Overview
Features and Benefits
- High common-mode input voltage range
±120 V at VS = ±15 V - Gain range 0.1 to 100
- Operating temperature range:
−40°C to +85°C - Supply voltage range
Dual supply: ±2.25 V to ±18 V
Single supply: 4.5 V to 36 V - Excellent ac and dc performance
- Offset temperature stability RTI: 10 μV/°C maximum
- Offset: ±1.5 V mV maximum
- CMRR RTI: 75 dB minimum, dc to 500 Hz,
G = +1
Product Details
The AD628 is a precision difference amplifier that combines excellent dc performance with high common-mode rejection over a wide range of frequencies. When used to scale high voltages, it allows simple conversion of standard control voltages or currents for use with single-supply ADCs. A wideband feedback loop minimizes distortion effects due to capacitor charging of Σ-Δ ADCs.
A reference pin (VREF) provides a dc offset for converting bipolar to single-sided signals. The AD628 converts +5 V, +10 V, ±5 V, ±10 V, and 4 to 20 mA input signals to a single-ended output within the input range of single-supply ADCs.
The AD628 has an input common mode and differential mode operating range of ±120 V. The high common mode, input impedance makes the device well suited for high voltage measurements across a shunt resistor. The inverting input of the buffer amplifier is available for making a remote Kelvin connection.
A precision 10 kΩ resistor connected to an external pin is provided for either a low-pass filter or to attenuate large differential input signals. A single capacitor implements a low-pass filter. The AD628 operates from single and dual supplies and is available in an 8-lead SOIC_N or an 8-lead MSOP. It operates over the standard industrial temperature range of −40°C to +85°C.
Applications
- High voltage current shunt sensing
- Programmable logic controllers
- Analog input front end signal conditioning
+5 V, +10 V, ±5 V, ±10 V, and 4 to 20 mA - Isolation Sensor signal conditioning
- Power supply monitoring
- Electrohydraulic controls
- Motor controls
Product Categories
Markets and Technologies
Product Lifecycle
Production
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.
Documentation & Resources
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AN-282: Fundamentals of Sampled Data Systems2/14/2015PDF2131 kB
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AN-669: Effectively Applying the AD628 Precision Gain Block (Rev. 0)2/14/2015PDF193 kB
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AN-589: Ways to Optimize the Performance of a Difference Amplifier (Rev. B)2/14/2015PDF115 kB
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AN-244: A User's Guide to I.C. Instrumentation Amplifiers11/23/2004PDF522 kB
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AN-245: Instrumentation Amplifiers Solve Unusual Design Problems11/23/2004PDF543 kB
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AN-671: Reducing RFI Rectification Errors in In-Amp Circuits11/23/2004PDF208 kB
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FAQs7/26/2017
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Simple Circuit Measures the RMS Value of an AC Power Line12/1/2012
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Auto-Zero Amplifiers3/1/2010DOC75 kB
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High-performance Adder Uses Instrumentation Amplifiers9/3/2009
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Input Filter Prevents Instrumentation-amp RF-Rectification Errors11/13/2003
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Simple circuit provides precision ADC interface8/21/2003
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Single IC provides gains of 10 and –108/7/2003
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The AD8221 - Setting a New Industry Standard for Instrumentation Amplifiers1/1/2000PDF582 kB
Tools & Simulations
SPICE Models
CIR
AD628 SPICE Macro Model
6.74 K
Reference Designs (1)
Design Resources
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.
PCN-PDN Information
Sample & Buy
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