Analog Devices Inc. AD7621ACP

Overview

AD7621ACP from Analog Devices is a 16-bit, 3 MSPS, fully differential SAR analog-to-digital converter operating from a single 2.5 V supply. It features ±2 LSB INL, 2.048 V internal reference, no pipeline delay, and supports parallel (16-/8-bit) or SPI/QSPI/MICROWIRE-compatible serial interfaces - used in high-speed medical instrumentation and spectrum analysis systems.

For engineers reviewing the AD7621ACP datasheet, AD7621ACP pinout, AD7621ACP application, or AD7621ACP equivalent, key selection considerations include its warp/normal/impulse mode throughput scaling (3/2/1.25 MSPS), differential input range (±V_REF), 89 dB SINAD at 100 kHz, 5 ps rms aperture jitter, and dual LQFP/LFCSP package compatibility.

Technical Context

The AD7621ACP uses charge redistribution SAR architecture with no pipeline latency, enabling immediate data availability post-conversion. Its conversion control logic supports three distinct throughput-power trade-off modes: wideband warp (3 MSPS, highest linearity), normal (2 MSPS, rate-agnostic accuracy), and impulse (1.25 MSPS, power scaled linearly with sampling rate).

It integrates a trimmed 2.048 V bandgap reference (±7 ppm/°C drift), configurable reference buffer (REFBUFIN/REF), and dual-domain power supplies (AVDD/DVDD = 2.5 V, OVDD = 2.3–3.6 V) to isolate analog, core digital, and interface logic domains - critical for maintaining 89 dB SINAD and −101 dB THD in noisy mixed-signal environments.

Key Specifications

Pinout & Package

AD7621ACP is available in a 48-lead LFCSP (Lead Frame Chip Scale Package) with exposed thermal pad, optimized for low-inductance analog grounding and thermal dissipation in high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7621ACP, AD7677BCPZ trades internal reference and higher throughput for lower cost and simpler biasing, while AD7626BCPZ sacrifices throughput flexibility for better linearity and reference integration - making AD7621ACP optimal for systems needing dynamic speed/power adaptation without external reference components.

Availability

AD7621ACP is available at Aetrix Electronics and suitable for medical imaging data acquisition, digital oscilloscope front-ends, and communications baseband processing requiring stable component supply and long-term production continuity.

Supply support for AD7621ACP 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 AD7621ACP belongs to Analog Devices' PulSAR® family of precision SAR ADCs, designed specifically for high-speed, high-accuracy data acquisition in instrumentation, medical, and communications systems where low latency and excellent dynamic performance are essential.

FAQ

What is the maximum sampling rate of the AD7621ACP and under what conditions is it achieved?

The AD7621ACP achieves a maximum sampling rate of 3 MSPS in wideband warp and warp modes. This requires WARP = high and IMPULSE = high (for wideband) or IMPULSE = low (for warp), with proper timing alignment of CNVST pulses and BUSY-driven readout. The 3 MSPS rate is validated with internal reference enabled (PDREF = low), AVDD/DVDD = 2.5 V, and OVDD ≥ 2.3 V. At this rate, power dissipation is 65–86 mW and INL remains within ±2 LSB.

Does the AD7621ACP require an external reference, or does it have an internal one?

The AD7621ACP includes a factory-trimmed 2.048 V internal reference with ±7 ppm/°C temperature drift, accessible via the REF pin when PDREF and PDBUF are low. It also supports external reference operation (1.8 V to AVDD) by setting PDREF = high. The internal reference eliminates need for external components in most applications, while the external option enables higher precision or different voltage ranges - both configurations are fully supported in the AD7621ACP datasheet.

How does the AD7621ACP handle power management across different sampling rates?

The AD7621ACP implements three dedicated power-performance modes: wideband warp/warp (3 MSPS), normal (2 MSPS), and impulse (1.25 MSPS). In impulse mode, power scales linearly with throughput - dropping from 65 mW at 3 MSPS to ~37–50 mW at 1.25 MSPS. Power-down is further controlled via the PD pin, reducing consumption to 600 μW. All modes retain full 16-bit resolution and no missing codes, making AD7621ACP suitable for battery-powered or thermally constrained systems.

Can the AD7621ACP interface directly with a 3.3 V microcontroller without level shifters?

Yes, the AD7621ACP supports direct interfacing with 3.3 V microcontrollers via its OVDD supply (2.3–3.6 V range) and OVDD-referenced digital I/O. When OVDD = 3.3 V, the AD7621ACP outputs meet VOH ≥ 3.0 V and VOL ≤ 0.4 V under load, and accepts VIH ≥ 1.7 V and VIL ≤ 0.6 V - satisfying standard 3.3 V CMOS logic thresholds. No level shifters are needed for parallel or serial communication, provided OVDD is set to 3.3 V and AVDD/DVDD remain at 2.5 V.

What is the function of the TEMP pin on the AD7621ACP, and how is it calibrated?

The TEMP pin on the AD7621ACP provides an analog voltage proportional to die temperature: 273 mV at 25°C with sensitivity of 0.85 mV/°C. It is internally buffered and requires no external components. Calibration is factory-trimmed; users can compute temperature as T(°C) = (V_TEMP − 273 mV) / 0.85 mV/°C. This output enables real-time thermal monitoring for gain/offset drift compensation in precision systems - a feature confirmed in the AD7621ACP datasheet Rev. A, Page 4 and Page 10.