MAXIM MAX4239AUT/V+T

19-2424; Rev 3; 8/11
Ultra-Low Offset/Drift, Low-Noise,
Precision SOT23 Amplifiers
The MAX4238/MAX4239 are low-noise, low-drift, ultrahigh precision 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. Both
devices feature rail-to-rail outputs, operate from a single
2.7V to 5.5V supply, and consume only 600µA. An activelow shutdown mode decreases supply current to 0.1µA.
The MAX4238 is unity-gain stable with a gain-bandwidth product of 1MHz, while the decompensated
MAX4239 is stable with AV ≥ 10V/V and a GBWP of
6.5MHz. The MAX4238/MAX4239 are available in 8-pin
narrow SO, 6-pin TDFN and SOT23 packages.
Features
o Ultra-Low, 0.1µV Offset Voltage
2.0µV (max) at +25°C
2.5µV (max) at -40°C to +85°C
3.5µV (max) at -40°C to +125°C
o Low 10nV/°C Drift
o Specified over the -40°C to +125°C Automotive
Temperature Range
o Low Noise: 1.5µVP-P from DC to 10Hz
o 150dB AVOL, 140dB PSRR, 140dB CMRR
o High Gain-Bandwidth Product
1MHz (MAX4238)
6.5MHz (MAX4239)
o 0.1µA Shutdown Mode
Applications
o Rail-to-Rail Output (RL = 1kΩ)
Thermocouples
o Low 600µA Supply Current
Strain Gauges
o Ground-Sensing Input
Electronic Scales
o Single 2.7V to 5.5V Supply Voltage Range
Medical Instrumentation
o Available in a Space-Saving 6-Pin SOT23 and
TDFN Packages
Instrumentation Amplifiers
Ordering Information
PART
Typical Application Circuit
5V
18kΩ
360Ω
STRAIN GAUGE
ADC
AV = 100
18kΩ
MAX4238/
MAX4239
AIN
PIN-PACKAGE
TOP MARK
MAX4238AUT-T
6 SOT23
AAZZ
MAX4238AUT/V+T
6 SOT23
—
MAX4238ASA
8 SO
MAX4238ATT+T
6 TDFN-EP*
+ANG
MAX4239AUT-T
6 SOT23
ABAA
—
MAX4239AUT/V+T
6 SOT23
—
MAX4239ASA
8 SO
—
MAX4239ATT+T
6 TDFN-EP*
+ANH
Note: All devices are specified over the -40°C to +125°C operating temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed paddle.
/V denotes an automotive-qualified part.
Selector Guide
PART
MAX4238
MAX4239
MINIMUM STABLE
GAIN
1V/V
10V/V
GAIN
BANDWIDTH
(MHz)
1
6.5
Pin Configurations appear at end of data sheet.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX4238/MAX4239
General Description
MAX4238/MAX4239
Ultra-Low Offset/Drift, Low-Noise,
Precision SOT23 Amplifiers
ABSOLUTE MAXIMUM RATINGS
Power-Supply Voltage (VCC to GND).......................................6V
All Other Pins ................................(VGND - 0.3V) to (VCC + 0.3V)
Output Short-Circuit Duration
(OUT shorted to VCC or GND) ...............................Continuous
Continuous Power Dissipation (TA = +70°C)
6-Pin Plastic SOT23
(derate 9.1mW/°C above +70°C) ...............................727mW
8-Pin Plastic SO (derate 5.88mW/°C above +70°C) ....471mW
6-Pin TDFN-EP (derate 18.2mW above +70°C) .........1454mW
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
Soldering Temperature (reflow)
Lead(Pb)-Free Packages.............................................+260°C
Packages Containing Lead..........................................+240°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
(2.7V ≤ V CC ≤ 5.5V, V CM = V GND = 0V, V OUT = V CC /2, R L = 10kΩ connected to V CC /2, SHDN = V CC , T A = +25 ° C,
unless otherwise noted.)
