Analog Devices Inc. AD7876BNZ

Overview

AD7876BNZ from Analog Devices is a complete monolithic 12-bit successive approximation analog-to-digital converter (ADC) with integrated track-and-hold amplifier, laser-trimmed internal clock, and on-chip 3 V buried Zener reference. It supports ±10 V bipolar 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 AD7876BNZ datasheet, AD7876BNZ pinout, AD7876BNZ application, or AD7876BNZ equivalent, this page provides verified technical context, real-world interface timing constraints, confirmed SOIC-24 package mapping, and validated alternatives for ±10 V high-accuracy sampling ADC selection.

Technical Context

The AD7876BNZ 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 including ±1 LSB integral nonlinearity and ±6 LSB bipolar zero error over −40°C to +85°C.

It supports three digital output formats-12-bit parallel, two-byte, and serial-via configurable pins (12/8/CLK, HBEN, SSTRB, SCLK, SDATA). The internal clock is laser-trimmed to guarantee 6.5–9 μs conversion time; external clock override is supported via CLK pin. All logic interfaces meet TTL voltage thresholds and are production-tested for timing across temperature.

Key Specifications

Pinout & Package

AD7876BNZ 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 functions are electrically identical to the DIP version but mapped to SOIC physical layout per Figure 2 of Rev. C datasheet.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit, ±10 V sampling ADC applications.

Compared with AD7876BNZ, AD7870BNZ offers identical form-factor and interface but reduced input range, while ADS8505IPW trades integration and bipolar support for higher resolution and speed - making AD7876BNZ optimal for cost-sensitive, ±10 V industrial DAQ where self-contained operation is essential.

Availability

AD7876BNZ is available at Aetrix Electronics and suitable for industrial process monitoring, test & measurement equipment, motor drive current sensing, and power quality analyzers requiring stable component supply across extended temperature ranges.

Supply support for AD7876BNZ 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD787x family was designed specifically for industrial data acquisition systems requiring complete, low-power, ±10 V capable ADCs with microprocessor-compatible interfaces and guaranteed dc accuracy over wide temperature ranges.

FAQ

What is the maximum sampling rate achievable with AD7876BNZ?

The AD7876BNZ achieves a maximum sustained sampling rate of 100 kSPS. This is derived from its 8 μs maximum conversion time with a 2.5 MHz external clock, plus track-and-hold acquisition time ≤2 μs. At full throughput, the device supports full-power analog input signals up to 50 kHz while maintaining 12-bit accuracy and specified SNR performance. The AD7876BNZ datasheet confirms this rate under "General Description" and "Timing Characteristics" sections.

Does AD7876BNZ require external components for basic operation?

No, the AD7876BNZ is a complete monolithic ADC requiring only power supply decoupling capacitors for basic operation. It integrates a 12-bit SAR core, 2 μs track-and-hold amplifier, laser-trimmed internal clock oscillator, and 3 V buried Zener reference. No external op-amps, clock crystals, or reference ICs are needed. The AD7876BNZ datasheet explicitly states "requiring no external components apart from power supply decoupling capacitors" in the "Converter Details" section.

Can AD7876BNZ interface directly with an 8-bit microprocessor bus?

Yes, the AD7876BNZ supports direct 8-bit microprocessor interfacing via its byte-mode operation. When the 12/8/CLK pin is set to 0 V or −5 V and HBEN is controlled appropriately, the device outputs two 8-bit bytes (high byte and low byte) on DB7–DB0. This mode is fully documented in Table 6 and "Two-Byte Read Interfacing" section of the AD7876BNZ datasheet, with timing parameters like t3 (RD pulse width) and t6 (data access time) guaranteed across temperature.

What is the purpose of separate AGND and DGND pins on AD7876BNZ?

The AD7876BNZ uses separate AGND and DGND pins to isolate analog and digital ground return paths, minimizing noise coupling from digital switching into the sensitive analog front-end. AGND serves as the reference for the track-and-hold amplifier, DAC, and internal reference; DGND references the parallel/serial interface logic. The AD7876BNZ datasheet mandates separate grounding in "Layout Hints" and specifies that AGND and DGND must be connected at a single point near the device to maintain PSRR and SNR performance.

Is the internal reference of AD7876BNZ suitable for use as a system reference?

Yes, the AD7876BNZ's internal 3 V buried Zener reference (REF OUT) is specified for external use with up to 500 μA load current and ±10 mV initial accuracy. It features ±35 ppm/°C tempco (B/C grade), making it suitable as a stable system reference for other converters or analog circuitry. The AD7876BNZ datasheet provides explicit guidance in "Internal Reference" and "Generating a 5 V or 10 V Reference" sections, including decoupling recommendations (200 Ω + 10 μF || 0.1 μF) to suppress switching noise.