Renesas 7025S45PF8

Overview

7025S45PF8 from IDT is a high-speed 8K × 16 (128 Kbit) true dual-port static RAM with independent asynchronous left/right ports, 45 ns maximum read cycle time, TTL-compatible 5 V ±10% supply, and industrial temperature range (–40°C to +85°C). It supports simultaneous reads of the same memory location and is used in real-time DSP co-processing, military avionics bus arbitration, and redundant controller memory subsystems.

For engineers reviewing the 7025S45PF8 datasheet, 7025S45PF8 pinout, 7025S45PF8 application, or 7025S45PF8 equivalent, key selection criteria include dual-port arbitration latency, BUSY flag timing under M/S = VIH, semaphore update pulse width (tSOP = 10 ns), battery backup capability (2 V data retention), and compatibility with 84-pin PLCC packaging for legacy board reuse.

Technical Context

The 7025S45PF8 implements full hardware port arbitration with on-chip semaphore logic and BUSY flag generation, enabling deterministic contention resolution between independent left and right ports. Its dual-port architecture permits concurrent access without external logic-critical for lock-step processor pairs and real-time inter-processor communication.

It operates fully asynchronously from either port, supports separate upper-byte (UB/UBR) and lower-byte (LB/LBR) control for multiplexed bus interfacing, and includes Master/Slave select (M/S) for cascading configurations where one device acts as master (BUSY output) and others as slaves (BUSY input).

Key Specifications

Pinout & Package

7025S45PF8 is housed in an 84-pin Plastic Leaded Chip Carrier (PLCC), designated PLG84 per IDT package code. The body size is approximately 1.15 in × 1.15 in × 0.17 in, with gull-wing leads suitable for automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C028V-45AXC and R1EX24002AS0I-45#U0, the 7025S45PF8 uniquely integrates hardware semaphore registers, deterministic BUSY arbitration, and 2 V data retention in a drop-in 84-pin PLCC package-making it irreplaceable for legacy 5 V industrial and defense systems requiring zero-modification upgrades.

Availability

7025S45PF8 is available at Aetrix Electronics and suitable for real-time DSP co-processing, military avionics bus arbitration, and industrial PLC redundancy modules requiring stable component supply across extended product lifecycles.

Supply support for 7025S45PF8 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, RF, and high-performance silicon solutions, now part of Renesas Electronics.

The IDT7025 family was designed specifically for deterministic, low-latency inter-processor communication in dual-CPU systems-targeting aerospace, defense, and industrial control applications demanding guaranteed arbitration and battery-backed state retention.

FAQ

What is the maximum operating frequency supported by the 7025S45PF8?

The 7025S45PF8 has a maximum read cycle time (tRC) of 45 ns, corresponding to a theoretical maximum sustained dual-port throughput of 22.2 MHz per port. This assumes ideal conditions: no bus turnaround delays, minimal trace skew, and proper termination. Real-world system clock rates depend on address/data setup/hold margins and arbitration overhead-but the 45 ns spec ensures reliable operation in industrial 20 MHz bus environments. The 7025S45PF8 does not use an internal clock; all timing is asynchronous and governed by external control signal edges.

Does the 7025S45PF8 support battery backup for data retention?

Yes, the 7025S45PF8 supports data retention at VCC = 2.0 V, as specified in Table 10 of the datasheet. This capability is inherited from the IDT7025L low-power variant and remains functional in the S-version. During main power loss, applying ≥2.0 V to VCC (e.g., via backup battery) preserves stored data across the full industrial temperature range (–40°C to +85°C). Retention current is ≤4000 µA at military temperatures and ≤1500 µA commercially, enabling multi-year backup with standard coin cells when paired with low-leakage power management circuitry.

How does the M/S pin affect BUSY flag behavior in the 7025S45PF8?

When M/S = HIGH, the 7025S45PF8 operates as a master: BUSYR becomes an output that asserts during port contention, signaling the right port to suspend writes until resolution. When M/S = LOW, it operates as a slave: BUSYL becomes an input, requiring an external master's BUSY signal to gate its own write operations. This configuration enables hierarchical arbitration in multi-device systems-e.g., one master coordinates up to seven slaves in a 128-bit memory bank. The 7025S45PF8's tBDD timing (BUSY disable to valid data) is 30 ns max at 45 ns speed grade, ensuring deterministic recovery.

Can the 7025S45PF8 perform simultaneous reads from both ports to the same address?

Yes, the 7025S45PF8 explicitly supports true simultaneous reads of the same memory location from both ports-this is a defining feature of its "true dual-ported memory cells." Unlike pseudo-dual-port devices, no arbitration or BUSY assertion occurs during concurrent reads, and both ports deliver valid data within their respective tAA (address access time) windows (≤45 ns). This capability is essential for applications like mirrored diagnostics or real-time data mirroring, where latency-critical consistency across processors must be guaranteed without software intervention or hardware penalty.

What are the key timing parameters for semaphore operations in the 7025S45PF8?

Semaphore operations in the 7025S45PF8 are governed by tSOP (semaphore flag update pulse) = 10 ns and tSAA (semaphore address access) = 45 ns max. To write a semaphore flag, SEM must be LOW while CE and byte enables are HIGH; A0–A2 select one of eight flags, and I/O0 carries the write value. To read, SEM = LOW and OE = LOW enable output of the selected flag across I/O0–I/O15. The 7025S45PF8 guarantees tSWRD (write-to-read time) = 5 ns, enabling rapid lock acquire/release cycles critical for high-frequency inter-processor signaling without added pipeline stalls.