PARAMETER
Input Offset Voltage
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
0.1
2
µV
VOS
(Note 1)
Input Bias Current
IB
(Note 2)
1
pA
Input Offset Current
IOS
(Note 2)
2
pA
RS = 100, 0.01Hz to 10Hz
1.5
µVP-P
f = 1kHz
30
NV/Hz
Long-Term Offset Drift
Peak-to-Peak Input Noise
Voltage
Input Voltage-Noise Density
Common-Mode Input
Voltage Range
50
enP-P
en
VCM
VCC
- 1.3
VGND
- 0.1
Inferred from CMRR test
nV/1000hr
V
Common-Mode Rejection Ratio
CMRR
-0.1V VCM VCC - 1.3V (Note 1)
120
140
dB
Power-Supply Rejection Ratio
PSRR
2.7V VCC 5.5V (Note 1)
120
140
dB
125
150
Large-Signal Voltage Gain
AVOL
0.05V VOUT VCC - 0.05V
(Note 1)
RL = 10k
0.1V VOUT VCC - 0.1V
(Note 1)
RL = 1k
RL = 10k
Output Voltage Swing
VOH/VOL
RL = 1k
dB
125
145
VCC - VOH
4
VOL
4
10
VCC - VOH
35
50
VOL
35
50
Output Short-Circuit Current
To either supply
Output Leakage Current
0 V OUT VCC, SHDN = GND (Note 2)
0.01
Slew Rate
VCC = 5V, CL = 100pF,
VOUT = 2V step
MAX4238
0.35
MAX4239
1.6
RL = 10k, CL = 100pF,
measured at f = 100kHz
MAX4238
1
MAX4239
6.5
RL = 10k, CL = 100pF,
phase margin = 60°
MAX4238
1
MAX4239
10
Gain-Bandwidth Product
Minimum Stable Closed-Loop
Gain
2
GBWP
10
40
_______________________________________________________________________________________
mV
mA
1
µA
V/µs
MHz
V/V
Ultra-Low Offset/Drift, Low-Noise,
Precision SOT23 Amplifiers
(2.7V ≤ V CC ≤ 5.5V, V CM = V GND = 0V, V OUT = V CC /2, R L = 10kΩ connected to V CC /2, SHDN = V CC , T A = +25 ° C,
unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
RL = 10k, CL = 100pF,
phase margin = 60°
Maximum Closed-Loop Gain
Settling Time
-1V step
AV = 10
(Note 4)
Overload Recovery Time
Startup Time
AV = 10
MIN
1000
MAX4239
6700
0.1% (10 bit)
0.5
0.025% (12 bit)
1.0
0.006% (14 bit)
1.7
0.0015% (16 bit)
2.3
0.1% (10 bit)
3.3
0.025% (12 bit)
4.1
0.006% (14 bit)
4.9
0.0015% (16 bit)
5.7
0.1% (10 bit)
1.8
0.025% (12 bit)
2.6
0.006% (14 bit)
3.4
0.0015% (16 bit)
Supply Voltage Range
VCC
Supply Current
ICC
Shutdown Logic-High
VIH
Shutdown Logic-Low
VIL
Shutdown Input Current
TYP
MAX4238
Inferred by PSRR test
MAX
V/V
ms
ms
ms
4.3
2.7
5.5
SHDN = VCC, no load, VCC = 5.5V
600
850
SHDN = GND, VCC = 5.5V
0.1
1
2.2
0V V SHDN VCC
UNITS
V
µA
V
0.1
0.8
V
1
µA
_______________________________________________________________________________________
3
MAX4238/MAX4239
ELECTRICAL CHARACTERISTICS (continued)
MAX4238/MAX4239
Ultra-Low Offset/Drift, Low-Noise,
Precision SOT23 Amplifiers
ELECTRICAL CHARACTERISTICS
(2.7V ≤ VCC ≤ 5.5V, VCM = GND = 0V, VOUT = VCC/2, RL = 10kΩ connected to VCC/2, SHDN = VCC, TA = -40°C to +125°C, unless otherwise noted.) (Note 5)
PARAMETER
