Analog Devices Inc. AD7828BQ

Overview

AD7828BQ from Analog Devices is an 8-channel, 8-bit LC2MOS analog-to-digital converter with built-in track-and-hold, single 5 V supply operation, ±1 LSB total unadjusted error, 2.5 µs conversion time per channel, and 0 V to 5 V analog input range. It serves as a multichannel data acquisition front-end in industrial monitoring systems requiring simultaneous sampling of eight sensor signals at up to 10 kHz bandwidth.

For engineers reviewing the AD7828BQ datasheet, AD7828BQ pinout, AD7828BQ application, or AD7828BQ equivalent, this page delivers verified technical context, package-specific pin functions, real-world use cases, and validated alternative parts - all grounded in the official Rev. F datasheet and Analog Devices' product documentation.

Technical Context

The AD7828BQ employs a half-flash architecture: two 4-bit flash ADCs (MSB and LSB) plus an internal 4-bit DAC reconstruct the input voltage for successive approximation. This eliminates external clock requirements and enables deterministic 2.5 µs conversion timing per selected channel.

It features an 8-channel analog multiplexer with address inputs A0–A2, open-drain RDY and INT outputs, three-state parallel data bus (DB0–DB7), and fully differential reference inputs (VREF(+) and VREF(–)) supporting ratiometric and bipolar configurations via external op-amp conditioning.

Key Specifications

Pinout & Package

AD7828BQ is packaged in a 28-lead plastic DIP (Q-28), 0.6" wide, with 0.1" lead pitch and JEDEC MS-011AB compliance. Pin 1 identifier is marked by a notch or dot; leads are tin-lead plated for standard soldering.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-channel, 8-bit ADC applications.

Compared with AD7828CQ, AD7828BQ trades 0.5 LSB accuracy for cost and availability advantages while retaining identical timing, interface, and thermal specs; compared with MAX195BCPP, AD7828BQ provides integrated 8-channel MUX, track-and-hold, and parallel interface - eliminating four external ICs and reducing layout complexity.

Availability

AD7828BQ is available at Aetrix Electronics and suitable for industrial process monitoring, motor control feedback, and multi-sensor data loggers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for AD7828BQ 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, founded in 1965 and headquartered in Wilmington, MA.

The AD7828BQ belongs to Analog Devices' legacy LC2MOS precision data acquisition family, designed specifically for cost-sensitive, space-constrained industrial systems needing multichannel 8-bit digitization with minimal external components.

FAQ

What is the maximum analog input frequency supported by the AD7828BQ without external sample-and-hold?

The AD7828BQ supports full-scale sinusoidal inputs up to 10 kHz without external sample-and-hold, based on its specified 157 mV/µs slew-rate capability and inherent track-and-hold function. This applies to each of its eight channels independently, enabling simultaneous acquisition of multiple high-bandwidth sensor signals while maintaining ±1 LSB accuracy.

Does the AD7828BQ require an external clock signal for conversion?

No, the AD7828BQ does not require an external clock signal. Its half-flash conversion architecture uses internal timing control triggered solely by CS and RD logic transitions. Conversion begins on the falling edge of CS (with RD low in Mode 0), and timing is fully self-contained - eliminating clock generation circuitry and associated jitter concerns.

Can the AD7828BQ operate with a reference voltage less than 5 V?

Yes, the AD7828BQ supports fully differential reference inputs (VREF(+) and VREF(–)), allowing user-defined spans such as 2.0 V or 2.5 V. For example, a 2.0 V reference yields 7.8 mV/LSB resolution, increasing sensitivity for low-amplitude signals while maintaining ratiometric accuracy when the reference shares a source with the analog signal chain.

What are the key differences between AD7828BQ and AD7828CQ?

The AD7828BQ and AD7828CQ share identical pinout, timing, package (Q-28), and operating temperature range (–40°C to +85°C), but differ in accuracy: AD7828BQ specifies ±1 LSB total unadjusted error, while AD7828CQ guarantees ±1/2 LSB. Both are drop-in replacements in hardware; firmware remains unchanged.

How does the AD7828BQ handle channel selection and conversion sequencing?

The AD7828BQ uses address inputs A0–A2 to select one of eight analog channels (AIN1–AIN8). In Mode 0, CS and RD both go low to initiate conversion and read data upon completion; in Mode 1, RD latches the address on its rising edge, reads prior conversion data, and starts a new conversion - requiring two consecutive reads for updated results.