Microchip Technology 25C320-I/SN

Overview

25C320-I/SN from Microchip Technology Inc. is a 32 Kbit (4096 × 8) SPI serial EEPROM designed for nonvolatile data storage in embedded control and industrial systems. It operates at 4.5–5.5 V, supports up to 3 MHz clock frequency, features 32-byte page write capability, 5 ms max internal write cycle time, and offers hardware write protection via WP pin and STATUS register. It is used in power metering firmware storage, sensor calibration retention, and configuration backup in programmable logic controllers.

For engineers reviewing the 25C320-I/SN datasheet, 25C320-I/SN pinout, 25C320-I/SN application, or 25C320-I/SN equivalent, this page delivers verified electrical specs, validated SOIC-8 pin mapping, confirmed automotive-grade temperature range (−40°C to +125°C), and real-world design implications of its HOLD/CS timing, block protection granularity, and SPI mode compatibility.

Technical Context

The 25C320-I/SN implements a standard SPI Mode 0,0 (CPOL = 0, CPHA = 0) interface with separate SI and SO lines, requiring CS assertion before any instruction sequence. Its internal architecture includes an 8-bit instruction register, auto-incrementing address pointer for sequential reads, and a STATUS register with WIP, WEL, BP0/BP1, and WPEN bits controlling write enable state and 0%, 25%, 50%, or 100% array protection.

Write operations require explicit WREN instruction followed by WRITE command and address/data; page writes are limited to 32 bytes within the same 32-byte-aligned boundary. The HOLD pin suspends ongoing transfers without resetting the internal state, enabling interrupt servicing while preserving SPI context - critical in real-time microcontroller applications with shared bus resources.

Key Specifications

Pinout & Package

25C320-I/SN is packaged in an 8-pin Plastic Small Outline Integrated Circuit (SOIC-8, 150 mil body), compliant with JEDEC MS-012AA. Pin 1 is marked with a dot or notch; package dimensions: 4.9 mm × 3.9 mm × 1.75 mm (max height).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 25LC320-I/SN and 25AA320-I/SN, the 25C320-I/SN delivers highest clock speed (3 MHz) and widest temperature range (−40°C to +125°C), making it optimal for high-throughput, thermally demanding automotive and industrial control applications - but requires strict adherence to 4.5–5.5 V rail regulation.

Availability

25C320-I/SN is available at Aetrix Electronics and suitable for industrial power metering, automotive engine control units, and programmable logic controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 25C320-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 components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 25C320 belongs to Microchip's legacy SPI Serial EEPROM product line, engineered for robust, low-cost nonvolatile storage in 5 V industrial and automotive systems where reliability and long-term data integrity are critical.

FAQ

What is the maximum clock frequency supported by the 25C320-I/SN?

The 25C320-I/SN supports a maximum clock frequency of 3 MHz when operated at VCC = 4.5–5.5 V. This specification is explicitly defined in the Device Selection Table and confirmed in Table 1-2 AC Characteristics. Exceeding 3 MHz may result in setup/hold violations or failed read/write operations. The 25C320-I/SN achieves this higher speed relative to 25AA320 (1 MHz) and 25LC320 (2 MHz) due to its 5 V optimized internal timing.

Does the 25C320-I/SN support hardware write protection?

Yes, the 25C320-I/SN supports hardware write protection via the WP pin in conjunction with the WPEN bit in the STATUS register. When WP is low and WPEN = 1, writes to nonvolatile STATUS register bits are disabled - protecting configuration lock bits while permitting memory writes. This dual-layer protection is documented in Section 2.3 and Table 3-3 of the datasheet. The 25C320-I/SN implements this feature identically to other 25XX320 family members.

What package type does the 25C320-I/SN use?

The 25C320-I/SN uses an 8-pin Plastic Small Outline Integrated Circuit (SOIC-8) package with 150 mil body width, designated by the "SN" suffix in the part number. This is confirmed in the Product Identification System section (DS21227F-page 23) and Package Types diagram (DS21227F-page 1). Pin 1 is marked with a dot or notch; the package is RoHS-compliant and Pb-free per JEDEC standards.

Can the 25C320-I/SN operate at 3.3 V?

No, the 25C320-I/SN is specified only for 4.5–5.5 V operation, as stated in the Device Selection Table and Electrical Characteristics sections. Attempting to power it at 3.3 V will result in undefined behavior, including failure to execute instructions, corrupted writes, or inability to enter standby mode. For 3.3 V systems, Microchip recommends the 25LC320-I/SN (2.5–5.5 V) or 25AA320-I/SN (1.8–5.5 V) instead.

What is the purpose of the HOLD pin on the 25C320-I/SN?

The HOLD pin on the 25C320-I/SN suspends ongoing SPI communication without resetting the internal state - allowing the host MCU to service higher-priority interrupts (e.g., timer overflow or CAN message arrival) and then resume exactly where the transfer left off. As described in Section 2.6 and Figure 1-1, HOLD must be asserted while SCK is low; doing so places SO in high-impedance and ignores SI/SCK transitions until HOLD is deasserted under the same condition. This functionality is fully implemented in the 25C320-I/SN.