MAXIM MAX4252

19-1295; Rev 2; 4/98
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
Applications
Portable/Battery-Powered Equipment
Medical Instrumentation
____________________________Features
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
Low Input Voltage Noise Density: 7.9nV/√Hz
Low Input Current Noise Density: 0.5fA/√Hz
Low Distortion: 0.0002% THD (1kΩ load)
400µA Quiescent Supply Current per Amplifier
Single-Supply Operation from +2.4V to +5.5V
Input Common-Mode Voltage Range Includes
Ground
Outputs Swing within 8mV of Rails with a 10kΩ Load
3MHz GBW Product, Unity-Gain Stable
(MAX4250–MAX4254)
22MHz GBW Product, Stable with AV ≥ 10V/V
(MAX4249/MAX4255/MAX4256/MAX4257)
Excellent DC Characteristics:
VOS = 70µV
IBIAS = 1pA
Large-Signal Voltage Gain = 116dB
Low-Power Shutdown Mode:
Reduces Supply Current to 0.5µA
Places Outputs in a High-Impedance State
400pF Capacitive-Load Handling Capability
Available in Space-Saving SOT23 and µMAX
Packages
ADC Buffers
Digital Scales
Ordering Information
Strain Gauges
Sensor Amplifiers
TEMP. RANGE
PINPACKAGE
MAX4249ESD
-40°C to +85°C
14 SO
MAX4249EUB
-40°C to +85°C
10 µMAX
PART
Portable Communications Devices
Pin Configurations and Typical Operating Circuit appear at
end of data sheet.
MAX4250EUK-T -40°C to +85°C
SOT
TOP MARK
5 SOT23-5
—
—
ACCI
Ordering Information continued at end of data sheet.
Selector Guide
PART
GAIN
BANDWIDTH
(MHz)
MINIMUM
STABLE
GAIN (V/V)
NO. OF AMPLIFIERS
PER PACKAGE
SHUTDOWN
MODE
PACKAGES
MAX4249
22
10
2
Yes
10-pin µMAX, 14-pin SO
MAX4250
3
1
1
—
MAX4251
3
1
1
Yes
8-pin µMAX/SO
MAX4252
3
1
2
—
8-pin µMAX/SO
MAX4253
3
1
2
Yes
MAX4254
3
1
4
—
14-pin SO
MAX4255
22
10
1
—
5-pin SOT23
MAX4256
22
10
1
Yes
8-pin µMAX/SO
MAX4257
22
10
2
—
8-pin µMAX/SO
5-pin SOT23
10-pin µMAX, 14-pin SO
Rail-to-Rail is a registered trademark of Nippon Motorola Ltd.
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
MAX4249–MAX4257
General Description
The MAX4249–MAX4257 low-noise, low-distortion operational amplifiers offer Rail-to-Rail® outputs and singlesupply operation down to 2.4V. They draw only 400µA
of quiescent supply current per amplifier while featuring
ultra-low distortion (0.0002% THD), as well as low input
voltage noise density (7.9nV/√Hz) and low input current
noise density (0.5fA/√Hz). These features make the
devices an ideal choice for portable/battery-powered
applications that require low distortion and/or low noise.
For additional power conservation, the MAX4249/
MAX4251/MAX4253/MAX4256 offer a low-power shutdown mode that reduces supply current to 0.5µA and
puts the amplifiers’ outputs into a high-impedance state.
The MAX4249–MAX4257’s outputs swing rail-to-rail and
their input common-mode voltage range includes
ground. The MAX4250–MAX4254 are unity-gain stable;
the MAX4249/MAX4255/MAX4256/MAX4257 are internally compensated for gains of 10V/V or greater. The single
MAX4250/MAX4255 are available in a space-saving,
5-pin SOT23 package.
MAX4249–MAX4257
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
ABSOLUTE MAXIMUM RATINGS
Power-Supply Voltage (VDD to VSS) ......................+6.0V to -0.3V
Analog Input Voltage (IN_+, IN_-)....(VDD + 0.3V) to (VSS - 0.3V)
SHDN Input Voltage....................................+6.0V to (VSS - 0.3V)
Output Short-Circuit Duration to Either Supply ..........Continuous
Continuous Power Dissipation (TA = +70°C)
5-Pin SOT23 (derate 7.1mW/°C above +70°C)............571mW
8-Pin µMAX (derate 4.10mW/°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, 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.