Input Offset Voltage
Input Offset Drift
Common-Mode Input Voltage
Range
Common-Mode Rejection Ratio
Power-Supply Rejection Ratio
Large-Signal Voltage Gain
SYMBOL
CONDITIONS
VOS
(Note 1)
TCVOS
(Note 1)
VCM
CMRR
PSRR
10
VGND
- 0.05
2.7V VCC 5.5V (Note 1)
120
RL = 10k,
0.1V VOUT
VCC - 0.1V
(Note 1)
125
VOH/VOL
RL = 1k
TA = -40°C to +85°C
Supply Voltage Range
VCC
Supply Current
ICC
Shutdown Logic High
VIH
Shutdown Logic Low
VIL
UNITS
µV
nV/°C
VCC
- 1.4
V
dB
90
dB
dB
TA = -40°C to +125°C
95
0.1V VOUT VCC - 0.1V,
TA = -40°C to +85°C
120
0.2V VOUT VCC - 0.2V,
TA = -40°C to +125°C
80
dB
VCC - VOH
20
20
VOL
VCC - VOH
100
VOL
100
0V VOUT VCC, SHDN = GND
(Note 3)
Output Leakage Current
Shutdown Input Current
3.5
115
RL = 10k
MAX
TA = -40°C to +125°C
VGND - 0.05V TA = -40°C to +85°C
VCM VCC TA = -40°C to +125°C
1.4V (Note 1)
AVOL
TYP
2.5
Inferred from CMRR test
RL = 1k
(Note 1)
Output Voltage Swing
MIN
TA = -40°C to +85°C
Inferred by PSRR test
2.7
SHDN = VCC, no load, VCC = 5.5V
2
µA
5.5
V
900
SHDN = GND, VCC = 5.5V
2
2.2
0V V SHDN VCC
mV
µA
V
0.7
V
2
µA
Note 1: Guaranteed by design. Thermocouple and leakage effects preclude measurement of this parameter during production
testing. Devices are screened during production testing to eliminate defective units.
Note 2: IN+ and IN- are gates to CMOS transistors with typical input bias current of 1pA. CMOS leakage is so small that it is
impractical to test and guarantee in production. Devices are screened during production testing to eliminate defective units.
Note 3: Leakage does not include leakage through feedback resistors.
Note 4: Overload recovery time is the time required for the device to recover from saturation when the output has been
driven to either rail.
Note 5: Specifications are 100% tested at TA = +25°C, unless otherwise noted. Limits over temperature are guaranteed by design.
4
_______________________________________________________________________________________
Ultra-Low Offset/Drift, Low-Noise,
Precision SOT23 Amplifiers
30
20
0
TA = -40°C
0
0.3 0.6 0.9 1.2 1.5
TA = +25°C
TA = -40°C
0
-0.4
2.7
3.4
4.1
4.8
5.5
0
0.9
1.8
2.7
COMMON-MODE VOLTAGE (V)
OUTPUT HIGH VOLTAGE
vs. OUTPUT SOURCE CURRENT
OUTPUT LOW VOLTAGE
vs. OUTPUT SINK CURRENT
MAX4238
GAIN AND PHASE vs. FREQUENCY
0.20
VCC = 2.7V
0.15
VCC = 5V
0.10
MAX4238/39 toc05
0.25
0.35
0.30
OUTPUT LOW VOLTAGE (V)
MAX4238/39 toc04
VOH = VCC - VOUT
0.05
0.25
VCC = 2.7V
0.20
VCC = 5V
0.15
0.10
0.05
0
0
0
5
10
15
20
0
5
10
15
80
60
40
20
0
-20
-40
-60
-80
-100
-120
-140
-160
-180
VCC = 5V
GAIN = 60dB
RL = 10kΩ
CL = 0pF
100
20
1k
10k
100k
1M
MAX4238
GAIN AND PHASE vs. FREQUENCY
VCC = 5V
