Microchip Technology 25LC320AT-H/SN

Overview

25LC320AT-H/SN from Microchip Technology is a 32-Kbit SPI serial EEPROM organized as 4,096 × 8-bit memory, supporting byte- and page-write operations with 32-byte page size, 5 MHz max clock (at V_CC ≥ 4.5V), and extended temperature operation from –40°C to +150°C. It features hardware write protection via WP pin and STATUS register, HOLD functionality for interrupt-safe bus suspension, and AEC-Q100 qualification for automotive under-hood applications.

For engineers reviewing the 25LC320AT-H/SN datasheet, 25LC320AT-H/SN pinout, 25LC320AT-H/SN application, or 25LC320AT-H/SN equivalent, key selection criteria include high-temp SPI EEPROM compatibility, block-level write protection granularity, internal 6 ms write cycle timing, and SOIC-8 packaging with RoHS-compliant matte tin finish.

Technical Context

The 25LC320AT-H/SN implements a standard SPI Mode 0,0 interface with separate SI (data in) and SO (data out) lines, CS-controlled device selection, and SCK-synchronized data transfer-latching on rising edge (SI) and updating on falling edge (SO). Its internal architecture includes an 8-bit instruction register, status register with WIP/WEL/BP0/BP1 bits, and HV generator for EEPROM programming.

Write operations require explicit WREN instruction before WRITE or WRSR commands; CS must be raised after final data bit to initiate the self-timed 6 ms internal write cycle. The HOLD pin suspends ongoing serial sequences without resetting address pointers, enabling deterministic interrupt handling in real-time microcontroller systems.

Key Specifications

Pinout & Package

8-Lead SOIC (SN) package: narrow-body, 3.90 mm × 4.90 mm footprint, 1.27 mm pitch, matte tin (Sn) lead finish, RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT25DF321A-SHN-T and BR24G32FJ-3GE2, the 25LC320AT-H/SN uniquely delivers AEC-Q100 Grade 0 qualification, dedicated HOLD and WP pins, and guaranteed operation across –40°C to +150°C-making it the only viable option for under-hood automotive and high-reliability industrial control EEPROM needs.

Availability

25LC320AT-H/SN is available at Aetrix Electronics and suitable for automotive engine management, industrial programmable logic controllers, and medical infusion pump designs requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for 25LC320AT-H/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 25LCxxx family was designed specifically for robust, high-temperature SPI EEPROM applications in automotive, industrial, and aerospace systems-emphasizing data integrity, long-term retention, and interface simplicity.

FAQ

What is the maximum clock frequency supported by the 25LC320AT-H/SN?

The 25LC320AT-H/SN supports a maximum clock frequency of 5 MHz when V_CC is between 4.5V and 5.5V. At lower supply voltages (2.5V ≤ V_CC < 4.5V), the maximum clock rate is reduced to 3 MHz. These limits are defined in Table 1-2 of the DS20002131D datasheet and reflect guaranteed AC timing performance across the full –40°C to +150°C operating range. Exceeding these frequencies may result in unreliable read/write behavior.

Does the 25LC320AT-H/SN support page write operations, and what is its page size?

Yes, the 25LC320AT-H/SN supports page write operations with a fixed page size of 32 bytes. This allows up to 32 consecutive bytes to be loaded into the page buffer before initiating the internal write cycle. Writing across a 32-byte boundary wraps data to the start of the same page instead of advancing to the next page-so application firmware must enforce page alignment. This behavior is documented in Figure 3-3 and the "Page write operations are limited to writing bytes within a single physical page" note on page 9 of DS20002131D.

How does the HOLD pin function in the 25LC320AT-H/SN, and what are its timing requirements?

The HOLD pin in the 25LC320AT-H/SN pauses an ongoing SPI transaction without resetting the internal address pointer or losing synchronization. To activate HOLD, the pin must be pulled low while SCK is low; to resume, it must be raised while SCK remains low. Setup (THS) and hold (THH) times are 40 ns (at V_CC ≥ 4.5V) per Table 1-2. During HOLD, SI, SCK, and SO enter high-impedance states, allowing the host microcontroller to service interrupts and return seamlessly to the suspended operation.

What write protection mechanisms does the 25LC320AT-H/SN provide, and how are they configured?

The 25LC320AT-H/SN provides dual-layer write protection: software-based via BP0/BP1 bits in the STATUS register (enabling 0%, 25%, 50%, or 100% array protection), and hardware-based using the WP pin in conjunction with the WPEN bit. When WPEN=1 and WP=low, nonvolatile STATUS register bits are locked; all other operations remain functional. Protection granularity and mapping are detailed in Tables 3-3 and 3-4 of DS20002131D, with 32K density assigning protected regions like C00h–FFFh for upper 1/4.

Is the 25LC320AT-H/SN qualified for automotive applications, and what is its AEC-Q100 grade?

Yes, the 25LC320AT-H/SN is AEC-Q100 qualified for Grade 0, covering the extended temperature range of –40°C to +150°C. This qualification includes stress testing for reliability under high-temperature bias (1,000 hours at +150°C), electrostatic discharge (>4 kV HBM), and other automotive-specific failure modes. The "H" suffix in the part number explicitly denotes this high-temp automotive qualification, and the device is marked with "25LC32AT" on the SOIC-8 package per page 15 of DS20002131D.