ELECTRICAL CHARACTERISTICS
(VDD = +5V, VSS = 0V, VCM = 0V, VOUT = VDD/2, RL tied to VDD/2, SHDN = VDD or open, TA = -40°C to +85°C, unless otherwise
noted. Typical values are at TA = +25°C.) (Notes 1, 2)
PARAMETER
Supply-Voltage Range
Quiescent Supply Current
per Amplifier
SYMBOL
VDD
IQ
CONDITIONS
(Note 3)
Normal mode
MIN
2.4
VDD = 3V
400
VDD = 5V
420
Shutdown mode (SHDN = VSS) (Note 1)
Input Offset Voltage
VOS
Input Offset Voltage Tempco
Input Bias Current
TYP
MAX
UNITS
5.5
V
575
µA
0.5
1.5
±0.07
±0.75
0.3
IB
(Note 4)
±1
±100
Input Offset Current
IOS
(Note 4)
±1
±100
Differential Input Resistance
RIN
Input Common-Mode Voltage
Range
VCM
1000
Guaranteed by CMRR test
pA
pA
GΩ
VDD 1.1
-0.2
mV
µV/°C
V
Common-Mode Rejection
Ratio
CMRR
VSS - 0.2V ≤ VCM ≤ VDD - 1.1V
70
115
dB
Power-Supply Rejection Ratio
PSRR
VDD = 2.4V to 5.5V
75
100
dB
RL = 10kΩ to VDD/2, VOUT = 25mV to 4.97V
80
116
RL = 1kΩ to VDD/2, VOUT = 150mV to 4.75V
80
112
Large-Signal Voltage Gain
Output Voltage Swing
Output Short-Circuit Current
Output Leakage Current
SHDN Logic Low
SHDN Logic High
SHDN Input Current
Input Capacitance
2
AV
VOUT
VIN+ - VIN-≥ 10mV,
RL = 10kΩ to VDD/2
VDD - VOH
VOL - VSS
7
20
VIN+ - VIN-≥ 10mV,
VDD - VOH
77
200
RL = 1kΩ to VDD/2
VOL - VSS
47
100
8
ISC
ILEAK
25
68
Shutdown mode (SHDN = VSS),
VOUT = VSS to VDD
0.001
VIL
1.0
0.8 x VDD
SHDN = VSS to VDD
mV
mA
0.2 x VDD
VIH
IIL/IIH
dB
µA
V
V
0.5
11
_______________________________________________________________________________________
1.5
µA
pF
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
(VDD = +5V, VSS = 0V, VCM = 0V, VOUT = VDD/2, RL tied to VDD/2, SHDN = VDD or open, TA = -40°C to +85°C, unless otherwise
noted. Typical values are at TA = +25°C.) (Notes 1, 2)
PARAMETER
Gain-Bandwidth Product
Slew Rate
SYMBOL
GBW
SR
Peak-to-Peak Input Noise
Voltage
en(p-p)
Input Voltage Noise Density
en
Input Current Noise Density
in
CONDITIONS
THD+N
Capacitive-Load Stability
Gain Margin
GM
Phase Margin
ΦM
MAX4249/MAX4255/MAX4256/MAX4257
22
MAX4250–MAX4254
0.3
MAX4249/MAX4255/MAX4256/MAX4257
2.1
f = 0.1Hz to 10Hz
760
f = 10Hz
27
f = 1kHz
8.9
f = 30kHz
7.9
f = 1kHz
0.5
MAX4249/MAX4255/MAX4256/
MAX4257, AV = +10V/V,
RF = 100kΩ, RG = 11kΩ,
VOUT = 4Vp-p, RL = 10kΩ to GND
(Note 5)
f = 1kHz
0.0004
f = 20kHz
0.006
f = 1kHz
0.0012
f = 20kHz
0.007
No sustained oscillations
400
MAX4250–MAX4254, AV = +1V/V
10
MAX4249/MAX4255/MAX4256/MAX4257,
AV = +10V/V
74
MAX4249/MAX4255/MAX4256/MAX4257,
AV = +10V/V
68
MAX4250–MAX4254
6.7
MAX4249/MAX4255/MAX4256/
MAX4257
1.6
Shutdown Delay Time
tSH
MAX4251/MAX4253
IVDD = 5% of
normal operation MAX4249/MAX4256
Enable Delay Time
tEN
VOUT = 2.5V,
VOUT settles to
0.1%
Power-Up Delay Time
tPU
12.5
MAX4250–MAX4254, AV = +1V/V
To 0.01%,
VOUT = 2V step
Settling Time
TYP
3
MAX4250–MAX4254, AV = +1V/V,
VOUT = 2Vp-p, RL = 1kΩ to GND
(Note 5)
Total Harmonic
Distortion plus Noise
MIN
MAX4250–MAX4254
0.8
1.2
MAX4251/MAX4253
8
MAX4249/MAX4256
3.5
MAX
UNITS
MHz
V/µs
nVp-p
nV/√Hz
fA/√Hz
%
pF
dB
degrees
µs
µs
µs
VDD = 0V to 5V step, VOUT stable to 0.1%
6
µs
Note 1: SHDN is available on the MAX4249/MAX4251/MAX4253/MAX4256 only.
