Microchip Technology 23K640T-E/SN

Overview

23K640T-E/SN from Microchip Technology is a 64 Kbit (8192 × 8) low-power SPI Serial SRAM with 32-byte page architecture, 20 MHz max clock frequency, 2.7–3.6 V supply range, and automotive-grade temperature support (−40°C to +125°C). It operates in byte/page/sequential modes and integrates HOLD functionality for interrupt-safe SPI bus sharing in embedded control systems.

For engineers reviewing the 23K640T-E/SN datasheet, 23K640T-E/SN pinout, 23K640T-E/SN application, or 23K640T-E/SN equivalent, key selection criteria include its automotive-temp SPI SRAM interface, 4 µA max standby current at +85°C, 32-byte page write capability, and TSSOP-8 package compatibility with space-constrained automotive ECUs and industrial controllers.

Technical Context

The 23K640T-E/SN implements a standard SPI-compatible serial interface with separate SI (data in), SO (data out), SCK (clock), CS (chip select), and HOLD (pause) signals. Its internal 8-bit instruction register accepts READ (0x03), WRITE (0x02), RDSR (0x05), and WRSR (0x01) commands, all MSB-first, enabling direct integration with PIC® and other microcontrollers' hardware SPI peripherals.

Operating mode is controlled via STATUS register bits 7–6: 00 = byte mode (default), 10 = page mode (32-byte auto-increment within page), 01 = sequential mode (full-array wraparound). HOLD functionality requires STATUS bit 0 = 0 and is activated only when SCK is low, suspending SO/SI/SCK activity while preserving internal address state.

Key Specifications

Pinout & Package

23K640T-E/SN is housed in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm lead pitch, JEDEC MO-153 compliant, footprint-compatible with SOIC-8 but 30% smaller area and improved thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 23K640-I/SN, the 23K640T-E/SN adds automotive temperature qualification and tape-and-reel packaging for automated assembly, while MR25H10MDF replaces volatile SRAM behavior with persistent MRAM storage - trading cost and driver complexity for infinite write endurance and zero write latency.

Availability

23K640T-E/SN is available at Aetrix Electronics and suitable for automotive control units, ADAS sensor nodes, and industrial PLCs requiring stable component supply with guaranteed long-term lifecycle support.

Supply support for 23K640T-E/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, serving automotive, industrial, consumer, and communications markets with vertically integrated silicon and development tools.

The 23K640T-E/SN belongs to Microchip's 23X640 SPI Serial SRAM product line, designed specifically to replace parallel SRAM and battery-backed NVSRAM in space- and power-constrained automotive and industrial systems requiring fast, reliable serial memory expansion.

FAQ

What is the maximum clock frequency supported by the 23K640T-E/SN?

The 23K640T-E/SN supports a maximum clock frequency of 20 MHz at VCC = 3.0 V and TA = −40°C to +85°C (I-temp), and 16 MHz at VCC = 3.0 V and TA = −40°C to +125°C (E-temp). This is confirmed in Table 1-2, AC Characteristics, Param. No. 1 (FCLK). The 23K640T-E/SN must be operated within these limits to ensure reliable read/write timing margins across its full automotive temperature range.

Does the 23K640T-E/SN require external pull-up resistors on its SO or SI pins?

No, the 23K640T-E/SN does not require external pull-up resistors on SO or SI. Its SO pin is actively driven (not open-drain), and SI accepts standard CMOS input thresholds (VIH ≥ 0.7×VCC, VIL ≤ 0.2×VCC). Pull-ups are only needed if the SO line is shared with other open-drain devices - a configuration not required for standard SPI operation of the 23K640T-E/SN.

How does the HOLD function behave during an active 23K640T-E/SN transaction?

When HOLD is asserted low during an active 23K640T-E/SN transaction (with CS low and SCK low), the device enters hold state: SO, SI, and SCK go high-impedance, and internal address/state is preserved. Communication resumes from the exact point of suspension upon HOLD return to high (with SCK still low). This behavior is defined in Section 2.5 and Figure 1-1 of the 23K640T-E/SN datasheet.

What is the data retention voltage specification for the 23K640T-E/SN?

The 23K640T-E/SN specifies a RAM data retention voltage (VDR) of 1.2 V minimum - meaning it retains stored data as long as VCC remains ≥1.2 V, even in deep sleep or backup modes. This value is listed in Table 1-1, Param. No. D011, and applies across the full automotive temperature range. Below 1.2 V, data loss may occur.

Can the 23K640T-E/SN be used in place of the 23A640 series in a 3.3 V system?

No, the 23K640T-E/SN is not a drop-in replacement for the 23A640 series in a 3.3 V system. While both share pinout and instruction set, the 23A640 is specified for 1.5–1.95 V operation and will not function reliably at 3.3 V. The 23K640T-E/SN is designed for 2.7–3.6 V and is the correct choice for standard 3.3 V rail systems requiring automotive qualification.