Microchip Technology 23K640T-I/ST

Overview

23K640T-I/ST 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 temperature range (–40°C to +85°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 bus arbitration in microcontroller-based data logging systems.

For engineers reviewing the 23K640T-I/ST datasheet, 23K640T-I/ST pinout, 23K640T-I/ST application, or 23K640T-I/ST equivalent, key selection criteria include SPI-compatible serial interface timing compliance, TSSOP-8 package footprint compatibility, industrial-grade data retention voltage (1.2 V), and support for byte/page/sequential access modes without external address latches.

Technical Context

The 23K640T-I/ST implements a true SPI-compatible serial bus interface with separate SI (data in) and SO (data out) lines, requiring only CS, SCK, SI, SO, HOLD, VCC, and VSS connections. Its internal 16-bit address pointer supports automatic incrementing in Page (32-byte boundary wrap) and Sequential (full 0x0000–0x1FFF rollover) modes, controlled via STATUS register bits 7–6.

Hold functionality is hardware-activated: when HOLD is pulled low while SCK is low, SO enters high-impedance state and all inputs except CS are ignored-enabling host MCU to service higher-priority interrupts mid-sequence without reinitialization or data loss.

Key Specifications

Pinout & Package

23K640T-I/ST 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 offering 30% smaller board area and improved thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY14V101QS-SXIT and FM25V05-G, the 23K640T-I/ST delivers optimal cost-per-bit for moderate-write, SPI-constrained designs requiring HOLD-based interrupt handling and industrial temperature resilience-not nonvolatility or extreme endurance.

Availability

23K640T-I/ST is available at Aetrix Electronics and suitable for industrial data loggers, medical sensor hubs, automotive telematics modules, and smart energy meters requiring stable component supply, long-lifecycle availability, and RoHS-compliant TSSOP packaging.

Supply support for 23K640T-I/ST 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, mixed-signal, analog, and Flash-IP solutions, serving industrial, automotive, consumer, and communications markets with high-reliability silicon and development tools.

The 23K640T-I/ST belongs to Microchip's serial SRAM product line, engineered specifically for SPI-bus-constrained embedded systems needing low-power, interrupt-tolerant, page-structured memory expansion without parallel interface complexity.

FAQ

What is the maximum operating clock frequency for the 23K640T-I/ST?

The 23K640T-I/ST supports up to 20 MHz clock frequency at VCC = 3.0 V and TA = –40°C to +85°C. At lower voltages (e.g., 2.7 V), the maximum rated frequency reduces to 16 MHz per AC Characteristics Table 1-2. This timing allows sustained sequential read throughput exceeding 2.5 MB/s, making it suitable for high-speed sensor streaming applications where the 23K640T-I/ST serves as a low-latency buffer.

Does the 23K640T-I/ST require external pull-up resistors on its SPI lines?

No, the 23K640T-I/ST does not require external pull-ups on SI, SO, or SCK-its inputs meet standard SPI voltage thresholds (VIH ≥ 0.7×VCC, VIL ≤ 0.2×VCC), and SO is actively driven. However, CS and HOLD should be pulled up externally (typically 10 kΩ to VCC) to ensure defined states during power-up and reset, preventing unintended activation or hold assertion that could stall the 23K640T-I/ST interface.

How does the HOLD function interact with the STATUS register in the 23K640T-I/ST?

The HOLD function in the 23K640T-I/ST is hardware-controlled but can be disabled via bit 0 (HOLD) in the STATUS register: writing '1' to this bit disables HOLD pin responsiveness, while '0' enables it. This allows firmware to selectively disable HOLD during debug sessions or known-no-interrupt windows. The 23K640T-I/ST powers up with HOLD enabled (bit = 0), and the pin must be held high when unused to prevent accidental suspension of SPI traffic.

Can the 23K640T-I/ST be used in automotive applications requiring AEC-Q200 qualification?

The 23K640T-I/ST is rated for Industrial temperature (–40°C to +85°C) and is not AEC-Q200 qualified. For automotive under-hood or infotainment applications requiring AEC-Q200, Microchip offers the 23K640-E/ST variant (–40°C to +125°C, Automotive grade), which shares identical pinout, timing, and functionality-but the 23K640T-I/ST itself is intended for industrial and commercial environments where AEC-Q200 is not mandated.

What happens to the internal address counter when a Page Write reaches the end of a 32-byte page in the 23K640T-I/ST?

When a Page Write operation in the 23K640T-I/ST reaches the 32nd byte (address offset 0x1F), the internal address counter wraps around to the start of the same page (offset 0x00), overwriting the first byte written. This behavior is intentional and documented in Section 2.2: Page Operation. To avoid unintended overwrites, firmware must limit Page Writes to ≤32 bytes and align starting addresses to page boundaries (e.g., 0x0000, 0x0020)-a constraint inherent to the 23K640T-I/ST's page architecture.