Note 2: The MAX4249EUB, MAX425_EU_ specifications are 100% tested at TA = +25°C. Limits over the extended temperature
range are guaranteed by design, not production tested.
Note 3: Guaranteed by the Power-Supply Rejection Ratio (PSRR) test.
Note 4: Guaranteed by design.
Note 5: Lowpass filter bandwidth is 22kHz for f = 1kHz, and 80kHz for f = 20kHz. Noise floor of test equipment = 10nV/√Hz.
_______________________________________________________________________________________
3
MAX4249–MAX4257
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(VDD = +5V, VSS = 0V, VCM = VOUT = VDD/2, input noise floor of test equipment = 10nV/√Hz for all distortion measurements,
TA = +25°C, unless otherwise noted.)
OFFSET VOLTAGE
vs. TEMPERATURE
100
25
20
50
0
-50
15
-100
-150
-200
0
-250
-95
-75
-55
-35
-13
7
28
49
69
90
110
131
152
172
192
5
-20
0
20
40
MAX4249 TOC03
0.5
1.5
2.5
3.5
OUTPUT VOLTAGE SWING (VOH)
vs. TEMPERATURE
OUTPUT VOLTAGE SWING (VOL)
vs. TEMPERATURE
0.09
0.05
VOL
0.2
0.05
0.02
0.02
RL = 10kΩ
0.01
0.01
3
4
5
6
7
8
9
0
-40
10
RL = 10kΩ
RL = 100kΩ
RL = 100kΩ
0
2
0.03
0.04
0.03
0
RL = 1kΩ
0.04
0.06
VOL (V)
VDD - VOH (V)
0.3
RL = 1kΩ
0.08
-20
0
20
40
60
80
-40
-20
0
20
40
60
TEMPERATURE (°C)
TEMPERATURE (°C)
LARGE-SIGNAL VOLTAGE GAIN
vs. OUTPUT VOLTAGE SWING
LARGE-SIGNAL VOLTAGE GAIN
vs. OUTPUT VOLTAGE SWING
LARGE-SIGNAL VOLTAGE GAIN
vs. OUTPUT VOLTAGE SWING
130
AV (dB)
90
100
90
80
110
RL = 200kΩ
RL = 20kΩ
110
100
RL = 2kΩ
70
50
100
150
200
VOUT SWING FROM EITHER SUPPLY (mV)
VDD = 3V
RL REFERENCED TO VDD
60
50
250
RL = 2kΩ
90
70
70
VDD = 3V
RL REFERENCED TO GND
RL = 20kΩ
100
80
80
60
120
120
RL = 2kΩ
RL = 200kΩ
130
AV (dB)
RL = 20kΩ
110
140
MAX4249 TOC08
120
140
MAX4249TOC07
130
RL = 200kΩ
80
MAX4249TOC09
OUTPUT LOAD CURRENT (mA)
140
4.5
0.06
MAX4249 TOC05
MAX4249 TOC04
0.10
0.07
0.4
0
0
-50
-0.5
80
VDD = 5V
OUTPUT VOLTAGE
vs. OUTPUT LOAD CURRENT
VDD - VOH
1
VDD = 3V
50
INPUT COMMON-MODE VOLTAGE (V)
VDD = 3V OR 5V
VDIFF = ±10mV
0
100
TEMPERATURE (°C)
0.1
4
60
150
VOS (µV)
0.6
0.5
-40
200
MAX4249 TOC06
150
10
OUTPUT VOLTAGE (V)
VCM = 0V
200
VOS (µV)
NUMBER OF UNITS
30
MAX4249 TOC02
400 UNITS
VCM = 0V
TA = +25°C
35
250
MAX4249 TOC01
40
INPUT OFFSET VOLTAGE vs.