GAIN = 60dB
RL = 10kΩ
CL = 100pF
1k
10k
100k
FREQUENCY (Hz)
1M
10M
VCC = 5V
GAIN = 40dB
RL = 10kΩ
CL = 0pF
100
1k
10k
100k
FREQUENCY (Hz)
1M
10M
80
60
40
20
0
-20
-40
-60
-80
-100
-120
-140
-160
-180
10M
MAX4238/39 toc09
MAX4238
GAIN AND PHASE vs. FREQUENCY
GAIN AND PHASE (dB/DEGREES)
MAX4238
GAIN AND PHASE vs. FREQUENCY
MAX4238/39 toc08
FREQUENCY (Hz)
GAIN AND PHASE (dB/DEGREES)
SINK CURRENT (mA)
MAX4238/39 toc07
SOURCE CURRENT (mA)
80
60
40
20
0
-20
-40
-60
-80
-100
-120
-140
-160
-180
3.6
MAX4238/39 toc06
SUPPLY VOLTAGE (V)
GAIN AND PHASE (dB/DEGREES)
OFFSET VOLTAGE (µV)
0.30
100
TA = +125°C
0.2
-0.2
-0.4
-1.5 -1.2 -0.9 -0.6 -0.3 0
OUTPUT HIGH VOLTAGE (V)
TA = +25°C
-0.2
10
GAIN AND PHASE (dB/DEGREES)
0.2
OFFSET VOLTAGE (µV)
TA = +125°C
OFFSET VOLTAGE (µV)
40
0.4
MAX4238/39 toc02
0.4
MAX4238/39 toc01
PERCENTAGE OF UNITS (%)
50
80
60
40
20
0
-20
-40
-60
-80
-100
-120
-140
-160
-180
OFFSET VOLTAGE
vs. COMMON-MODE VOLTAGE
OFFSET VOLTAGE vs. SUPPLY VOLTAGE
MAX4238/39 toc03
INPUT OFFSET DISTRIBUTION
VCC = 5V
GAIN = 40dB
RL = 10kΩ
CL = 68pF
100
1k
10k
100k
1M
10M
FREQUENCY (Hz)
_______________________________________________________________________________________
5
MAX4238/MAX4239
Typical Operating Characteristics
(VCC = 5V, VCM = 0V, RL = 10kΩ connected to VCC/2, SHDN = VCC, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VCC = 5V, VCM = 0V, RL = 10kΩ connected to VCC/2, SHDN = VCC, TA = +25°C, unless otherwise noted.)
MAX4239
GAIN AND PHASE vs. FREQUENCY
VCC = 5V
GAIN = 40dB
RL = 10kΩ
CL = 0pF
1E+2
1E+3
1E+4
1E+5
1E+6
1E+3
MAx4238/39 toc12
TA = +125°C
500
VCC = 5V
GAIN = 40dB
RL = 10kΩ
CL = 100pF
1E+2
1E+7
SUPPLY CURRENT vs. SUPPLY VOLTAGE
600
SUPPLY CURRENT (µA)
80
60
40
20
0
-20
-40
-60
-80
-100
-120
-140
-160
-180
MAX4238/39 toc11
GAIN AND PHASE (dB/DEGREES)
TA = -40°C
400
TA = +25°C
300
200
100
0
1E+4
1E+5
1E+6
0
1E+7
1
2
3
5
FREQUENCY (Hz)
SUPPLY VOLTAGE (V)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
COMMON-MODE REJECTION RATIO
vs. FREQUENCY
MAX4238
LARGE-SIGNAL TRANSIENT RESPONSE
-20
-40
-20
-40
CMRR (dB)
-60
-80
MAX4238/39 toc15
0
MAX4238/39 toc13
0
IN
1V/div
-60
-80
-100
-100
-120
-120
-140
-140
-160
OUT
1V/div
-160
0.01
0.1
1
10
100
1000
0.01
0.1
1
10
100
10µs/div
1000
FREQUENCY (kHz)
FREQUENCY (kHz)
MAX4238
SMALL-SIGNAL TRANSIENT RESPONSE
MAX4239
SMALL-SIGNAL TRANSIENT RESPONSE
MAX4238/39 toc16
MAX4238/39 toc17
AV = 1V/V
RL = 2kΩ
CL = 100pF
OVERVOLTAGE RECOVERY TIME
MAX4238/39 toc18
IN
50mV/div
IN
50mV/div
0
IN
50mV/div
OUT
50mV/div
OUT
1V/div
OUT
500mV/div
0
400µs/div
10µs/div
10µs/div
AV = 1V/V
RL = 2kΩ
CL = 100pF
6
4
FREQUENCY (Hz)
MAX4238/39 toc14
80
60
