Digitally Programmable Sensor Signal Amplifier
The AD8557 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 AD8557 accurately amplifies many other differential or single-ended sensor outputs. The AD8557 uses the Analog Devices, Inc., proprietary low noise auto-zero and DigiTrim® technologies to create an accurate and flexible signal processing solution in a compact footprint.
Gain is digitally programmable in a wide range from 28 to 1300 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.
In addition to extremely low input offset voltage and input offset voltage drift and very high dc and ac CMRR, the AD8557 also includes a pull-up current source at the input pins and a pull-down current source at the VCLAMP pin. Output clamping set via an external reference voltage allows the AD8557 to drive lower voltage analog-to-digital converters (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 AD8557 is fully specified from −40°C to +125°C. Operating from single-supply voltages of 2.7 V to 5.5 V, the AD8557 is offered in an 8-lead SOIC, and a 4 mm × 4 mm, 16-lead LFCSP.
- Automotive sensors
- Pressure and position sensors
- Precision current sensing
- Thermocouple amplifiers
- Industrial weigh scales
- Strain gages
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
The AD8556-EVALZ/AD8556CP-EBZ evaluation boards allow the quick demonstration and evaluation of the AD8555/AD8556/AD8557 zero-drift, digitally programmable sensor signal amplifiers.
The AD8555/AD8556/AD8557 are auto-zero instrumentation amplifiers with programmable gain and output offset adjustment features. The evaluation board enables a PC to communicate with the AD8555/AD8556/AD8557. The user can send commands to the evaluation board and read back the programmed values for the device that is being evaluated.
The user guide UG-896 supplements the information in the AD8555, AD8556, and AD8557 data sheets, which should be consulted in conjunction with this user guide when working with the evaluation board.
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The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.