-loop gain of +2V/V to
accommodate the input voltage range, VOUT = 4Vp-p.
Note 6: Lowpass-filter bandwidth is 22kHz for f = 1kHz and 80kHz for f = 20kHz. Noise floor of test equipment = 10nV/√Hz.
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Typical Operating Characteristics
(VDD = +5V, VSS = 0, VCM = 0, VOUT = VDD/2, RL tied to VDD/2, input noise floor of test equipment =10nV/√Hz for all distortion measurements, TA = +25°C, unless otherwise noted.)
12
10
8
6
4
2
150
100
50
0
-50
-100
-150
50
40
30
20
VDD = 3V
10
VDD = 5V
-200
0
0
-250
-50 -40 -30 -20 -10 0 10 20 30 40 50
VOS (µV)
4
VCOM = 0
200
INPUT OFFSET VOLTAGE (µV)
14
250
MAX4475 toc02
16
INPUT OFFSET VOLTAGE (µV)
MAX4475-8 toc1
18
INPUT OFFSET VOLTAGE
vs. INPUT COMMON-MODE VOLTAGE
OFFSET VOLTAGE vs. TEMPERATURE
MAX4475 toc03
INPUT OFFSET VOLTAGE DISTRIBUTION
PERCENTAGE OF UNITS (%)
MAX4475–MAX4478/MAX4488/MAX4489
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
-50
-25
0
25
50
75
TEMPERATURE (°C)
100
125
-0.5
0.5
1.5
2.5
3.5
INPUT COMMON-MODE VOLTAGE (V)
_______________________________________________________________________________________
4.5
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
OUTPUT VOLTAGE
vs. OUTPUT LOAD CURRENT
0.20
70
60
60
50
VDD - VOH
0.10
VOL
VOL (mV)
VDD - VOH (mV)
50
0.15
40
30
RL = 1kΩ
20
30
RL = 1kΩ
0
10
RL = 10kΩ
2
3
4
5
6
7
8
9
10
-50
0
25
50
75
100
-50
125
50
75
100
LARGE-SIGNAL VOLTAGE GAIN
vs. OUTPUT VOLTAGE SWING
LARGE-SIGNAL VOLTAGE GAIN
vs. OUTPUT VOLTAGE SWING
LARGE-SIGNAL VOLTAGE GAIN
vs. OUTPUT VOLTAGE SWING
MAX4475 toc07
130
120
120
80
90
RL = 2kΩ
80
70
70
VDD = 3V
RL REFERENCED TO VDD
60
50
50
100
150
200
250
50
0
50
100
150
200
VOUT SWING FROM EITHER SUPPLY (mV)
VOUT SWING FROM EITHER SUPPLY (mV)
LARGE-SIGNAL VOLTAGE GAIN
vs. OUTPUT VOLTAGE SWING
LARGE-SIGNAL VOLTAGE GAIN
vs. TEMPERATURE
140
MAX4475 toc10
RL = 200kΩ
130
120
110
RL = 20kΩ
RL = 2kΩ
90
80
RL = 10kΩ
100
90
70
VDD = 5V
RL REFERENCED TO VDD
60
50
60
100
150
200
VOUT SWING FROM EITHER SUPPLY (mV)
250
100
150
200
250
3.0
PER AMPLIFIER
2.5
2.0
1.5
1.0
0.5
VOUT = 150mV TO 4.75V
0
50
50
50
SUPPLY CURRENT vs. TEMPERATURE
80
70
0
VOUT SWING FROM EITHER SUPPLY (mV)
110
AVOL (dB)
100
RL = 100kΩ
250
SUPPLY CURRENT (mA)
130
VDD = 5V
RL REFERENCED TO GND
60
MAX4475 toc11
50
90
80
70
VDD = 3V
RL REFERENCED TO GND
RL = 200kΩ
RL = 20kΩ
100
AV (dB)
AV (dB)
100
60
RL = 2kΩ
110
RL = 20kΩ RL = 200kΩ
90
125
130
110
RL = 20kΩ RL = 200kΩ
100
0
25
TEMPERATURE (°C)
RL = 2kΩ
120
0
TEMPERATURE (°C)
120
0
-25
OUTPUT LOAD CURRENT (mA)
130
110
-25
MAX4475 toc12
1
MAX4475 toc08
0
RL = 10kΩ
0
0
MAX4475 toc09
10
AV (dB)
40
20
0.05
AV (dB)
MAX4475 toc06
VDD = 3V OR 5V
VDIFF = ±10mV
MAX4475 toc05
70
MAX4475 toc04
0.25
