Analog Devices Inc. AD7381-4BCPZ-RL

Overview

AD7381-4BCPZ-RL from Analog Devices is a 14-bit, quad-channel, simultaneous-sampling SAR ADC with fully differential analog inputs, 4 MSPS throughput, ±1.5 LSB INL (max), and integrated 2.5 V reference (10 ppm/°C). It operates from −40°C to +125°C in motor control current sense and position feedback systems requiring precise multichannel synchronization.

For engineers reviewing the AD7381-4BCPZ-RL datasheet, AD7381-4BCPZ-RL pinout, AD7381-4BCPZ-RL application, or AD7381-4BCPZ-RL equivalent, this page delivers verified specifications, validated pin functions, confirmed oversampling behavior (up to 2-bit resolution boost), real-world SNR performance (90.6 dB at OSR = 8×), and exact thermal and timing constraints for embedded industrial designs.

Technical Context

The AD7381-4BCPZ-RL integrates four independent SAR cores sharing a common clock and CS-triggered acquisition, enabling true simultaneous sampling across all four differential input pairs (AINA± to AIND±). Its on-chip oversampling block supports both normal averaging and rolling average modes, delivering up to 2 extra effective bits at reduced bandwidths without external processing.

It features a buffered internal 2.5 V reference (10 ppm/°C max) and accepts external references from 2.5 V to 3.3 V via REFIO. The serial interface supports 1-wire, 2-wire, and 4-wire output modes with separate SDOA–SDOD pins, and includes ALERT functionality for out-of-range detection with sub-220 ns latency after CS assertion.

Key Specifications

Pinout & Package

AD7381-4BCPZ-RL uses a 4 mm × 4 mm, 24-lead LFCSP package with exposed pad (EPAD) requiring GND connection. Pin 1 is top-left corner (AIND−), and the EPAD must be soldered to a thermal GND plane for θJC = 0.432 °C/W operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7380-4BCPZ-RL, AD7381-4BCPZ-RL trades 2-bit resolution for 14% lower power and lower cost while retaining identical timing, oversampling flexibility, and thermal robustness. Versus AD7389-4BCPZ-RL, it delivers double the throughput and full rolling average support-critical for real-time control loops above 1 kHz bandwidth.

Availability

AD7381-4BCPZ-RL is available at Aetrix Electronics and suitable for motor control position feedback, motor control current sense, and data acquisition systems requiring stable component supply across automotive-grade temperature ranges and long production lifecycles.

Supply support for AD7381-4BCPZ-RL 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 and ISO 9001-certified manufacturing.

The AD7381-4BCPZ-RL belongs to Analog Devices' high-speed precision SAR ADC family, engineered specifically for industrial automation, motor control, and optical communications where simultaneous multichannel sampling, low latency, and wide temperature operation are mandatory.

FAQ

What is the maximum sampling rate supported by the AD7381-4BCPZ-RL?

The AD7381-4BCPZ-RL supports a maximum throughput rate of 4 MSPS per channel with simultaneous sampling across all four differential inputs. This is achieved using a 70 MHz SCLK with tSCLK = 12.5 ns minimum period and requires CLOAD ≤ 10 pF for SCLK ≥ 70 MHz. At this rate, conversion time is 190 ns and acquire time is 110 ns, enabling full 14-bit settling within each 250 ns cycle.

Does the AD7381-4BCPZ-RL include an internal voltage reference?

Yes, the AD7381-4BCPZ-RL integrates a buffered 2.5 V internal voltage reference with a maximum temperature coefficient of 10 ppm/°C and 7 µV rms noise. This reference is enabled by default and can be disabled to use an external reference from 2.5 V to 3.3 V applied to the REFIO pin. The internal reference output appears on REFCAP and must be decoupled with a 0.1 µF capacitor to GND.

How does the oversampling feature of the AD7381-4BCPZ-RL improve dynamic performance?

The AD7381-4BCPZ-RL implements two oversampling modes: normal averaging and rolling average. At OSR = 8× in rolling average mode, SNR improves from 85.3 dB to 90.6 dB - a 5.3 dB gain corresponding to ~0.9-bit ENOB increase. Combined with resolution boost, this yields up to 16-bit effective resolution at reduced bandwidth, lowering SCLK requirements and easing anti-alias filter design for applications like EDFA monitoring.

What is the purpose of the ALERT pin on the AD7381-4BCPZ-RL?

The ALERT pin (Pin 24, shared with SDOD) is an open-drain output that asserts low within 220 ns of the CS falling edge when any of the four channel conversion results exceed user-programmed high or low thresholds stored in Alert Threshold Registers. It provides hardware-level fault signaling without CPU polling, enabling immediate shutdown or correction in motor control safety chains.

Can the AD7381-4BCPZ-RL operate with different logic voltage levels?

Yes, the AD7381-4BCPZ-RL supports independent logic supply (VLOGIC) from 1.65 V to 3.6 V, allowing seamless interface with 1.8 V, 2.5 V, or 3.3 V digital controllers. Digital inputs (CS, SCLK, SDI) accept VIH = 0.8 × VLOGIC and VIL = 0.2 × VLOGIC, while digital outputs (SDOA–SDOD) drive VOH = VLOGIC − 0.3 V and VOL = 0.4 V, ensuring reliable level compatibility without external translators.