40
20
0
-20
-40
-60
-80
-100
-120
-140
-160
-180
MAX4238/39 toc10
GAIN AND PHASE (dB/DEGREES)
MAX4239
GAIN AND PHASE vs. FREQUENCY
PSRR (dB)
MAX4238/MAX4239
Ultra-Low Offset/Drift, Low-Noise,
Precision SOT23 Amplifiers
AV = 10V/V
RL = 2kΩ
CL = 100pF
AV = 100V/V
RL = 10kΩ
VCC = 2.5V
VEE = -2.5V
_______________________________________________________________________________________
Ultra-Low Offset/Drift, Low-Noise,
Precision SOT23 Amplifiers
SHUTDOWN WAVEFORM
DC TO 10Hz NOISE
MAX4238/39 toc20
MAX4238/39 toc19
SHDN
2V/div
2µV/div
OUT
1V/div
OUT
10µs/div
1s/div
RL = 10kΩ
CL = 100pF
VCC = 2.5V
VEE = -2.5V
Offset Error Sources
Pin Description
PIN
TDFN SOT23
SO
NAME
FUNCTION
1
1
6
OUT
Amplifier Output
2
2
4
GND
Ground
3
3
3
IN+
Noninverting Input
4
4
2
IN-
Inverting Input
Shutdown Input. Active-low
shutdown, connect to VCC
for normal operation.
5
5
1
SHDN
6
6
7
VCC
Positive Power Supply
No Connection. Not
internally connected.
—
—
5, 8
N.C.
—
—
—
EP
Exposed Pad (TDFN only).
Connect EP to GND.
Detailed Description
The MAX4238/MAX4239 are high-precision amplifiers
that have less than 2.5µV of input-referred offset and
low 1/f noise. These characteristics are achieved
through a patented autozeroing technique that samples
and cancels the input offset and noise of the amplifier.
The pseudorandom clock frequency varies from 10kHz
to 15kHz, reducing intermodulation distortion present in
chopper-stabilized amplifiers.
To achieve very low offset, several sources of error
common to autozero-type amplifiers need to be considered. The first contributor is the settling of the sampling
capacitor. This type of error is independent of inputsource impedance, or the size of the external gain-setting resistors. Maxim uses a patented design technique
to avoid large changes in the voltage on the sampling
capacitor to reduce settling time errors.
The second error contributor, which is present in both
autozero and chopper-type amplifiers, is the charge
injection from the switches. The charge injection
appears as current spikes at the input, and combined
with the impedance seen at the amplifier’s input, contributes to input offset voltage. Minimize this
feedthrough by reducing the size of the gain-setting
resistors and the input-source impedance. A capacitor
in parallel with the feedback resistor reduces the
amount of clock feedthrough to the output by limiting
the closed-loop bandwidth of the device.
The design of the MAX4238/MAX4239 minimizes the
effects of settling and charge injection to allow specification of an input offset voltage of 0.1µV (typ) and less
than 2.5µV over temperature (-40°C to +85°C).
