Renesas 70V25S55J8

Overview

70V25S55J8 from Integrated Device Technology (IDT) is a high-speed 4K x 16 dual-port static RAM with true asynchronous dual-port architecture, 55 ns read/write cycle time, 3.3 V single-supply operation, and integrated semaphore logic for inter-processor communication in real-time embedded systems.

For engineers reviewing the 70V25S55J8 datasheet, 70V25S55J8 pinout, 70V25S55J8 application, or 70V25S55J8 equivalent, this device supports simultaneous independent access from left/right ports, on-chip arbitration, BUSY/INT flag signaling, and byte-selectable I/O control-critical for FPGA-to-processor bridging, digital signal co-processing, and industrial motion controller memory buffers.

Technical Context

The 70V25S55J8 implements fully asynchronous dual-port SRAM cells with separate address, data, and control buses per port, enabling concurrent read/write operations to the same or different addresses without external arbitration logic. Its internal semaphore register set (A0–A2 addressed, 8 flags) provides hardware-level mutual exclusion between ports.

It uses CMOS process technology optimized for 3.3 V operation, with TTL-compatible input thresholds and push-pull output drivers. The device supports Master/Slave cascading via M/S pin to expand bus width beyond 16 bits, and includes automatic power-down when CE is deasserted.

Key Specifications

Pinout & Package

70V25S55J8 is housed in a 100-pin Thin Quad Flatpack (TQFP) package with 0.5 mm pitch, body size 14 mm × 14 mm × 1.4 mm. All VDD (pins 26, 42, 59, 76) and VSS (pins 25, 41, 58, 75, 85, 95) pins require proper decoupling. A12 is No Connect on this variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C024AV-55AXC, 70V25S55J8 offers integrated arbitration and cascading-reducing BOM count and PCB area. Against IDT70V24L55J, it trades 3× higher standby power for commercial-grade cost optimization and simplified thermal design.

Availability

70V25S55J8 is available at Aetrix Electronics and suitable for industrial motion control, FPGA interface, digital audio co-processing, and redundant safety PLC applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for 70V25S55J8 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 interface, RF, and sensor signal conditioning ICs for communications, computing, and industrial markets.

The IDT70V25 family was designed specifically for high-reliability, low-latency dual-processor memory sharing in real-time embedded systems-prioritizing deterministic timing, hardware arbitration, and seamless bus expansion over density or cost-per-bit.

FAQ

What is the maximum operating frequency supported by the 70V25S55J8?

The 70V25S55J8 supports a maximum read cycle rate of 18.2 MHz, derived from its 55 ns read cycle time (tRC). This is the sustained throughput limit under worst-case commercial temperature and voltage conditions. It does not specify a clock input-operation is fully asynchronous, with timing governed by CE, OE, R/W, and address setup/hold constraints per AC table.

Does the 70V25S55J8 support simultaneous read and write to the same memory location?

Yes, the 70V25S55J8 implements true dual-port SRAM cells that permit simultaneous reads from both ports to the same address. However, simultaneous write-to-same-address is not permitted: the BUSY flag asserts to indicate contention, and internal arbitration blocks conflicting writes. Reads remain valid during contention, preserving data integrity.

How is semaphore functionality implemented in the 70V25S55J8?

The 70V25S55J8 includes eight dedicated hardware semaphore flags accessed via A0–A2 address lines and I/O0 data line. When SEM is low and CE/UB/LB are high, the device enters semaphore mode: writing to I/O0 sets the flag; reading returns the flag state across all I/O pins. Contention window (tSPS = 5 ns) ensures atomic acquisition.

Can the 70V25S55J8 be used in a Master/Slave configuration with other IDT dual-port RAMs?

Yes, the 70V25S55J8 supports Master/Slave cascading using the M/S pin. When M/S = VIH, BUSY is an output flag indicating port contention; when M/S = VIL, BUSY is an input used by a Master device to detect Slave readiness. This enables expansion to 32-bit or wider data buses without external logic.

What are the key differences between the 70V25S55J8 and the 70V24L55J variants?

The 70V25S55J8 and 70V24L55J share identical 4K × 16 organization, 55 ns timing, and pinout. Key differences: 70V25S55J8 is commercial-grade (0°C to +70°C) with 400 mW active power and 3.3 mW standby; 70V24L55J is industrial-grade (-40°C to +85°C) with 380 mW active and 660 µW standby. Both support same features and interfaces.