EVALUATION KIT AVAILABLE
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
General Description
Features
The MAX44241/MAX44243/MAX44246 are 36V, ultraprecision, low-noise, low-drift, single/quad/dual operational amplifiers that offer near-zero DC offset and drift
through the use of patented chopper stabilized and
auto-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 single/quad/dual devices feature rail-to-rail outputs, operate from a single 2.7V to 36V supply or dual
±1.35V to ±18V supplies, and consume only 0.42mA per
channel, with only 9nV/√Hz input-referred voltage noise.
S2.7V to 36V Power-Supply Range
The ICs are unity-gain stable with a gain-bandwidth
product of 5MHz. With excellent specifications such as
offset voltage of 5FV (max), drift of 20nV/NC (max), and
117nVP-P noise in 0.1Hz to 10Hz, these 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.
SLow 0.55mA Per Channel (max) Quiescent Current
SUltra-Low Input VOS: 5µV (max)
SLow 20nV/°C (max) of Offset Drift
SLow 9nV/√Hz noise at 1kHz
S1µs Fast Settling Time
S5MHz Gain-Bandwidth Product
SRail-to-Rail Output
SIntegrated EMI Filter
S8-Pin µMAX/SO Package
Ordering Information appears at end of data sheet.
For related parts and recommended products to use with this part,
refer to www.maximintegrated.com/MAX44246.related.
The ICs are available in 8-pin FMAXM or SO packages
and are rated over the -40NC to +125NC temperature
range.
Applications
Transducer Amplifiers
µMAX is a registered trademark of Maxim Integrated Products, Inc.
Battery-Powered
Equipment
Load Cell Amplifiers
PLC Analog I/O
Modules
Precision
Instrumentation
Typical Operating Circuit
15V
3.3V
½ MAX44246
R1
BUFFER
R
15V
-15V
50RG
BUFFER
R
VREF
VIN+
MICROPROCESSOR
MAX11211 OUTPUT
15V
R
BUFFER
VDD
15V
R
50RG
VOUT
MAX6126
VDD
RG
3V
1.5V
-15V
VIN-
VSS
½ MAX44246
C1
½ MAX44246
-15V
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-6375; Rev 5; 1/14
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (VDD to GND) ..............................-0.3V to +40V
All Other Pins.................................(GND - 0.3V) to (VDD + 0.3V)
Short-Circuit Duration, OUTA,
OUTB to Either Supply Rail………………………….............. 1s
Continuous Input Current (Any Pin) ...................................20mA
Differential Input Current.................................................. Q20mA
Differential Input Voltage (Note 1)........................................ .Q6V
Continuous Power Dissipation (TA = +70NC)
5-Pin SOT23 (derate 3.9mW/NC above +70NC).......312.6mW
8-Pin FMAX (derate 4.8mW/NC above +70NC).........387.8mW
8-Pin SO (derate 7.60mW/NC above +70NC)...........606.1mW
14-Pin SO (derate 12.30mW/NC above +70NC).......987.7mW
14-Pin TSSOP (derate 10mW/NC above +70NC)......796.8mW
Operating Temperature Range......................... -40NC to +125NC
Junction Temperature .....................................................+150NC
Storage Temperature Range............................. -65NC to +150NC
Lead Temperature (soldering,10s)..................................+300NC
Soldering Temperature (reflow).......................................+260NC
Note 1: The amplifier inputs are connected by internal back-to-back clamp diodes. In order to minimize noise in the input stage,
current-limiting resistors are not used. If differential input voltages exceeding ±1V are applied, limit input current to 20mA.
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 2)
µMAX
Junction-to-Ambient Thermal Resistance (qJA)......206.3NC/W
Junction-to-Case Thermal Resistance (qJC) ...............42NC/W
SO-8
Junction-to-Ambient Thermal Resistance (qJA).........132NC/W
Junction-to-Case Thermal Resistance (qJC) ...............38NC/W
SO-14
Junction-to-Ambient Thermal Resistance (qJA)...........81NC/W
Junction-to-Case Thermal Resistance (qJC) ...............32NC/W
SOT23
Junction-to-Ambient Thermal Resistance (qJA)......255.9NC/W
Junction-to-Case Thermal Resistance (qJC) ...............81NC/W
TSSOP
Junction-to-Ambient Thermal Resistance (qJA)......100.4NC/W
Junction-to-Case Thermal Resistance (qJC) ...............30NC/W
Note 2: 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.maximintegrated.com/thermal-tutorial.
