Analog Devices Inc. AD7895AR-2REEL

Overview

AD7895AR-2REEL from Analog Devices is a 12-bit, single-supply successive-approximation analog-to-digital converter (ADC) with integrated track/hold amplifier, on-chip clock, and high-speed serial interface. It operates from +5 V ±5%, delivers 3.8 µs conversion time in Mode 1, supports 0 V to +2.5 V unipolar input range, and consumes ≤20 mW. It is used in precision data acquisition systems requiring compact size and low power, such as portable instrumentation and industrial sensor interfaces.

For engineers reviewing the AD7895AR-2REEL datasheet, AD7895AR-2REEL pinout, AD7895AR-2REEL application, or AD7895AR-2REEL equivalent, key selection considerations include its straight-binary output coding, 0–2.5 V input range, SOIC-8 package, 15 MHz max SCLK compatibility, and automatic power-down mode for battery-sensitive designs.

Technical Context

The AD7895AR-2REEL implements a laser-trimmed internal clock driving a 12-bit R-2R ladder SAR core, with on-chip track/hold enabling full-scale sine wave digitization up to >100 kHz input bandwidth. Its analog front-end accepts 0 V to +2.5 V directly at VIN with <500 nA input current and no external scaling resistors.

It features two operating modes: Mode 1 (high-speed, 3.8 µs conversion, BUSY active during conversion) and Mode 2 (auto-sleep after conversion, 9.8 µs total cycle including 6 µs wake-up). Serial data output is 16-bit (4 leading zeros + 12-bit result), valid on falling SCLK edge, with 10 ns hold time and 603 ns bus relinquish time.

Key Specifications

Pinout & Package

AD7895AR-2REEL is housed in an 8-pin SOIC (SO-8) package, 3.9 mm × 4.9 mm body, 1.27 mm pitch, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7895AR-2REEL, AD7894ARZ-10 offers higher resolution but demands bipolar signal conditioning and firmware adaptation, while ADS7822U supports lower supply voltages but shifts track/hold design responsibility to the system engineer - making AD7895AR-2REEL optimal for 5 V, 0–2.5 V, space-constrained applications needing integrated signal conditioning.

Availability

AD7895AR-2REEL is available at Aetrix Electronics and suitable for portable instrumentation, industrial sensor interfaces, and medical monitoring equipment requiring stable component supply and long-term manufacturability.

Supply support for AD7895AR-2REEL 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 AD7895 belongs to Analog Devices' precision data acquisition ADC family, designed specifically for space-constrained, low-power, single-supply systems requiring integrated track/hold and serial interface - targeting portable, industrial, and medical measurement applications.

FAQ

What is the input voltage range supported by the AD7895AR-2REEL?

The AD7895AR-2REEL supports a unipolar analog input range of 0 V to +2.5 V. This is fixed for the "-2" variant and does not require external scaling resistors. The input presents high impedance (<500 nA bias current) and connects directly to the on-chip track/hold amplifier. Operation outside this range may cause damage or invalid conversion results.

Does the AD7895AR-2REEL require an external clock source?

No, the AD7895AR-2REEL contains a laser-trimmed on-chip oscillator that generates the internal conversion clock. Only an external serial clock (SCLK) is required for data readout - up to 15 MHz - and this clock does not affect conversion timing. The internal clock ensures consistent 3.8 µs conversion time across temperature and supply voltage variations.

What is the output data format of the AD7895AR-2REEL?

The AD7895AR-2REEL outputs data in straight (natural) binary format, not 2's complement. Each conversion yields a 16-bit serial frame: four leading zero bits followed by the 12-bit result. For example, a full-scale input (2.5 V) produces "0000 1111 1111 1111". This simplifies firmware interpretation in microcontrollers without sign-extension logic.

How does the power-down mode work on the AD7895AR-2REEL?

In Mode 2 (auto-sleep), the AD7895AR-2REEL automatically enters power-down after conversion completes (when BUSY goes low), reducing supply current to ≤5 µA. It "wakes up" upon the rising edge of CONVST, with a 6 µs wake-up time before the next conversion starts. This mode cuts average power significantly in low-duty-cycle applications without software overhead.

Can the AD7895AR-2REEL be used with a 3.3 V microcontroller interface?

Yes - the AD7895AR-2REEL's digital outputs (SDATA, BUSY) are CMOS-compatible and specified for VOH ≥4.0 V (at 200 µA) and VOL ≤0.4 V (at 1.6 mA) with VDD = 5 V. These levels safely interface with 3.3 V logic inputs when using appropriate pull-up/pull-down or level-shifter circuits. However, SCLK must remain within 0–5 V limits; direct 3.3 V SCLK is acceptable per input voltage specs (VINL ≤0.8 V, VINH ≥2.4 V).