Analog Devices Inc. AD7938BSUZ-6

Overview

AD7938BSUZ-6 from Analog Devices is a 12-bit, 8-channel, 625 kSPS successive approximation register (SAR) analog-to-digital converter with integrated channel sequencer, on-chip 2.5 V reference (±0.2% max at 25°C), and high-speed parallel interface supporting word/byte modes. It operates from a single 2.7 V to 5.25 V supply, consumes only 3.6 mW at 3 V/625 kSPS, and supports software-configurable single-ended, pseudo-differential, or fully differential input configurations - used in multichannel data acquisition systems for industrial process monitoring.

For engineers reviewing the AD7938BSUZ-6 datasheet, AD7938BSUZ-6 pinout, AD7938BSUZ-6 application, or AD7938BSUZ-6 equivalent, key selection criteria include guaranteed no-missed-codes performance (±0.95 LSB DNL in differential mode), 69 dB SINAD at 50 kHz, CONVST-triggered sampling control, VDRIVE-independent logic interface, and support for autostandby (160 μA typ) and full shutdown (2 μA max) power modes.

Technical Context

The AD7938BSUZ-6 implements a SAR architecture with a low-noise, wide-bandwidth track-and-hold amplifier capable of handling 50 MHz input frequencies. Its sequencer enables preprogrammed, automatic conversion across up to eight analog inputs without host intervention.

Conversion is initiated on the falling edge of CONVST; timing is governed by a 10 MHz master clock (CLKIN), with fixed 13-clock-cycle conversion time (t₂ + 13 t_CLKIN). The parallel interface supports both 12-bit word mode (DB0–DB11) and byte mode (DB0–DB7 + DB8/HBEN), with logic levels determined by VDRIVE - decoupled independently from VDD.

Key Specifications

Pinout & Package

AD7938BSUZ-6 is housed in a 32-lead TQFP package (SU-32-2) with exposed pad (EPAD) requiring connection to AGND/DGND plane via multiple vias. Pin 1 identifier located at top-left corner; pin functions validated per Analog Devices Rev. F datasheet Figure 3 and Table 5.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multichannel SAR ADC applications.

Compared with AD7938BCPZ-6, AD7938BSUZ-6 offers easier hand-soldering and higher thermal resistance tolerance; compared with AD7682BCPZ, it provides double the channel count, 2.5× higher throughput, and hardware sequencer autonomy - critical for deterministic multichannel acquisition.

Availability

AD7938BSUZ-6 is available at Aetrix Electronics and suitable for industrial process monitoring, motor control feedback, and portable test equipment requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for AD7938BSUZ-6 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 AD7938 family was designed for high-speed, multichannel data acquisition in industrial, instrumentation, and automation systems - emphasizing low power, flexible input configuration, and deterministic timing without pipeline latency.

FAQ

What is the maximum sampling rate supported by the AD7938BSUZ-6?

The AD7938BSUZ-6 supports a maximum throughput rate of 625 kSPS, achieved with a 10 MHz master clock (CLKIN) and 13-clock-cycle conversion time. This rate is maintained across its full operating temperature range (−40°C to +85°C) and supply range (2.7 V to 5.25 V), making AD7938BSUZ-6 suitable for real-time control applications requiring consistent timing margins.

Does the AD7938BSUZ-6 require an external reference voltage?

No, the AD7938BSUZ-6 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 - AD7938BSUZ-6 achieves full specified performance using its internal reference.

How does the channel sequencer in the AD7938BSUZ-6 operate?

The AD7938BSUZ-6 sequencer automatically cycles through up to eight analog input channels (VIN0–VIN7) in user-defined order without processor intervention. Channel sequence is programmed via the control register's SEQ and SHDW bits, and operation is enabled by setting the appropriate MODE bits. Once started, the sequencer performs consecutive conversions, reducing firmware overhead in multichannel DAQ systems using AD7938BSUZ-6.

Can the AD7938BSUZ-6 interface directly with a 3.3 V microcontroller?

Yes - the AD7938BSUZ-6 features a dedicated VDRIVE pin that sets the logic interface voltage independently of VDD. By connecting VDRIVE to 3.3 V, all digital I/O pins (DB0–DB11, RD, WR, CS, etc.) operate at 3.3 V logic levels, enabling direct, level-shift-free connection to 3.3 V microcontrollers even when VDD is 5 V - a key design advantage of AD7938BSUZ-6.

What power-saving modes does the AD7938BSUZ-6 support?

The AD7938BSUZ-6 offers three power management modes: Normal (1.5 mA max at 5 V), Autostandby (160 μA typ at 100 kSPS), and Full Shutdown (2 μA max). Autostandby automatically activates between conversions at reduced throughput rates, while Full Shutdown disables the analog core entirely. These modes are configured via the control register, allowing dynamic power optimization in battery-powered AD7938BSUZ-6 applications.