AD8556ACPZ-R2 datasheet(4/28 Pages) AD

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Data Sheet

AD8556

GENERAL DESCRIPTION

The AD8556 is a zero-drift, sensor signal amplifier with

digitally programmable gain and output offset. Designed to

easily and accurately convert variable pressure sensor and

strain bridge outputs to a well-defined output voltage range,

the AD8556 accurately amplifies many other differential or

single-ended sensor outputs. The AD8556 uses the Analog

Devices, Inc. patented low noise, auto-zero and DigiTrim®

technologies to create an incredibly accurate and flexible

signal processing solution in a very compact footprint.

Gain is digitally programmable in a wide range from 70 to

1280 through a serial data interface. Gain adjustment can

be fully simulated in-circuit and then permanently pro-

grammed with reliable polyfuse technology. Output offset

voltage is also digitally programmable and is ratiometric to

the supply voltage. The AD8556 also features internal EMI

filters on the VNEG, VPOS, FILT and VCLAMP pins.

In addition to extremely low input offset voltage, low input offset

voltage drift, and very high dc and ac CMRR, the AD8556 also

includes a pull-up current source at the input pins and a pull-

down current source at the VCLAMP pin, which allows open

wire and shorted wire fault detection. A low-pass filter function

is implemented via a single low cost external capacitor. Output

clamping set via an external reference voltage allows the AD8556

to drive lower voltage ADCs safely and accurately.

When used in conjunction with an ADC referenced to the same

supply, the system accuracy becomes immune to normal supply

voltage variations. Output offset voltage can be adjusted with a

resolution of better than 0.4% of the difference between VDD

and VSS. A lockout trim after gain and offset adjustment further

ensures field reliability.

The AD8556 is fully specified from −40°C to +140°C.

Operating from single-supply voltages of 4.5 V to 5.5 V, the

AD8556 is offered in the 8-lead SOIC_N and 4 mm × 4 mm

16-lead LFCSP_WQ.

Rev. B | Page 3 of 27

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