Renesas 70V28L25PF

Overview

70V28L25PF from IDT (Integrated Device Technology) is a high-speed, 3.3V, 64K × 16 true dual-ported static RAM with independent left/right ports, 20 ns max access time (industrial grade), LVTTL-compatible I/O, and on-chip semaphore/arbiration logic for multi-processor synchronization. It enables simultaneous read/write to the same memory location in systems requiring deterministic inter-processor communication - such as real-time motion control PLCs.

For engineers reviewing the 70V28L25PF datasheet, 70V28L25PF pinout, 70V28L25PF application, or 70V28L25PF equivalent, key selection criteria include BUSY arbitration timing (tBAA ≤ 20 ns), dual CE support for depth expansion, M/S-configurable master/slave operation, and integrated semaphore flag handling without external logic.

Technical Context

The 70V28L25PF implements fully asynchronous dual-port architecture with separate address, control, and data buses per port. Its on-chip arbitration logic resolves contention via push-pull BUSY flags (BUSYL/BUSYR), with tBDD ≤ 17 ns propagation delay from write to valid read data under master mode (M/S = VIH).

It integrates eight dedicated semaphore latches accessible via A0–A2 and controlled by SEM pins, supporting token-passing protocols between processors. Semaphore updates require tSOP = 10 ns pulse width and exhibit tSPS = 5 ns contention window, ensuring deterministic mutual exclusion without software polling overhead.

Key Specifications

Pinout & Package

70V28L25PF is housed in a 100-pin Thin Quad Flatpack (TQFP) with 0.5 mm pitch; package body measures 14 mm × 14 mm × 1.4 mm. All GND and VCC pins must be connected per datasheet Note 1–2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C028V-20AXC and AS7C364B-20TIN, the 70V28L25PF uniquely delivers integrated semaphore, interrupt, and push-pull BUSY logic in a single 100-pin TQFP - eliminating board space, bill-of-materials, and firmware complexity associated with discrete arbitration solutions.

Availability

70V28L25PF is available at Aetrix Electronics and suitable for industrial motion controllers, redundant PLC communication modules, and avionics data concentrators requiring stable component supply across extended product lifecycles.

Supply support for 70V28L25PF 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 70V28L25PF belongs to IDT's legacy high-speed dual-port SRAM family, engineered specifically for deterministic multi-processor synchronization in real-time embedded systems where software-only coordination introduces unacceptable latency.

FAQ

What is the maximum operating temperature range certified for the 70V28L25PF?

The 70V28L25PF is specified for industrial operation from −40°C to +85°C. This rating is confirmed in the Absolute Maximum Ratings table and DC Operating Conditions section of the official IDT datasheet DSC-4849/8. The device maintains full 20 ns access time performance across this entire range, making it suitable for factory-floor and outdoor embedded deployments where thermal stability is critical. All timing parameters in Table 12 and Table 14 are guaranteed within this temperature envelope.

Does the 70V28L25PF support true simultaneous read/write to the same memory address?

Yes, the 70V28L25PF implements true dual-ported memory cells that allow independent, asynchronous access to any location - including simultaneous read and write operations to the identical address. When contention occurs, the on-chip arbitration logic asserts BUSYL or BUSYR to stall the later-accessing port, ensuring data integrity. This behavior is explicitly described in the Functional Description and Truth Table V sections of the datasheet.

How does the M/S pin affect BUSY pin functionality on the 70V28L25PF?

When M/S = VIH, the 70V28L25PF operates as a master: BUSYL and BUSYR become push-pull outputs that signal address contention. When M/S = VIL, it operates as a slave: BUSYL and BUSYR become inputs that externally inhibit writes - allowing external arbitration control. This dual-mode capability is documented in Notes 1 and 2 of the Functional Block Diagram and confirmed in Truth Table V.

Can the 70V28L25PF be used without enabling the semaphore or interrupt features?

Yes. The 70V28L25PF functions as a standard dual-port SRAM even when SEM = VIH and INTL/INTR are unused. Addresses FFFEh and FFFFh behave as regular memory locations unless explicitly written to trigger interrupt flags. Semaphore latches remain inactive unless SEM = VIL and CE = VIH - no configuration or initialization is required to disable these features.

What is the minimum pulse width required to update a semaphore flag on the 70V28L25PF?

The minimum semaphore write pulse width (tSOP) is 10 ns, as specified in Table 12 (AC Electrical Characteristics). This parameter applies to both left and right ports and is measured at the OE or SEM input. The timing waveform in Figure 9 confirms that a 10 ns pulse reliably updates the selected semaphore latch (A0–A2) without requiring additional setup/hold margins beyond those defined in tAS and tDH.