Microchip Technology 23K640-E/SN

Overview

23K640-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, and industrial/automotive temperature support (−40°C to +125°C). It operates from 2.7–3.6 V, draws only 3 mA at 1 MHz read current and ≤4 µA standby current at +85°C, and integrates HOLD functionality for interrupt-safe SPI bus sharing in embedded microcontroller systems.

For engineers reviewing the 23K640-E/SN datasheet, 23K640-E/SN pinout, 23K640-E/SN application, or 23K640-E/SN equivalent, key selection criteria include its SPI-compatible serial interface, 32-byte page write capability, HOLD pin behavior under interrupt latency constraints, and automotive-grade reliability across −40°C to +125°C ambient operation.

Technical Context

The 23K640-E/SN implements a true SPI-compatible serial bus interface with separate SI (MOSI) and SO (MISO) lines, SCK synchronization on rising edge for input and falling edge for output, and CS-controlled chip select enabling multi-device bus sharing. Its internal 16-bit address pointer supports byte, page (32-byte), and sequential read/write modes via STATUS register configuration.

HOLD functionality suspends active SPI transactions without resetting the internal address counter-requiring HOLD assertion while SCK is low and resumption only when HOLD is deasserted during SCK low phase. The device powers up in standby mode (CS high), and all I/O pins meet standard SPI voltage thresholds (VIH ≥ 0.7×VCC, VIL ≤ 0.2×VCC).

Key Specifications

Pinout & Package

23K640-E/SN is housed in an 8-lead SOIC (3.90 mm body) package, marked "23K640" with temperature grade "E" and date code, compliant with Pb-free and RoHS requirements.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY14V104Q2L-BAI and IS66WV51216BLL-100BLI, the 23K640-E/SN delivers optimal trade-offs for SPI-constrained, automotive-grade, low-power embedded systems-offering pin-compatible upgrade paths within Microchip's 23X640 family while avoiding parallel bus complexity or battery dependency.

Availability

23K640-E/SN is available at Aetrix Electronics and suitable for automotive ECU development, industrial PLC data logging, and medical infusion pump design requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 23K640-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 microcontrollers, analog devices, and memory solutions, headquartered in Chandler, Arizona, with global manufacturing and support infrastructure.

The 23X640 product line was designed specifically for SPI-based embedded systems needing reliable, low-power serial memory with HOLD functionality-targeting automotive, industrial, and medical applications where deterministic interrupt response and extended temperature operation are critical.

FAQ

What is the maximum clock frequency supported by the 23K640-E/SN?

The 23K640-E/SN supports a maximum clock frequency of 20 MHz when operated at VCC = 3.0 V over the industrial temperature range. At automotive temperature (−40°C to +125°C), the maximum rated frequency remains 20 MHz per DS22126E, verified under worst-case VCC and temperature conditions. This enables high-throughput data streaming in time-critical applications such as motor control feedback buffering. The 23K640-E/SN maintains full AC timing compliance-including setup/hold times-up to this limit.

Does the 23K640-E/SN require external pull-up resistors on its SPI lines?

No, the 23K640-E/SN does not require external pull-up resistors on SI, SO, or SCK lines-the device uses CMOS input buffers with defined VIH/VIL thresholds and SO is actively driven or tri-stated. However, CS and HOLD lines may benefit from weak pull-ups (e.g., 100 kΩ) in noisy environments to prevent spurious activation. The 23K640-E/SN datasheet specifies no mandatory external biasing, and proper SPI master drive strength eliminates need for pull-ups in standard PCB layouts.

How does the HOLD function behave during a write operation in the 23K640-E/SN?

During an active write operation, asserting HOLD low on the 23K640-E/SN pauses the transaction immediately-freezing the internal address pointer and holding SI, SCK, and SO in high-impedance. When HOLD is deasserted (brought high while SCK is low), the 23K640-E/SN resumes exactly where it left off, continuing to accept remaining data bytes without retransmitting the WRITE instruction or address. This behavior is confirmed in Figure 1-1 and Section 2.5 of the 23K640-E/SN datasheet.

What is the data retention voltage specification for the 23K640-E/SN?

The 23K640-E/SN guarantees RAM data retention down to VCC = 1.2 V, as specified in Parameter D011 (VDR) of Table 1-1. Below this threshold, data loss may occur. This allows graceful degradation during brown-out conditions and supports use with undervoltage lockout circuits that maintain VCC above 1.2 V during power-down sequences. The 23K640-E/SN retains valid data indefinitely at or above this voltage, independent of temperature or cycle count.

Can the 23K640-E/SN be used with a 1.8 V microcontroller SPI interface?

No-the 23K640-E/SN requires a 2.7–3.6 V supply and is not compatible with 1.8 V I/O logic levels. Its VIH minimum is 0.7×VCC (≥1.89 V at VCC = 2.7 V), and VIL maximum is 0.2×VCC (≤0.72 V at VCC = 3.6 V). Driving it from a 1.8 V MCU would violate input thresholds and risk unreliable operation. For 1.8 V systems, the pin-compatible 23A640 variant (1.5–1.95 V) should be used instead of the 23K640-E/SN.