Microchip Technology 23K256-E/ST

Overview

23K256-E/ST from Microchip Technology is a 256 Kbit (32,768 × 8-bit) SPI serial SRAM with automotive-grade temperature support (−40°C to +125°C), 3.6 V max supply voltage, 32-byte page write capability, and HOLD pin for interrupt-safe bus suspension. It serves as nonvolatile-adjacent fast-access memory in engine control units, ADAS sensor buffers, and automotive infotainment systems requiring deterministic low-latency read/write.

For engineers reviewing the 23K256-E/ST datasheet, 23K256-E/ST pinout, 23K256-E/ST application, or 23K256-E/ST equivalent, this device delivers verified 20 MHz SPI clock operation, 4 µA max standby current at +85°C, and flexible byte/page/sequential access modes - critical for power-constrained automotive microcontroller interfaces.

Technical Context

The 23K256-E/ST implements a true SPI-compatible serial interface with separate SI/SO lines, CS-controlled selection, and HOLD-driven pause/resume functionality. Its internal 16-bit address pointer supports automatic rollover in sequential mode and page-boundary wraparound in page mode - all governed by two configurable bits in the STATUS register.

It operates exclusively in CMOS logic with rail-to-rail input thresholds (VIH = 0.7×VCC, VIL = 0.2×VCC), supports 10 ns data setup/hold timing at 3.0 V, and maintains data retention down to 1.2 V VCC - enabling robust operation during automotive battery transients.

Key Specifications

Pinout & Package

23K256-E/ST is housed in an 8-lead TSSOP (Thin Shrink Small Outline Package) with 0.65 mm lead pitch, JEDEC MO-153 compliant, and RoHS/halogen-free. The package supports automated optical inspection and high-density PCB layouts.

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 23K256-E/ST uniquely combines automotive temperature qualification, SPI simplicity, HOLD-based interrupt safety, and optimal 256 Kbit density for cost-sensitive ECU and ADAS subsystems.

Availability

23K256-E/ST is available at Aetrix Electronics and suitable for automotive engine control, ADAS camera processing, and telematics gateway applications requiring stable component supply across extended product lifecycles.

Supply support for 23K256-E/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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory solutions for industrial, automotive, and consumer markets.

The 23K256-E/ST belongs to Microchip's 23X256 SPI Serial SRAM family, designed specifically to replace parallel SRAMs in space-constrained automotive and industrial systems while maintaining deterministic timing and low-power operation.

FAQ

What is the maximum operating clock frequency of the 23K256-E/ST?

The 23K256-E/ST supports up to 20 MHz SPI clock frequency at VCC = 3.0 V and TA = −40°C to +125°C. This is confirmed in Table 1-2 of DS22100F, where FCLK Max = 20 MHz under those conditions. At lower voltages or ambient temperatures, the maximum clock may be reduced - for example, 16 MHz at 3.0 V in automotive temperature range per the same table. The 23K256-E/ST must be operated within these validated limits to ensure reliable read/write timing compliance.

Does the 23K256-E/ST have built-in data retention during power loss?

No, the 23K256-E/ST is a volatile SRAM and does not retain data without continuous power. However, it guarantees data retention down to VCC = 1.2 V (per D011 in Table 1-1), meaning stored contents remain valid during brief brown-out events - such as automotive cold cranking - as long as supply does not drop below that threshold. For true nonvolatile retention, external backup circuitry or a different memory type (e.g., FRAM or NVSRAM) would be required. The 23K256-E/ST itself relies on stable VCC.

How does the HOLD pin function in the 23K256-E/ST?

The HOLD pin on the 23K256-E/ST suspends an ongoing SPI transaction without resetting the internal address pointer or command state. When asserted low (while SCK is low), SI/SO/SCK inputs are ignored except CS, and SO enters high-impedance. Resuming requires bringing HOLD high while SCK remains low. This behavior is documented in Section 2.5 and Figure 1-1 of DS22100F. The HOLD feature must be enabled via the STATUS register's HOLD bit (bit 0); if set to '1', the pin is disabled. This makes the 23K256-E/ST ideal for interrupt-driven MCU environments.

What package type is used for the 23K256-E/ST?

The 23K256-E/ST uses an 8-lead TSSOP (Thin Shrink Small Outline Package), designated by the "ST" suffix in the part number per Microchip's Product Identification System (DS22100F, page 25). This package has a 4.4 mm body width, 0.65 mm lead pitch, and complies with JEDEC MO-153. It is Pb-free, RoHS-compliant, and halogen-free. The TSSOP variant is explicitly listed in the Device Selection Table (page 1) and Package Marking section (page 14) for the 23K256-E/ST.

Can the 23K256-E/ST operate in byte, page, and sequential modes simultaneously?

No - the 23K256-E/ST operates in only one mode at a time, selected by bits 7 and 6 of the STATUS register: 00 = Byte mode (default), 10 = Page mode, 01 = Sequential mode. These are mutually exclusive operational states defined in Section 2.2 of DS22100F. Mode changes require issuing the WRSR (Write Status Register) instruction. Each mode imposes distinct addressing and increment behavior: Byte mode accesses single locations; Page mode auto-increments within 32-byte boundaries; Sequential mode wraps across the full 32,768-byte array. The 23K256-E/ST does not support concurrent or hybrid mode execution.