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE SWING (VOL)
vs. TEMPERATURE
OUTPUT VOLTAGE SWING (VOH)
vs. TEMPERATURE
-50
-25
0
25
50
75
TEMPERATURE (°C)
100
125
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
_______________________________________________________________________________________
5
MAX4475–MAX4478/MAX4488/MAX4489
Typical Operating Characteristics (continued)
(VDD = +5V, VSS = 0, VCM = 0, VOUT = VDD/2, RL tied to VDD/2, input noise floor of test equipment =10nV/√Hz for all distortion measurements, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VDD = +5V, VSS = 0, VCM = 0, VOUT = VDD/2, RL tied to VDD/2, input noise floor of test equipment =10nV/√Hz for all distortion measurements, TA = +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
1.5
1.0
0.5
2.0
VDD = 3V
1.5
1.0
0.5
0
3.0
3.5
4.0
4.5
5.0
5.5
1
2
3
4
GAIN
40
GAIN (dB)
30
3.0
50
108
40
108
72
30
72
20
36
10
0
0
-36
144
0
-36
-72
-108
-20
-30
-144
-30
-40
-180
100M
-40
-10
-72
VDD = 3V OR 5V
RL = 50kΩ
CL = 20pF
AV = +1000V/V
100
1k
10k
-108
PHASE
-144
100k
1M
10M
-180
100M
INPUT FREQUENCY (Hz)
MAX4475–MAX4478
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
OUTPUT IMPEDANCE vs. FREQUENCY
OUTPUT IMPEDANCE (Ω)
MAX4475 toc19
MAX4475 toc18
1000
100
10
AV = +5
1
AV = +1
0.1
0.01
10
FREQUENCY (kHz)
1000
4.5
100,000
180
0
-20
10M
GAIN
10
-10
PHASE
MAX4475 toc17
144
36
1M
4.0
60
20
100k
3.5
SUPPLY VOLTAGE (V)
INPUT FREQUENCY (Hz)
PSRR (dB)
2.5
180
GAIN (dB)
VDD = 3V OR 5V
RL = 50kΩ
CL = 20pF
AV = +1000V/V
0
VDD = 3V OR 5V
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
-110
-120
-130
0.001
0.1
-10
MAX4488/MAX4489
GAIN AND PHASE vs. FREQUENCY
PHASE (degrees)
60
10k
-5
OUTPUT VOLTAGE (V)
MAX4475 toc16
1k
0
5
MAX4475–MAX4478
GAIN AND PHASE vs. FREQUENCY
100
5
-20
0
SUPPLY VOLTAGE (V)
50
10
-15
0
2.5
6
15
1
10
100
1k
10k
FREQUENCY (Hz)
_______________________________________________________________________________________
PHASE (degrees)
2.0
20
INPUT OFFSET VOLTAGE (µV)
2.5
SUPPLY CURRENT (mA)
2.5
VDD = 5V
MAX4475 toc15
3.0
MAX4475 toc14
PER AMPLIFIER
INPUT OFFSET VOLTAGE
vs. SUPPLY VOLTAGE
SUPPLY CURRENT vs. OUTPUT VOLTAGE
MAX4475 toc13
3.0
SUPPLY CURRENT (mA)
MAX4475–MAX4478/MAX4488/MAX4489
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
5.0
5.5
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
MAX4475 toc21
10
AV = +1
1
THD + N (%)
20
VDD = 3V OR 5V
Vp-p NOISE = 260nVp-p
15
200nV/div
10
0.1
0.01
fO = 20kHz, FILTER BW = 80kHz
5
0.001
0
0.0001
fO = 3kHz, FILTER BW = 30kHz
100
1k
10k
1s/div
100k
0
FREQUENCY (Hz)
0.01
MAX4475 toc24
1
MAX4488/MAX4489
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
0.01
MAX4475 toc23
AV = +5
VDD = +3V, fO = 20kHz
FILTER BW = 80kHz
0.001
0.001
AV = +10, VDD = 3V
AV = +10, VDD = 5V
