Renesas 7140LA55PF8

Overview

7140LA55PF8 from IDT (Integrated Device Technology) is a 1K × 8 dual-port static RAM configured as a slave device in MASTER/SLAVE memory expansion systems, supporting fully asynchronous left/right port access with 55 ns maximum read cycle time, 1 µA typical full-standby current (CMOS-level CE), and battery-backed data retention at 2 V - deployed in real-time interprocessor communication and military-grade avionics bus arbitration.

For engineers reviewing the 7140LA55PF8 datasheet, 7140LA55PF8 pinout, 7140LA55PF8 application, or 7140LA55PF8 equivalent, this page delivers verified timing parameters, BUSY-input arbitration behavior, dual-port I/O isolation, industrial temperature support (–40°C to +85°C), and direct replacement guidance for legacy IDT dual-port SRAM designs requiring low-power, contention-aware shared memory.

Technical Context

The 7140LA55PF8 operates as a SLAVE dual-port SRAM with dedicated BUSY input pins (BUSYL, BUSYR) that inhibit writes when asserted low - unlike the MASTER IDT7130 which drives open-drain BUSY outputs. It lacks on-chip arbitration logic but relies on external MASTER coordination for address-matching contention resolution.

Its 55 ns speed grade supports tRC = 55 ns, tAA = 55 ns, and tACE = 55 ns under commercial/industrial/military conditions; write pulse width tWP is 30 ns min, and BUSY-input timing tWB is 0 ns - enabling immediate write blocking upon BUSY assertion from the MASTER port.

Key Specifications

Pinout & Package

7140LA55PF8 is packaged in a 48-pin ceramic flatpack (FP48), 0.75″ × 0.75″ × 0.11″ body size, with 2×24 pin grid, dual-row layout, and hermetically sealed construction suitable for high-reliability applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C135-55JC and IDT7130LA55PF8, the 7140LA55PF8 uniquely provides slave-specific BUSY input behavior and interrupt flag generation without arbitration overhead - making it irreplaceable in MASTER/SLAVE topologies requiring minimal external logic and guaranteed write-blocking latency.

Availability

7140LA55PF8 is available at Aetrix Electronics and suitable for avionics data bus interfaces, real-time interprocessor communication, military vehicle control systems, and industrial PLC memory expansion requiring stable component supply across extended temperature and long lifecycle programs.

Supply support for 7140LA55PF8 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 memory, timing, and interface solutions, now part of Renesas Electronics since 2019.

The IDT7130/7140 family was designed specifically for deterministic, low-latency shared memory in safety-critical dual-processor systems - emphasizing bus arbitration integrity, battery backup, and military-grade reliability.

FAQ

What is the role of BUSYL and BUSYR on the 7140LA55PF8?

On the 7140LA55PF8, BUSYL and BUSYR are dedicated input-only signals - unlike the MASTER IDT7130, which drives them as open-drain outputs. When either BUSYL or BUSYR is pulled low by the MASTER device, the corresponding port's write operations are internally inhibited. This prevents data corruption during address contention and is fundamental to the MASTER/SLAVE arbitration scheme. The 7140LA55PF8 itself does not generate BUSY signals.

Does the 7140LA55PF8 support battery backup operation?

Yes, the 7140LA55PF8 supports battery backup operation with guaranteed data retention at VCC = 2.0 V, as confirmed by its "LA" suffix designation and documented in Table 7 (Data Retention Characteristics). In this mode, ICCDR is specified at ≤ 4000 µA (military) or ≤ 1500 µA (commercial), enabling extended hold-up time using small backup cells - a key feature distinguishing LA from SA variants.

Can the 7140LA55PF8 operate as a standalone dual-port SRAM without a MASTER device?

No - the 7140LA55PF8 is explicitly designed as a SLAVE device and lacks on-chip arbitration logic, BUSY output capability, and autonomous contention resolution. It requires pairing with an IDT7130 MASTER to manage address matching, assert BUSY signals, and coordinate interrupt flag setting. Attempting standalone use results in undefined write behavior during port conflicts and non-functional BUSY inputs.

What is the meaning of the "PF8" suffix in 7140LA55PF8?

The "PF8" suffix denotes a 48-pin ceramic flatpack (FP48) package with 0.050″ lead pitch and hermetic sealing - a high-reliability, military-grade package variant compliant with MIL-PRF-38535 QML requirements. It differs from plastic DIP (PDG48), LCC (LC48), PLCC (PLG52), and TQFP (PPG64/PNG64) variants in thermal performance, moisture resistance, and long-term stability under thermal cycling and vibration stress.

How does interrupt flag handling work on the 7140LA55PF8?

The 7140LA55PF8 supports hardware-generated interrupt flags (INTL and INTR) via special address writes: writing to address 3FFh sets the opposite port's interrupt flag (e.g., left-port write to 3FFh sets INTR), while writing to 3FEh clears it. These are open-drain outputs requiring external pull-up resistors. Timing is characterized - tINS ≤ 45 ns (55 ns grade) - enabling fast inter-processor signaling without software polling overhead.