ADI AD8428BRZ

The AD8428 is an ultralow noise instrumentation amplifier designed for precise measurement of small, high-speed signals, delivering industry-leading gain accuracy, noise, and bandwidth performance. All gain-setting resistors in the AD8428 are integrated on-chip and precisely matched. The pinout and layout are carefully designed to minimize gain drift and enable fast settling to the final gain value after power-up. The AD8428 features high CMRR to prevent interference signals from corrupting the target signal. The pinout design eliminates parasitic capacitance mismatches, preventing CMRR degradation at high frequencies. The AD8428 is one of the fastest instrumentation amplifiers available. The circuit architecture is optimized for high bandwidth and high gain. The input preamplifier gain stage uses a current feedback topology with a gain of 200, followed by a differential amplifier stage with a gain of 10. At a gain of 2000, the bandwidth is 3.5 MHz, yielding an equivalent gain-bandwidth product of 7 GHz. The AD8428 pinout provides access to the internal nodes between the first and second stages. This feature allows modification of the frequency response between the two amplifier stages, thereby preventing interference signals from affecting the output. The AD8428 is rated for the −40°C to +85°C industrial temperature range and is available in an 8-lead plastic SOIC package.

• Fixed gain: 2000
• Flexibility via internal node access
• Low noise: 1.5 nV/√Hz input voltage noise
• High-precision DC performance — gain drift: 5 ppm/°C, offset drift: 0.3 μV/°C, gain accuracy: 0.05%, CMRR: 140 dB (min)
• Excellent AC characteristics — bandwidth: 3.5 MHz, slew rate: 40 V/μs
• Supply voltage range: ±4 V to ±18 V
• 8-pin SOIC package
• ESD protection: 5000 V (HBM)
• Rated temperature range: -40°C to +85°C
• Operating temperature up to 125°C

• Sensor interface
• Medical instrumentation
• Patient monitoring