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 ADI
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
1,280 through a serial data interface. Gain adjustment can
be fully simulated in-circuit and then permanently programmed
with reliable polyfuse technology. Output offset
voltage is also digitally programmable and is ratiometric to the
supply voltage. 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. This
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 2.7 V to 5.5 V, the
AD8556 is offered in the 8-lead SOIC_N, and 4 mm × 4 mm
16-lead LFCSP_VQ.
Applications
- Automotive Sensors
- Pressure and Position Sensors
- Precision Current Sensing
- Strain Gages
