Microchip Technology 25LC320AT-E/ST

Overview

25LC320AT-E/ST from Microchip Technology Inc. is a 32-Kbit SPI Serial EEPROM with 4096 × 8-bit organization, 32-byte page size, and automotive-grade AEC-Q100 qualification for extended temperature operation (–40°C to +125°C). It features 10 MHz max clock speed at 4.5–5.5 V, self-timed 5 ms write cycles, and hardware write protection via dedicated WP pin and STATUS register control. Used in engine control units, ADAS sensor modules, and automotive infotainment firmware storage.

For engineers reviewing the 25LC320AT-E/ST datasheet, 25LC320AT-E/ST pinout, 25LC320AT-E/ST application, or 25LC320AT-E/ST equivalent, key selection criteria include its AEC-Q100 Extended Temp rating, 8-lead TSSOP package (ST), SPI interface timing compliance at 125°C, and block-level write protection granularity (none/1/4/1/2/all array).

Technical Context

The 25LC320AT-E/ST implements a standard SPI Mode 0,0 or Mode 1,1 serial interface with separate SI (data in) and SO (data out) lines, controlled by CS, SCK, HOLD, and WP signals. Its internal architecture includes an 8-bit instruction register, page latches, and high-voltage generator for EEPROM programming.

Write operations require explicit WREN instruction followed by CS high-to-low transition to initiate self-timed internal erase/write; read operations support sequential addressing with automatic address roll-over at 0FFFh. HOLD pin suspends ongoing transfers without resetting state, enabling interrupt servicing on host microcontrollers.

Key Specifications

Pinout & Package

25LC320AT-E/ST is packaged in an 8-lead TSSOP (ST) with 0.65 mm pitch, JEDEC MO-153 compliant, body size 4.4 mm × 3.0 mm × 1.2 mm. Pin 1 marked via notch or bevel; exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25LC320AT-I/ST, the 25LC320AT-E/ST adds AEC-Q100 Grade 1 qualification and guaranteed operation to +125°C - essential for powertrain and ADAS. Versus AT25DF321A-SH-B, it offers simpler SPI-legacy compatibility, deterministic 5 ms writes, and dedicated hardware protection - critical for functional safety-critical parameter storage.

Availability

25LC320AT-E/ST is available at Aetrix Electronics and suitable for automotive powertrain control, ADAS sensor calibration, and infotainment firmware storage requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 25LC320AT-E/ST 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 Inc. is a leading provider of microcontrollers, analog devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25LC320A family delivers automotive-qualified serial EEPROMs optimized for robust, low-power, SPI-based nonvolatile storage in harsh environments - targeting ECU, body control, and ADAS subsystems where data integrity and longevity are mission-critical.

FAQ

What is the maximum clock frequency supported by the 25LC320AT-E/ST across its full voltage and temperature range?

The 25LC320AT-E/ST supports up to 10 MHz at VCC = 4.5–5.5 V and TA = –40°C to +125°C. Frequency scales down to 5 MHz at VCC = 2.5–4.5 V and 3 MHz at VCC = 1.8–2.5 V. All AC timing parameters in DS20001828H Table 1-2 are specified across the full extended temperature range, ensuring reliable operation in automotive under-hood applications. The 25LC320AT-E/ST maintains timing compliance without derating at +125°C.

Does the 25LC320AT-E/ST support hardware write protection independent of software commands?

Yes. The 25LC320AT-E/ST implements dual-layer write protection: a dedicated WP pin and STATUS register bits (WPEN, BP0, BP1). When WP is low and WPEN = 1, writes to nonvolatile STATUS bits are blocked - preventing accidental corruption of protection settings during power transients. This hardware lock operates independently of WREN/WRDI commands and remains active even if the write enable latch is set. The 25LC320AT-E/ST datasheet confirms this behavior in Section 2.3 and Table 3-4.

How does the HOLD function operate during an active SPI read or write sequence on the 25LC320AT-E/ST?

The HOLD pin on the 25LC320AT-E/ST pauses serial communication mid-sequence without resetting internal state. When pulled low while SCK is low, SO immediately tri-states, and SI/SCK transitions are ignored - allowing the host MCU to service interrupts. Resuming requires HOLD high while SCK is low; communication continues from the exact bit position. Timing parameters THS and THH (Table 1-2) guarantee hold stability down to 1.8V. This behavior is fully documented for the 25LC320AT-E/ST in Figures 1-1 and Section 2.6.

What package type and footprint does the 25LC320AT-E/ST use, and is it RoHS-compliant?

The 25LC320AT-E/ST uses an 8-lead TSSOP package (ST suffix), JEDEC MO-153 compliant, with 4.4 mm × 3.0 mm body and 0.65 mm lead pitch. It is RoHS-compliant and AEC-Q100 qualified. Land pattern recommendations are provided in Microchip Drawing C04-2057-SN Rev F. The ST package is pin-compatible with other 8-lead TSSOP EEPROMs in the 25XX320A family, enabling layout reuse across temperature grades. No exposed pad is present.

Can the 25LC320AT-E/ST be used in systems requiring >1 million write cycles, and what is its data retention specification?

Yes. The 25LC320AT-E/ST is rated for >1 million erase/write cycles at +25°C and 5.5V (DS20001828H Table 1-2, Note 3), with characterization confirming robustness across temperature. Its data retention exceeds 200 years under normal operating conditions - verified per JEDEC standards. This endurance and retention meet ASIL-B functional safety requirements for automotive control modules. The 25LC320AT-E/ST specification sheet explicitly states both values in the Features section and Table 1-2.