Microchip Technology 23A256-I/SN

Overview

23A256-I/SN from Microchip Technology Inc. is a 256 Kbit (32,768 × 8-bit) low-voltage SPI Serial SRAM with 1.5–1.95 V supply range, 20 MHz max clock, 3 mA read current at 1 MHz, and industrial temperature support (–40°C to +85°C). It integrates HOLD functionality, 32-byte page write capability, and operates in byte/page/sequential modes for embedded microcontroller memory expansion.

For engineers reviewing the 23A256-I/SN datasheet, 23A256-I/SN pinout, 23A256-I/SN application, or 23A256-I/SN equivalent, key selection criteria include its 1.8 V operation, SPI bus compatibility with PIC® and other MCUs, low standby current (≤4 µA), and SOIC-8 package suitability for space-constrained industrial control and portable systems.

Technical Context

The 23A256-I/SN implements a true SPI-compatible serial interface with separate SI (data in) and SO (data out) lines, requiring only CS, SCK, SI, SO, HOLD, VCC, and VSS. Its internal 8-bit instruction register accepts READ (0x03), WRITE (0x02), RDSR (0x05), and WRSR (0x01) commands, all MSB-first, enabling direct integration with hardware SPI peripherals or bit-banged GPIO.

It supports three configurable operating modes via STATUS register bits 7–6: Byte (default), Page (32-byte auto-increment within page), and Sequential (full-array wraparound). The HOLD pin suspends ongoing transfers without resetting the address pointer, allowing host interrupt servicing while preserving transaction state.

Key Specifications

Pinout & Package

23A256-I/SN is packaged in an 8-lead SOIC (SN) with 150 mil body width, compliant with JEDEC MS-012AA, and features gull-wing leads for standard reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 23A256-I/SN, 23K256-I/SN offers higher voltage flexibility but lacks 1.8 V optimization, while FM25V20-G trades SRAM-like interface for F-RAM endurance and zero write latency - making 23A256-I/SN optimal for cost-sensitive, 1.8 V industrial buffering where moderate write endurance suffices.

Availability

23A256-I/SN is available at Aetrix Electronics and suitable for industrial sensor nodes, portable medical devices, PLC I/O modules, and smart energy meters requiring stable component supply and long-term manufacturability.

Supply support for 23A256-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 microcontroller, analog, FPGA, and memory solutions, headquartered in Chandler, Arizona, with global design, manufacturing, and sales operations.

The 23X256 family was designed specifically to deliver low-power, SPI-compatible serial SRAM for memory expansion in space- and power-constrained embedded systems, emphasizing ease of integration with PIC® and other 8/16-bit microcontrollers.

FAQ

What is the maximum clock frequency supported by the 23A256-I/SN at 1.8 V?

The 23A256-I/SN supports up to 20 MHz clock frequency when operated at VCC = 1.8 V and TA = –40°C to +85°C. This value is specified in Table 1-2 (AC CHARACTERISTICS) of the DS22100F datasheet under Param. No. 1 (FCLK) for VCC = 1.8V (I-Temp). Performance degrades at lower voltages: 10 MHz max at 1.5 V.

Does the 23A256-I/SN require external pull-up resistors on its SPI pins?

No, the 23A256-I/SN does not require external pull-ups on SI, SO, or SCK. Its inputs (CS, SI, HOLD) have CMOS-compatible thresholds and internal weak pull-downs are not present; external pull-ups may be needed only on CS or HOLD in floating-bus scenarios to ensure defined inactive states. SO is actively driven or tri-stated - no pull-up required.

How does the HOLD function interact with the STATUS register in the 23A256-I/SN?

The HOLD function in the 23A256-I/SN is disabled if the HOLD bit (bit 0) in the STATUS register is set to '1'. By default, the HOLD bit is '0' after power-up, enabling the pin. To use HOLD, the bit must remain '0'; setting it to '1' disables the pin's suspend capability regardless of its logic level. This is documented in Section 2.5 and Table 2-2 of DS22100F.

Can the 23A256-I/SN retain data during a complete power loss?

No, the 23A256-I/SN is volatile SRAM and cannot retain data without power. However, it supports data retention down to VCC = 1.2 V (per D011 in Table 1-1), meaning it holds contents during brown-out conditions above that threshold. For true non-volatility, an external backup source or FRAM alternative like FM25V20-G is required.

What package variants are available for the 23A256-I/SN besides SOIC-8?

The 23A256-I/SN is specified only in the SOIC-8 (SN) package per the Device Selection Table on DS22100F-page 1. While the broader 23X256 family includes PDIP (P) and TSSOP (ST), the 23A256 variant is explicitly listed with packages P, SN, ST - confirming SOIC-8 (SN) is a valid and standard offering for this part number.