FILTER BW = 22kHz
RL = 10kΩ TO GND
R1 = 5.6kΩ, R2 = 53kΩ
VOUT = 2Vp-p
VDD = 3V, fO = 3kHz
FILTER BW = 30kHz
0.0001
1
2
0
3
5k
10k
15k
MAX4488/MAX4489
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX4475–MAX4478
LARGE-SIGNAL PULSE RESPONSE
RL TO VDD
0
5k
10k
15k
20k
MAX4475–MAX4478
SMALL-SIGNAL PULSE RESPONSE
MAX4475 toc27
MAX4475 toc26
FILTER BW = 80kHz
RL = 10kΩ TO GND
R1 = 5.6kΩ, R2 = 53kΩ
VOUT = 2.75Vp-p
RL TO GND
FREQUENCY (Hz)
FREQUENCY (Hz)
1
FILTER BW = 80kHz
VOUT = 2Vp-p
AV = +1
RL = 1kΩ
0.001
20k
OUTPUT VOLTAGE (Vp-p)
0.1
4
MAX4475–MAX4478
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
RL TO VDD/2
0.0001
0.00001
0
3
THD + N (%)
THD + N (%)
THD + N (%)
0.1
0.01
2
OUTPUT VOLTAGE (Vp-p)
MAX4488/MAX4489
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT VOLTAGE SWING
10
1
MAX4475 toc25
10
THD + N (%)
MAX4475 toc22
MAX4475
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT VOLTAGE SWING
0.1Hz TO 10Hzp-p NOISE
25
MAX4475 toc20
VIN EQUIVALENT INPUT NOISE VOLTAGE (nV/√Hz)
INPUT VOLTAGE NOISE DENSITY
vs. FREQUENCY
MAX4475–MAX4478/MAX4488/MAX4489
Typical Operating Characteristics (continued)
(VDD = +5V, VSS = 0, VCM = 0, VOUT = VDD/2, RL tied to VDD/2, input noise floor of test equipment =10nV/√Hz for all distortion measurements, TA = +25°C, unless otherwise noted.)
MAX4475 toc28
0.6V
2.5V
20mV/div
0.01
AV = +5, VDD = 3V
0.001
0.5V
0.5V
AV = +5, VDD = 5V
0.0001
0
5k
10k
FREQUENCY (Hz)
15k
20k
1µs/div
VDD = 3V, RL = 10kΩ, CL = 100pF
VIN = 2V
4µs/div
VDD = 3V, RL = 10kΩ, CL = 100pF
VIN = 100mV PULSE
_______________________________________________________________________________________
7
Typical Operating Characteristics (continued)
(VDD = +5V, VSS = 0, VCM = 0, VOUT = VDD/2, RL tied to VDD/2, input noise floor of test equipment =10nV/√Hz for all distortion measurements, TA = +25°C, unless otherwise noted.)
MAX4488/MAX4489
SMALL-SIGNAL PULSE RESPONSE
MAX4488/MAX4489
LARGE-SIGNAL PULSE RESPONSE
MAX4477/MAX4478/MAX4489
CROSSTALK vs. FREQUENCY
MAX4475 toc30
MAX4475 toc29
MAX4475 toc31
-20
-30
1.6V
VOUT
50mV/div
VOUT
200mV/div
1.5V
-40
CROSSTALK (dB)
MAX4475–MAX4478/MAX4488/MAX4489
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
-50
-60
-70
-80
-90
1µs/div
1µs/div
10
100
VDD = 3V, RL = 10kΩ, CL = 50pF
VIN = 20mV PULSE, AV = +5V/V
VDD = 3V, RL = 10kΩ, CL = 50pF
VIN = 20mV PULSE, AV = +5V/V
1000
10k 100k
1M
10M 100M
FREQUENCY (Hz)
Pin Description
PIN
MAX4475/
MAX4488
MAX4475/
MAX4488
MAX4476
MAX4477/
MAX4489
MAX4478
SOT23
8 SO/µMAX
SOT23
8 SO/µMAX
SO/TSSOP
1
6
1
1, 7
1, 7, 8, 14
OUT, OUTA,
OUTB, OUTC,
OUTD
2
4
2
4
11
VSS
3
3
3
3, 5
3, 5, 10, 12
IN+, INA+,
INB+, INC+,
IND+
4
2
4
2, 6
2, 6, 9, 13
IN-, INA-, INB-,
INC-, IND-
6
7
5
8
4
VDD
5
8
—
—
—
SHDN
—
1, 5
—
—
—
N.C.
