Analog Devices Inc. AD7812YN

Overview

AD7812YN from Analog Devices is a 10-bit, 8-channel sampling ADC with successive approximation architecture, onboard track-and-hold and 2.5 V ±2.5% internal reference, operating from 2.7 V to 5.5 V supply and delivering 350 kSPS throughput. It supports pseudo-differential or single-ended input configurations and features DSP/microcontroller-compatible serial interface for embedded data acquisition in automotive and industrial sensor systems.

For engineers reviewing the AD7812YN datasheet, AD7812YN pinout, AD7812YN application, or AD7812YN equivalent, key selection considerations include its 20-pin DIP package, 8 analog input channels with configurable topology, 2.3 µs conversion time, automatic power-down modes (down to 1 µA), and support for shared serial bus via A0 address pin in multi-ADC systems.

Technical Context

The AD7812YN implements a charge redistribution DAC-based successive approximation converter with integrated track-and-hold amplifier and programmable input multiplexer. Its control register enables software-configurable channel selection (CH2–CH0), differential/single-ended mode (DIF/SGL), reference source (EXTREF), and power-down state (PD1/PD0).

It uses a 3-wire serial interface with independent RFS (receive frame sync) and TFS (transmit frame sync), supporting simultaneous read/write operations and enabling two devices to share one serial bus via hardware-addressed A0 pin and software-addressed A0 bit in the control byte.

Key Specifications

Pinout & Package

AD7812YN is housed in a 20-lead plastic dual-in-line package (mini-DIP, N-20), with 0.3" body width and through-hole mounting. Pin spacing is 0.1" (2.54 mm), standard for legacy PCB layouts and prototyping.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit multi-channel ADC applications.

Compared with AD7812YR, AD7812YN offers identical electrical performance in a through-hole DIP package for prototyping and legacy systems; compared with AD7910BRMZ, AD7812YN provides integrated 8-channel multiplexing, internal reference, and bus-sharing capability at lower throughput-making it optimal for cost-sensitive, multi-sensor embedded systems.

Availability

AD7812YN is available at Aetrix Electronics and suitable for motor control feedback, automotive sensor hubs, industrial PLC I/O modules, and portable data loggers requiring stable component supply across long production lifecycles.

Supply support for AD7812YN 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, founded in 1965 and headquartered in Wilmington, MA.

The AD7812YN belongs to Analog Devices' legacy SAR ADC product line, designed specifically for cost-effective, low-power, multi-channel data acquisition in automotive, industrial, and instrumentation applications where integration and ease of use outweigh ultra-high-speed requirements.

FAQ

What is the maximum sampling rate supported by the AD7812YN?

The AD7812YN supports a maximum sampling rate of 350 kSPS, corresponding to a 2.3 µs conversion time. This rate is achievable across all eight input channels when using the internal clock and proper serial interface timing. At this rate, the device maintains specified dynamic performance including 58 dB SNR and –66 dB THD, making it suitable for medium-bandwidth signal acquisition in motor control and sensor monitoring applications. The AD7812YN achieves this while consuming only 10.5 mW at 3 V supply.

Does the AD7812YN require an external reference voltage?

No, the AD7812YN does not require an external reference voltage because it integrates a 2.5 V ±2.5% internal reference. This reference is enabled by default and powers down automatically when the EXTREF bit in the control register is set to 1 and an external source (1.2 V to VDD) is applied to the VREF pin. Using the internal reference simplifies design and reduces BOM count, while the option to switch to external reference allows improved accuracy or flexibility in systems where VDD is noisy or unstable. The AD7812YN's reference input range supports direct connection to VDD if needed.

How many analog input channels does the AD7812YN support, and how are they configured?

The AD7812YN supports eight analog input channels (VIN1–VIN8), configurable either as eight single-ended inputs referenced to AGND or as four independent pseudo-differential pairs (e.g., VIN1+/VIN2−). Configuration is controlled via the DIF/SGL and VIN8/AGND bits in the 10-bit control register, along with CH2–CH0 for channel selection. This flexibility eliminates the need for external differential amplifiers in many applications and allows mixed-mode acquisition-for example, measuring both single-ended thermistor outputs and differential bridge sensors on the same device. The AD7812YN's pinout dedicates pins 1–4 and 5–11 exclusively to analog inputs, confirming full 8-channel physical support.

Can multiple AD7812YN devices share the same serial interface bus?

Yes, two AD7812YN devices can share the same 3-wire serial interface bus using hardware and software addressing. Each device's A0 pin is hardwired to a unique logic level (high or low), and the control register includes an A0 address bit that must match the hardware setting for commands to be accepted. This allows independent configuration and readback without bus contention. The RFS pin further enables bus arbitration in multi-device systems. This capability is explicitly documented in the AD7812YN datasheet and verified in the functional block diagram and timing specifications-enabling scalable channel expansion, such as combining AD7812YN (8 ch) with AD7811YN (4 ch) for 12-channel solutions.

What power-saving modes are available on the AD7812YN?

The AD7812YN offers three power-saving modes: normal operation (3.5 mA at 3 V), partial power-down (350 µA), and full power-down (1 µA). Partial power-down retains the internal reference active, allowing faster wake-up; full power-down disables the reference and most circuitry, minimizing leakage. Both modes are triggered automatically at the end of conversion when PD1/PD0 bits are set accordingly in the control register-or forced manually via software. At 10 kSPS, average power drops to 315 µW, and at 1 kSPS to just 31.5 µW. These modes are validated across the full –40°C to +105°C temperature range and are integral to the AD7812YN's suitability for battery-powered and thermally constrained applications.