Renesas IDT71256SA15TP

Overview

IDT71256SA15TP from Renesas Electronics is a 32K × 8-bit (256 Kbit) high-speed CMOS static RAM with 15 ns access time, TTL-compatible I/O, single 5 V supply operation, and industrial-grade temperature range (–40°C to +85°C). It serves as a non-refreshing, fully static memory buffer in real-time control systems, legacy industrial controllers, and embedded instrumentation requiring deterministic read/write timing.

For engineers reviewing the IDT71256SA15TP datasheet, IDT71256SA15TP pinout, IDT71256SA15TP application, or IDT71256SA15TP equivalent, key selection criteria include guaranteed 15 ns tAA/tRC timing under industrial conditions, dual active-low chip select and output enable control logic, low standby current (ISB = 40 mA max), and compatibility with 28-pin 300-mil plastic DIP packaging.

Technical Context

The IDT71256SA15TP implements fully static asynchronous architecture-no clocks, no refresh cycles-enabling deterministic timing across all operating modes. Its control logic supports independent chip select (CS) and output enable (OE) pins, allowing selective output gating without deselection, and uses standard TTL voltage thresholds (VIH = 2.2 V min, VIL = 0.8 V max) for seamless interface with legacy microcontrollers and FPGAs.

It delivers 15 ns address access time (tAA) and 15 ns read cycle time (tRC) over the full industrial temperature range, with output enable propagation delay as fast as 7 ns (tOE), and supports write pulse widths down to 10 ns (tWP). Standby current drops to 15 mA (ISB1) when CS is held at CMOS-high level, enabling low-power hold states in battery-backed systems.

Key Specifications

Pinout & Package

Package: 28-pin 300-mil plastic DIP (PTG28), 0.3 inch wide body, 0.1 inch lead pitch, through-hole mounting.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY62256ELL-15ZXI and AS6C4008-15ZIN, the IDT71256SA15TP uniquely combines 5 V TTL compatibility, through-hole DIP packaging, and 15 ns industrial-grade timing-making it the sole viable option for drop-in replacement in aging 5 V industrial control hardware.

Availability

IDT71256SA15TP is available at Aetrix Electronics and suitable for industrial automation, legacy test equipment, and battery-backed telemetry systems requiring stable component supply and long-term obsolescence management.

Supply support for IDT71256SA15TP 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 IDT71256SA15TP belongs to Renesas' legacy high-speed CMOS SRAM product line, designed specifically for reliability-critical 5 V embedded systems where pin compatibility, timing predictability, and industrial temperature resilience are mandatory.

FAQ

What is the maximum guaranteed access time for IDT71256SA15TP across its full operating temperature range?

The IDT71256SA15TP guarantees a maximum address access time (tAA) of 15 ns and read cycle time (tRC) of 15 ns over the full industrial temperature range of –40°C to +85°C at VCC = 4.5 V to 5.5 V. This specification is production-tested and documented in the Renesas datasheet revision dated June 29, 2020, ensuring deterministic timing for hard real-time applications without derating.

Does IDT71256SA15TP support true bidirectional data I/O without external direction control?

Yes, the IDT71256SA15TP features fully bidirectional I/O0–I/O7 pins controlled entirely by internal logic driven by CS, OE, and WE signals-no external transceivers or direction lines are needed. When CS is low and OE is low, data flows from memory to bus; when CS is low and WE is low, data flows from bus to memory. The IDT71256SA15TP automatically manages bus direction based on active control states.

Can IDT71256SA15TP operate reliably at 4.5 V supply voltage under worst-case industrial conditions?

Yes, the IDT71256SA15TP is fully specified and tested at VCC = 4.5 V minimum across –40°C to +85°C. All timing parameters-including tAA = 15 ns, tRC = 15 ns, and tWP = 10 ns-are guaranteed at this voltage. DC characteristics such as VOH ≥ 2.4 V and VOL ≤ 0.4 V also hold at 4.5 V, ensuring robust TTL interfacing even under brown-out conditions.

Is IDT71256SA15TP pin-compatible with other members of the IDT71256SA family?

Yes, all IDT71256SA variants-including IDT71256SA12TP, IDT71256SA15TP, IDT71256SA20TP, and IDT71256SA25TP-share identical 28-pin PTG28 DIP pinout, address/data/control signal mapping, and functional behavior. Only timing parameters and temperature grade differ; the IDT71256SA15TP may be substituted for slower versions without PCB modification.

What is the standby current consumption of IDT71256SA15TP when CS is held high at CMOS logic level?

When CS is held above VHC (VCC – 0.2 V) with all other inputs stable, the IDT71256SA15TP draws a maximum standby current (ISB1) of 15 mA at VCC = 5.5 V and TA = +25°C. This ultra-low standby mode is explicitly characterized and guaranteed in the datasheet, enabling extended battery-backed data retention in systems like utility meters and remote sensors.