Analog Devices Inc. AD7863BRZ-3

Overview

AD7863BRZ-3 from Analog Devices is a dual, simultaneous-sampling 14-bit analog-to-digital converter with ±2.5 V input range, 5.2 μs conversion time, and single 5 V supply operation. It integrates two track/hold amplifiers, internal 2.5 V reference, and high-speed parallel interface - designed for phase-critical signal acquisition in motor control, power quality monitoring, and digital oscilloscope front-ends.

For engineers reviewing the AD7863BRZ-3 datasheet, AD7863BRZ-3 pinout, AD7863BRZ-3 application, or AD7863BRZ-3 equivalent, key selection criteria include simultaneous dual-channel sampling, aperture delay matching ≤350 ps, channel-to-channel isolation of −86 dB, and support for ±2.5 V bipolar input with ±7 V overvoltage protection.

Technical Context

The AD7863BRZ-3 implements two independent successive approximation register (SAR) ADCs sharing a common CONVST trigger to enforce strict simultaneity. Each ADC pairs with a dedicated track/hold amplifier and shares a single internal 2.5 V reference, enabling matched gain and offset performance across channels.

Its parallel 14-bit interface uses standard CS/RD handshaking with BUSY status signaling; conversion results are read sequentially - first VA1/VB1, then VA2/VB2 - controlled by A0 multiplexer select. The device operates in Mode 1 (high-speed, 175 kSPS) or Mode 2 (auto-power-down), with 0.5 μs track/hold acquisition time ensuring fidelity after channel switching or signal transients.

Key Specifications

Pinout & Package

AD7863BRZ-3 is housed in a 28-lead SOIC_W (Wide-body Small Outline IC) package with 0.6 mm lead pitch and exposed pad thermal enhancement. Pin layout supports compact PCB routing while maintaining analog/digital ground separation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-channel simultaneous-sampling ADC applications.

Compared with AD7863ARZ-3, the AD7863BRZ-3 trades minor DC accuracy for lower cost and broader availability; compared with AD7656ASTZ, it delivers superior inter-channel timing integrity at the expense of resolution and channel count - making AD7863BRZ-3 the optimal choice for phase-coherent dual-channel acquisition at 14-bit precision.

Availability

AD7863BRZ-3 is available at Aetrix Electronics and suitable for motor control feedback, power quality monitoring, and digital oscilloscope front-ends requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for AD7863BRZ-3 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD7863 product line delivers dual-channel simultaneous-sampling ADCs for applications demanding precise inter-channel timing - especially in motor control, power electronics, and test equipment where phase coherence is non-negotiable.

FAQ

What is the maximum sampling rate supported by the AD7863BRZ-3?

The AD7863BRZ-3 achieves a sustained throughput of 175 kSPS per channel in Mode 1 (high-speed mode), with a fixed 5.2 μs conversion time. This rate assumes proper timing margins - including 400 ns quiet time before the next CONVST pulse - and is validated under specified operating conditions (VDD = 5 V ± 5%, T = −40°C to +85°C). The AD7863BRZ-3 does not support oversampling or decimation modes beyond its native 175 kSPS capability.

Does the AD7863BRZ-3 require an external reference voltage?

No, the AD7863BRZ-3 includes an internal 2.5 V reference with ±10 mV accuracy at 25°C and 25 ppm/°C temperature coefficient. It is fully functional with this reference enabled via the VREF pin. However, the VREF pin also accepts an external 2.5 V source for improved stability or tighter tolerance - in which case the internal reference is disabled. The AD7863BRZ-3 reference section is designed for direct use without external components unless higher precision is required.

How does the AD7863BRZ-3 handle simultaneous sampling of two channels?

The AD7863BRZ-3 uses two physically separate track/hold amplifiers, each tied to one channel (A or B), triggered synchronously by the falling edge of the CONVST signal. This architecture ensures both inputs are captured at precisely the same instant, with aperture delay matching ≤350 ps. The resulting digitized values retain their true phase relationship - a requirement for vector control algorithms and FFT-based spectral analysis. No external clock synchronization or firmware coordination is needed.

What are the overvoltage protection limits for the AD7863BRZ-3 analog inputs?

The AD7863BRZ-3 analog inputs (VA1, VA2, VB1, VB2) tolerate up to ±7 V continuously without damage - exceeding its ±2.5 V nominal input range. This protection applies across the full operating temperature range and is implemented via on-chip clamping circuitry. It allows safe operation in electrically noisy environments such as motor drives or industrial sensors, reducing the need for external TVS diodes or resistor networks in many designs.

Can the AD7863BRZ-3 operate from a single 5 V supply?

Yes, the AD7863BRZ-3 is specified for single-supply operation at VDD = 5 V ± 5%. Both analog and digital circuitry share this rail, with separate AGND and DGND pins to maintain noise isolation. Power dissipation is 70 mW typical in active mode and drops to 105 μW maximum in auto-power-down (Mode 2), making it suitable for battery-powered or thermally sensitive applications without requiring split or negative supplies.