1nV/√Hz Low Noise

210°C Instrumentation Amplifier

AD8229

Rev. 0

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FEATURES

Designed for 210°C operation

Low noise

1 nV/√Hz input noise

45 nV/√Hz output noise

High CMRR

126 dB CMRR (minimum), G = 100

80 dB CMRR (minimum) to 5 kHz, G = 1

Excellent ac specifications

15 MHz bandwidth (G = 1)

1.2 MHz bandwidth (G = 100)

22 V/μs slew rate

THD: 130 dB (1 kHz, G = 1)

Versatile

±4 V to ±17 V dual supply

Gain set with single resistor (G = 1 to 1000)

Temperature range: −40°C to +210°C

APPLICATIONS

Down-hole instrumentation

Harsh environment data acquisition

Exhaust gas measurements

Vibration analysis

GENERAL DESCRIPTION

The AD8229 is an ultralow noise instrumentation amplifier

designed for measuring small signals in the presence of large

common-mode voltages and high temperatures.

The AD8229 has been designed for high temperature operation.

The process is dielectrically isolated to avoid leakage currents at

high temperatures. The design architecture was chosen to

enhance long term reliability, the wire bonding in the packaging

is designed to avoid intermetallic absorption at high

temperatures.

The AD8229 excels at distinguishing tiny signals. It delivers

industry leading 1 nV/√Hz input noise performance. The

AD8229’s high CMRR prevents unwanted signals from

corrupting the acquisition. The CMRR increases as the gain

increases, offering high rejection when it is most needed.

FUNCTIONAL BLOCK DIAGRAM

TOP VIEW

(Not to Scale)

–IN

1

2

3

+IN

4

8

7

REF

6

5

AD8229

Figure 1.

100

80

60

40

20

0

–20

–40

–60

–80

–100

–55 –35 –15

5

25

45

65

85 105 125 145 165 185 205 225

TEMPERATURE (°C)

Figure 2. Typical Input Offset vs. Temperature (G = 100)

The AD8229 is one of the fastest instrumentation amplifiers

available. Its current feedback architecture provides bandwidth

that is quite high, even at high gains, for example, 1.2 MHz at

G = 100. With the high bandwidth comes excellent distortion

performance, allowing use in demanding applications such as

vibration analysis.

Gain is set from 1 to 1000 with a single resistor. A reference pin

allows the user to offset the output voltage. This feature is useful

when interfacing with analog-to-digital converters.

The AD8229 is available in an 8-pin ceramic DIP package.