COMMON-MODE INPUT VOLTAGE
INPUT OFFSET VOLTAGE (µV)
MAX4251/MAX4256 INPUT OFFSET
VOLTAGE DISTRIBUTION
AV (dB)
MAX4249–MAX4257
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
0
50
100
150
200
VOUT SWING FROM EITHER SUPPLY (mV)
VDD = 5V
RL REFERENCED TO GND
60
50
250
0
50
100
150
200
VOUT SWING FROM EITHER SUPPLY (mV)
_______________________________________________________________________________________
250
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
LARGE-SIGNAL VOLTAGE GAIN
vs. OUTPUT VOLTAGE SWING
120
RL = 2kΩ
110
115
AV (dB)
100
RL = 100kΩ
VOUT = 10mV
to 4.99V
110
90
80
70
105
VDD = 5V
RL REFERENCED TO VDD
60
50
50
100
150
200
250
SHDN = VDD
SHDN = VSS
RL = 10kΩ
VOUT = 20mV
to 4.975V
360
0.373
340
-40
-20
0
20
40
60
-40
80
-20
0
20
40
60
TEMPERATURE (°C)
TEMPERATURE (°C)
SUPPLY CURRENT AND SHUTDOWN
SUPPLY CURRENT vs. SUPPLY VOLTAGE
SUPPLY CURRENT
vs. OUTPUT VOLTAGE
INPUT OFFSET VOLTAGE
vs. SUPPLY VOLTAGE
0.4
SHDN = VSS
0.3
360
0.2
340
0.1
320
2.3
2.8
3.3
3.8
4.3
4.8
MAX4249 TOC13B
140
VDD = 5V
100
0.001
40
0.01
0.1
1
1.8
5
40
72
30
-36
0
-10
PHASE
GAIN (dB)
50
108
VDD = 3V, 5V
RL = 50kΩ
CL = 20pF
AV = 1000
GAIN
180
0
144
-10
108
-20
72
20
36
10
0
0
-36
PHASE
-10
-108
-20
-108
-90
-72
-30
-144
-100
-180
10M
-110
FREQUENCY (Hz)
10k
100k
FREQUENCY (Hz)
1M
MAX4249 TOC17
PSRR+
-80
-40
1k
5.3
-70
-72
100
4.8
VDD = 3V, 5V
-60
-180
10M
1M
4.3
-50
-144
100k
3.8
-40
-40
10k
3.3
-30
-30
1k
2.8
MAX4250–MAX4254
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
PHASE (DEGREES)
144
0
100
2.3
SUPPLY VOLTAGE (V)
MAX4249 TOC16
60
180
36
10
-20
RL = 100kΩ
MAX4249, MAX4255/MAX4256/MAX4257
GAIN AND PHASE vs. FREQUENCY
PHASE (DEGREES)
GAIN
20
80
OUTPUT VOLTAGE (V)
MAX4249 TOC15
30
RL = 1kΩ
60
5.3 5.5
VDD = 3V, 5V
RL = 50kΩ
CL = 20pF
AV = 1000
40
RL = 10kΩ
100
VDD = 3V
MAX4250–MAX4254
GAIN AND PHASE vs. FREQUENCY
50
120
400
SUPPLY VOLTAGE (V)
60
VCM = 0V
VOUT = VDD/2
RL REFERENCED TO GND
160
1000
0
1.8
180
PSRR (dB)
380
SUPPLY CURRENT (µA)
0.5
SHDN = VDD
SHUTDOWN SUPPLY CURRENT (µA)
420
2000
80
MAX4249 TOC14
0.6
PER AMPLIFIER
400
0.374
380
VOUT SWING FROM EITHER SUPPLY (mV)
MAX4249 TOC 13A
440
GAIN (dB)
400
100
0
SUPPLY CURRENT (µA)
RL = 1kΩ
VOUT = 150mV
to 4.75V
0.375
420
VOS (µV)
AV (dB)
120
440
SUPPLY CURRENT (µA)
RL REFERENCED T0 VDD/2
VDD = 5V
0.376
PER AMPLIFIER
PSRR-
1
10
100
1k
10k
100k
1M
10M
FREQUENCY (Hz)
_______________________________________________________________________________________
5
SHUTDOWN SUPPLY CURRENT (µA)
RL = 20kΩ
130
MAX4249 TOC12
460
MAX4249 TOC11
RL = 200kΩ
140
125
MAX4249 TOC10
150
SUPPLY CURRENT AND SHUTDOWN
SUPPLY CURRENT vs. TEMPERATURE
LARGE-SIGNAL VOLTAGE GAIN
vs. TEMPERATURE
MAX4249–MAX4257
Typical Operating Characteristics (continued)
(VDD = +5V, VSS = 0V, VCM = VOUT = 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 = 0V, VCM = VOUT = VDD/2, input noise floor of test equipment = 10nV/√Hz for all distortion measurements,
TA = +25°C, unless otherwise noted.)
