Microchip Technology 23K256-E/SN

Overview

23K256-E/SN 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 only 3 mA at 1 MHz read current, and features HOLD pin for interrupt-safe bus suspension - used in real-time data buffering for automotive telematics and industrial PLCs.

For engineers reviewing the 23K256-E/SN datasheet, 23K256-E/SN pinout, 23K256-E/SN application, or 23K256-E/SN equivalent, key selection criteria include SPI-compatible timing compliance, 32-byte page write capability, HOLD functionality integration, standby current ≤4 µA at +85°C, and TSSOP-8 package compatibility with high-density PCB layouts.

Technical Context

The 23K256-E/SN implements a true 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 16-bit address pointer supports byte, page (32-byte), and sequential read/write modes controlled via STATUS register bits 7–6.

Operation relies on strict timing: CS setup/hold ≥25 ns at 3.0 V (I-temp), SCK rise/fall ≤2 µs, and output valid delay ≤25 ns. The HOLD pin suspends ongoing transfers without resetting the address counter - critical for deterministic interrupt handling in safety-critical automotive microcontroller systems.

Key Specifications

Pinout & Package

23K256-E/SN is packaged in an 8-lead TSSOP (ST package code), 3.0 mm × 4.4 mm body, 0.65 mm lead pitch, RoHS-compliant and halogen-free.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 23LC256-I/SN, the 23K256-E/SN adds automotive temperature qualification and identical pinout but same power profile; versus FM25V20A-G, it trades infinite endurance and speed for lower standby current and lower cost in moderate-write applications.

Availability

23K256-E/SN is available at Aetrix Electronics and suitable for automotive telematics, industrial PLC I/O buffering, medical device data logging, and smart energy metering requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 23K256-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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory solutions, with global manufacturing and quality certifications including ISO/TS 16949 for automotive products.

The 23X256 family was designed specifically for SPI-based data buffering in resource-constrained embedded systems requiring low-power, deterministic timing, and automotive-grade reliability - targeting ECU, sensor hub, and industrial controller applications.

FAQ

What is the maximum clock frequency supported by the 23K256-E/SN?

The 23K256-E/SN supports up to 20 MHz clock frequency at VCC = 3.0 V and TA = −40°C to +85°C (Industrial), and 16 MHz at VCC = 3.0 V and TA = −40°C to +125°C (Automotive E-grade). This is confirmed in Table 1-2 AC Characteristics of DS22100F. The 20 MHz rating applies to industrial operation; for full automotive temperature range, 16 MHz is the guaranteed maximum. The 23K256-E/SN must be operated within these limits to ensure timing compliance and data integrity.

Does the 23K256-E/SN require external pull-up resistors on its SPI lines?

No, the 23K256-E/SN does not require external pull-up resistors on SI, SO, or SCK. Its inputs meet standard CMOS thresholds (VIH ≥ 0.7×VCC, VIL ≤ 0.2×VCC), and SO is actively driven or tri-stated - not open-drain. Pull-ups may cause timing violations or excessive current if applied to SI or SCK. Only CS and HOLD should be pulled up if left floating in system design, per Microchip's layout recommendations in DS22100F.

How does the HOLD function behave during a write operation in the 23K256-E/SN?

During an active write sequence, asserting HOLD (low) pauses the transfer mid-byte without resetting the internal address counter. The 23K256-E/SN tri-states SO and ignores SI/SCK transitions until HOLD is raised while SCK is low. Upon resumption, writing continues from the exact byte position where it paused. This behavior is documented in Section 2.5 and Figure 1-1 of DS22100F and ensures deterministic recovery in interrupt-driven firmware using the 23K256-E/SN.

What is the data retention voltage for the 23K256-E/SN, and how does it affect backup operation?

The 23K256-E/SN guarantees RAM data retention down to 1.2 V (VDR), as specified in Parameter D011 of Table 1-1. Below this voltage, data loss may occur. This allows the 23K256-E/SN to retain contents during brownout conditions typical in automotive stop-start systems, provided the backup supply remains ≥1.2 V. The 23K256-E/SN does not include internal battery switching; external circuitry must maintain VCC above 1.2 V for retention.

Can the 23K256-E/SN be used with a 1.8 V microcontroller SPI interface?

No - the 23K256-E/SN requires VCC = 2.7–3.6 V and is incompatible with 1.8 V I/O. Its input thresholds (VIH ≥ 0.7×VCC ≈ 1.89 V min) and output drive levels (VOH ≥ VCC − 0.5 V) are specified for 3.3 V operation. A 1.8 V MCU would fail to reliably drive CS, SI, or HOLD high, and SO outputs would exceed 1.8 V absolute maximum ratings. For 1.8 V systems, use the pin-compatible 23A256 variant instead of the 23K256-E/SN.