EVALUATION KIT AVAILABLE
19-6000; Rev 1; 12/11
MAX44251/MAX44252
20V, Ultra-Precision, Low-Noise Op Amps
General Description
The MAX44251/MAX44252 are 20V, ultra-precision, lownoise, low-drift amplifiers that offer near-zero DC offset
and drift through the use of patented autocorrelating
zeroing techniques. This method constantly measures
and compensates the input offset, eliminating drift over
time and temperature and the effect of 1/f noise. These
dual and quad devices feature rail-to-rail outputs, operate from a single 2.7V to 20V supply, and consume only
1.15mA per channel, while providing 5.9nV/√Hz inputreferred voltage noise. The ICs are unity-gain stable with
a gain-bandwidth product of 10MHz.
With excellent specifications such as offset voltage of
6µV (max), drift of 19nV/°C (max), and 123nV
0.1Hz to 10Hz, the ICs are ideally suited for applications
requiring ultra-low noise and DC precision such as interfacing with pressure sensors, strain gauges, precision
weight scales, and medical instrumentation.
The ICs are available in 8-pin SOT23, 8-pin µMAXM,
and 14-pin SOIC packages and are rated over the
-40°C to +125°C temperature range.
Ordering Information appears at end of data sheet.
Functional Diagrams appear at end of data sheet.
For related parts and recommended products to use with this part,
refer to www.maxim-ic.com/MAX44251.related.
noise in
P-P
Benefits and Features
S 2.7V to 20V Power-Supply Range
S Integrated EMI Filter
S 6µV Input Offset Voltage (max) at Room
Temperature
S TCV OS of 19nV/° C (max)
S Low 5.9nV/ √Hz Input-Referred Voltage Noise
S 123nV
in 0.1Hz to 10Hz
P-P
S Fast 400ns Settling Time
S 10MHz Gain-Bandwidth Product
S Rail-to-Rail Output
S High Accuracy Enables Precision Signal Chain
Acquisition
Applications
Strain Gauges
Pressure Transducers
Medical Instrumentation
Precision Instrumentation
Load Cell and Bridge Transducer Amplification
Typical Operating Circuit
3.3V
20V
MAX44251
1.5V
R
20V
BUFFER
MAX44251
V
IN+
V
IN-
V
DD
MAX11211
V
SS
V
REF
OUTPUT
20V
R
G
BUFFER
50R
50R
20V
BUFFER
G
G
MAX44251
R
R
R
µMAX is a registered trademark of Maxim Integrated Products, Inc.
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For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
3V
V
R
C
1
OUT
1
MAX6126
V
DD
MICRO-
PROCESSOR
MAX44251/MAX44252
20V, Ultra-Precision, Low-Noise Op Amps
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VDD to VSS).................................-0.3V to +22V
All Other Pins ..................................(VSS - 0.3V) to (VDD + 0.3V)
Short-Circuit Duration to Either Supply Rail ............................ 1s
Continuous Input Current (any pin) ................................. ±20mA
Differential Input Voltage ...................................................... ±6V
Maximum Power Dissipation (TA = +70°C)
SOT23 (derate 9.1 mW/°C above +70°C) ...................727mW
µMAX (derate 4.5 mW/°C above +70°C) ....................362mW
SOIC (derate 8.3 mW/°C above +70°C) ..................666.7mW
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.
PACKAGE THERMAL CHARACTERISTICS (Note 1)
SOT23
Junction-to-Ambient Thermal Resistance (ΘJA) ....... 196°C/W
Junction-to-Case Thermal Resistance (ΘJC) ...............70°C/W
µMAX
Junction-to-Ambient Thermal Resistance (ΘJA) ........221°C/W
Junction-to-Case Thermal Resistance (ΘJC) ...............42°C/W
Operating Temperature Range ........................ -40°C to +125NC
Junction Temperature .....................................................+150N C
Storage Temperature Range ............................ -65°C to +150NC
Lead Temperature (soldering, 10s) .............................. +300NC
Soldering Temperature (reflow) .................................... +260NC
SOIC
Junction-to-Ambient Thermal Resistance (ΘJA) ........120°C/W
Junction-to-Case Thermal Resistance (ΘJC) ...............37°C/W
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial .
