Analog Devices Inc. AD7934BRU

Overview

AD7934BRU from Analog Devices is a 12-bit, 4-channel, 1.5 MSPS successive approximation register (SAR) analog-to-digital converter with integrated channel sequencer, on-chip 2.5 V reference (±0.2% max @ 25°C), and parallel word/byte interface. It operates from a single 2.7 V to 5.25 V supply, supports single-ended/pseudo-differential/differential input configurations, and delivers 70 dB SINAD at 50 kHz - used in high-speed data acquisition systems for industrial process control and motor feedback.

For engineers reviewing the AD7934BRU datasheet, AD7934BRU pinout, AD7934BRU application, or AD7934BRU equivalent, key selection criteria include its 12-bit resolution with no missing codes, sequenced multi-channel sampling without pipeline delay, VDRIVE-independent 3 V/5 V interface compatibility, and low-power operation (6 mW max at 3 V, 1.5 MSPS).

Technical Context

The AD7934BRU implements a SAR architecture with a differential track-and-hold amplifier supporting up to 50 MHz input bandwidth and 72 ps aperture jitter. Its internal sequencer enables preprogrammed channel cycling across VIN0–VIN3 without host intervention, while the control register configures input mode (single-ended/differential), range (0–VREF or 0–2×VREF), output coding (straight binary/twos complement), and power modes.

Conversion is initiated by a falling edge on CONVST, with timing synchronized to CLKIN (25.5 MHz typical); result availability is signaled via BUSY, and data is read via CS/RD-controlled parallel bus. The VDRIVE pin decouples logic interface voltage from VDD, enabling direct interfacing to 3 V or 5 V microprocessors independent of analog supply.

Key Specifications

Pinout & Package

AD7934BRU is housed in a 28-lead TSSOP package (JEDEC MO-153, 4.4 mm × 9.7 mm body, 0.65 mm pitch), optimized for mixed-signal PCB layout with separate AGND/DGND pins and dedicated decoupling recommendations (0.1 μF + 10 μF on VDD, 470 nF on VREFIN/VREFOUT).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed SAR ADC applications.

Compared with AD7934BRU, AD7933BRU trades 2-bit resolution and 9 dB SINAD for lower cost and identical integration, while AD7934-6BRU sacrifices throughput for reduced power and relaxed timing - neither is pin-compatible nor functionally identical without firmware timing adjustments.

Availability

AD7934BRU is available at Aetrix Electronics and suitable for industrial motor control, power quality monitoring, medical ultrasound beamforming, and automated test equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for AD7934BRU 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, with design centers worldwide.

The AD793x family was designed specifically for high-speed, low-power, multi-channel data acquisition in space-constrained industrial and instrumentation systems - emphasizing integration, configurability, and ease of microprocessor interfacing.

FAQ

What is the maximum sampling rate supported by the AD7934BRU?

The AD7934BRU supports a maximum throughput rate of 1.5 MSPS, achieved with a 25.5 MHz master clock (CLKIN) and confirmed in the AD7934 specifications table. This rate is sustained across all input configurations (single-ended, pseudo-differential, differential) and supply voltages (2.7 V to 5.25 V), with conversion time defined as t2 + 13 tCLK.

Does the AD7934BRU require an external reference voltage?

No, the AD7934BRU includes an accurate on-chip 2.5 V reference with ±0.2% maximum initial error at 25°C and 25 ppm/°C temperature coefficient. The VREFIN/VREFOUT pin can be used as a reference output or overdriven with an external reference (0.1 V to VDD), but external reference is optional - the internal reference meets full 12-bit accuracy specifications.

How does the channel sequencer operate in the AD7934BRU?

The AD7934BRU's on-chip sequencer automatically cycles through up to four analog input channels (VIN0–VIN3) in user-defined order without host processor involvement. Sequencing behavior is configured via the control register's SEQ bit and channel address bits; once enabled, consecutive conversions occur on falling edges of CONVST, eliminating software polling overhead in multi-sensor systems.

What are the logic voltage requirements for interfacing with the AD7934BRU's parallel bus?

The AD7934BRU uses the VDRIVE pin to define logic thresholds independently of VDD: digital inputs (CS, RD, WR, CONVST, etc.) recognize VIH ≥ 2.4 V and VIL ≤ 0.8 V, while outputs (DB0–DB11, BUSY) drive VOH ≥ 2.4 V (at 200 μA) and VOL ≤ 0.4 V (at 200 μA). This allows direct connection to 3 V or 5 V processors without level translation.

Can the AD7934BRU operate with a single 3.3 V supply?

Yes, the AD7934BRU operates with VDD from 2.7 V to 5.25 V, including standard 3.3 V supplies. At 3.3 V, it delivers 6 mW maximum power dissipation at 1.5 MSPS, maintains full 12-bit performance (70 dB SINAD, ±1 LSB INL), and supports all input configurations. VDRIVE may also be set to 3.3 V for 3.3 V logic interfacing.

What is the purpose of the W/B (Word/Byte) pin on the AD7934BRU?

The W/B pin selects parallel data transfer mode: logic high enables 12-bit word mode (DB0–DB11 active), while logic low enables byte mode (DB0–DB7 carry data + channel ID, DB8/HBEN becomes high-byte enable). Byte mode reduces bus width requirements and simplifies interface to 8-bit microcontrollers, with channel identification embedded in DB4–DB5 during reads.