ELECTRICAL CHARACTERISTICS
(VDD = 30V, VGND = 0V, VIN+ = VIN- = VDD /2, RL = 5kΩ to VDD /2, TA = -40°C to +125°C, unless otherwise noted. Typical values at
TA = +25°C.) (Note 3)
PARAMETER
Supply Voltage Range
Power-Supply Rejection Ratio
(Note 4)
SYMBOL
VDD
PSRR
Quiescent Current per Amplifier
IDD
Power-Up Time
tON
CONDITIONS
MIN
Guaranteed by PSRR
2.7
VDD = 2.7V to 36V, TA = +25NC
148
VDD = 2.7V to 36V, -40NC < TA < +125NC
146
RL = J
TA = +25NC
TYP
MAX
UNITS
36
V
166
0.42
-40NC < TA < +125NC
dB
0.55
0.60
20
mA
Fs
DC SPECIFICATIONS
Input Common-Mode Range
Common-Mode Rejection Ratio
(Note 4)
Input Offset Voltage (Note 4)
Maxim Integrated
VCM
CMRR
VOS
Guaranteed by CMRR test
VCM = (V GND - 0.05V) to (VDD - 1.5V)
(V GND
- 0.05)
146
(VDD
- 1.5)
166
1
V
dB
5
FV
2
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
ELECTRICAL CHARACTERISTICS (continued)
(VDD = 30V, VGND = 0V, VIN+ = VIN- = VDD /2, RL = 5kΩ to VDD /2, TA = -40°C to +125°C, unless otherwise noted. Typical values at
TA = +25°C.) (Note 3)
PARAMETER
Input Offset Voltage Drift
(Note 4)
SYMBOL
IB
Input Offset Current (Note 4)
IOS
AVOL
Output Short-Circuit Current
Output Voltage Low
Output Voltage High
MIN
TC VOS
Input Bias Current (Note 4)
Open-Loop Gain (Note 4)
CONDITIONS
TA = +25NC
VOH
MAX
UNITS
1
20
nV/NC
300
600
-40NC < TA < +125NC
1250
TA = +25NC
600
-40NC < TA < +125NC
(V GND + 0.5V) P VOUT P (VDD – 0.5V)
Noncontinuous
VOL
TYP
2500
154
168
Sinking
40
Sourcing
30
TA = +25NC
90
-40NC < TA < +125NC
TA = +25NC
-40NC < TA < +125NC
1200
pA
dB
mA
115
180
(VDD 0.17)
(VDD 0.25)
pA
(VDD 0.13)
mV
V
AC SPECIFICATIONS
Input Voltage-Noise Density
eN
9
nV/√Hz
117
nVP-P
CIN
2
pF
GBW
5
MHz
60
Degrees
Input Voltage Noise
Input Capacitance
Gain-Bandwidth Product
Phase Margin
f = 1kHz
0.1Hz < f < 10Hz
PM
CL = 20pF
Slew Rate
SR
AV = 1V/V, VOUT = 4VP-P
3.8
V/Fs
Capacitive Loading
CL
No sustained oscillation, AV = 1V/V
300
pF
Total Harmonic Distortion
THD
VOUT = 4VP-P,
AV = +1V/V
f = 1kHz
-96
f = 20kHz
-77
VOUT = 2VP-P,
AV = +1V/V
f = 1kHz
-91
f = 20kHz
-76
dB
dB
ELECTRICAL CHARACTERISTICS
(VDD = 10V, VGND = 0V, VIN+ = VIN- = VDD /2, RL = 5kΩ to VDD /2, TA = -40°C to +125°C, unless otherwise noted. Typical values at
TA = +25°C.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
0.42
0.55
UNITS
POWER SUPPLY
Quiescent Current per Amplifier
IDD
Power-Up Time
tON
Maxim Integrated
RL = J
TA = +25NC
-40NC < TA < +125NC
0.60
20
mA
Fs
3
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