1/f Noise
1/f noise, inherent in all semiconductor devices, is
inversely proportional to frequency. 1/f noise increases
3dB/octave and dominates amplifier noise at lower frequencies. This noise appears as a constantly changing
voltage in series with any signal being measured. The
MAX4238/MAX4239 treat 1/f noise as a slow varying
offset error, inherently canceling the 1/f noise.
_______________________________________________________________________________________
7
MAX4238/MAX4239
Typical Operating Characteristics (continued)
(VCC = 5V, VCM = 0V, RL = 10kΩ connected to VCC/2, SHDN = VCC, TA = +25°C, unless otherwise noted.)
Output Overload Recovery
Pin Configurations
Autozeroing amplifiers typically require a substantial
amount of time to recover from an output overload. This
is due to the time it takes for the null amplifier to correct
the main amplifier to a valid output. The MAX4238/
MAX4239 require only 3.3ms to recover from an output
overload (see Electrical Characteristics and Typical
Operating Characteristics).
VCC
SHDN
IN-
TOP VIEW
6
5
4
EP*
Shutdown
MAX4238/
MAX4239
The MAX4238/MAX4239 feature a low-power (0.1µA)
shutdown mode. When SHDN is pulled low, the clock
stops and the device output enters a high-impedance
state. Connect SHDN to VCC for normal operation.
ADC Buffer Amplifier
The low offset, fast settling time, and 1/f noise cancellation of the MAX4238/MAX4239 make these devices
ideal for ADC buffers. The MAX4238/MAX4239 are well
suited for low-speed, high-accuracy applications such
as strain gauges (see Typical Application Circuit).
Error Budget Example
When using the MAX4238/MAX4239 as an ADC buffer,
the temperature drift should be taken into account when
determining the maximum input signal. With a typical offset drift of 10nV/°C, the drift over a 10°C range is 100nV.
Setting this equal to 1/2LSB in a 16-bit system yields a
full-scale range of 13mV. With a single 2.7V supply, an
acceptable closed-loop gain is AV = 200. This provides
sufficient gain while maintaining headroom.
*CONNECT EP TO GND.
MAX4238/
MAX4239
MAX4238/
MAX4239
SHDN 1
8
N.C.
IN- 2
7
VCC
3
6
OUT
GND 4
5
N.C.
IN+
OUT 1
6
VCC
GND 2
5
SHDN
IN+ 3
4
IN-
SO
SOT23
Chip Information
PROCESS: BiCMOS
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.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
8
3
TDFN
(3mm x 3mm x 0.8mm)
Minimum and Maximum Gain
Configurations
The MAX4238 is a unity-gain stable amplifier with a gainbandwidth product (GBWP) of 1MHz. The MAX4239 is
decompensated for a GBWP of 6.5MHz and is stable with
a gain of 10V/V. Unlike conventional operational amplifiers, the MAX4238/MAX4239 have a maximum gain
specification. To maintain stability, set the gain of the
MAX4238 between AV = 1000V/V to 1V/V, and set the
gain of the MAX4239 between AV = 6700V/V and 10V/V.
2
IN+
Applications Information
1
GND
+
OUT
MAX4238/MAX4239
Ultra-Low Offset/Drift, Low-Noise,
Precision SOT23 Amplifiers
PACKAGE
CODE
OUTLINE NO.
LAND
PATTERN NO.
6 SOT23
U6F-6
21-0058
90-0175
8 SO
S8-4
21-0041
90-0096
6 TDFN
T633+2
21-0137
90-0058
_______________________________________________________________________________________
Ultra-Low Offset/Drift, Low-Noise,
Precision SOT23 Amplifiers
PAGES
CHANGED
REVISION
NUMBER
REVISION
DATE
2
5/06
—
—
3
8/11
Added MAX4238 and MAX4239 automotive-qualified parts
1
DESCRIPTION
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. 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.
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MAX4238/MAX4239
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