Microchip Technology 25LC320A-E/MS

Overview

25LC320A-E/MS from Microchip Technology is a 32-Kbit SPI Serial EEPROM with 4096 × 8-bit organization, 32-byte page size, and automotive-grade Extended temperature support (–40°C to +125°C). It operates at up to 10 MHz clock frequency, features hardware write protection via WP pin and STATUS register, and delivers 1 million erase/write cycles with >200-year data retention. It is used in engine control units, ADAS sensor modules, and automotive infotainment systems for nonvolatile configuration storage.

For engineers reviewing the 25LC320A-E/MS datasheet, 25LC320A-E/MS pinout, 25LC320A-E/MS application, or 25LC320A-E/MS equivalent, key selection criteria include its AEC-Q100 qualification, 2.5V–5.5V VCC range, HOLD pin support for interrupt-safe SPI pausing, and block-level write protection covering 0%, 25%, 50%, or 100% of memory array.

Technical Context

The 25LC320A-E/MS implements a standard SPI Mode 0,0/Master-Slave interface with separate SI (data-in) and SO (data-out) lines, requiring CS, SCK, SI, SO, WP, HOLD, VCC, and VSS. Its internal architecture includes an 8-bit instruction register, page latches, HV generator for EEPROM programming, and status-controlled write-enable logic.

Write operations require explicit WREN instruction followed by CS high-to-low transition to initiate self-timed internal write cycle (≤5 ms), while read operations support sequential addressing with automatic address roll-over at 0FFFh. The HOLD pin suspends ongoing SPI transfers without resetting state, enabling deterministic host interrupt handling.

Key Specifications

Pinout & Package

25LC320A-E/MS uses an 8-lead MSOP (150 mil) package with exposed pad (optional VSS connection), footprint-compatible with SOIC and TSSOP variants but with reduced board area (3.0 mm × 3.0 mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25LC320A-E/MS, the 25AA320A-I/MS offers broader voltage flexibility but sacrifices automotive qualification, while the AT25DF041A-SSH-T provides greater capacity at the cost of interface compatibility and deterministic interrupt handling-making 25LC320A-E/MS optimal for AEC-Q100-compliant, interrupt-sensitive, medium-density EEPROM needs.

Availability

25LC320A-E/MS is available at Aetrix Electronics and suitable for automotive powertrain control, ADAS sensor calibration, and infotainment personalization requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 25LC320A-E/MS 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 microcontroller, analog, FPGA, and memory solutions, serving automotive, industrial, communications, and consumer markets with vertically integrated silicon and development tools.

The 25LC320A-E/MS belongs to Microchip's AEC-Q100-qualified serial EEPROM product line, engineered specifically for automotive subsystems requiring guaranteed data integrity, extended temperature operation, and robust SPI interface behavior in safety-critical environments.

FAQ

What is the maximum clock frequency supported by the 25LC320A-E/MS?

The 25LC320A-E/MS supports up to 10 MHz clock frequency when VCC is 4.5V to 5.5V. At 2.5V ≤ VCC < 4.5V, the maximum clock drops to 5 MHz, and at 1.8V ≤ VCC < 2.5V (not applicable to 25LC320A-E/MS due to its 2.5V min VCC), it would be 3 MHz. This scaling ensures timing margin across voltage variations in automotive electrical systems.

Does the 25LC320A-E/MS require external pull-up resistors on its SPI lines?

The 25LC320A-E/MS does not require external pull-ups on SI, SCK, or CS for basic operation, as these inputs have CMOS-compatible thresholds. However, SO and HOLD are open-drain capable and may need pull-ups in multi-drop bus configurations or noise-prone environments. WP and HOLD should be actively driven or pulled to defined states (VCC or VSS) in production designs to prevent floating-induced erratic behavior.

How does the HOLD function operate during an active SPI transaction in the 25LC320A-E/MS?

The HOLD function in the 25LC320A-E/MS pauses an ongoing SPI sequence without resetting internal state: SO tri-states immediately on HOLD low, SI and SCK transitions are ignored, and communication resumes from the exact bit position when HOLD returns high while SCK is low. This enables deterministic host interrupt handling without retransmitting commands or addresses.

What write protection mechanisms are implemented in the 25LC320A-E/MS?

The 25LC320A-E/MS implements three-tiered write protection: (1) software-controlled WREN/WRDI latch, (2) STATUS register BP0/BP1 bits for 0%/25%/50%/100% array block locking, and (3) hardware WP pin + WPEN bit enabling physical write-disable independent of firmware state. All layers remain active during power cycling and brown-out events.

Is the 25LC320A-E/MS pin-compatible with other Microchip 32-Kbit SPI EEPROMs like the 25AA320A?

Yes, the 25LC320A-E/MS is pin-compatible with the 25AA320A-I/MS and other 8-lead MSOP variants in the 25XX320A family, sharing identical pinout, package dimensions, and SPI instruction set. However, differences in VCC range (2.5V–5.5V vs. 1.8V–5.5V) and temperature grade (Extended vs. Industrial) require validation of system-level voltage and thermal margins before substitution.