ELECTRICAL CHARACTERISTICS (continued)
(VDD = 10V, VGND = 0V, VIN+ = VIN- = VDD /2, RL = 5kΩ to VDD /2, TA = -40°C to +125°C, unless otherwise noted. Typical values at
TA = +25°C.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
(VDD –
1.5)
V
DC SPECIFICATIONS
Input Common-Mode Range
Common-Mode Rejection Ratio
(Note 4)
Input Offset Voltage (Note 4)
Input Offset Voltage Drift (Note 4)
VCM
CMRR
158
dB
1
5
FV
2.4
20
nV/NC
300
600
Input Offset Current (Note 4)
IOS
AVOL
Output Short-Circuit Current
Output Voltage High
140
TC VOS
IB
Output Voltage Low
VCM = (V GND - 0.05V) to (VDD - 1.5V)
(VGND
- 0.05)
VOS
Input Bias Current (Note 4)
Open-Loop Gain (Note 4)
Guaranteed by CMRR test
TA = +25NC
-40NC < TA < +125NC
TA = +25NC
VOH
600
-40NC < TA < +125NC
(V GND + 0.5V) ≤ VOUT ≤ (VDD - 0.5V)
Noncontinuous
VOL
1100
1200
2200
144
164
Sinking
40
Sourcing
30
TA = +25NC
30
-40NC < TA < +125NC
(VDD 0.06)
-40NC < TA < +125NC
(VDD 0.09)
(VDD 0.05)
pA
dB
mA
40
60
TA = +25NC
pA
mV
V
AC SPECIFICATIONS
Input Voltage-Noise Density
eN
Input Voltage Noise
Input Capacitance
Gain-Bandwidth Product
f = 1kHz
0.1Hz < f < 10Hz
9
117
nV/√Hz
nVP-P
CIN
2
pF
GBW
5
MHz
60
Degrees
Phase Margin
PM
Slew Rate
SR
AV = +1V/V, VOUT = 2VP-P, 10% to 90%
3.8
V/µs
Capacitive Loading
CL
No sustained oscillation, AV = 1V/V
f = 1kHz
VOUT = 2VP-P,
AV = 1V/V
f = 20kHz
300
pF
Total Harmonic Distortion
Settling Time
THD
CL = 20pF
To 0.01%, VOUT = 2V step, AV = 1V/V
-92
-76
1
dB
µs
Note 3: All devices are 100% production tested at TA = +25°C. Temperature limits are guaranteed by design.
Note 4: Guaranteed by design.
Maxim Integrated
4
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
Typical Operating Characteristics
(VDD = 10V, VGND = 0V, VIN+ = VIN- = VDD/2, RL = 5kΩ to VDD/2, TA = -40°C to +125°C, unless otherwise noted. Typical values are
at TA = +25°C.) (Note 3)
INPUT OFFSET VOLTAGE DRIFT
HISTOGRAM
20
15
10
5
-1.0
-1.5
MAX44241 toc02
400
30
25
20
15
-0.5
0
0.5
1.0
300
250
200
150
10
100
5
50
0
0
0.002 0.003 0.005
5
10
15
20
25
30
OFFSET VOLTAGE DRIFT (µV/°C)
SUPPLY VOLTAGE (V)
SUPPLY CURRENT PER AMPLIFIER
vs. TEMPERATURE
INPUT OFFSET VOLTAGE vs. INPUT
COMMON-MODE VOLTAGE
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
440
430
420
410
1
0
-1
40
100
125
MAX44241 toc06
2
35
5
INPUT OFFSET VOLTAGE (µV)
450
3
INPUT OFFSET VOLTAGE (µV)
VIN = VDD/2
NO LOAD
460
-0.006 -0.004 -0.002
1.5
VIN = VDD/2
NO LOAD
350
OFFSET VOLTAGE (µV)
MAX44241 toc04
470
0
-2
400
0
25
50
100
