Renesas 71256L25YG

Overview

71256L25YG from Renesas is a 256K (32K × 8-bit) low-power CMOS static RAM with 25ns maximum access time, TTL-compatible I/O, and 2V battery-backed data retention. It operates across commercial temperature range (0°C to +70°C), supports full standby mode (1.5mA ISB1), and is packaged in 28-pin 300-mil SOJ for high-density board layouts - used in legacy industrial controllers and avionics subsystems requiring nonvolatile SRAM hold.

For engineers reviewing the 71256L25YG datasheet, 71256L25YG pinout, 71256L25YG application, or 71256L25YG equivalent, key selection criteria include its 25ns tAA/tACS timing at 5V, 2V data retention capability, military-grade reliability heritage (MIL-STD-883 Class B compliant variants exist), and SOJ package compatibility with legacy PCB footprints.

Technical Context

The 71256L25YG implements a fully decoded 15-bit address space (A0–A14) driving a 262,144-bit memory array with bidirectional 8-bit I/O (I/O0–I/O7). Its control logic uses three independent enables - CS (chip select), WE (write enable), and OE (output enable) - supporting both CS-controlled and WE-controlled write cycles per JEDEC-standard SRAM timing protocols.

It features dual standby modes: TTL-level standby (ISB = 3mA max at VCC = 5.5V) triggered by CS > VIH, and full CMOS-level standby (ISB1 = 1.5mA max) activated when CS > VHC. The L-version's 5μW typical retention current at 2V enables long-term battery backup without external power management circuitry.

Key Specifications

Pinout & Package

71256L25YG is supplied in a 28-pin 300-mil Small Outline J-Lead (SOJ) package (package code PJG28), with gull-wing leads and 1.27mm pitch. Pin 1 is marked by a notch or dot; pin numbering follows standard counter-clockwise convention from top view.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 71256L25YG, CY62256LL-25ZSXI offers modern 3.3V efficiency but removes 2V retention, while AS6C4008-25ZIN achieves nanoamp standby at the cost of zero retention capability - making 71256L25YG uniquely suited for legacy 5V systems requiring battery-backed persistence.

Availability

71256L25YG is available at Aetrix Electronics and suitable for avionics data logging, industrial PLC memory buffering, and military radio firmware caching requiring stable component supply across extended product lifecycles.

Supply support for 71256L25YG 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

Renesas Electronics Corporation is a global semiconductor leader delivering microcontrollers, analog, power, and memory solutions for automotive, industrial, and infrastructure markets.

The 71256L25YG belongs to Renesas' legacy high-reliability SRAM product line, originally developed by IDT and optimized for mission-critical systems demanding MIL-STD-883 compliance, long-term data retention, and 5V TTL interoperability.

FAQ

What is the maximum clock frequency supported by the 71256L25YG for synchronous read operations?

The 71256L25YG does not include an internal clock; it is an asynchronous SRAM. Its 25ns access time (tAA/tACS) supports effective bus rates up to 40MHz (1/25ns) in systems with zero wait-state controllers. Timing depends on external address setup/hold and control signal propagation - no clock input pin exists on the 71256L25YG.

Does the 71256L25YG require external pull-up resistors on its control lines?

No, the 71256L25YG does not require external pull-ups on CS, WE, or OE. Its TTL-compatible inputs have defined VIH (2.2V min) and VIL (0.8V max) thresholds, and internal input structures tolerate floating inputs without latch-up. However, best practice dictates tying unused control lines to GND or VCC via 10kΩ resistors in production designs to prevent noise-induced glitches.

Can the 71256L25YG retain data when VCC drops to 2.0V, and for how long?

Yes, the 71256L25YG guarantees data retention at VCC ≥ 2.0V across its commercial temperature range (0°C to +70°C). Retention duration depends on leakage current: at 25°C, typical ICCDR is 120μA, enabling multi-year retention with a 220mAh CR2032 cell. Actual hold time must be validated per application load and temperature per Renesas datasheet Table 11.

Is the 71256L25YG pin-compatible with the 71256S25YG or other speed grades in the same package?

Yes, all 71256x25YG variants (L and S versions) share identical 28-pin SOJ pinouts, electrical signaling, and functional behavior. The only difference is power consumption: the 'L' version draws 1.5mA ISB1 versus 20mA for the 'S' version. No PCB changes are required when substituting 71256L25YG for 71256S25YG in commercial-temperature applications.

What is the meaning of the 'Y' and 'G' suffixes in the 71256L25YG part number?

In the 71256L25YG ordering code, 'Y' denotes the commercial temperature grade (0°C to +70°C) and 'G' specifies the 300-mil SOJ package (PJG28). The full designation confirms: Low-power (L), 25ns speed (25), Commercial temp (Y), SOJ package (G). This matches Renesas' official ordering information table on page 10 of the datasheet.