Analog Devices Inc. AD7939BCPZ-REEL7

Overview

AD7939BCPZ-REEL7 from Analog Devices is a 10-bit, 8-channel, 1.5 MSPS successive approximation register (SAR) ADC with integrated channel sequencer and on-chip 2.5 V reference. It operates from a single 2.7 V to 5.25 V supply, supports software-configurable single-ended/pseudo-differential/fully differential inputs, and delivers 61 dB SINAD at 50 kHz input frequency in differential mode. It targets high-speed data acquisition in industrial PLC I/O modules.

For engineers reviewing the AD7939BCPZ-REEL7 datasheet, AD7939BCPZ-REEL7 pinout, AD7939BCPZ-REEL7 application, or AD7939BCPZ-REEL7 equivalent, key selection criteria include its 1.5 MSPS throughput with no pipeline delay, VDRIVE-independent 3 V/5 V parallel interface, 2 µA shutdown current, and LFCSP-32 package compatibility with space-constrained embedded systems.

Technical Context

The AD7939BCPZ-REEL7 implements a SAR architecture with a differential track-and-hold amplifier supporting up to 50 MHz full-power bandwidth. Its sequencer enables preprogrammed conversion of up to eight analog channels without host intervention, reducing microcontroller overhead in multi-sensor monitoring systems.

It features dual-supply flexibility: VDD powers analog/digital circuitry (2.7–5.25 V), while VDRIVE independently sets parallel I/O voltage levels (2.7–5.25 V), enabling direct interfacing with 3 V or 5 V processors regardless of VDD. The on-chip 2.5 V reference exhibits ±0.2% accuracy at 25°C and 25 ppm/°C drift, usable as either source or sink.

Key Specifications

Pinout & Package

AD7939BCPZ-REEL7 uses a 32-lead, 5 mm × 5 mm LFCSP package with exposed pad (CP-32-7). The package supports thermal dissipation up to 108.2°C/W (θJA) and requires soldering the EPAD to PCB ground plane via multiple vias per Analog Devices layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7939BCPZ-REEL7, AD7938BCPZ-REEL7 trades higher resolution and power for improved noise performance, while AD7934BRUZ-REEL7 sacrifices channel count and integration to reduce size and bill-of-materials cost-making each optimal for distinct system-level trade-offs in precision, density, and power.

Availability

AD7939BCPZ-REEL7 is available at Aetrix Electronics and suitable for industrial PLC analog input modules, motor drive feedback systems, portable power quality analyzers, and multi-sensor environmental monitoring nodes requiring stable component supply and long-term production continuity.

Supply support for AD7939BCPZ-REEL7 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 semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The AD7939 belongs to Analog Devices' precision SAR ADC product line, engineered for high-speed, low-power data acquisition in industrial automation, energy metering, and test equipment where accuracy, timing determinism, and integration are critical.

FAQ

What is the maximum sample rate of the AD7939BCPZ-REEL7?

The AD7939BCPZ-REEL7 achieves a maximum throughput rate of 1.5 MSPS under specified conditions (fCLKIN = 25.5 MHz, VDD = 2.7–5.25 V). This rate is sustained across all 8 input channels when using the internal sequencer, with conversion time fixed at 13 clock cycles plus t2 setup delay. Performance remains stable over the full −40°C to +85°C operating temperature range.

Does the AD7939BCPZ-REEL7 require an external reference voltage?

No, the AD7939BCPZ-REEL7 includes an accurate on-chip 2.5 V reference with ±0.2% initial accuracy at 25°C and 25 ppm/°C temperature coefficient. This internal reference can be used directly for analog-to-digital conversion. Alternatively, the VREFIN/VREFOUT pin accepts an external reference between 0.1 V and VDD, overriding the internal source when driven.

How does the AD7939BCPZ-REEL7 handle different analog input configurations?

The AD7939BCPZ-REEL7 supports single-ended, pseudo-differential, and fully differential inputs via software configuration of its control register. Single-ended mode uses VINx versus AGND; pseudo-differential allows VIN+ and VIN− with asymmetric common-mode ranges; fully differential requires matched VIN+/VIN− pairs referenced to VCM. Input ranges scale automatically based on the RANGE bit setting (0–VREF or 0–2×VREF).

What is the purpose of the VDRIVE pin on the AD7939BCPZ-REEL7?

The VDRIVE pin on the AD7939BCPZ-REEL7 sets the logic voltage level for the parallel data bus (DB0–DB11) and control signals (RD, WR, CS, etc.), independent of the main supply VDD. This allows the AD7939BCPZ-REEL7 to interface directly with 3 V or 5 V microprocessors without level shifters-even when VDD is set to a different voltage-ensuring robust signal integrity and simplified system design.

Can the AD7939BCPZ-REEL7 operate in low-power modes?

Yes, the AD7939BCPZ-REEL7 offers three power management states: Normal Mode (2.7 mA max at 5 V), Autostandby Mode (160 µA typ at 100 kSPS), and Full/Autoshutdown Mode (2 µA max). These modes are controlled via the on-chip control register and enable significant power savings during idle periods while retaining fast wake-up capability-critical for battery-operated instrumentation.