Renesas 70V25S55J

Overview

70V25S55J from Integrated Device Technology (IDT) is a high-speed 4K x 16 true dual-port static RAM with independent asynchronous left/right ports, 55 ns read cycle time, 3.3 V single-supply operation, and on-chip semaphore arbitration-designed for real-time inter-processor communication in industrial motion controllers.

For engineers reviewing the 70V25S55J datasheet, 70V25S55J pinout, 70V25S55J application, or 70V25S55J equivalent, key selection criteria include its 55 ns access timing, 100-pin TQFP package with verified dual-port I/O mapping, industrial temperature range (–40°C to +85°C), and full hardware semaphore support for lock-free resource sharing between CPUs.

Technical Context

The 70V25S55J implements fully asynchronous dual-port architecture with separate address, control, and data buses per port-enabling simultaneous read/write operations to the same memory location without contention. Its on-chip arbitration logic resolves port conflicts via BUSY flag signaling and supports MASTER/SLAVE cascading for 32-bit+ bus expansion.

It integrates dedicated semaphore registers (A0–A2 addressed, 8 flags) accessible via SEM pin control, with guaranteed 5 ns semaphore write-to-read delay (tSWRD) and 5 ns contention window (tSPS). All I/Os are LVTTL-compatible, and power management includes CE-controlled active/standby modes with typ. 400 mW active and 3.3 mW standby current.

Key Specifications

Pinout & Package

70V25S55J is housed in a 100-pin Thin Quad Flatpack (TQFP, package code PNG100), measuring 14 mm × 14 mm × 1.4 mm, with exposed pad not electrically connected. All VDD and VSS pins require local decoupling per datasheet layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C024AV-55AXC, 70V25S55J delivers integrated BUSY arbitration and TQFP packaging for simplified layout; versus IDT70V24L15J, it trades speed for lower power and broader commercial/industrial availability at 55 ns.

Availability

70V25S55J is available at Aetrix Electronics and suitable for industrial motion controllers, redundant PLC modules, avionics data concentrators, and digital signal processor co-processor interfaces requiring stable component supply across extended product lifecycles.

Supply support for 70V25S55J 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, designs high-performance timing, memory, and interface solutions for communications, computing, and industrial markets.

The IDT70V25 family targets real-time embedded systems requiring deterministic, contention-free inter-processor communication-optimized for industrial automation, test equipment, and aerospace data handling.

FAQ

What is the maximum operating temperature range for the 70V25S55J?

The 70V25S55J is specified for industrial temperature operation from –40°C to +85°C. This rating is validated across all electrical parameters including 55 ns read cycle time, 400 mW active power, and semaphore timing (tSWRD, tSPS), making it suitable for deployment in motor drives, factory automation, and outdoor infrastructure equipment without derating.

Does the 70V25S55J support true simultaneous read/write operations on both ports?

Yes, the 70V25S55J implements true dual-port SRAM architecture allowing independent, fully asynchronous read or write access to any memory location from either port-even the same address. Hardware arbitration via BUSY flag and semaphore logic prevents data corruption during contention, eliminating software locks or polling overhead in multi-CPU systems.

What package type and pin count does the 70V25S55J use?

The 70V25S55J uses a 100-pin Thin Quad Flatpack (TQFP) package, designated PNG100, with physical dimensions of 14 mm × 14 mm × 1.4 mm. Pinout follows the IDT70V25 family layout: A12 is No Connect, and I/O0–I/O15 are assigned per port with dedicated upper/lower byte controls (UBL/UBR, LBL/LBR).

How does semaphore functionality work on the 70V25S55J?

The 70V25S55J includes eight hardware semaphore flags accessed via A0–A2 address lines and controlled by the SEM pin. When SEM = VIL and CE = VIH (or UB/LB = VIH), writes to I/O0 set flags and reads return flag state across all I/O pins. Timing guarantees include 5 ns write-to-read delay (tSWRD) and 5 ns contention window (tSPS), ensuring deterministic lock acquisition in real-time systems.

Is the 70V25S55J pin-compatible with other IDT70V25 variants like the 70V25S15J?

Yes, the 70V25S55J shares identical pinout, package (100-pin TQFP), and signal naming with all IDT70V25 speed grades-including 70V25S15J and 70V25S20J. Differences are limited to AC timing parameters (e.g., tRC = 15 ns vs. 55 ns) and power consumption; no PCB redesign is needed when upgrading or downgrading speed grades within the same S-series industrial temperature variant.