Microchip Technology 23A640T-I/SN

Overview

23A640T-I/SN from Microchip Technology is a 64 Kbit (8192 × 8-bit), 1.5–1.95 V industrial-temperature SPI Serial SRAM with 32-byte page write, HOLD pin support, and 20 MHz max clock frequency. It operates in Byte, Page, and Sequential modes and delivers 3 mA read current at 1 MHz and ≤4 µA standby current at +85°C - optimized for low-power embedded memory expansion in microcontroller-based systems.

For engineers reviewing the 23A640T-I/SN datasheet, 23A640T-I/SN pinout, 23A640T-I/SN application, or 23A640T-I/SN equivalent, key selection criteria include its 1.8 V supply compatibility, SPI bus timing compliance (tCSS/tCSH ≤32 ns at 1.8 V), HOLD functionality for interrupt-safe pausing, and SOIC-8 (SN) tape-and-reel packaging for automated assembly.

Technical Context

The 23A640T-I/SN implements a standard 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, with address and data latched on rising SCK edge.

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 active transfers without resetting the internal address pointer, provided it is asserted while SCK is low and the device remains selected.

Key Specifications

Pinout & Package

23A640T-I/SN is packaged in an 8-lead SOIC (3.90 mm body), designated by suffix "SN", and supplied in tape-and-reel format ("T" in part number).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 23K640-I/SN, 23A640T-I/SN enables direct 1.8 V integration and cuts standby current by >90%; versus FM25V05-G, it offers lower cost and SOIC-8 compatibility but requires write-cycle management and has finite endurance.

Availability

23A640T-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 across extended production lifecycles.

Supply support for 23A640T-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 U.S.-based semiconductor manufacturer specializing in microcontrollers, analog devices, and memory solutions for embedded control applications.

The 23A640T-I/SN belongs to Microchip's 23X640 SPI Serial SRAM product line, designed specifically to provide low-voltage, low-power, pin-compatible memory expansion for 1.8 V microcontroller systems in industrial and commercial environments.

FAQ

What is the maximum clock frequency supported by the 23A640T-I/SN at 1.8 V?

The 23A640T-I/SN supports a maximum clock frequency of 20 MHz when operated at VCC = 1.8 V and TA = −40°C to +85°C, as specified in Table 1-2 (Param. No. 1, FCLK). This timing is validated under industrial temperature conditions and requires tCSS/tCSH ≤32 ns and tHI/tLO ≤32 ns.

Does the 23A640T-I/SN require external write-enable hardware or command sequencing?

No - the 23A640T-I/SN does not require external write-enable circuitry. Write operations are initiated solely by issuing the WRITE instruction (0x02) followed by address and data via the SPI interface. The STATUS register contains no write-protection bits, and no pre-write enable command is needed.

What is the function of the HOLD pin on the 23A640T-I/SN, and how must it be used?

The HOLD pin on the 23A640T-I/SN pauses ongoing SPI communication without resetting the internal address pointer. To activate HOLD, the pin must be pulled low while SCK is low and CS remains low; the STATUS register HOLD bit (bit 0) must also be cleared to '0'. Resuming requires bringing HOLD high while SCK is low.

Can the 23A640T-I/SN retain data during brief power interruptions?

Yes - the 23A640T-I/SN guarantees RAM data retention down to VCC = 1.2 V (D011, VDR), allowing it to hold contents during short brownouts or controlled power-down sequences. However, it is volatile memory and loses data when VCC falls below 1.2 V or is removed entirely.

Is the 23A640T-I/SN pin-compatible with other members of the 23X640 family?

Yes - the 23A640T-I/SN shares identical pinout, package dimensions, and SPI interface behavior with 23K640-I/SN and 23A640-I/SN. All variants use the same 8-pin SOIC (SN) footprint, identical pin functions (CS, SO, VSS, SI, SCK, HOLD, VCC), and fully compatible command set and timing.