Microchip Technology 23A256-I/P

Overview

23A256-I/P from Microchip Technology is a 256 Kbit (32,768 × 8-bit) low-voltage SPI Serial SRAM designed for embedded systems requiring nonvolatile-adjacent fast-access memory with minimal power draw. It operates from 1.5V to 1.95V, supports up to 20 MHz clock frequency at 1.8V, delivers 3 mA read current at 1 MHz, and features a 32-byte page write capability plus HOLD pin for interrupt-safe bus arbitration. It is used in battery-powered IoT sensor nodes where rapid data buffering and ultra-low standby current (≤4 µA at +85°C) are critical.

For engineers reviewing the 23A256-I/P datasheet, 23A256-I/P pinout, 23A256-I/P application, or 23A256-I/P equivalent, this page provides verified electrical specs, validated SPI timing constraints, confirmed industrial-temperature operation (–40°C to +85°C), package-specific pin mapping for PDIP-8, and two technically documented alternative serial SRAMs with voltage and timing differentials.

Technical Context

The 23A256-I/P 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 - no internal address latches or parallel bus overhead. Its STATUS register controls three distinct access modes: Byte (default), Page (32-byte auto-increment within page), and Sequential (full 32K-byte wraparound).

It uses low-power CMOS technology with data retention down to 1.2V and supports hold functionality that suspends ongoing SPI transactions without resetting internal address pointers - enabling host microcontrollers to service higher-priority interrupts while preserving transaction state.

Key Specifications

Pinout & Package

23A256-I/P is supplied in an 8-lead Plastic Dual In-line Package (PDIP) with 0.300-inch body width. Pin numbering follows standard DIP orientation (pin 1 in top-left corner, counterclockwise). All pins are TTL-compatible with defined input thresholds and output drive strength per DC characteristics table.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 23K256-I/P, the 23A256-I/P enables lower-system-voltage designs with tighter power budgets, while FM25V20-G trades deterministic timing control for infinite write endurance - making 23A256-I/P optimal for cost-sensitive, battery-operated SPI-buffering applications where 1.8V compatibility and interrupt-safe HOLD are essential.

Availability

23A256-I/P is available at Aetrix Electronics and suitable for smart metering, wearable health monitoring, industrial PLC I/O caching, and POS terminal transaction logging requiring stable component supply across extended production lifecycles.

Supply support for 23A256-I/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 leading provider of microcontroller, mixed-signal, analog, and Flash-IP solutions, serving automotive, industrial, consumer, and communications markets with high-reliability silicon and development tools.

The 23A256-I/P belongs to Microchip's 23X256 SPI Serial SRAM product line, engineered specifically for low-voltage embedded systems needing fast, byte-addressable, low-quiescent-current memory with robust SPI interoperability and industrial temperature resilience.

FAQ

What is the maximum clock frequency supported by the 23A256-I/P at its nominal 1.8V supply?

The 23A256-I/P supports up to 20 MHz clock frequency when operated at VCC = 1.8V within the industrial temperature range (–40°C to +85°C). This value is specified in Table 1-2 (AC Characteristics) of the DS22100F datasheet under "FCLK" parameter for VCC = 1.8V (I-Temp). At 1.5V, the maximum clock drops to 10 MHz.

Does the 23A256-I/P require external pull-up resistors on its SPI interface lines?

No, the 23A256-I/P does not require external pull-ups on SI, SO, or SCK. Its CS, HOLD, and SI inputs have defined VIH/VIL thresholds and internal weak pull-downs are not present; proper signal driving from the host MCU is sufficient. Pull-ups may be added only if bus contention or noise immunity is a concern in long-trace layouts - not a datasheet requirement.

How does the HOLD function behave if asserted mid-byte during a 23A256-I/P SPI transfer?

When HOLD is pulled low while SCK is low, the 23A256-I/P immediately pauses the ongoing SPI transaction - freezing the internal address pointer and placing SO, SI, and SCK in high-impedance. The exact bit position within the current byte is preserved. Resuming requires bringing HOLD high while SCK remains low; the device then continues from the paused bit on the next SCK cycle.

Can the 23A256-I/P retain data during a complete power removal?

No - the 23A256-I/P is a volatile SRAM and loses all stored data when VCC falls below the data retention voltage of 1.2V. It is not a nonvolatile memory. For persistent storage, it must be paired with a backup power source (e.g., supercapacitor) or external EEPROM/Flash. Its 1.2V retention spec applies only to brown-out conditions, not full power-off.

Is the 23A256-I/P pin-compatible with the 23K256-I/P in the same PDIP-8 package?

Yes - the 23A256-I/P and 23K256-I/P share identical 8-pin PDIP (P) packaging, identical pin functions (CS, SO, VSS, SI, SCK, HOLD, VCC), and identical SPI instruction set and timing protocol. They differ only in supply voltage range and AC timing limits; no PCB layout change is needed when substituting between them in existing 1.8V or 3.3V designs.