-3
125
-5
0
1
2
3
4
5
6
7
8
9
-50
-25
0
25
50
75
TEMPERATURE (°C)
VCM (V)
TEMPERATURE (°C)
INPUT BIAS CURRENT vs. VCM
vs. TEMPERATURE
INPUT BIAS CURRENT
vs. TEMPERATURE
COMMON-MODE REJECTION RATIO
vs. TEMPERATURE
IB- (TA = +25°C)
IB- (TA = +125°C)
IB- (TA = -40°C)
0
1
2
3
VCM (V)
Maxim Integrated
IB+ (TA = +25°C)
IB+ (TA = -40°C)
4
5
6
7
700
8
9
600
toc08
180
170
IB+
500
160
400
150
300
140
200
100
IB-
0
130
120
110
-100
100
-200
90
-300
MAX44241 toc09
INPUT BIAS CURRENT (pA)
IB+ (TA = +125°C)
-1
75
INPUT BIAS CURRENT (pA)
2000
1800
1600
1400
1200
1000
800
600
400
200
0
-200
-400
-600
-800
-1000
-25
MAX44241 toc07
-50
CMRR (dB)
SUPPLY CURRENT (µA)
35
450
0
0
390
500
SUPPLY CURRENT (µA)
25
40
MAX44241 toc05
PERCENT OCCURENCE (%)
30
45
PERCENT OCCURRENCE (%)
MAX44241 toc01
35
SUPPLY CURRENT PER AMPLIFIER
vs. SUPPLY VOLTAGE
MAX44241 toc03
INPUT OFFSET VOLTAGE HISTOGRAM
80
-50
0
50
100
TEMPERATURE (°C)
150
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
5
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
Typical Operating Characteristics (continued)
(VDD = 10V, VGND = 0V, VIN+ = VIN- = VDD/2, RL = 5kΩ to VDD/2, TA = -40°C to +125°C, unless otherwise noted. Typical values are
at TA = +25°C.) (Note 3)
POWER-SUPPLY REJECTION RATIO
vs. TEMPERATURE
170
140
60
40
120
110
0
100
-20
90
-40
1
10
100
1k
10k 100k 1M 10M
-25
25
50
75
100
OUTPUT VOLTAGE LOW
vs. OUTPUT SINK CURRENT
OUTPUT VOLTAGE HIGH
vs. OUTPUT SOURCE CURRENT
300
250
200
150
100
70
MAX44241 toc14
350
60
50
300
250
200
150
0
4
6
8
0
10
2
4
6
8
OUTPUT VOLTAGE HIGH
vs. TEMPERATURE
2
MAX44241 toc16
9.965
9.960
0
-2
NORMALIZED GAIN,
VIN = 100mVP-P
9.955
9.950
9.945
9.935
9.930
50
75
TEMPERATURE (°C)
Maxim Integrated
100
125
25
50
75
100
125
LARGE-SIGNAL GAIN vs. FREQUENCY
0
-5
NORMALIZED GAIN,
VIN = 2VP-P
-10
-6
-8
-10
-12
-15
-20
-25
-30
-35
-14
9.940
25
0
5
MAGNITUDE (dB)
MAGNITUDE (dB)
-4
0
-25
TEMPERATURE (°C)
SMALL-SIGNAL GAIN vs. FREQUENCY
9.970
-25
-50
OUTPUT SOURCE CURRENT (mA)
OUTPUT SINK CURRENT (mA)
-50
0
10
MAX44241 toc17
2
30
10
50
0
40
20
100
0
10 100 1k 10k 100k 1M 10M100M
OUTPUT VOLTAGE LOW
vs. TEMPERATURE
VOL (mV)
350
400
OUTPUT VOLTAGE HIGH (mV)
MAX44241 toc13
400
0.01 0.1 1
125
FREQUENCY (Hz)
450
50
OUTPUT VOLTAGE HIGH (V)
0
TEMPERATURE (°C)
450
50
-50
-50
FREQUENCY (Hz)
500
100
0
80
0.1
OUTPUT VOLTAGE LOW (mV)
130
20
150
MAX44241 toc15
80
VIN = 100mVP-P
MAX44241 toc18
150
MAGNITUDE (dB)
160
100
PSRR (dB)
MAGNITUDE (dB)
120
OPEN-LOOP GAIN vs. FREQUENCY
