Renesas 70261L15PF8

Overview

70261L15PF8 from IDT (Integrated Device Technology) is a high-speed 16K × 16 true dual-port static RAM with interrupt and semaphore logic, operating at 15 ns max access time (commercial grade), 5 V ±10% supply, and featuring independent left/right ports with full asynchronous operation. It enables concurrent read/write access to the same memory location and supports MASTER/SLAVE cascading for 32-bit+ bus expansion in real-time embedded systems.

For engineers reviewing the 70261L15PF8 datasheet, 70261L15PF8 pinout, 70261L15PF8 application, or 70261L15PF8 equivalent, key selection criteria include dual-port arbitration timing (tBDD ≤ 18 ns), low standby power (1 mW typ.), 100-pin TQFP package compatibility, and hardware semaphore support for multi-processor synchronization.

Technical Context

The 70261L15PF8 implements fully asynchronous dual-port architecture with on-chip arbitration logic that resolves contention via BUSY flag assertion-either by address match (tBAA ≤ 15 ns) or chip enable transition (tBAC ≤ 15 ns). Its semaphore subsystem uses A0–A2 addressing to control eight independent flags accessible via I/O0 write and full I/O0–I/O15 read.

Interrupt functionality is implemented through dedicated mailbox addresses: INTL asserts on right-port write to 3FFE_H, INTR asserts on left-port write to 3FFF_H; both flags clear via port-specific read/write cycles per Truth Table III. The device operates exclusively in TTL-compatible 5 V logic with push-pull BUSY/INT outputs and no level-shifting capability.

Key Specifications

Pinout & Package

70261L15PF8 is housed in a 100-pin TQFP (PNG100) package with 0.5 mm pitch, requiring all 12 VCC and 12 GND pins to be properly decoupled. Pin functions are strictly segregated between left port (L-suffixed) and right port (R-suffixed) signal groups, with no shared control lines except M/S and global power/ground.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV18 and AS7C3316PFS, the 70261L15PF8 uniquely delivers integrated 5 V dual-port operation with hardware semaphore, interrupt mailbox, and BUSY arbitration-enabling direct replacement of discrete logic in real-time multi-processor systems without redesigning timing-critical control paths.

Availability

70261L15PF8 is available at Aetrix Electronics and suitable for real-time digital signal processing, multi-processor communication bridges, industrial motion controllers, and telecom line card buffers requiring stable component supply and long-term obsolescence management.

Supply support for 70261L15PF8 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 computing solutions, acquired by Renesas Electronics in 2019.

The IDT70261 product line was designed specifically for deterministic, low-latency inter-processor communication in embedded real-time systems-emphasizing hardware arbitration, interrupt signaling, and seamless bus-width scalability without external glue logic.

FAQ

What is the maximum operating frequency supported by the 70261L15PF8?

The 70261L15PF8 supports a maximum read cycle time (tRC) of 15 ns, corresponding to a theoretical maximum operating frequency of 66.7 MHz for random access patterns. This assumes proper setup/hold timing compliance (e.g., tAS = 0 ns, tDH = 0 ns) and valid address/control transitions under commercial temperature conditions (0°C to +70°C). Actual system clock rates depend on board layout, signal integrity, and bus loading.

Does the 70261L15PF8 support industrial temperature range operation?

No, the 70261L15PF8 is rated for commercial temperature range only (0°C to +70°C). Industrial-grade variants exist in the IDT70261 family (e.g., 70261L20PF8), but the '15' speed grade (15 ns access) is explicitly designated "Com'l Only" in the AC Electrical Characteristics tables. Operation outside 0°C–70°C is not characterized or guaranteed.

How does the BUSY arbitration logic function in MASTER vs. SLAVE configuration?

In MASTER mode (M/S = H), BUSYL and BUSYR are outputs that assert LOW when address contention occurs, stalling the contending port's write cycle. In SLAVE mode (M/S = L), BUSYL and BUSYR become inputs; an external MASTER's BUSY signal must be applied to inhibit writes. The 70261L15PF8 itself cannot act as SLAVE unless driven by a companion MASTER device-no internal arbitration occurs in SLAVE-only configurations.

Can the interrupt mailbox addresses (3FFE_H, 3FFF_H) be reconfigured or relocated?

No, the interrupt mailbox addresses are hardwired into the 70261L15PF8 silicon. INTL asserts exclusively on right-port write to address 3FFE_H, and INTR asserts exclusively on left-port write to 3FFF_H, as defined in Truth Table III. These locations cannot be remapped via configuration registers or external logic; they are fixed functional addresses within the 16K × 16 memory map.

What is the role of the SEM pin during normal RAM access versus semaphore register access?

During normal RAM access, SEM must be held HIGH (SEML = SEMR = VIH); asserting SEM LOW disables RAM access and enables the 8-bit semaphore register bank addressed by A0–A2. The 70261L15PF8 uses separate access paths: CE = VIL + SEM = VIH for RAM, and CE = VIH + SEM = VIL for semaphores. Mixing these conditions (e.g., CE = VIL + SEM = VIL) results in undefined behavior per Truth Table IV.