Microchip Technology 23K256-E/P

Overview

23K256-E/P from Microchip Technology Inc. is a 256 Kbit (32,768 × 8-bit) 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 ≤3 mA read current at 1 MHz, and features HOLD pin for interrupt-safe bus suspension - used in embedded data buffering, firmware parameter storage, and real-time logging in automotive control units.

For engineers reviewing the 23K256-E/P datasheet, 23K256-E/P pinout, 23K256-E/P application, or 23K256-E/P equivalent, key selection criteria include SPI timing compliance (TCSH = 50 ns, TV = 25 ns @ 3.0 V), standby current ≤4 µA at +85°C, VCC range (2.7–3.6 V), and automotive-grade qualification (E-temp).

Technical Context

The 23K256-E/P implements a true SPI-compatible serial interface with separate SI/SO lines and standard four-wire protocol (CS, SCK, SI, SO), supporting byte, page (32-byte), and sequential read/write modes via STATUS register configuration. Its HOLD pin enables deterministic pause/resume of ongoing transfers without sequence restart.

It uses CMOS SRAM core with no refresh requirement, retains data down to 1.2 V (VDR), and supports full memory access across –40°C to +125°C ambient with guaranteed AC timing at E-temp conditions (e.g., FCLK = 16 MHz @ VCC = 3.0 V).

Key Specifications

Pinout & Package

23K256-E/P is packaged in 8-lead PDIP (Plastic Dual In-line Package), 300 mil body width, with through-hole mounting and industry-standard pinout.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 23LC256-I/P, the 23K256-E/P adds automotive temperature qualification and tighter AC timing at high temperature; compared with FM25V20A-G, it trades unlimited endurance for integrated HOLD functionality and lower standby current (4 µA vs. 15 µA), making it preferable for battery-constrained ECU subsystems.

Availability

23K256-E/P is available at Aetrix Electronics and suitable for automotive control units, industrial data loggers, and medical infusion pump controllers requiring stable component supply with long-term lifecycle assurance.

Supply support for 23K256-E/P 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 systems.

The 23X256 product line delivers low-power, SPI-compatible serial SRAMs optimized for automotive, industrial, and medical applications requiring deterministic timing, extended temperature operation, and robust interrupt-handling capabilities.

FAQ

What is the maximum operating clock frequency of the 23K256-E/P and under what conditions is it guaranteed?

The 23K256-E/P supports up to 20 MHz clock frequency at VCC = 3.0 V and TA = +85°C. At automotive temperature extremes (–40°C to +125°C), the guaranteed maximum is 16 MHz per Table 1-2. This ensures reliable SPI communication in engine control modules where ambient temperature and voltage variation must be accommodated without timing margin violation. The 23K256-E/P datasheet specifies setup/hold times (e.g., TCSH = 50 ns) that remain valid across the full E-temp range.

Does the 23K256-E/P require an external pull-up resistor on the HOLD pin?

No, the 23K256-E/P does not require an external pull-up on the HOLD pin. The HOLD function is enabled only when the STATUS register HOLD bit is cleared to '0', and the pin must be actively driven low to invoke pause mode. When unused, HOLD should be tied to VCC (not left floating) to prevent unintended activation. This behavior is explicitly defined in Section 2.5 and Figure 2-7 of the 23K256-E/P datasheet.

How does the 23K256-E/P handle power loss during a write operation?

Because the 23K256-E/P is volatile SRAM, it loses data when VCC drops below the data retention voltage (VDR = 1.2 V minimum). To prevent corruption during brown-out, system designers must ensure clean power-down sequencing or use a backup capacitor to maintain VCC above 1.2 V long enough to complete writes or flush critical data to nonvolatile storage. The 23K256-E/P itself has no internal power-loss protection or write abort detection - integrity relies entirely on host-controlled write completion before VCC decay.

Can the 23K256-E/P be used in a daisy-chained SPI configuration?

No, the 23K256-E/P does not support daisy-chaining. It uses standard 4-wire SPI with dedicated SI and SO pins, requiring individual CS lines for each device on the bus. Multi-drop operation is supported via independent chip select signals - not shared SO/SI lines. Attempting daisy-chain wiring will result in signal contention and undefined behavior, as confirmed by the pin function table and Figure 1-1 timing diagrams in the 23K256-E/P datasheet.

What is the purpose of the "don't care" bit in the 16-bit address field during READ and WRITE commands?

The most significant bit (MSB) of the 16-bit address field is marked "don't care" in the 23K256-E/P instruction format because the device's 32,768-byte memory space maps exactly to 15 address bits (2¹⁵ = 32,768). This reserved bit simplifies firmware address handling - software may transmit any value (0 or 1) in bit 15 without affecting memory access. It is not decoded internally and has no functional impact, as verified in Figures 2-1 and 2-2 of the 23K256-E/P datasheet.