Renesas IDT71256L35Y

Overview

IDT71256L35Y from Integrated Device Technology is a 256K (32K × 8-bit) low-power CMOS static RAM with 35ns maximum access time, TTL-compatible I/O, and 2V battery backup data retention. It operates across industrial temperature range (–40°C to +85°C), consumes ≤3µA standby current in full CMOS-level standby mode, and is packaged in a 28-pin 300-mil SOJ for high-density board layouts. It serves as main memory or buffer in real-time industrial controllers requiring non-volatile data hold during power loss.

For engineers reviewing the IDT71256L35Y datasheet, IDT71256L35Y pinout, IDT71256L35Y application, or IDT71256L35Y equivalent, key selection criteria include its guaranteed 35ns read cycle time at 5V ±10%, sub-5µW battery-backed standby power, industrial-grade reliability per MIL-STD-883 Class B compliance, and direct TTL-level interface compatibility without level-shifting.

Technical Context

The IDT71256L35Y implements a fully decoded 15-bit address space (A0–A14) driving a 262,144-bit memory array with bidirectional 8-bit data I/O (I/O0–I/O7). Its control architecture uses three independent active-low enables - CS (chip select), WE (write enable), and OE (output enable) - enabling flexible read/write timing via either WE-controlled or CS-controlled cycles.

Two distinct standby modes are supported: TTL-level standby (ISB ≤3mA) when CS > VIH, and full CMOS-level standby (ISB1 ≤3µA) when CS > VHC, with automatic transition. Data retention at 2V is guaranteed over the full industrial temperature range, with tCDR = 0ns and ICCDR ≤120µA at 3.0V.

Key Specifications

Pinout & Package

Package: 28-pin SOJ (Small Outline J-Lead), 300-mil width, lead pitch 0.050", JEDEC MO-097 compliant. RoHS-compliant lead finish per ordering code Y.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY62256ELL-45ZSXI and AS6C4008-35TIN, the IDT71256L35Y uniquely combines 35ns speed, 5V TTL compatibility, industrial temperature rating, and guaranteed 2V data retention - making it irreplaceable in legacy 5V systems requiring battery-backed memory resilience.

Availability

IDT71256L35Y is available at Aetrix Electronics and suitable for industrial PLCs, avionics data loggers, and railway signaling controllers requiring stable component supply across extended lifecycle programs.

Supply support for IDT71256L35Y 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

Integrated Device Technology (IDT), now part of Renesas Electronics, is a fabless semiconductor company specializing in timing, memory, and interface solutions for communications, computing, and industrial markets.

The IDT71256L35Y belongs to IDT's legacy high-reliability SRAM product line, designed specifically for mission-critical industrial and aerospace applications demanding guaranteed data retention, wide temperature operation, and long-term supply stability.

FAQ

What is the guaranteed data retention voltage for IDT71256L35Y?

IDT71256L35Y guarantees data retention down to 2.0V across its full industrial operating temperature range (–40°C to +85°C). This specification is explicitly validated in the datasheet Table 11, enabling reliable operation during brownout conditions or when powered solely by backup batteries. The IDT71256L35Y achieves this with ICCDR ≤120µA at 3.0V, ensuring minimal energy draw during retention mode.

Does IDT71256L35Y support both WE-controlled and CS-controlled write cycles?

Yes, IDT71256L35Y supports both WE-controlled and CS-controlled write cycles as defined in Figures 10 and 11 of the datasheet. In WE-controlled mode, write timing is governed by tWP (min 30ns) and tDW (min 15ns); in CS-controlled mode, tCW (min 30ns) and tAW (min 30ns) apply. The IDT71256L35Y's dual-mode flexibility allows integration with diverse controller architectures without timing constraint violations.

What is the maximum operating current for IDT71256L35Y during active read cycles?

IDT71256L35Y draws a maximum dynamic operating current (ICC) of 115mA under worst-case conditions: VCC = 5.5V, all outputs open, and address inputs cycling at fMAX = 1/tRC (i.e., 28.6MHz for 35ns tRC). This value is specified in Table 7 for the "71256L35" speed grade under industrial/military columns and reflects peak power demand during sustained random-access bursts.

Is IDT71256L35Y pin-compatible with other speed grades in the IDT71256L family?

IDT71256L35Y is mechanically and electrically pin-compatible with all other IDT71256L variants (e.g., IDT71256L25Y, IDT71256L45Y) in the same SOJ-28 package. Pin functions, voltage levels, timing conventions, and DC characteristics are identical - only access time and associated AC parameters differ. This allows direct speed-grade substitution in existing designs without layout changes.

What packaging and lead finish does IDT71256L35Y use?

IDT71256L35Y is supplied in a 28-pin Small Outline J-Lead (SOJ) package, 300-mil body width, with lead finish specified by the suffix 'Y' - indicating 100% matte tin (Sn) per J-STD-609, RoHS-compliant and compatible with standard Pb-free reflow profiles. The package conforms to JEDEC MO-097 and supports automated placement and reflow soldering.