200
MAX44241 toc11
100mVP-P
140
180
MAX44241 toc10
160
MAX44241 toc12
COMMON-MODE REJECTION RATIO
vs. FREQUENCY
-16
-40
-18
-45
-50
-20
10
100
1k
10k
100k
FREQUENCY (Hz)
1M
10M 100M
10
100
1k
10k
100k
1M
10M 100M
FREQUENCY (Hz)
6
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
Typical Operating Characteristics (continued)
(VDD = 10V, VGND = 0V, VIN+ = VIN- = VDD/2, RL = 5kΩ to VDD/2, TA = -40°C to +125°C, unless otherwise noted. Typical values are
at TA = +25°C.) (Note 3)
INPUT VOLTAGE NOISE vs. FREQUENCY
MAX44241 toc19
INPUT VOLTAGE NOISE (nV/√Hz)
INPUT VOLTAGE 0.1Hz TO 10Hz NOISE
MAX44241 toc20
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
0
200nV/div
1
10
100
1k
100k
10k
1s/div
FREQUENCY (Hz)
LARGE-SIGNAL (2VP-P)
STEP RESPONSE vs. TIME
SMALL-SIGNAL (100mVP-P)
STEP RESPONSE vs. TIME
MAX44241 toc22
MAX44241 toc21
VIN
50mV/div
VIN
1V/div
VOUT
50mV/div
VOUT
1V/div
1µs/div
1µs/div
STABILITY vs. CAPACITIVE AND
RESISTIVE LOAD IN PARALLEL
STABILITY vs. CAPACITIVE LOAD AND
SERIES ISOLATION RESISTANCE
10
RISO (I)
10
RESISTIVE LOAD (kI)
STABLE
UNSTABLE
1
POWER-UP TIME
MAX44246 toc24
100
MAX44241 toc23
100
MAX44241 toc25
VDD = VSS = 0V
VDD = 10V
5V/div
1
UNSTABLE
0.1
STABLE
VIN = VOUT = 0V
0.01
200mV/div
0.001
0.1
100
1k
10k
CAPACITIVE LOAD (pF)
Maxim Integrated
100k
100
1k
10k
CAPACITIVE LOAD (pF)
100k
20µs
7
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
Typical Operating Characteristics (continued)
(VDD = 10V, VGND = 0V, VIN+ = VIN- = VDD/2, RL = 5kΩ to VDD/2, TA = -40°C to +125°C, unless otherwise noted. Typical values are
at TA = +25°C.) (Note 3)
TOTAL HARMONIC DISTORTION
vs. OUTPUT AMPLITUDE
MAX44241 toc27
-40
-50
-40
-60
-70
-120
100
1k
10k
1
2
3 4 5 6 7 8
OUTPUT AMPLITUDE (V)
10
100
1k
10k
100k
1M
10M
FREQUENCY (Hz)
MAX44241 toc29
90
80
70
-40
-50
-60
-70
-80
-90
-100
-110
60
50
40
30
2VP-P INPUT
20
4VP-P INPUT
10
0
-120
10
100
1k
FREQUENCY (Hz)
Maxim Integrated
1
10
100
EMIRR (dB)
THD (dB)
-20
-30
9
EMIRR
vs. FREQUENCY (VDD = 3.3V)
TOTAL HARMONIC DISTORTION
vs. FREQUENCY
VDD = 30V
-100
-160
0
FREQUENCY (Hz)
0
-10
-80
-140
-120
100k
-60
-120
-100
4VP-P OUTPUT
10
-60
-80
2VP-P OUTPUT
-40
MAX44246 toc30
-80
-90
-100
-110
-20
CROSSTALK (dB)
-20
THD (dB)
THD (dB)
-20
-30
CROSSTALK vs. FREQUENCY
0
0
MAX44241 toc26
0
-10
MAX44241 toc28
TOTAL HARMONIC DISTORTION
vs. FREQUENCY
10k
100k
1
10
100
1000
10,000
FREQUENCY (MHz)
8
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
Pin Configurations
TOP VIEW
+
N.C.