ELECTRICAL CHARACTERISTICS
(V DD = 10V, VSS = 0V, V
at TA = +25°C.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
POWER SUPPLY
Supply Voltage Range V
Power-Supply Rejection Ratio
(Note 3)
Quiescent Current per Amplifier I
Power-Up Time t
DC SPECIFICATIONS
Input Common-Mode Range V
Common-Mode Rejection Ratio
(Note 3)
IN+
= V
= VDD/2, RL = 10kI to VDD/2, TA = -40°C to +125°C, unless otherwise noted. Typical values are
IN-
DD
PSRR VDD = 2.7V to 20V, VCM = 0V 140 145 dB
DD
ON
CM
CMRR
Guaranteed by PSRR 2.7 20 V
RL = J
Guaranteed by CMRR test
TA = +25N C, VCM = -0.05V to (VDD -
1.5V)
-40N C < TA < +125N C
TA = +25N C
-40N C < TA < +125N C
VSS -
0.05
133 140
130
1.15 1.55
1.75
25
VDD -
1.5
mA
F s
V
dB
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MAX44251/MAX44252
20V, Ultra-Precision, Low-Noise Op Amps
ELECTRICAL CHARACTERISTICS (continued)
(V DD = 10V, VSS = 0V, V
at TA = +25°C.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Offset Voltage (Note 3) V
Input Offset Voltage Drift
(Note 3)
Input Bias Current (Note 3) I
Input Offset Current (Note 3) I
Open-Loop Gain (Note 3) A
Output Short-Circuit Current To VDD or V
Output Voltage Low V
Output Voltage High V
AC SPECIFICATIONS
Input Voltage-Noise Density e
Input Voltage Noise 0.1Hz < f < 10Hz 123 nV
Input Current-Noise Density i
Input Capacitance C
Gain-Bandwidth Product GBW 10 MHz
Phase Margin PM CL = 20pF 60 Degrees
Slew Rate SR AV = 1V/V, V
Capacitive Loading C
Total Harmonic Distortion THD
Settling Time To 0.01%, V
IN+
= V
= VDD/2, RL = 10kI to VDD/2, TA = -40°C to +125°C, unless otherwise noted. Typical values are
IN-
3 6
7
5 19
200 1300
2400
400 pA
12 25
45 85
18 37
71 135
2 pF
8
TC V
OS
VOL
OS
B
OL
OH
N
N
IN
L
TA = +25N C
-40N C < TA < +125N C
OS
TA = +25N C
-40N C < TA < +125N C
250mV P V
P VDD - 250mV,
RL = 10kI to
VDD/2
V
- V
OUT
VDD - V
SS
OUT
OUT
SS
TA = +25N C
-40N C < TA < +125N C
145 154
136
Noncontinuous 96 mA
RL = 10kI to VDD/2
RL = 2kI to VDD/2
RL = 10kI to VDD/2
RL = 2kI to VDD/2
f = 1kHz 5.9
f = 1kHz 0.6
= 2V
OUT
P-P
No sustained oscillation, AV = 1V/V 500 pF
V
= 2V
OUT
AV = +1V/V,
RL = 10kI to
VDD/2
,
P-P
f = 1kHz -124
f = 20kHz -119
= 2V step, AV = -1V/V 400 ns
OUT
nV/N C
mV
mV
nV/√ Hz
pA/√ Hz
V/F s
F V
pA
dB
P-P
dB
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MAX44251/MAX44252
20V, Ultra-Precision, Low-Noise Op Amps
ELECTRICAL CHARACTERISTICS
(V DD = 3.3V, VSS = 0V, V
are at TA = +25°C.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
POWER SUPPLY
Quiescent Current per Amplifier I
Power-Up Time t
DC SPECIFICATIONS
Input Common-Mode Range V
Common-Mode Rejection Ratio
(Note 3)
Input Offset Voltage (Note 3) V
Input Offset Voltage Drift
(Note 3)