INPUT VOLTAGE N0ISE DENSITY
vs. FREQUENCY
1
AV = +1 (MAX4250–MAX4254)
0.1
1k
10k
100k
1M
Vp-p NOISE = 760nVp-p
0
10
100
1k
10k
-100
HD2 HD4
VIN
-40
-140
11k
10k
100k
0.1
100k
RL = 1kΩ
-80
HD2
0.01
HD3
RL = 10kΩ
-120
-160
-140
5k
10k
15k
20k
5k
15k
10k
20k
0
4
5
MAX4250–MAX4254
THD PLUS NOISE vs.
OUTPUT VOLTAGE SWING (VDD = 3V)
MAX4249/MAX4255/MAX4256/MAX4257
THD PLUS NOISE vs. OUTPUT VOLTAGE SWING
MAX4250–MAX4254
THD PLUS NOISE vs. FREQUENCY
AV = +10
RL
100k
11k
0.1
RL = 1kΩ
VIN
VOUT
THD+N (%)
11k
1
MAX4249 TOC24
RL
1
1
VIN
VOUT
RL
0.1
100k
fO = 20kHz, FILTER BW = 80kHz
R1
AV = +10
VDD = 3V
fO = 3kHz
FILTER BW = 30kHz
1
AV = 10
0.001
RL = 100kΩ
FILTER BW= 22kHz
RL = 10kΩ TO GND
VO = 2Vp-p
AV = 1
fO = 3kHz, FILTER BW = 30kHz
0.001
OUTPUT VOLTAGE (Vp-p)
AV = 100
R1 = 560Ω, R2 = 53kΩ
R1 = 5.6kΩ, R2 = 53kΩ
RL = 10kΩ
2
R2
0.01
0.01
0
3
OUTPUT VOLTAGE (Vp-p)
VOUT
0.001
2
FREQUENCY (Hz)
VIN
0.01
1
FREQUENCY (Hz)
10
0.1
RL = 100kΩ
0.001
10
THD+N (%)
10
6
VO
RL
VO
11k
-100
HD5
AV = +10
VIN
fO = 3kHz
FILTER BW = 30kHz
1
fO
-60
10
THD+N (%)
-20
fO
HD3
VOUT = 4Vp-p
fO = 1kHz
0
MAX4250–MAX4254
THD PLUS NOISE
vs. OUTPUT VOLTAGE (VDD = 5V)
MAX4249 TOC22
20
MAX4249 TOC21
RLOAD = 1kΩ
fO = 1kHz
AV = +1
1sec/div
100k
MAX4249/MAX4255/MAX4256/MAX4257
FFT OF DISTORTION AND NOISE
AMPLITUDE (dBc)
AMPLITUDE (dBc)
5
10M
-60
-120
10
MAX4250–MAX4254
FFT OF DISTORTION AND NOISE
-40
-80
200nV/
div
15
FREQUENCY (Hz)
VOUT = 2Vp-p
-20
20
FREQUENCY (Hz)
0
VDD = 3V OR 5V
3
MAX4249 TOC23
10
25
0.0001
0
1
2
3
OUTPUT VOLTAGE (Vp-p)
4
5
10
100
1k
FREQUENCY (Hz)
_______________________________________________________________________________________
10k
MAX4249 TOC26
100
MAX4249 TOC20
MAX4249 TOC25
OUTPUT IMPEDANCE (Ω)
AV = +10 (MAX4249/MAX4255/
MAX4256/MAX4257)
0.1Hz TO 10Hz p-p NOISE
30
MAX4249 TOC19
MAX4249 TOC18
1000
Vn-EQUIVALENT INPUT NOISE VOLTAGE (nV/√Hz)
OUTPUT IMPEDANCE
vs. FREQUENCY
THD+N (%)
MAX4249–MAX4257
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
MAX4249/MAX4255–MAX4257
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
VDD = 5V
0.01
VDD = 3V
AV = +10, R1 = 11kΩ
VDD = 5V
MAX4249 TOC29
0.1
FILTER BW = 80kHz
AV = +1
RL = 1kΩ
VOUT = 2Vp-p
RL TO VDD/2
RL TO GND
VOUT
200mV/
div
RL TO VDD
0.5V
0.001
VOUT
R1
1.5V
0.01
VDD = 3V
RL = 10kΩ
CL = 100pF
VIN = 1V PULSE
RL = 10kΩ
100kΩ
0.001
0.0001
100
1k
10k
10
FREQUENCY (Hz)
100
1k
2µs/div
10k
FREQUENCY (Hz)
MAX4250–MAX4254
SMALL-SIGNAL PULSE RESPONSE
MAX4249/MAX4255/MAX4256/MAX4257
LARGE-SIGNAL PULSE RESPONSE
MAX4249 TOC30
MAX4249 TOC31
0.6V
2V
VOUT
20mV/
div
0.5V
VOUT
200mV/
div
VDD = 3V
RL = 10kΩ
CL = 100pF
VIN = 100mV PULSE
VDD = 3V
RL = 10kΩ
CL = 100pF
VIN = 100mV PULSE
AV = +10
1V
2µs/div
2µs/div
MAX4249/MAX4255/MAX4256/MAX4257
SMALL-SIGNAL PULSE RESPONSE
MAX4252/MAX4253/MAX4254
CHANNEL SEPARATION vs. FREQUENCY
