Analog Devices Inc. AD7381-4BCPZ

Overview

AD7381-4BCPZ 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 sensing and position feedback systems requiring precise multi-channel synchronization.

For engineers reviewing the AD7381-4BCPZ datasheet, AD7381-4BCPZ pinout, AD7381-4BCPZ application, or AD7381-4BCPZ equivalent, key selection considerations include simultaneous sampling integrity, oversampling-enabled SNR boost (up to 90.6 dB at OSR = 8×), 4 mm × 4 mm LFCSP package thermal performance, and ALERT threshold monitoring for real-time out-of-range detection.

Technical Context

The AD7381-4BCPZ integrates four independent SAR cores sharing a common clock and CS-controlled acquisition, enabling true simultaneous sampling across all four differential input pairs (AINA± to AIND±). Its internal 2.5 V reference delivers 7 µV_rms noise and supports external reference up to 3.3 V via REFIO.

Oversampling is implemented via configurable on-chip blocks supporting both normal averaging and rolling average modes, delivering up to 2-bit resolution enhancement and SNR improvement from 85.3 dB (base) to 90.6 dB (OSR = 8×, RES = 1). The serial interface supports 1-wire, 2-wire, and 4-wire output modes with SCLK frequencies up to 80 MHz and 1.8 V/2.5 V/3.3 V logic compatibility via separate VLOGIC supply.

Key Specifications

Pinout & Package

AD7381-4BCPZ uses a 4 mm × 4 mm, 24-lead lead frame chip scale package (LFCSP) with exposed pad (EPAD) requiring connection to GND for thermal and electrical integrity. Pin 1 is located at top-left per JEDEC MO-220 standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7381-4BCPZ, AD7380-4BCPZ provides higher resolution at the expense of increased power and cost, while AD7389-4BCPZ trades throughput for lower power-making AD7381-4BCPZ the optimal balance of speed, accuracy, and efficiency for 4 MSPS industrial sensing.

Availability

AD7381-4BCPZ is available at Aetrix Electronics and suitable for motor control systems, industrial data acquisition, optical amplifier monitoring, and high-reliability embedded sensing requiring stable component supply across extended temperature ranges.

Supply support for AD7381-4BCPZ 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The AD7381-4BCPZ belongs to Analog Devices' high-speed SAR ADC product line, designed specifically for demanding multi-channel, simultaneous-sampling applications in motor drives, energy systems, and precision instrumentation.

FAQ

What is the maximum sampling rate of the AD7381-4BCPZ?

The AD7381-4BCPZ achieves a maximum throughput rate of 4 MSPS (million samples per second) with full 14-bit resolution and simultaneous sampling across all four channels. This rate is maintained under specified conditions: VCC = 3.0 V to 3.6 V, VLOGIC ≥ 2.25 V, and no oversampling enabled. At this rate, the device delivers 85.3 dB SNR with VREF = 3.3 V and supports real-time capture of fast transient events in motor control and data acquisition systems.

Does the AD7381-4BCPZ support external reference voltage?

Yes, the AD7381-4BCPZ supports external reference voltage via the REFIO pin, accepting 2.5 V to 3.3 V with typical input current of 1.05 mA. When using an external reference, the internal 2.5 V reference is automatically disabled. The device maintains full specification compliance-including 84.5 dB SNR at 4 MSPS and ±1.5 LSB INL-with external references, provided proper decoupling (1 µF capacitor from REFIO to GND) is implemented per the datasheet layout guidelines.

How does the oversampling function improve performance in the AD7381-4BCPZ?

The AD7381-4BCPZ implements on-chip oversampling using configurable normal or rolling average modes, improving SNR by up to 5.3 dB (e.g., from 85.3 dB to 90.6 dB at OSR = 8×, RES = 1) and enabling up to 2-bit effective resolution enhancement. Oversampling reduces noise floor without increasing analog front-end complexity and lowers required SCLK frequency-critical for reducing EMI and simplifying PCB routing in dense industrial layouts.

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

The ALERT pin (Pin 24, shared with SDOD) is an open-drain output that asserts low when any of the four ADC channels produces a conversion result exceeding user-programmable high or low threshold registers. This hardware interrupt eliminates software polling overhead and enables immediate fault response-such as disabling IGBT gates in overcurrent conditions-within 220 ns of CS assertion, making it essential for safety-critical motor protection schemes.

Is the AD7381-4BCPZ pin-compatible with other devices in its family?

Yes, the AD7381-4BCPZ is pin-compatible with AD7380-4BCPZ (16-bit) and AD7389-4BCPZ (2 MSPS), sharing identical 24-lead LFCSP footprint, pin assignments, and register map. This allows direct substitution in existing PCB layouts when upgrading resolution or downgrading speed-provided power delivery, decoupling, and thermal design accommodate the respective current and thermal profiles of each variant.