Digitally Programmable Sensor Signal Amplifier with EMI Filters
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.
- Automotive Sensors
- Pressure and Position Sensors
- Precision Current Sensing
- Strain Gages
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
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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ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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.