Renesas 70V261L25PFI8

Overview

70V261L25PFI8 from IDT (now Renesas) is a high-speed, 3.3V, 16K × 16 (256 Kbit) true dual-port static RAM with independent left/right ports, on-chip semaphore logic, interrupt flag support, and BUSY arbitration-designed for real-time inter-processor communication in telecom switching, network packet buffering, and industrial motion control systems.

For engineers reviewing the 70V261L25PFI8 datasheet, 70V261L25PFI8 pinout, 70V261L25PFI8 application, or 70V261L25PFI8 equivalent, this device delivers 25 ns max access time, 660 µW standby power, industrial temperature range (−40°C to +85°C), and full hardware port arbitration without external logic-critical for deterministic dual-CPU memory sharing.

Technical Context

The 70V261L25PFI8 implements fully asynchronous dual-port operation with separate address, control, and I/O buses per port. Its arbitration logic uses chip enable (CE) and address match detection-not R/W state-to assert BUSY, enabling deterministic conflict resolution during simultaneous access to identical memory locations.

It integrates three coexisting coordination mechanisms: (1) push-pull BUSY outputs (configurable as input in slave mode via M/S pin), (2) eight dedicated semaphore registers accessed via A0–A2 with write-to-I/O0/read-from-all-I/O protocol, and (3) interrupt flags (INTL/INTR) triggered by writes to fixed mailbox addresses 3FFEh (left) and 3FFFh (right).

Key Specifications

Pinout & Package

70V261L25PFI8 is housed in a 100-pin Thin Quad Flatpack (TQFP) with exposed thermal pad (not electrically connected). Pin 1 is located at top-left corner (marking dot adjacent), and pin numbering proceeds counter-clockwise. All VCC (pins 12, 38, 64, 90) and GND (pins 11, 25, 50, 75, 89) must be individually decoupled per layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C026V-25AXC and AS7C3256A-25JCIN, the 70V261L25PFI8 uniquely integrates arbitration, semaphores, and interrupts in one package-reducing PCB area by ≥35%, eliminating external logic, and guaranteeing sub-25 ns conflict resolution without firmware intervention.

Availability

70V261L25PFI8 is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and medical imaging systems requiring stable component supply, long-term lifecycle assurance, and industrial-grade temperature performance.

Supply support for 70V261L25PFI8 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), now part of Renesas Electronics, is a fabless semiconductor company specializing in high-performance timing, memory, and interface solutions for communications and industrial markets.

The 70V261L25PFI8 belongs to IDT's high-speed dual-port SRAM product line, engineered specifically for deterministic, low-latency inter-processor communication in real-time embedded systems where software arbitration introduces unacceptable jitter or overhead.

FAQ

What is the maximum operating frequency supported by the 70V261L25PFI8?

The 70V261L25PFI8 does not operate on a clock signal-it is fully asynchronous. Its 25 ns maximum access time (tAA) supports effective interface rates up to 40 MHz when used with standard TTL-level control timing. System-level throughput depends on CE, OE, and R/W setup/hold timing margins, not an internal clock. The 70V261L25PFI8 achieves deterministic latency without clock domain constraints, making it ideal for mixed-signal real-time systems.

How does the BUSY arbitration logic function in master vs. slave configuration for the 70V261L25PFI8?

In master mode (M/S = VIH), the 70V261L25PFI8 asserts BUSYL/BUSYR as push-pull outputs when address and CE match on both ports-stalling the later access. In slave mode (M/S = VIL), BUSYL/BUSYR become inputs that internally inhibit writes when driven low. This dual-mode architecture enables scalable width expansion: one master arbitrates while multiple slaves obey its BUSY signal, eliminating split-decision conflicts in multi-chip arrays.

Can the 70V261L25PFI8 be used without enabling the semaphore or interrupt features?

Yes-the 70V261L25PFI8 operates as a standard dual-port SRAM even when SEM is held high (disabling semaphore access) and INTL/INTR are unconnected. Addresses 3FFEh and 3FFFh function as regular memory locations unless explicitly used as mailboxes. The device retains full 16K × 16 capacity and 25 ns access performance regardless of semaphore/interrupt usage, providing design flexibility for phased feature implementation.

What is the power consumption difference between active and standby modes for the 70V261L25PFI8?

The 70V261L25PFI8 draws 100 mA typical dynamic current (ICC) with both ports active at fMAX, equating to ~330 mW at 3.3 V. In full standby (ISB3), with CMOS-level inputs and both CEs high, it consumes only 0.2 mA typical-just 660 µW. This >500× reduction enables energy-efficient operation in always-on systems, such as remote telemetry nodes, where the 70V261L25PFI8 remains ready for instant wake-up without battery drain.

Is the 70V261L25PFI8 pin-compatible with other members of the IDT70V261 family?

Yes-the 70V261L25PFI8 shares identical pinout and footprint with all IDT70V261 variants (e.g., 70V261S25PFI8, 70V261L35PFI), differing only in speed grade (25 ns vs. 35 ns) and power profile (L = low-standby, S = standard-standby). This allows drop-in replacement during design optimization or qualification-no PCB revision needed when upgrading to faster or lower-power versions within the same package.