Analog Devices Inc. AD7854AD

Overview

AD7854AD from Analog Devices is a 12-bit, 200 kSPS sampling analog-to-digital converter (ADC) with pseudo-differential input, on-chip 2.5 V reference, and flexible parallel interface. It operates from a single 3 V to 5.5 V supply, supports unipolar (0 V to VREF) and bipolar (±VREF/2) input ranges, and features self- and system-calibration for precision in battery-powered instrumentation.

For engineers reviewing the AD7854AD datasheet, AD7854AD pinout, AD7854AD application, or AD7854AD equivalent, this page delivers verified specifications including conversion rate (200 kSPS), power dissipation (15 mW at 3 V), integral nonlinearity (±1 LSB), track-and-hold acquisition time (500 ns), and package mapping to 28-lead SOIC - all confirmed from Analog Devices' official AD7854/AD7854L Rev. B datasheet.

Technical Context

The AD7854AD implements a successive approximation register (SAR) architecture with integrated track-and-hold, charge redistribution DAC, and calibration memory. Its control logic supports software-triggered conversions via the CONVST bit in the write-only control register and enables multiple power-down modes through PMGT1/PMGT0 bits.

It uses a pseudo-differential input structure with AIN(+) and AIN(–), accepts external references from 1.2 V to AVDD, and outputs straight binary (unipolar) or two's complement (bipolar) data across DB0–DB11. The 28-pin SOIC package accommodates both 12-bit parallel reads and byte-mode access using HBEN for 8-bit bus compatibility.

Key Specifications

Pinout & Package

AD7854AD is packaged in a 28-lead small outline integrated circuit (SOIC) with 0.3-inch body width and standard JEDEC MS-013AC footprint. Pin functions are electrically validated per Analog Devices AD7854/AD7854L Rev. B datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7854LAR3, the AD7854AD delivers double the sampling rate and higher dynamic range but consumes ~2.7× more power in normal mode; compared with ADS7822U, it provides 4× resolution, parallel interface, on-chip reference, and calibration - making it suitable for precision, self-contained measurement systems rather than basic digitization.

Availability

AD7854AD is available at Aetrix Electronics and suitable for battery-powered medical instrumentation, portable data acquisition systems, pen-based computing interfaces, and high-speed modem analog front ends requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for AD7854AD 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 Wilmington, MA, with design centers worldwide.

The AD7854AD belongs to Analog Devices' precision SAR ADC product line, engineered for high-accuracy, low-power data acquisition in portable and embedded instrumentation where calibration integrity and supply flexibility are critical.

FAQ

What is the maximum sampling rate supported by the AD7854AD?

The AD7854AD supports a maximum sampling rate of 200 kSPS when operated with a 4 MHz master clock (CLKIN). This is achieved with a fixed conversion time of 18 clock cycles (t_CONVERT = 4.5 µs). The AD7854AD datasheet confirms this specification applies to the AD7854 variant - distinct from the AD7854L's 100 kSPS limit - and is valid across the full operating temperature range of –40°C to +85°C.

Does the AD7854AD include an internal voltage reference?

Yes, the AD7854AD integrates a 2.5 V bandgap reference with typical output of 2.3 V to 2.75 V (REFOUT) and 20 ppm/°C temperature coefficient. The REFIN/REFOUT pin serves as both output and input: it delivers the internal reference but can also accept an external reference from 1.2 V to AVDD, allowing system-level accuracy tuning. This dual-role capability is explicitly documented in the AD7854/AD7854L Rev. B datasheet.

How does the AD7854AD handle bipolar versus unipolar input configurations?

The AD7854AD supports both unipolar (0 V to VREF) and bipolar (±VREF/2) input ranges via the AMODE bit in its write-only control register. In unipolar mode (AMODE = 0), AIN(+) must remain ≥ AIN(–), and output coding is straight binary. In bipolar mode (AMODE = 1), AIN(–) must be biased to +VREF/2, and output coding switches to two's complement. These behaviors are defined in the "Analog Input" and "CONTROL REGISTER" sections of the AD7854AD datasheet.

Can the AD7854AD operate from a 3 V supply?

Yes, the AD7854AD is fully specified for operation from a single 3.0 V to 5.5 V supply applied to both AVDD and DVDD. At 3 V, it delivers 15 mW normal-mode power dissipation, 200 kSPS throughput, and maintains all AC/DC performance specs including ±1 LSB integral nonlinearity and 70 dB SNR. The absolute maximum rating allows up to +7 V, but functional operation is guaranteed only within the 3–5.5 V range per the AD7854AD datasheet.

What package type is used for the AD7854AD part number?

The AD7854AD is supplied in a 28-lead small outline integrated circuit (SOIC) package, designated as "R-28" in Analog Devices' ordering guide. This package matches the mechanical dimensions and pinout of industry-standard SOIC-28 (JEDEC MS-013AC), with 0.3-inch body width and 0.050-inch lead pitch. The pin configuration and thermal characteristics (θ_JA = 75°C/W) are fully detailed on page 6 of the AD7854/AD7854L Rev. B datasheet.