MAX4249 TOC32
140
MAX4249 TOC33
10
130
1.6V
VOUT
50mV/div
1.5V
VDD = 3V
RL = 10kΩ
CL = 100pF
VIN = 10mV PULSE
AV = +10
CHANNEL SEPARATION (dB)
THD PLUS NOISE (%)
AV = +100, R1 = 1kΩ
MAX4250–MAX4254
LARGE-SIGNAL PULSE RESPONSE
MAX4249 TOC28
VDD = 3V
THD PLUSE NOISE (%)
VOUT = 2.75Vp-p
FILTER BW = 80kHz
MAX4249 TOC27
0.1
MAX4250–MAX4254
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
120
110
100
90
80
70
0
2µs/div
1k
10k
100k
1M
10M
FREQUENCY (Hz)
_______________________________________________________________________________________
7
MAX4249–MAX4257
Typical Operating Characteristics (continued)
(VDD = +5V, VSS = 0V, VCM = VOUT = VDD/2, input noise floor of test equipment = 10nV/√Hz for all distortion measurements,
TA = +25°C, unless otherwise noted.)
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
MAX4249–MAX4257
Pin Description
PIN
MAX4250
MAX4255
5 SOT23
MAX4251
MAX4256
MAX4252
MAX4257
8 µMAX/SO
MAX4249/MAX4253
10 µMAX
14 SO
14 SO
NAME
FUNCTION
1
6
1, 7
1, 9
1, 13
1, 7, 8, 14
OUT, OUTA,
OUTB, OUTC,
OUTD
2
4
4
4
4
11
VSS
Negative Supply. Connect
to ground for single-supply
operation.
3
3
3, 5
3, 7
3, 11
3, 5, 10, 12
IN+, INA+, INB+,
INC+, IND+
Noninverting Amplifier Input
4
2
2, 6
2, 8
2, 12
2, 6, 9, 13
IN-, INA-, INB-,
INC-, IND-
Inverting Amplifier Input
5
7
8
10
14
4
VDD
Shutdown Input. Connect to
VDD or leave unconnected for
normal operation (amplifier(s)
enabled).
No Connection. Not internally
connected.
—
8
—
5, 6
6, 9
—
SHDN,
SHDNA,
SHDNB
—
1, 5
—
—
5, 7, 8, 10
—
N.C.
_______________Detailed Description
The MAX4249–MAX4257 single-supply operational
amplifiers feature ultra-low noise and distortion while
consuming very little power. Their low distortion and
low noise make them ideal for use as preamplifiers in
wide dynamic-range applications, such as 16-bit analog-to-digital converters (see Typical Operating Circuit).
Their high input 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 output operation,
drive loads as low as 1kΩ while maintaining DC accuracy, and can drive capacitive loads up to 400pF without
oscillation. The input common-mode voltage range
extends from VDD - 1.1V to 200mV beyond the negative
rail. The push/pull output stage maintains excellent DC
characteristics, while delivering up to ±5mA of current.
The MAX4250–MAX4254 are unity-gain stable, whereas
the MAX4249/MAX4255/MAX4256/MAX4257 have a
higher slew rate and are stable for gains ≥10V/V. The
MAX4249/ MAX4251/MAX4253/MAX4256 feature a lowpower shutdown mode, which reduces the supply current to 0.5µA and disables the outputs.
8
MAX4254
Amplifier Output
Positive Supply
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. Large-value feedback resistors can significantly improve distortion. 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.)