1
INA-
2
INA+
3
VSS
4
+
MAX44241
8
N.C.
7
VDD
6
OUTA
5
N.C.
OUTA
1
VSS
2
INA+
3
5
VDD
4
INA-
MAX44241
µMAX
SOT-23
OUTA 1
+
14 OUTD
INA- 2
INA+ 3
13 IND-
MAX44243
12 IND+
OUTA
1
+
14
OUTD
INA-
2
13
IND-
INA+
3
12
IND+
11
VSS
MAX44243
VDD 4
11 VSS
VDD
4
INB+ 5
10 INC+
INB+
5
10
INC+
INB-
6
9
INC-
OUTB
7
8
OUTC
INB- 6
9 INC-
OUTB 7
8 OUTC
TSSOP
SO
+
OUTA 1
8
VDD
INA- 2
7
OUTB
INA+
3
6
INB-
GND 4
5
INB+
MAX44246
µMAX/SO
Maxim Integrated
9
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
Pin Descriptions
PIN
MAX44241
MAX44243
MAX44246
NAME
FUNCTION
SOT23-5
µMAX-8
SO-14
TSSOP-14
SO-8
µMAX-8
1
6
1
1
1
1
OUTA
2
4
11
11
4
4
VSS
Negative Supply Voltage
3
3
3
3
3
3
INA+
Channel A Positive Input
4
2
2
2
2
2
INA-
Channel A Negative Input
5
7
4
4
8
8
VDD
Positive Supply Voltage
—
—
5
5
5
5
INB+
Channel B Positive Input
—
—
6
6
6
6
INB-
Channel B Negative Input
—
—
7
7
7
7
OUTB
Channel B Output
—
—
8
8
—
—
OUTC
Channel C Output
—
—
9
9
—
—
INC-
Channel C Negative Input
—
—
10
10
—
—
INC+
Channel C Positive Input
—
—
12
12
—
—
IND+
Channel D Positive Input
—
—
13
13
—
—
IND-
Channel D Negative Input
—
—
14
14
—
—
OUTD
—
1, 5, 8
—
—
—
—
N.C.
Maxim Integrated
Channel A Output
Channel D Output
No Connection. Not internally
connected.
10
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
Detailed Description
The MAX44241/MAX44243/MAX44246 are high-precision
amplifiers that provide below 5µV of maximum inputreferred offset and low flicker noise. These characteristics are achieved by using a combination of proprietary
auto-zeroing and chopper stabilized techniques. This
combination of auto-zeroing and chopping ensures that
these amplifiers give all the benefits of zero-drift amplifiers, while still ensuring low noise, minimizing chopper
spikes, and providing wide bandwidth. Offset voltages
due to power ripple/spikes as well as common-mode
variation, are corrected resulting in excellent PSRR and
CMRR specifications.
Noise Suppression
Flicker noise, inherent in all active devices, is inversely proportional to frequency present. Charges at the
oxide-silicon interface that are trapped-and-released
by MOSFET oxide occurs at low frequency more often.
For this reason, flicker noise is also called 1/f noise. The
MAX44241/MAX44243/MAX44246 eliminate the 1/f noise
internally, thus making them ideal choices for DC or subHz precision applications. The 1/f noise appears as a
slow varying offset voltage and is eliminated by the chopping technique used.
Electromagnetic interference (EMI) noise occurs at higher
frequency, resulting in malfunction or degradation of electrical equipment. The ICs have an input EMI filter to avoid
the output being affected by radio frequency interference.
The EMI filter composed of passive devices, presents significant higher impedance to higher frequency.
Applications Information
ADC Buffer Amplifier
The MAX44241/MAX44243/MAX44246 have low input
offset voltage, low noise, and fast settling time that make
these amplifiers ideal for ADC buffers. Weight scales
are one application that often requires a low-noise, highvoltage amplifier in front of an ADC. The Typical Operating
Maxim Integrated
VSUPPLY
ILOAD
½ MAX44246
OUT
RSENSE
R2
R1
Figure 1. Low-Side Current Sensing
Circuit details an example of a load cell and amplifier driven from the same ±10V supplies, along with the
MAX11211 18-bit delta sigma ADC. Load cells produce a
very small voltage change at their outputs; therefore driving the excitation source with a higher voltage produces
a wider dynamic range that can be measured at the ADC
inputs.