8
NAME
FUNCTION
Amplifier Output
Negative Supply. Connect
to ground for singlesupply operation
Noninverting Amplifier
Input
Inverting Amplifier Input
Positive Supply
Shutdown Input. Connect
to VDD for normal
operation (amplifier(s)
enabled).
No Connection. Not
internally connected.
_______________________________________________________________________________________
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
The MAX4475–MAX4478/MAX4488/MAX4489 singlesupply operational amplifiers feature ultra-low noise
and distortion. Their low distortion and low noise make
them ideal for use as preamplifiers in wide dynamicrange applications, such as 16-bit analog-to-digital
converters (see Typical Operating Circuit). Their highinput impedance and low noise are also useful for signal conditioning of high-impedance sources, such as
piezoelectric transducers.
These devices have true rail-to-rail ouput operation,
drive loads as low as 1kΩ while maintining DC accuracy, and can drive capactive loads up to 200pF without
oscillation. The input common-mode voltage range
extends from (VDD - 1.6V) to 200mV below the negative
rail. The push/pull output stage maintains excellent DC
characteristics, while delivering up to ±5mA of current.
The MAX4475–MAX4478 are unity-gain stable, while
the MAX4488/MAX4489 have a higher slew rate and
are stable for gains ≥ 5V/V. The MAX4475/MAX4488
feature a low-power shutdown mode, which reduces
the supply current to 0.01µA and disables the outputs.
MAX4475–MAX4478/MAX4488/MAX4489
Detailed Description
CZ
RF
RG
VOUT
VIN
Figure 1. Adding Feed-Forward Compensation
AV = +2
RF = RG = 100kΩ
VIN
100mV/div
100mV
0
Low Distortion
Many factors can affect the noise and distortion that the
device contributes to the input signal. The following
guidelines offer valuable information on the impact of
design choices on Total Harmonic Distortion (THD).
Choosing proper feedback and gain resistor values for
a particular application can be a very important factor
in reducing THD. In general, the smaller the closedloop gain, the smaller the THD generated, especially
when driving heavy resistive loads. The THD of the part
normally increases at approximately 20dB per decade,
as a function of frequency. Operating the device near
or above the full-power bandwidth significantly
degrades distortion.
Referencing the load to either supply also improves the
part’s distortion performance, because only one of the
MOSFETs of the push/pull output stage drives the output. Referencing the load to mid-supply increases the
part’s distortion for a given load and feedback setting.
(See the Total Harmonic Distortion vs. Frequency graph
in the Typical Operating Characteristics.)
For gains ≥ 5V/V, the decompensated devices
MAX4488/MAX4489 deliver the best distortion performance, since they have a higher slew rate and provide
a higher amount of loop gain for a given closed-loop
gain setting. Capacitive loads below 100pF do not significantly affect distortion results. Distortion performance is relatively constant over supply voltages.
VOUT
100mV/div
2µs/div
Figure 2a. Pulse Response with No Feed-Forward
Compensation
AV = +2
RF = RG = 100kΩ
VIN
100mV/div
VOUT
100mV/div
2µs/div
Figure 2b. Pulse Response with 10pF Feed-Forward
Compensation
_______________________________________________________________________________________
9
MAX4475–MAX4478/MAX4488/MAX4489
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
Low Noise
The amplifier’s input-referred noise voltage density is
dominated by flicker noise at lower frequencies, and by
thermal noise at higher frequencies. Because the thermal noise contribution is affected by the parallel combination of the feedback resistive network (R F || R G ,
Figure 1), these resistors should be reduced in cases
where the system bandwidth is large and thermal noise
is dominant. This noise contribution factor decreases,
however, with increasing gain settings.