_______________________________________________________________________________________
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
MAX4249–MAX4257
For gains ≥10V/V, the decompensated devices
(MAX4249/MAX4255/MAX4256/MAX4257) 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 400pF do not significantly affect distortion
results. Distortion performance remains relatively constant over supply voltages.
CZ
RF
RG
VOUT
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 = 10V/V) is
e n = 15nV/√Hz. e n can be reduced to 9nV/√Hz by
choosing RF = 10kΩ, RG = 1.1kΩ (AV = 10V/V), at the
expense of greater current consumption and potentially
higher distortion. For a gain of 100V/V with RF = 100kΩ,
RG = 1.1kΩ, the en is low (9nV/√Hz).
VIN
Figure 1. Adding Feed-Forward Compensation
AV = +2
RF = RG = 100kΩ
100mV
VIN
(50mV/
div)
0mV
VOUT
(100mV/
div)
Using a Feed-Forward
Compensation Capacitor, CZ
The amplifier’s input capacitance is 11pF. 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 (C Z) 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 ≈ 11 x (RF / RG) [pF]
In the unity-gain-stable MAX4250–MAX4254, the use
of a proper CZ is most important for AV = +2V/V, and
A V = -1V/V. In the decompensated MAX4249/
MAX4255/MAX4256/MAX4257, CZ is most important for
A V = ±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RF is greater than 20kΩ (MAX4250–MAX4254) or
greater than 5kΩ (MAX4249/MAX4255/MAX4256/
MAX4257).
2µs/div
Figure 2a. Pulse Response with No Feed-Forward
Compensation
100mV
AV = +2
RF = RG = 100kΩ
CZ = 11pF
50mV/
div
VIN
0mV
100mV/
div
VOUT
2µs/div
Figure 2b. Pulse Response with 10pF Feed-Forward
Compensation
_______________________________________________________________________________________
9
MAX4249–MAX4257
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
Applications Information
The MAX4249–MAX4257 combine good driving capability with ground-sensing input and rail-to-rail output
operation. With their low distortion, low noise and low
power consumption, they are ideal for use in portable
instrumentation systems and other low-power, noisesensitive applications.
RISO
VOUT
CL
VIN
MAX4250
MAX4251
MAX4252
MAX4253
MAX4254
4.25V
Figure 5. Capacitive-Load Driving Circuit
VOUT
0
OV
Ground-Sensing and
Rail-to-Rail Outputs
4.45V
The common-mode input range of the MAX4249–
MAX4257 extends down to ground, and offers excellent
common-mode rejection. These devices are guaranteed not to undergo phase reversal when the input is
overdriven (Figure 3).
VIN
0
AV = +1
VDD = +5V
RL = 10kΩ
-200mV
20µs/div
Figure 3. Overdriven Input Showing No Phase Reversal
Figure 4 showcases the true rail-to-rail output operation
of the amplifier, configured with AV = 10V/V. The output
swings to within 8mV of the supplies with a 10kΩ load,
making the devices ideal in low-supply-voltage applications.
Output Loading and Stability
5V
VOUT
0V
1V/
div
VDD = +5V
RL = 10kΩ
AV = +10
f = 1kHz
200µs/div
Figure 4. Rail-to-Rail Output Operation
Even with their low quiescent current of 400µA, these
amplifiers can drive 1kΩ loads while maintaining excellent DC accuracy. Stability while driving heavy capacitive loads is another key feature.
These devices maintain stability while driving loads up
to 400pF. To drive higher capacitive loads, place a
small isolation resistor in series between the output of
the amplifier and the capacitive load (Figure 5). This
resistor improves the amplifier’s phase margin by isolating the capacitor from the op amp’s output.
Reference Figure 6 to select a resistance value that will
ensure a load capacitance that limits peaking to <2dB
(25%). For example, if the capacitive load is 1000pF,
the corresponding isolation resistor is 150Ω. Figure 7
shows that peaking occurs without the isolation resistor.
Figure 8 shows the unity-gain bandwidth vs. capacitive
load for the MAX4250–MAX4254.
Power Supplies and Layout
The MAX4249–MAX4257 operate from a single +2.4V
to +5.5V power supply or from dual supplies of ±1.20V
to ±2.75V. For single-supply operation, bypass the
10
______________________________________________________________________________________
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
4.0
UNITY-GAIN BANDWIDTH (MHz)
4.5
140
RISO (Ω)
120
100
80
60
SHADED AREA INDICATES
STABLE OPERATION
WITH NO NEED FOR
ISOLATION RESISTOR.
40
20
VDD = 3V
3.5
3.0
2.5
2.0
1.5
SHADED AREA INDICATES
STABLE OPERATION
WITH NO NEED FOR
ISOLATION RESISTOR.
