Analog Devices Inc. AD4021BCPZ-R2

Overview

AD4021BCPZ-R2 from Analog Devices is a 20-bit, 1 MSPS differential successive approximation register (SAR) analog-to-digital converter with Easy Drive architecture. It operates from a single 1.8 V supply, supports external reference voltages from 2.4 V to 5.1 V, delivers ±3.1 ppm INL and 100.5 dB SNR at 1 kHz, and targets precision data acquisition in automated test equipment and industrial instrumentation.

For engineers reviewing the AD4021BCPZ-R2 datasheet, AD4021BCPZ-R2 pinout, AD4021BCPZ-R2 application, or AD4021BCPZ-R2 equivalent, key selection considerations include its 1 MSPS throughput, high-Z mode input current reduction to 1 µA, 770 ns acquisition phase, SPI/QSPI/MICROWIRE-compatible interface, and 3 mm × 3 mm LFCSP-10 package with exposed pad grounded.

Technical Context

The AD4021BCPZ-R2 implements a differential SAR architecture with integrated input overvoltage clamp (±50 mA), span compression for single-supply operation, and programmable high-Z mode that extends acquisition time to ≥77% of cycle time. Its serial interface supports CS-mode (3-/4-wire) and daisy-chain configurations with status bit reporting and turbo mode enabled by default.

It features separate VDD (1.71–1.89 V) and VIO (1.71–5.5 V) supplies, enabling logic-level flexibility across 1.8 V/2.5 V/3 V/5 V hosts. The REF pin accepts 2.4–5.1 V external references, and the analog input range is ±VREF (or ±0.8×VREF with span compression), with common-mode range centered at VREF/2 ±125 mV.

Key Specifications

Pinout & Package

AD4021BCPZ-R2 is housed in a 3 mm × 3 mm, 10-lead LFCSP package (CP-10-9) with exposed pad connected to GND. The package supports reflow soldering per JEDEC J-STD-020 and offers θJA = 114°C/W under standard 2S2P JEDEC board conditions.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD4020BCPZ-R2 and AD4022BCPZ-R2, the AD4021BCPZ-R2 uniquely balances 1 MSPS throughput, 8.3–13 mW total power, and 770 ns acquisition time - making it the optimal choice for mid-speed precision acquisition where speed, noise, and power must coexist without compromise.

Availability

AD4021BCPZ-R2 is available at Aetrix Electronics and suitable for automated test equipment, industrial process monitoring, and medical diagnostic imaging requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for AD4021BCPZ-R2 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 R&D and manufacturing operations worldwide.

The AD4021BCPZ-R2 belongs to the Easy Drive SAR ADC family designed specifically for precision data acquisition systems where reduced input drive requirements, low power, and high DC/ac performance converge in compact packages.

FAQ

What is the maximum achievable throughput for AD4021BCPZ-R2 in CS mode with turbo enabled?

The AD4021BCPZ-R2 achieves a guaranteed 1 MSPS throughput in CS mode with turbo mode enabled. This requires a minimum SCK frequency of 40 MHz when VIO ≥ 2.7 V. At 1 MSPS, the acquisition phase is 770 ns and conversion time is 320 ns, ensuring first-conversion accuracy without pipeline delay. The AD4021BCPZ-R2 does not support 1.8 MSPS - that speed is exclusive to the AD4020BCPZ-R2 variant.

Does AD4021BCPZ-R2 require an external reference voltage, and what is its valid range?

Yes, the AD4021BCPZ-R2 requires an external reference voltage applied to the REF pin. The valid VREF range is 2.4 V to 5.1 V, referenced to GND. A 10 µF X7R ceramic capacitor must be placed close to the REF pin and GND for stability. The device supports both full-scale differential input ranges of ±VREF and compressed ranges of ±0.8×VREF, enabling flexible single-supply system design without negative rails.

How does the Easy Drive feature of AD4021BCPZ-R2 reduce system design complexity?

The Easy Drive feature of AD4021BCPZ-R2 reduces system design complexity by lowering input current to 1 µA at 1 MSPS and extending the acquisition phase to 770 ns - eliminating the need for high-output-current, high-bandwidth op-amp drivers in most applications. Its integrated input overvoltage clamp (±50 mA) also removes external protection diodes, and span compression allows full 20-bit code utilization using only a positive supply. These features collectively simplify signal chain layout, reduce BOM count, and improve channel density.

What digital interface protocols does AD4021BCPZ-R2 support, and how is mode selection handled?

The AD4021BCPZ-R2 supports SPI-, QSPI-, MICROWIRE-, and DSP-compatible serial interfaces. Interface mode is selected dynamically on the CNV rising edge: if SDI is high, CS mode (3- or 4-wire) activates; if SDI is low, daisy-chain mode engages. In CS mode, either CNV or SDI low enables SDO output and activates busy indicator functionality. All modes use 20-bit twos-complement data format and support status bit reporting for real-time diagnostics.

Is AD4021BCPZ-R2 pin-compatible with other members of the AD402x family, and what package does it use?

Yes, AD4021BCPZ-R2 is pin-compatible with AD4020BCPZ-R2 and AD4022BCPZ-R2, all sharing the same 10-lead LFCSP package (3 mm × 3 mm, CP-10-9). It is also pin-compatible with the AD4003/AD4007/AD4011 family, enabling drop-in upgrades in existing designs. The exposed pad must be connected to GND for optimal thermal and electrical performance, though operation remains functional without it per datasheet specification.