Microchip Technology 25C320-E/P

Overview

25C320-E/P from Microchip Technology Inc. is a 32 Kbit SPI serial EEPROM IC designed for nonvolatile data storage in embedded control systems. It features 4096 × 8-bit organization, 3 MHz max clock frequency at 4.5–5.5 V, 5 ms max write cycle time, and industrial/automotive temperature support (−40°C to +125°C). It is used in firmware parameter storage for programmable power supplies.

For engineers reviewing the 25C320-E/P datasheet, 25C320-E/P pinout, 25C320-E/P application, or 25C320-E/P equivalent, key selection criteria include VCC range (4.5–5.5 V), automotive-grade temperature operation, page-write capability (32-byte pages), hardware write protection via WP pin, and SPI interface timing compliance with Mode 0,0 and Mode 1,1.

Technical Context

The 25C320-E/P implements a standard SPI-compatible serial bus with separate SI (data in), SO (data out), SCK (clock), CS (chip select), HOLD (suspend), and WP (write-protect) signals. Its internal architecture includes an 8-bit instruction register, STATUS register with WIP/WEL/BP0/BP1 bits, and high-voltage generator for EEPROM programming.

It supports sequential read, byte/page write, and status register access. Write operations require explicit WREN instruction and CS high-to-low transition to initiate self-timed erase-and-write cycles. Block protection is configurable via BP0/BP1 bits to lock 0%, 25%, 50%, or 100% of the 4096-byte array.

Key Specifications

Pinout & Package

25C320-E/P is supplied in an 8-pin Plastic DIP (300 mil) package with through-hole mounting. Pin 1 is CS (Chip Select), pin 2 is SO (Serial Output), pin 3 is WP (Write-Protect), pin 4 is VSS (Ground), pin 5 is SI (Serial Input), pin 6 is SCK (Serial Clock), pin 7 is HOLD (Hold Input), and pin 8 is VCC (Supply Voltage).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25AA320-I/P and 25LC320-E/P, the 25C320-E/P delivers highest SPI throughput (3 MHz) and strictest 4.5–5.5 V supply constraint-making it optimal for legacy 5 V automotive modules where timing margin and noise immunity are prioritized over voltage flexibility.

Availability

25C320-E/P is available at Aetrix Electronics and suitable for industrial PLC configuration storage, automotive body control modules, medical infusion pump calibration, and smart energy meter firmware parameters requiring stable component supply and long-term lifecycle support.

Supply support for 25C320-E/P 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, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25C320 belongs to Microchip's legacy 25XX320 serial EEPROM product line, engineered for robust, low-power nonvolatile storage in 5 V embedded systems requiring automotive-grade reliability and SPI simplicity.

FAQ

What is the maximum clock frequency supported by the 25C320-E/P?

The 25C320-E/P supports a maximum clock frequency of 3 MHz when operated within its specified VCC range of 4.5 V to 5.5 V. This value is confirmed in the Device Selection Table and AC Characteristics section of the DS21227F datasheet. Operation above 3 MHz may result in timing violations and unreliable communication. The 25C320-E/P must not be used at 3 MHz outside this VCC window-the 25LC320-E/P variant supports only 2 MHz, and the 25AA320-I/P supports 1 MHz.

Does the 25C320-E/P support hardware write protection?

Yes, the 25C320-E/P supports hardware write protection using the WP (Write-Protect) pin in conjunction with the WPEN bit in the STATUS register. When WPEN = 1 and WP = low, writes to nonvolatile STATUS register bits are disabled-preventing accidental corruption of block protection settings. This feature is explicitly documented in Section 2.3 and Table 3-3 of the DS21227F datasheet. The 25C320-E/P implements this functionality identically to the 25AA320 and 25LC320 variants.

What package type is used for the 25C320-E/P?

The 25C320-E/P uses an 8-pin Plastic DIP (PDIP) package with 300 mil body width, as indicated by the "P" suffix in the part number per Microchip's Product Identification System (DS21227F, page 23). Pin 1 is CS, pin 4 is VSS, and pin 8 is VCC. This through-hole package is suitable for prototyping, legacy board upgrades, and applications requiring mechanical robustness. It is distinct from SOIC (SN), TSSOP (ST), and 14-lead TSSOP (ST14) variants.

How many bytes can be written in a single page write operation for the 25C320-E/P?

The 25C320-E/P supports up to 32 bytes per page write operation, as defined by its 32-byte page size. Writes crossing page boundaries will wrap to the start of the same page, overwriting previously written data. This constraint is enforced in hardware and documented in Section 3.3 (Write Sequence) of DS21227F. To avoid data loss, firmware must ensure all bytes in a page write reside within the same 32-byte aligned boundary (e.g., addresses 0x000–0x01F, 0x020–0x03F).

What is the endurance rating of the 25C320-E/P?

The 25C320-E/P has an endurance rating of 1 million erase/write cycles per memory location, as specified in Table 1-2 (AC Characteristics, Note 2) and confirmed in the Revision History (DS21227F, page 19). This value applies across the full operating temperature range (−40°C to +125°C) and is based on characterization-not 100% tested-but established per Microchip's Total Endurance™ Model. It exceeds the 100K-cycle rating of earlier revisions.