Renesas 7005S55PF8

Overview

7005S55PF8 from IDT is a high-speed 8K × 8 (64 Kbit) true dual-port static RAM with independent left/right ports, 55 ns maximum read cycle time, TTL-compatible 5 V ±10% supply, and integrated semaphore/arbitration logic for inter-processor communication in real-time embedded systems.

For engineers reviewing the 7005S55PF8 datasheet, 7005S55PF8 pinout, 7005S55PF8 application, or 7005S55PF8 equivalent, this device supports simultaneous asynchronous access to shared memory, hardware-based port arbitration, battery-backed data retention down to 2 V, and master/slave cascading for 16-bit+ bus expansion without external logic.

Technical Context

The 7005S55PF8 implements fully asynchronous dual-port operation with separate address, control, and I/O buses per port - enabling concurrent reads/writes to any memory location. Its on-chip arbitration logic resolves contention via BUSY flag assertion and priority timing (tAPS = 5 ns), while semaphore registers (A0–A2 addressed) provide eight hardware flags for inter-port synchronization.

It supports two distinct operational modes: RAM access (CE = LOW, SEM = HIGH) and semaphore access (CE = HIGH, SEM = LOW), with dedicated timing parameters for each (e.g., tSAA ≤ 55 ns, tSOP = 15 ns). The M/S pin configures the device as master (BUSY output) or slave (BUSY input), enabling multi-device systems with deterministic arbitration behavior.

Key Specifications

Pinout & Package

7005S55PF8 is housed in a 64-pin thin quad flatpack (TQFP, package code PNG64), with power (VCC), ground (GND), and bidirectional I/O pins distributed across all four sides to minimize trace length and signal skew between ports.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C028V-55AXC and R1EX24064AS0I#U0, the 7005S55PF8 uniquely delivers true dual-port concurrency, hardware semaphore support, and 5 V native operation - making it irreplaceable in deterministic real-time inter-processor communication where latency and atomicity are critical.

Availability

7005S55PF8 is available at Aetrix Electronics and suitable for industrial automation, avionics subsystems, and medical imaging equipment requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for 7005S55PF8 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 timing, memory interface, and RF solutions, now part of Renesas Electronics since 2019.

The IDT7005 family was designed specifically for high-reliability dual-processor systems requiring deterministic memory sharing - targeting industrial control, defense electronics, and telecom infrastructure where bus arbitration latency and data coherency are mission-critical.

FAQ

What is the maximum operating frequency supported by the 7005S55PF8?

The 7005S55PF8 does not operate at a fixed clock frequency; instead, its 55 ns maximum read cycle time (tRC) defines the fastest sustainable access rate - approximately 18.2 MHz per port under ideal conditions. Actual throughput depends on address stability, control timing margins, and whether operations are read-only or include writes. The device is fully asynchronous, so no system clock is required.

Does the 7005S55PF8 support battery backup operation, and what voltage range is valid?

Yes, the 7005S55PF8 supports battery backup operation with guaranteed data retention down to VCC = 2.0 V. This is explicitly specified in the "Data Retention Characteristics" table (Table 9) for the L-version variants. The 7005S55PF8 is an S-version (standard power), but retains the same 2 V retention capability per IDT documentation. Below 2 V, data integrity is not assured.

How does the M/S pin affect BUSY pin functionality on the 7005S55PF8?

When M/S = HIGH, the 7005S55PF8 operates as a master: BUSYL and BUSYR become push-pull outputs that assert LOW during port-to-port address contention. When M/S = LOW, it operates as a slave: BUSYL and BUSYR become inputs that must be driven LOW by a master device to inhibit writes - enabling hierarchical arbitration in multi-chip configurations.

Can the 7005S55PF8 perform simultaneous reads from both ports to the same memory address?

Yes, the 7005S55PF8 supports true simultaneous reads to the same memory location from both ports - a core feature of its "true dual-ported memory cells." This is confirmed in the Features section ("True Dual-Ported memory cells which allow simultaneous reads of the same memory location") and requires no arbitration or BUSY assertion, unlike write operations.

What are the key timing differences between RAM access and semaphore access on the 7005S55PF8?

RAM access requires CE = LOW and SEM = HIGH, with timing governed by tRC (55 ns), tAA, and tACE. Semaphore access requires CE = HIGH and SEM = LOW, using separate parameters: tSAA (≤55 ns) for address setup and tSOP (15 ns) for flag update pulse width. These are distinct timing domains - mixing modes within one cycle violates specification and may cause undefined behavior.