Input Bias Current (Note 3) I
Input Offset Current (Note 3) I
Open-Loop Gain (Note 3) A
Output Short-Circuit Current To VDD or V
Output Voltage Low V
Output Voltage High V
AC SPECIFICATIONS
Input Voltage-Noise Density e
Input Voltage Noise 0.1Hz < f < 10Hz 123 nV
Input Current-Noise Density i
Input Capacitance C
Gain-Bandwidth Product GBW 10 MHz
IN+
= V
= VDD/2, RL = 10kI to VDD/2, TA = -40°C to +125°C, unless otherwise noted. Typical values
IN-
DD
ON
CM
CMRR
OS
TC V
B
OS
VOL
OL
OH
N
N
IN
RL = J
Guaranteed by CMRR test
TA = +25N C, VCM = -0.05V to (VDD -
1.5V)
-40N C < TA < +125N C
TA = +25N C
-40N C < TA < +125N C
OS
TA = +25N C
-40N C < TA < +125N C
250mV P V
P VDD - 250mV,
RL = 10kI to
VDD/2
V
- V
OUT
SS
VDD - V
OUT
f = 1kHz 6.2
f = 1kHz 0.3
TA = +25N C
-40N C < TA < +125N C
OUT
TA = +25N C
-40N C < TA < +125N C
Noncontinuous 58 mA
SS
RL = 10kI to VDD/2
RL = 2kI to VDD/2
RL = 10kI to VDD/2
RL = 2kI to VDD/2
VSS -
0.05
120 129
117
136 151
133
1.1 1.5
1.65
25
VDD -
1.5
3 5.5
6.5
8 18
200 1100
1200
400 pA
5 22
17 42
9 22
29 52
2 pF
nV/N C
nV/√ Hz
pA/√ Hz
mA
F s
V
dB
F V
pA
dB
mV
mV
P-P
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MAX44251/MAX44252
20V, Ultra-Precision, Low-Noise Op Amps
ELECTRICAL CHARACTERISTICS (continued)
(V DD = 3.3V, VSS = 0V, V
at TA = +25°C.) (Note 2)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Phase Margin PM CL = 20pF 60 Degrees
Slew Rate SR AV = 1V/V, V
Capacitive Loading C
Total Harmonic Distortion THD
IN+
= V
= VDD/2, RL = 10kI to VDD/2, TA = -40°C to +125°C, unless otherwise noted. Typical values are
IN-
= 1V
OUT
No sustained oscillation, AV = 1V/V 500 pF
L
V
OUT
= 1V
P-P
,
AV = +1V/V,
, 10% to 90% 5
P-P
f = 1kHz -124
VCM = VDD/4,
RL = 10kI to
VDD/2
f = 20kHz -100
V/F s
dB
Settling Time To 0.01%, V
= 1V step, AV = -1V/V 200 ns
OUT
Note 2: All devices are 100% production tested at T A = +25°C. Temperature limits are guaranteed by design.
Note 3: Guaranteed by design.
Typical Operating Characteristics
(VDD = 10V, VSS = 0V, outputs have RL = 10kI to VDD/2. TA = +25N C, unless otherwise specified.)
OFFSET VOLTAGE HISTOGRAM
75
70
65
60
55
50
45
40
35
30
25
20
PERCENT OCCURRENCE (%)
15
10
5
0
0 5.5 5.0
OFFSET VOLTAGE (µV)
INPUT OFFSET VOLTAGE DRIFT HISTOGRAM
45
40
MAX44251 toc01
35
30
25
20
15
PERCENT OCCURRENCE (%)
10
5
4.5 4.0 3.0 2.0 3.5 1.5 2.5 1.0 0.5
0
0.005 0.004 0.002 0.003 0 0.001 -0.001
OFFSET VOLTAGE DRIFT (µV/°C)
MAX44251 toc02
0.006
SUPPLY CURRENT vs. SUPPLY VOLTAGE
1.4
TA = +125°C
1.2
1.0
0.8
0.6
SUPPLY CURRENT (mA)
0.4
0.2
TA = +25°C
0
SUPPLY VOLTAGE (V)
TA = 0°C
SUPPLY CURRENT
TA = +85°C
TA = -40°C
PER AMPLIFIER
20 15 10 5
MAX44251 toc03
5
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