The MAX11211 ADC operates from a single 2.7V to 3.6V
analog supply, offers 18-bit noise-free resolution and
0.86mW power dissipation. The MAX11211 also offers
> 100dB rejection at 50Hz and 60Hz. This ADC is part of
a family of 16-, 18-, 20-, and 24-bit delta sigma ADCs with
high precision and < 1mW power dissipation.
The low input offset voltage and low noise of MAX44241/
MAX44243/MAX44246 allow a gain circuit to precede the
MAX11211 without losing any dynamic range at the ADC.
See the Typical Operating Circuit.
Precision Low-Side Current Sensing
The ICs’ ultra-low offset voltage and drift make them
ideal for precision current-sensing applications. Figure 1
shows the ICs in a low-side current-sense configuration.
This circuit produces an accurate output voltage, VOUT
equal to ILOAD x RSENSE x (1 + R2 /R1).
11
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
Layout Guidelines
The MAX44241/MAX44243/MAX44246 feature ultra-low
offset voltage and noise. Therefore, to get optimum performance follow the following layout guidelines.
Avoid temperature gradients at the junction of two dissimilar metals. The most common dissimilar metals used
on a PCB are solder-to-component lead and solder-toboard trace. Dissimilar metals create a local thermocouple. A variation in temperature across the board can
cause an additional offset due to Seebeck effect at the
solder junctions. To minimize the Seebeck effect, place
the amplifier away from potential heat sources on the
board, if possible. Orient the resistors such that both
the ends are heated equally. It is a good practice to
match the input signal path to ensure that the type and
number of thermoelectric junctions remain the same. For
example, consider using dummy 0Ω resistors oriented
in such a way that the thermoelectric sources, due to
the real resistors in the signal path, are cancelled. It is
recommended to flood the PCB with ground plane. The
ground plane ensures that heat is distributed uniformly
reducing the potential offset voltage degradation due to
Seebeck effect.
Maxim Integrated
Ordering Information
TOP
MARK
-40NC to +125NC
PINPACKAGE
8 FMAX
-40NC to +125NC
5 SOT23
AFMR
MAX44243ASD+
-40NC to +125NC
14 SO
—
MAX44243AUD+
-40NC to +125NC
14 TSSOP
—
MAX44246ASA+
-40NC to +125NC
8 SO
—
MAX44246AUA+
-40NC to +125NC
8 FMAX
—
PART
TEMP RANGE
MAX44241AUA+
MAX44241AUK+
—
+Denotes a lead(Pb)-free/RoHS-compliant package.
Chip Information
PROCESS: BiCMOS
Package Information
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a
“+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but the
drawing pertains to the package regardless of RoHS status.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
5 SOT23
U5+1
21-0057
90-0174
8 SO
S8+4
21-0041
90-0096
8 µMAX
U8+1
21-0036
90-0092
14 SO
S14M+4
21-0041
90-0112
14 TSSOP
U14M+1
21-0066
90-0113
12
MAX44241/MAX44243/MAX44246
36V, Low-Noise, Precision,
Single/Quad/Dual Op Amps
Revision History
REVISION
NUMBER
REVISION
DATE
0
7/12
Initial release
1
9/12
Revised the Electrical Characteristics and the Typical Operating Characteristics.
DESCRIPTION
PAGES
CHANGED
—
1, 2, 3, 5
2
2/13
Revised the Typical Operating Characteristics.
3
5/13
Updated General Description, Typical Application Circuit, and Pin Description.
1, 9
8
4
9/13
Added the MAX44241/MAX44243 to the data sheet. Revised the Typical Operating
Circuit.
1–13
5
1/14
Revised Electrical Characteristics and the Typical Operating Characteristics.
2, 5
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent
licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and
max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
© 2014
Maxim Integrated
13
The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc.
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