Renesas 70V261S25PF8

Overview

70V261S25PF8 from IDT is a high-speed 3.3V 16K × 16 true dual-port static RAM with independent left/right ports, 25 ns max access time (commercial & industrial), integrated semaphore logic, interrupt flag support, and master/slave arbitration for 32-bit+ bus expansion. It enables simultaneous read/write to the same memory location in real-time embedded inter-processor communication systems.

For engineers reviewing the 70V261S25PF8 datasheet, 70V261S25PF8 pinout, 70V261S25PF8 application, or 70V261S25PF8 equivalent, key selection criteria include dual-port contention handling via BUSY arbitration, TTL-compatible 3.3V operation, on-chip semaphore addressing (A0–A2), interrupt mailbox addresses (3FFEh/3FFFh), and TQFP-100 packaging with 14 mm × 14 mm footprint.

Technical Context

The 70V261S25PF8 implements fully asynchronous dual-port architecture with separate address, control, and I/O buses per port-no shared timing constraints between left and right sides. Its on-chip arbitration logic resolves simultaneous accesses using chip-enable and address-match detection, asserting BUSY outputs (push-pull) without external logic.

Semaphore functionality operates independently of main memory: eight dedicated flags are accessed via CE = VIH and SEM = VIL, with writes driven by I/O0 and reads broadcast across all 16 I/O lines. Interrupts use fixed SRAM mailboxes (3FFEh for INTL, 3FFFh for INTR), supporting software-synchronized inter-processor signaling.

Key Specifications

Pinout & Package

70V261S25PF8 is housed in a 100-pin Thin Quad Flatpack (TQFP) with 0.5 mm pitch, 14 mm × 14 mm body size, and exposed thermal pad (not electrically connected). Pin 1 is marked by dot or bevelled corner at top-left when viewed top-side with pin 1 identifier in upper-left quadrant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C026V-25AXC and IDT70V25L25PF, the 70V261S25PF8 uniquely delivers hardware semaphore, interrupt mailbox, and industrial-grade BUSY arbitration in a single TQFP-100 package - reducing system-level component count and validation effort for safety-critical dual-processor platforms.

Availability

70V261S25PF8 is available at Aetrix Electronics and suitable for industrial PLC communication hubs, real-time avionics data exchange, and medical imaging frame buffers requiring stable component supply across extended lifecycle programs.

Supply support for 70V261S25PF8 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 interface, and RF solutions, now part of Renesas Electronics since 2019.

The 70V261S25PF8 belongs to IDT's legacy high-speed dual-port SRAM product line, engineered specifically for deterministic inter-processor communication in industrial automation, aerospace, and medical systems demanding hardware-enforced concurrency control.

FAQ

What is the maximum operating temperature range supported by the 70V261S25PF8?

The 70V261S25PF8 is qualified for industrial temperature operation from −40°C to +85°C, as confirmed in its DC electrical characteristics table and functional description. This rating applies to both commercial and industrial speed grades, making it suitable for under-hood automotive, factory-floor PLC, and outdoor telecom infrastructure applications where thermal stability is critical. The 70V261S25PF8 maintains full 25 ns access time performance across this entire range.

How does the BUSY arbitration logic function in master versus slave configuration for the 70V261S25PF8?

In master mode (M/S = VIH), the 70V261S25PF8 asserts BUSYL/BUSYR as push-pull outputs when address contention is detected - directly stalling the contending port's write cycle. In slave mode (M/S = VIL), BUSYL/BUSYR become inputs that internally inhibit writes when driven LOW, allowing centralized arbitration by a master device. This dual-mode behavior enables scalable multi-chip arrays without external AND gates or timing-critical glue logic.

Can the 70V261S25PF8 be used without enabling the semaphore or interrupt features?

Yes - the 70V261S25PF8 operates as a standard dual-port SRAM even when semaphore (SEM = VIH) and interrupt (3FFEh/3FFFh) functions are unused. Address locations 3FFEh and 3FFFh behave as regular memory cells, and semaphore registers remain inaccessible unless SEM = VIL. No configuration registers or initialization sequences are required; the device defaults to basic memory operation upon power-up with CE asserted.

What is the purpose of the UBL/UBR and LBL/LBR pins on the 70V261S25PF8?

The UBL/UBR (Upper Byte Select) and LBL/LBR (Lower Byte Select) pins on the 70V261S25PF8 enable independent 8-bit access to the 16-bit data bus per port. When only UBL and LBL are active, full 16-bit transfers occur; when only UBL is active, only I/O8–I/O15 are driven; when only LBL is active, only I/O0–I/O7 respond. This supports byte-level granularity for legacy 8-bit peripherals or partial-word updates without corrupting adjacent data.

Is the 70V261S25PF8 pin-compatible with other devices in the IDT70V261 family?

Yes - the 70V261S25PF8 shares identical pinout, package (TQFP-100), and signal definitions with all members of the IDT70V261 family, including 70V261L25PF8 (low-power variant) and speed variants like 70V261S35PF8. Differences are limited to internal power optimization and AC timing parameters; no PCB redesign is needed when substituting within the same speed/temperature grade.