Renesas 70V05S55J

Overview

70V05S55J from IDT is a high-speed 3.3V 8K × 8 dual-port static RAM with true independent left/right ports, 15 ns (max) commercial access time, on-chip semaphore and interrupt logic, and full asynchronous operation-used in real-time inter-processor communication systems requiring simultaneous read/write access to shared memory.

For engineers reviewing the 70V05S55J datasheet, 70V05S55J pinout, 70V05S55J application, or 70V05S55J equivalent, key selection considerations include bus arbitration timing (tAPS), BUSY flag behavior under address contention, port-to-port delay (tDDD), 3.3V-only supply compliance, and TQFP-64 package compatibility with industrial temperature support.

Technical Context

The 70V05S55J implements fully asynchronous dual-port architecture with separate address, control, and I/O buses per port, enabling concurrent reads/writes-including simultaneous reads of the same location. It integrates hardware semaphore flags (8-bit, addressed via A0–A2), dedicated INTL/INTR outputs, and MASTER/SLAVE mode selection via M/S pin for cascaded 16-bit+ data bus expansion.

Arbitration is handled by on-chip logic supporting two BUSY assertion modes: address-match (tBAA/tBDA) and CE-controlled (tBAC/tBDC), with tAPS defining minimum setup for deterministic port priority. Port-to-port write-read delay (tDDD ≤ 53 ns) and BUSY deassertion timing (tBDD) are explicitly characterized for coherency-critical designs.

Key Specifications

Pinout & Package

64-pin thin quad flatpack (TQFP), package code PNG64, body size 14 mm × 14 mm × 1.4 mm. All VDD pins require local decoupling; all GND pins must be connected to system ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C024AV-15AXC and AS7C38098B-15JCIN, the 70V05S55J delivers integrated arbitration and signaling-reducing BOM count and PCB area while guaranteeing deterministic timing in real-time inter-processor communication.

Availability

70V05S55J is available at Aetrix Electronics and suitable for industrial automation, avionics data acquisition, and medical imaging systems requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for 70V05S55J 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

IDT (Integrated Device Technology) is a fabless semiconductor company specializing in high-performance timing, memory, and interface solutions, now part of Renesas Electronics.

The 70V05S55J belongs to IDT's legacy dual-port SRAM product line, designed specifically for deterministic real-time inter-processor communication in industrial, aerospace, and medical systems demanding hardware-enforced memory coherency.

FAQ

What is the maximum operating frequency supported by the 70V05S55J?

The 70V05S55J does not specify a clock frequency-it is a fully asynchronous SRAM. Its performance is defined by access time (tAA ≤ 15 ns) and cycle time (tRC ≤ 15 ns). When used in systems with synchronous controllers, the effective maximum data rate is ~66 MHz per port, constrained by tAA and tRC timing limits-not by an internal clock.

Does the 70V05S55J support 5V-tolerant I/O?

No, the 70V05S55J is strictly a 3.3V device: VDD = 3.3 V ± 0.3 V, and all I/O pins (including address, control, and data) are TTL-compatible but not 5V-tolerant. Applying 5V signals risks permanent damage. Level translation is mandatory for interfacing with 5V logic families.

How does the BUSY arbitration work when both ports access the same address simultaneously?

When both ports drive addresses that match (A0L–A12L = A0R–A12R), the 70V05S55J asserts BUSYL and BUSYR based on tAPS timing. If M/S = VIH (MASTER), BUSY outputs indicate which port wins arbitration. tAPS = 0 ns means the port with earlier address/enable stabilization gains immediate access-no software intervention needed.

Can the 70V05S55J be used in MASTER/SLAVE configuration with more than two devices?

Yes-the 70V05S55J supports multi-device cascading using the MASTER/SLAVE architecture. One device is configured as MASTER (M/S = VIH), others as SLAVES (M/S = VIL). BUSY outputs from the MASTER feed BUSY inputs of SLAVES, enabling hierarchical arbitration across three or more devices in wide-data systems (e.g., 32-bit or 64-bit buses).

What is the purpose of the SEM pins, and how are semaphores accessed?

The SEML and SEMR pins enable hardware semaphore register access. When SEM = VIL and CE = VIH, writes to I/O0–I/O7 (addressed by A0–A2) set/clear one of eight semaphore flags. Reads return the flag state. This provides atomic resource-locking without CPU intervention-critical for preventing race conditions in multi-processor environments using the 70V05S55J.