Microchip Technology 23K256-I/SN

Overview

23K256-I/SN from Microchip Technology is a 256 Kbit (32,768 × 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 max standby current, and supports byte/page/sequential read/write modes for embedded microcontroller memory expansion.

For engineers reviewing the 23K256-I/SN datasheet, 23K256-I/SN pinout, 23K256-I/SN application, or 23K256-I/SN equivalent, this device serves as a drop-in SPI-compatible RAM replacement in space-constrained, low-power systems requiring nonvolatile-adjacent fast-access storage - especially where HOLD functionality enables interrupt-safe bus arbitration.

Technical Context

The 23K256-I/SN implements a standard 4-wire SPI interface (CS, SCK, SI, SO) with dedicated HOLD input for pausing ongoing transfers without resetting the internal address pointer. Its STATUS register controls three operating modes: byte (default), page (32-byte auto-increment within page), and sequential (full-array wraparound).

It uses CMOS technology with TTL-compatible inputs, supports 1.5–3.6 V supply across variants (this part: 2.7–3.6 V), and retains data down to 1.2 V V_CC. All timing parameters - including t_CSS, t_CSH, t_SU, t_HD, and t_V - are specified over full industrial temperature range and validated at up to 20 MHz clock rate.

Key Specifications

Pinout & Package

23K256-I/SN is housed in an 8-lead SOIC (3.90 mm body), designated by package code "SN". Pin functions are electrically and mechanically identical across PDIP (P), SOIC (SN), and TSSOP (ST) variants per Microchip DS22100F.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 23K256-I/SN, 23LCV256-I/SN adds voltage monitoring but increases standby power, while FM25V20-G trades HOLD support and speed for infinite write endurance - making each alternative optimal only under distinct system-level constraints.

Availability

23K256-I/SN is available at Aetrix Electronics and suitable for industrial sensor nodes, medical data buffers, automotive body control modules, and POS terminal caches requiring stable component supply across long production lifecycles.

Supply support for 23K256-I/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 design and manufacturing operations.

The 23X256 family was designed specifically to deliver low-power, pin-efficient serial SRAM for resource-constrained embedded systems needing reliable, SPI-native memory expansion - particularly where EEPROM wear-out or parallel bus complexity must be avoided.

FAQ

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

The 23K256-I/SN supports up to 20 MHz SPI clock frequency at V_CC = 3.0 V and TA = –40°C to +85°C. This is confirmed in Table 1-2 of DS22100F, where FCLK max = 20 MHz under industrial temperature and 3.0 V conditions. At lower voltages (e.g., 2.7 V), the maximum rated frequency may decrease per AC characterization limits.

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

No, the 23K256-I/SN does not require external pull-ups on CS, SCK, SI, or SO. Its inputs meet TTL voltage thresholds (VIH ≥ 0.7 V_CC, VIL ≤ 0.2 V_CC) and have ±0.5 µA leakage current (D006/D007), allowing direct connection to standard SPI masters. Pull-ups are only needed if bus contention or open-drain topology is used externally.

How does the HOLD function behave during an active SPI transaction on the 23K256-I/SN?

When HOLD is pulled low during an active transaction, the 23K256-I/SN pauses communication immediately - SI, SCK, and SO enter high-impedance states, and the internal address pointer freezes. The transaction resumes from the exact same point when HOLD returns high while SCK is low. This behavior is defined in Section 2.5 and Figure 1-1 of DS22100F.

What is the data retention capability of the 23K256-I/SN at low supply voltage?

The 23K256-I/SN guarantees data retention down to 1.2 V V_CC (parameter D011), meaning stored SRAM contents remain intact even during brown-out conditions as low as 1.2 V. This value is periodically sampled and applies across the full industrial temperature range, enabling robust operation in unstable power environments.

Can the 23K256-I/SN be used in automotive applications requiring AEC-Q100 qualification?

The 23K256-I/SN is rated for industrial temperature (–40°C to +85°C) and is not AEC-Q100 qualified. For automotive use, Microchip specifies the 23K256-E/ST variant (–40°C to +125°C, TSSOP package), which undergoes additional stress testing. Using 23K256-I/SN in automotive contexts requires explicit validation by the end customer per their safety and reliability requirements.