For example, the input noise voltage density of the circuit with R F = 100kΩ, R G = 11kΩ (A V = +5V/V) is
e n = 14nV/√Hz, e n can be reduced to 6nV/√Hz by
choosing RF = 10kΩ, RG = 1.1kΩ (AV = +5V/V), at the
expense of greater current consumption and potentially
higher distortion. For a gain of 100V/V with R F =
100kΩ, RG = 1.1kΩ, the en is still a low 6nV/√Hz.
Using a Feed-Forward Compensation
Capacitor, CZ
The amplifier’s input capacitance is 10pF. If the resistance seen by the inverting input is large (feedback
network), this can introduce a pole within the amplifier’s
bandwidth resulting in reduced phase margin.
Compensate the reduced phase margin by introducing
a feed-forward capacitor (CZ) between the inverting
input and the output (Figure 1). This effectively cancels
the pole from the inverting input of the amplifier.
Choose the value of CZ as follows:
CZ = 10 x (RF / RG) [pF]
In the unity-gain stable MAX4475–MAX4478 , the use of
a proper CZ is most important for AV = +2V/V, and AV
= -1V/V. In the decompensated MAX4488/MAX4489,
CZ is most important for AV = +10V/V. Figures 2a and
2b show transient response both with and without CZ.
Using a slightly smaller CZ than suggested by the formula above achieves a higher bandwidth at the
expense of reduced phase and gain margin. As a general guideline, consider using CZ for cases where RG ||
R F is greater than 20kΩ (MAX4475–MAX4478) or
greater than 5kΩ (MAX4488/MAX4489).
Applications Information
The MAX4475–MAX4478/MAX4488/MAX4489 combine
good driving capability with ground-sensing input and
rail-to-rail output operation. With their low distortion and
low noise, they are ideal for use in ADC buffers, medical instrumentation systems and other noise-sensitive
applications.
10
AV = +1
VDD = +5V
RL = 10kΩ
VIN
2V/div
0
VOUT
2V/div
40µs/div
Figure 3. Overdriven Input Showing No Phase Reversal
5V
VOUT
1V/div
0
20µs/div
Figure 4. Rail-to-Rail Output Operation
Ground-Sensing and Rail-to-Rail Outputs
The common-mode input range of these devices
extends below ground, and offers excellent commonmode rejection. These devices are guaranteed not to
undergo phase reversal when the input is overdriven
(Figure 3).
Figure 4 showcases the true rail-to-rail output operation
of the amplifier, configured with AV = 5V/V. The output
swings to within 8mV of the supplies with a 10kΩ load,
making the devices ideal in low-supply-voltage applications.
Power Supplies and Layout
The MAX4475–MAX4478/MAX4488/MAX4489 operate
from a single +2.7V to +5.5V power supply or from dual
supplies of ±1.35V to ±2.75V. For single-supply operation, bypass the power supply with a 0.1µF ceramic
______________________________________________________________________________________
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
+5V
+5V
7
VDD
CS
SERIAL
INTERFACE
+2.5V
U1
3
OUT
SCLK
MAX5541ESA
DIN
U2
REF
MAX4475AUA
0 to +2.5V
OUTPUT
6
AGND
DGND
2
4
8
SHDN
Typical Operating Circuit
5V
470pF
0.1µF
3.09kΩ
1%
7.87kΩ
1%
220pF
3
8
220pF
1
3.83kΩ
1%
13.7kΩ
1%
5
1/2 MAX4477
7
220pF
2
4
7.15kΩ
1%
1/2 MAX4477
220pF
6
10.0kΩ
1%
10.0kΩ
1%
10.0kΩ
1%
capacitor placed close to the VDD pin. If operating from
dual supplies, bypass each supply to ground.
