MAX4238AUT+T Maxim Integrated Products, MAX4238AUT+T Datasheet - Page 7

• Manufacturer Part Number: MAX4238AUT+T
• Description: IC AMP ULT HIGH PREC LN SOT23-6
• Manufacturer: Maxim Integrated Products

Specifications of MAX4238AUT+T

• Amplifier Type: General Purpose
• Number Of Circuits: 1
• Output Type: Rail-to-Rail
• Slew Rate: 0.35 V/µs
• Gain Bandwidth Product: 1MHz
• Current - Input Bias: 1pA
• Voltage - Input Offset: 0.1µV
• Current - Supply: 600µA
• Current - Output / Channel: 40mA
• Voltage - Supply, Single/dual (±): 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SOT-23-6
• Number Of Channels: 1
• Voltage Gain Db: 150 dB
• Common Mode Rejection Ratio (min): 120 dB
• Input Offset Voltage: 0.002 mV
• Operating Supply Voltage: 3 V, 5 V
• Supply Current: 0.85 mA
• Maximum Power Dissipation: 727 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• -3db Bandwidth: -
• Lead Free Status / Rohs Status: Details
• Other names: MAX4238AUT+T

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 an 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.
(V
TDFN
CC
EP
—
1
2
3
4
5
6
= 5V, V CM = 0V, R
SOT23
OUT
PIN
—
—
1
2
3
4
5
6
V
V
CC
EE
= -2.5V
= 2.5V
5, 8
SO
—
6
4
3
2
1
7
_______________________________________________________________________________________
DC TO 10Hz NOISE
L
Detailed Description
NAME
SHDN
= 10kΩ connected to V
GND
OUT
N.C.
V
IN+
IN-
EP
CC
1s/div
Amplifier Output
Ground
Noninverting Input
Inverting Input
Shutdown Input. Active-low
shutdown, connect to V
normal operation.
Positive Power Supply
No Connection. Not internally
connected.
Exposed Pad. Connect EP to
GND.
Pin Description
Ultra-Low Offset/Drift, Low-Noise,
MAX4238/39 toc19
FUNCTION
2μV/div
Typical Operating Characteristics (continued)
CC
/2, SHDN = V
Precision SOT23 Amplifiers
CC
for
CC
, T
To achieve very low offset, several sources of error
common to autozero-type amplifiers need to be consid-
ered. The first contributor is the settling of the sampling
capacitor. This type of error is independent of input-
source impedance, or the size of the external gain-set-
ting resistors. Maxim uses a 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, con-
tributes 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 specifi-
cation of an input offset voltage of 0.1µV (typ) and less
than 2.5µV over temperature (-40°C to +85°C).
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 fre-
quencies. 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.
A
= +25°C, unless otherwise noted.)
SHDN
OUT
R
C
L
L
= 10kΩ
= 100pF
SHUTDOWN WAVEFORM
10μs/div
Offset Error Sources
MAX4238/39 toc20
1/f Noise
2V/div
1V/div
7