Microchip Technology AT24C32E-SSHM-B

Overview

AT24C32E-SSHM-B from Microchip Technology is a 32-Kbit I²C-compatible serial EEPROM organized as 4,096 × 8 bits, operating from 1.7V to 3.6V across -40°C to +85°C, with hardware write protection (WP), 32-byte page write capability, and 1 MHz Fast Mode Plus support - used for nonvolatile configuration storage in microcontroller-based industrial sensors and embedded control modules.

For engineers reviewing the AT24C32E-SSHM-B datasheet, AT24C32E-SSHM-B pinout, AT24C32E-SSHM-B application, or AT24C32E-SSHM-B equivalent, key selection criteria include I²C bus voltage compatibility (1.7–3.6V), WP pin functionality for hardware lock, page write timing (≤5 ms), endurance (1M cycles), and SOIC-8 package mechanical fit in space-constrained PCB layouts.

Technical Context

The AT24C32E-SSHM-B implements a two-wire I²C interface with Schmitt-triggered SCL/SDA inputs and integrated noise filtering, supporting Standard (100 kHz), Fast (400 kHz), and Fast Mode Plus (1 MHz) clock rates depending on VCC level. Its memory array is segmented into 128 pages of 32 bytes each, enabling partial-page writes without erasing adjacent data.

It features an internal power-on reset (POR) circuit with 100 µs tPUP delay, automatic pull-down on A0/A1/A2/WP pins when floating, and open-drain SDA with external pull-up requirement (≤10 kΩ). Write protection is implemented via direct VCC/GND connection to the WP pin - no software enable required.

Key Specifications

Pinout & Package

AT24C32E-SSHM-B is supplied in an 8-lead SOIC package (SOIC-8, 150 mil width), with gull-wing leads and RoHS-compliant matte tin plating. Pin 1 is marked by a beveled corner or notch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial EEPROM applications.

Compared with M24C32-WMN6TP and CAT24C32HU4I-GT3, the AT24C32E-SSHM-B uniquely balances 1.7V operation, 1 MHz FM+ speed, and 0.8 µA standby in an industry-standard SOIC-8 - making it optimal for compact, low-power industrial controllers where voltage headroom and update latency are constrained.

Availability

AT24C32E-SSHM-B is available at Aetrix Electronics and suitable for industrial sensor calibration storage, microcontroller boot configuration, smart meter firmware patch storage, and medical device usage log applications requiring stable component supply, long-lifecycle assurance, and RoHS-compliant sourcing.

Supply support for AT24C32E-SSHM-B 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 devices, and memory solutions, with ISO 9001-certified manufacturing and global distribution infrastructure.

The AT24C32E-SSHM-B belongs to Microchip's AT24Cxx family of I²C serial EEPROMs, designed specifically for reliable, low-voltage nonvolatile data storage in space- and power-constrained embedded systems.

FAQ

What is the maximum I²C clock frequency supported by the AT24C32E-SSHM-B?

The AT24C32E-SSHM-B supports up to 1 MHz in Fast Mode Plus (FM+) when VCC is between 2.5V and 3.6V. At 1.7V–3.6V, it operates at 400 kHz (Fast Mode) and 100 kHz (Standard Mode). This graded speed support allows designers to maximize throughput in 3.3V systems while maintaining compatibility with legacy 1.8V controllers - all without changing firmware I²C timing registers.

Does the AT24C32E-SSHM-B require external pull-up resistors on SDA and SCL lines?

Yes, the AT24C32E-SSHM-B requires external pull-up resistors on both SDA and SCL lines because both pins are open-drain. Microchip specifies ≤10 kΩ for standard-mode operation and recommends lower values (e.g., 4 kΩ for 400 kHz, 1.3 kΩ for 1 MHz) to meet rise-time requirements. The AT24C32E-SSHM-B itself does not integrate pull-ups - omission will result in bus failure.

How does the write-protect (WP) pin function on the AT24C32E-SSHM-B?

The WP pin on the AT24C32E-SSHM-B provides hardware-level write inhibition: when pulled to VCC, it disables all write operations to the entire memory array; when grounded, writes are enabled. If left floating, the internal strong pull-down defaults WP to GND - but Microchip recommends explicit biasing to prevent noise-induced glitches. This feature enables safe field upgrades without software vulnerabilities.

What is the memory organization of the AT24C32E-SSHM-B, and how does it affect write efficiency?

The AT24C32E-SSHM-B organizes its 32-Kbit array into 128 pages of 32 bytes each. This structure enables 32-byte page writes - allowing up to 32 bytes to be written in a single I²C transaction with ≤5 ms completion time. Partial-page writes are permitted, so updating a single register doesn't require reading-modifying-writing an entire page - significantly improving efficiency in dynamic configuration storage.

Is the AT24C32E-SSHM-B compatible with other AT24Cxx EEPROMs in terms of pinout and addressing?

Yes, the AT24C32E-SSHM-B uses the same 8-pin SOIC footprint and identical I²C addressing scheme (1010xxx) as other AT24Cxx devices like AT24C02 and AT24C16. A0–A2 pins determine the 3 LSBs of the 7-bit slave address, enabling up to eight devices on one bus. However, memory size and page boundaries differ - firmware must validate page length (32 bytes) and total address space (0x0000–0x0FFF) to avoid wraparound errors.