Good layout improves performance by decreasing the
amount of stray capacitance and noise at the op amp’s
inputs and output. To decrease stray capacitance, minimize PC board trace lengths and resistor leads, and
place external components close to the op amp’s pins.
Typical Application Circuit
The Typical Application Circuit shows the single
MAX4475 configured as an output buffer for the
MAX5541 16-bit DAC. Because the MAX5541 has an
unbuffered voltage output, the input bias current of the
op amp used must be less than 6nA to maintain 16-bit
accuracy. The MAX4475 has an input bias current of
only 150pA (max), virtually eliminating this as a source
15.0kΩ
1%
of error. In addition, the MAX4475 has excellent openloop gain and common-mode rejection, making this an
excellent ouput buffer amplifier.
DC-Accurate Low-Pass Filter
The MAX4475–MAX4478/MAX4488/MAX4489 offer a
unique combination of low noise, wide bandwidth, and
high gain, making them an excellent choice for active
filters up to 1MHz. The Typical Operating Circuit shows
the dual MAX4477 configured as a 5th order
Chebyschev filter with a cutoff frequency of 100kHz.
The circuit is implemented in the Sallen-Key topology,
making this a DC-accurate filter.
______________________________________________________________________________________
11
MAX4475–MAX4478/MAX4488/MAX4489
Typical Application Circuit
MAX4475–MAX4478/MAX4488/MAX4489
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
Pin Configurations
TOP VIEW
TOP VIEW
N.C. 1
INA- 2
INA+
MAX4475
MAX4488
3
VSS 4
8
SHDN
7
VDD
OUTA 1
INA- 2
6
OUT
5
N.C.
INA+
3
MAX4477
MAX4489
VSS 4
14 OUTD
INA-
2
13 IND-
INA+
3
12 IND+
VDD 4
MAX4478
7
OUTB
6
INB-
5
INB+
TOP VIEW
TOP VIEW
OUTA 1
VDD
SO/µMAX
SO/µMAX
TOP VIEW
8
OUT 1
VSS 2
MAX4475
MAX4488
OUT
1
6
VDD
5
SHDN
VSS 2
4
IN-
IN+ 3
MAX4476
6
VDD
5
N.C.
4
IN-
11 VSS
INB+ 5
10 INC+
INB- 6
9
INC-
OUTB 7
8
OUTC
IN+ 3
SOT23-6
SOT23-6
SO/TSSOP
Ordering Information (continued)
PART
TEMP. RANGE
PINPACKAGE
MAX4477AUA
-40°C to +125°C
8 µMAX
—
MAX4477ASA
-40°C to +125°C
8 SO
—
MAX4478AUD
-40°C to +125°C
14 TSSOP
—
MAX4478ASD
-40°C to +125°C
14 SO
—
MAX4488AUT-T
-40°C to +125°C
6 SOT23-6
MAX4488AUA
-40°C to +125°C
8 µMAX
—
MAX4488ASA
-40°C to +125°C
8 SO
—
MAX4489AUA
-40°C to +125°C
8 µMAX
—
MAX4489ASA
-40°C to +125°C
8 SO
—
12
TOP
MARK
Chip Information
MAX4475/MAX4476 TRANSISTOR COUNT: 1095
MAX4477 TRANSISTOR COUNT: 2132
MAX4478 TRANSISTOR COUNT: 4244
MAX4488 TRANSISTOR COUNT: 1095
MAX4489 TRANSISTOR COUNT: 2132
PROCESS: BiCMOS
AAZW
______________________________________________________________________________________
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
8LUMAXD.EPS
______________________________________________________________________________________
13
MAX4475–MAX4478/MAX4488/MAX4489
Package Information
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
TSSOP,NO PADS.EPS
MAX4475–MAX4478/MAX4488/MAX4489
Package Information (continued)
14
_______________________________________________________________________________________
SOT23, Low-Noise, Low-Distortion, Wide-Band,
Rail-to-Rail Op Amps
SOICN.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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 15
© 2001 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
MAX4475–MAX4478/MAX4488/MAX4489
Package Information (continued)