Microchip Technology 25LC320T-I/SN

Overview

25LC320T-I/SN from Microchip Technology Inc. is a 32 Kbit SPI serial EEPROM with 4096 × 8-bit organization, 2.5–5.5 V supply range, and industrial temperature rating (−40°C to +85°C). It features 32-byte page write capability, 5 ms max internal write cycle time, and hardware write protection via WP pin and STATUS register. It is used in microcontroller-based systems for nonvolatile parameter storage, calibration data retention, and firmware configuration.

For engineers reviewing the 25LC320T-I/SN datasheet, 25LC320T-I/SN pinout, 25LC320T-I/SN application, or 25LC320T-I/SN equivalent, key selection criteria include SPI interface compatibility, 2.5 V minimum operating voltage, industrial-temperature reliability, and hardware block protection granularity (none/¼/½/all array).

Technical Context

The 25LC320T-I/SN implements a standard SPI Mode 0,0 interface with separate SI (data-in) and SO (data-out) lines, CS-controlled selection, and HOLD pin for transaction suspension. Its internal architecture includes an 8-bit instruction register, auto-incrementing address pointer for sequential reads, and a nonvolatile STATUS register with BP0/BP1 bits for configurable block protection.

Write operations require explicit WREN instruction followed by WRITE command and address/data; the write enable latch resets after each successful write or power-up. The device supports up to 2 MHz clock frequency at VCC ≥ 2.5 V and guarantees 1 million erase/write cycles with >200 years data retention.

Key Specifications

Pinout & Package

25LC320T-I/SN is packaged in an 8-pin plastic SOIC (150 mil body), surface-mount package with standard JEDEC MS-012AC footprint and RoHS-compliant matte tin lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25LC320T-I/SN, 25AA320T-I/SN enables lower-voltage operation but requires validation at 1.8 V, while 25LC320A-I/SN provides backward-compatible reliability upgrades and is Microchip's designated replacement for new designs.

Availability

25LC320T-I/SN is available at Aetrix Electronics and suitable for industrial control systems, medical instrumentation, automotive body electronics, and smart metering applications requiring stable component supply and long-term obsolescence management.

Supply support for 25LC320T-I/SN 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 25LC320 series belongs to Microchip's SPI serial EEPROM product line, designed specifically for reliable, low-power nonvolatile data storage in resource-constrained embedded systems across industrial, medical, and automotive markets.

FAQ

What is the maximum clock frequency supported by the 25LC320T-I/SN?

The 25LC320T-I/SN supports a maximum SPI clock frequency of 2 MHz when VCC is 2.5 V or higher. This specification is validated across the full industrial temperature range (−40°C to +85°C) and enables efficient data transfer without compromising timing margins. Operation above 2 MHz is not guaranteed and may result in communication errors or failed writes.

Does the 25LC320T-I/SN require external pull-up resistors on its SPI lines?

The 25LC320T-I/SN does not require external pull-ups on SI, SCK, or CS lines, as these inputs have internal weak pull-downs. However, SO and HOLD lines are open-drain capable and may require external pull-ups depending on system topology-particularly when shared with other SPI slaves or when using HOLD for interrupt arbitration. Refer to Microchip's AN865 for recommended values.

How does the HOLD function operate in the 25LC320T-I/SN during an active SPI transaction?

In the 25LC320T-I/SN, the HOLD pin suspends an ongoing SPI sequence when pulled low while SCK is low; SI, SCK, and SO enter high-impedance states, and the internal address pointer retains position. Resuming requires bringing HOLD high while SCK remains low. This allows the host MCU to service urgent interrupts without restarting the entire command sequence-critical for deterministic real-time response.

Can the 25LC320T-I/SN be used in automotive applications rated for −40°C to +125°C?

No-the 25LC320T-I/SN is specified only for the industrial temperature range (−40°C to +85°C), denoted by the 'I' suffix. For automotive-grade operation up to +125°C, Microchip offers the 25LC320-E/SN variant. Using the 25LC320T-I/SN outside its rated range risks parametric failure, reduced endurance, and invalidates qualification compliance for AEC-Q100 applications.

What happens to the write enable latch in the 25LC320T-I/SN after a successful write operation?

After a successful WRITE or WRSR instruction completes in the 25LC320T-I/SN, the write enable latch (WEL bit) is automatically reset to '0', disabling further writes until WREN is reissued. This safety mechanism prevents unintended overwrites due to noise or software faults. The latch is also reset on power-up and after WRDI execution, ensuring default write-protection at system startup.