Analog Devices Inc. AD7876TQ

Overview

AD7876TQ from Analog Devices is a complete monolithic 12-bit successive approximation ADC with integrated track-and-hold amplifier, laser-trimmed internal clock, and on-chip 3 V buried Zener reference. It supports ±10 V bipolar analog input range, achieves 8 μs conversion time with external 2.5 MHz clock, and delivers 57 ns data access time for microprocessor interfacing in industrial data acquisition systems.

For engineers reviewing the AD7876TQ datasheet, AD7876TQ pinout, AD7876TQ application, or AD7876TQ equivalent, key selection considerations include its ±10 V input range compatibility, T-grade (−55°C to +125°C) operation, SOIC-24 package, and support for parallel/byte/serial digital interfaces without external timing components.

Technical Context

The AD7876TQ implements a SAR architecture with a fast-settling DAC, high-speed comparator, and internal 3 V temperature-compensated Zener reference. Its track-and-hold acquires signals to 12-bit accuracy in ≤2 μs, enabling full-power conversion up to 50 kHz while maintaining dc accuracy specifications including ±1 LSB integral nonlinearity and ±6 LSB bipolar zero error over temperature.

It operates from ±5 V supplies and uses a dual-ground architecture (AGND/DGND) with separate analog and digital power domains. The 12/8/CLK pin selects between 12-bit parallel, two-byte, or serial output formats, and the BUSY/INT pin provides asynchronous status signaling for real-time system coordination.

Key Specifications

Pinout & Package

AD7876TQ is housed in a 24-pin small outline integrated circuit (SOIC) package with 0.3-inch body width and standard 0.050-inch lead pitch. Pin 1 is identified by a notch or dot; the package is RoHS-compliant and rated for extended-temperature operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with AD7875TQ, AD7876TQ provides bipolar input capability critical for industrial transducers, while ADS8505IPFBT trades integration for higher resolution and modern serial interface-neither offers drop-in replacement due to input range or interface mismatch.

Availability

AD7876TQ is available at Aetrix Electronics and suitable for industrial process monitoring, aerospace sensor data acquisition, test & measurement equipment, and energy metering front-end designs requiring stable component supply across extended temperature ranges.

Supply support for AD7876TQ 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 AD7876TQ belongs to the AD787x LC2MOS 12-bit sampling ADC family, designed specifically for high-accuracy, low-power, and self-contained data acquisition in demanding industrial and military environments.

FAQ

What is the maximum sampling rate supported by the AD7876TQ?

The AD7876TQ achieves a maximum sampling rate of 100 kHz when using its internal or external 2.5 MHz clock, as conversion time is 8 μs max and track-and-hold acquisition adds ≤2 μs. This throughput enables full-power digitization of signals up to 50 kHz while maintaining 12-bit accuracy and specified SNR performance.

Does the AD7876TQ require external components to operate?

No, the AD7876TQ is a complete ADC requiring only ±5 V supply decoupling capacitors. It integrates a 3 V buried Zener reference, laser-trimmed clock oscillator, and 2 μs track-and-hold amplifier. External components like pull-up resistors (4.7 kΩ on SSTRB/SDATA, 2 kΩ on SCLK) are needed only for serial interface operation-not for basic parallel-mode functionality.

How does the AD7876TQ handle bipolar ±10 V inputs internally?

The AD7876TQ uses an internal resistor network (2.1R/7R/3R) shown in Figure 9 to scale the ±10 V input to match the 3 V reference range. This passive scaling ensures 1 LSB = 4.88 mV (20 V / 4096) and maintains twos-complement output coding, allowing direct interpretation of negative values without software sign extension or offset correction.

Can the AD7876TQ be used with a microcontroller lacking a parallel bus?

Yes, the AD7876TQ supports serial data output via SDATA, SCLK, and SSTRB pins. When 12/8/CLK is set to 0 V or −5 V, it outputs 12-bit serial data synchronized to SCLK falling edges while SSTRB is low-enabling interface with any microcontroller GPIO or UART peripheral capable of bit-banged SPI-like timing.

What is the purpose of the 12/8/CLK pin on the AD7876TQ?

The 12/8/CLK pin configures three distinct operating modes: at +5 V it enables 12-bit parallel output only; at 0 V it enables byte or serial output with gated SCLK; at −5 V it enables byte or serial output with continuous SCLK. This single pin eliminates external mode-select logic and simplifies hardware configuration across multiple interface requirements.