1.0
0.5
0
MAX4249–MAX4257
160
0
10
100
1000
10,000
10
CAPACITIVE LOADING (pF)
100
1000
10,000
CAPACITIVE LOAD (pF)
NOTE: RISO CHOSEN FOR PEAKING <2dB.
NOTE: USING AN ISOLATION RESISTOR REDUCES PEAKING.
Figure 6. Isolation Resistance vs. Capacitive Loading to
Minimize Peaking (<2dB)
Figure 8. MAX4250–MAX4254 Unity-Gain Bandwidth vs.
Capacitive Load
___________________Chip Information
25
MAX4250–MAX4254 (AV = +1)
MAX4249/MAX4255–MAX4257 (AV = +10)
RISO = 0
PEAKING (dB)
20
TRANSISTOR COUNTS:
MAX4250/MAX4251/MAX4255/MAX4256: 170
MAX4249/MAX4252/MAX4253/MAX4257: 340
SHADED AREA INDICATES
STABLE OPERATION
WITH NO NEED FOR
ISOLATION RESISTOR.
15
MAX4254: 680
10
Ordering Information (continued)
5
TEMP. RANGE
PINPACKAGE
MAX4251ESA
-40°C to +85°C
8 SO
—
MAX4251EUA
-40°C to +85°C
8 µMAX
—
MAX4252ESA
-40°C to +85°C
8 SO
—
MAX4252EUA
-40°C to +85°C
8 µMAX
—
MAX4253EUB
-40°C to +85°C
10 µMAX
—
MAX4253ESD
-40°C to +85°C
14 SO
—
MAX4254ESD
-40°C to +85°C
PART
0
10
100
1000
10,000
CAPACITIVE LOAD (pF)
Figure 7. Peaking vs. Capacitive Load
power supply with a 0.1µF ceramic 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.
14 SO
SOT
TOP MARK
—
MAX4255EUK-T -40°C to +85°C
5 SOT23-5
ACCJ
MAX4256ESA
-40°C to +85°C
8 SO
—
MAX4256EUA
-40°C to +85°C
8 µMAX
—
MAX4257ESA
-40°C to +85°C
8 SO
—
MAX4257EUA
-40°C to +85°C
8 µMAX
—
______________________________________________________________________________________
11
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
MAX4249–MAX4257
Pin Configurations
TOP VIEW
OUT
1
VSS 2
5
VDD
IN- 2
MAX4250
MAX4255
IN+ 3
N.C. 1
IN+
4
IN-
3
VSS 4
INA- 2
INA+
3
MAX4252
MAX4257
VSS 4
8
VDD
7
OUTB
6
INB-
5
INB+
OUTA 1
INA-
2
INA+
3
INA-
2
INA+
3
VSS 4
N.C. 5
12
6
OUT
5
N.C.
VSS
SHDNA
10 VDD
OUTB
8
INB-
4
7
INB+
5
6
SHDNB
MAX4249
MAX4253
INA-
2
12 INB-
INA+
3
11 INB+
VDD 4
10 N.C.
INB+ 5
9
SHDNB
N.C. 7
8
N.C.
14 OUTD
OUTA 1
13 OUTB
SHDNA 6
SO
VDD
µMAX
14 VDD
MAX4249
MAX4253
7
9
µMAX/SO
OUTA 1
SHDN
µMAX/SO
SOT23
OUTA 1
MAX4251
MAX4256
8
13 IND12 IND+
MAX4254
11 VSS
10 INC+
INB- 6
9
INC-
OUTB 7
8
OUTC
SO
______________________________________________________________________________________
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
+5V
VDD
50k
2
MAX195
7
6
3
VIN
MAX4256
4
8
(16-BIT ADC)
AIN
DOUT
SHDN
SCLK
SERIAL
INTERFACE
CS
5k
REF
4.096V
VSS
-5V
SHDN
______________________________________________________________________________________
13
MAX4249–MAX4257
Typical Operating Circuit
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
8LUMAXD.EPS
SOT5L.EPS
MAX4249–MAX4257
Package Information
14
______________________________________________________________________________________
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail Op Amps
10LUMAXB.EPS
______________________________________________________________________________________
15
MAX4249–MAX4257
___________________________________________Package Information (continued)
___________________________________________Package Information (continued)
SOICN.EPS
MAX4249–MAX4257
SOT23, Single-Supply, Low-Noise,
Low-Distortion, Rail-to-Rail 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
© 1998 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.