Microchip Technology MCP3021A3T-E/OT

Overview

MCP3021A3T-E/OT from Microchip Technology is a 10-bit successive approximation ADC with I²C interface, single-ended analog input, on-chip sample-and-hold, and internal conversion clock. It operates from 2.7V to 5.5V, draws ≤250 µA during conversion and ≤1 µA in standby, and delivers up to 22.3 ksps in Fast-mode I²C (400 kHz) - ideal for battery-powered remote sensing and portable instrumentation.

For engineers reviewing the MCP3021A3T-E/OT datasheet, MCP3021A3T-E/OT pinout, MCP3021A3T-E/OT application, or MCP3021A3T-E/OT equivalent, key selection criteria include its SOT-23-5 package footprint, guaranteed ±1 LSB INL/DNL linearity over –40°C to +125°C, I²C addressability for multi-device bus configurations, and ultra-low power consumption enabling long-life operation in energy-constrained systems.

Technical Context

The MCP3021A3T-E/OT implements a classic SAR architecture with an integrated sample-and-hold capacitor and self-timed internal oscillator - decoupling conversion timing from I²C clock (SCL). Its straight-binary output format and fixed 10-bit resolution are synchronized to the master's I²C protocol, supporting both Standard (100 kHz) and Fast (400 kHz) modes without external timing components.

It functions as a slave-only I²C device with a base address of 1001xxx (A2–A0 configurable), where the R/W bit triggers conversion on logic '1'. No registers are writable; all communication is read-only, with acquisition initiated on the falling edge of the R/W bit - eliminating software configuration overhead and simplifying host firmware integration.

Key Specifications

Pinout & Package

Package: 5-pin SOT-23 - surface-mount, 2.9 mm × 1.6 mm × 1.1 mm profile optimized for space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit I²C ADC applications.

Compared with ADS7822UID and MCP3221A0T-E/OT, the MCP3021A3T-E/OT uniquely balances 10-bit precision, ultra-low standby current, and drop-in I²C integration - making it optimal for cost-sensitive, battery-limited designs requiring verified linearity and minimal firmware overhead.

Availability

MCP3021A3T-E/OT is available at Aetrix Electronics and suitable for data logging, handheld portable instrumentation, and multi-zone monitoring requiring stable component supply across automotive, industrial, and medical OEM programs.

Supply support for MCP3021A3T-E/OT 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

Microchip Technology is a U.S.-based semiconductor company specializing in microcontrollers, analog, and interface ICs for embedded control applications.

The MCP3021 product line delivers low-power, easy-to-integrate ADCs targeting space- and energy-constrained systems - emphasizing simplified I²C connectivity, guaranteed linearity, and extended temperature operation without calibration firmware.

FAQ

What is the maximum I²C clock frequency supported by the MCP3021A3T-E/OT?

The MCP3021A3T-E/OT supports I²C Fast mode up to 400 kHz, enabling a maximum sample rate of 22.3 ksps in continuous conversion mode. It also fully complies with I²C Standard mode (100 kHz) for backward compatibility with legacy controllers. Timing parameters including THIGH, TLOW, and TAA are specified across the full –40°C to +125°C range and 2.7V–5.5V supply, ensuring robust operation in diverse environments. The MCP3021A3T-E/OT does not require external clock sources or configuration registers to achieve these rates.

Does the MCP3021A3T-E/OT require external components for basic operation?

No, the MCP3021A3T-E/OT operates autonomously with only two external pull-up resistors on SDA and SCL - typically 2 kΩ for 400 kHz or 10 kΩ for 100 kHz - and bypass capacitors on VDD. It integrates an on-chip sample-and-hold circuit, conversion clock, and reference derived from VDD, eliminating external op-amps, capacitors, or crystal oscillators. This makes the MCP3021A3T-E/OT a true plug-and-play ADC solution with minimal external BOM.

How is the I²C address configured on the MCP3021A3T-E/OT?

The MCP3021A3T-E/OT uses a 7-bit I²C address formed by a fixed 4-bit device code (1001) followed by three programmable address bits (A2, A1, A0) tied to VDD or VSS. The default configuration (A2=1, A1=0, A0=1) yields address 0x4D. All eight combinations (0x48–0x4F) are valid, allowing up to eight devices on one bus. Address pins are sampled at power-up; no register writes or firmware initialization is needed. The MCP3021A3T-E/OT has no writable registers - every transaction is a read-only conversion request.

What is the analog input voltage range for the MCP3021A3T-E/OT?

The MCP3021A3T-E/OT accepts a single-ended analog input (AIN) from VSS to VDD - i.e., 0 V to the applied supply voltage - with no level-shifting required. Input leakage remains ≤±1 µA across –40°C to +125°C, preserving accuracy when interfacing high-impedance sources like thermistors or photodiodes. The device does not support negative inputs or rail-to-rail beyond VDD/VSS; exceeding VSS – 0.3 V or VDD + 0.3 V risks damage per absolute maximum ratings.

Is the MCP3021A3T-E/OT pin-compatible with other Microchip 10-bit I²C ADCs?

Yes, the MCP3021A3T-E/OT shares identical SOT-23-5 pinout and I²C protocol with the MCP3021 family variants (e.g., MCP3021A0T-E/OT, MCP3021A1T-E/OT), differing only in factory-programmed I²C address bits (A2–A0). It is not pin-compatible with the MCP3221 (12-bit) or MCP3421 (18-bit delta-sigma), which use different internal architectures and timing - though all share the same physical package and pin assignments. Firmware migration between MCP3021 variants requires only address byte adjustment.