Renesas 7140LA35J8

Overview

7140LA35J8 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 35 ns maximum read cycle time, 2V data retention capability, and industrial temperature operation (–40°C to +85°C). It enables error-free 16-bit-or-wider memory systems without external arbitration logic.

For engineers reviewing the 7140LA35J8 datasheet, 7140LA35J8 pinout, 7140LA35J8 application, or 7140LA35J8 equivalent, this page delivers verified specifications, package mapping, port arbitration behavior, BUSY input timing, and real-world use cases for embedded control, real-time inter-processor communication, and battery-backed buffer memory design.

Technical Context

The 7140LA35J8 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 BUSY outputs. Its arbitration logic responds only to address match detection between ports, requiring tAPS ≥5 ns setup to guarantee deterministic priority resolution.

It supports independent TTL-compatible 5V ±10% operation per port, with CE-controlled power-down modes yielding 1 µA full-standby current (ISB3) and 200 µW typical battery-retention draw at 2V. All I/Os are bidirectional with three-state control via OEL/OER and R/WL/R/WR.

Key Specifications

Pinout & Package

7140LA35J8 is supplied in a 48-pin ceramic flatpack (FP48) package measuring approximately 0.75 in × 0.75 in × 0.11 in, with lead finish suitable for high-reliability military and industrial soldering processes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C135-35JC and IDT7134LA35JG, the 7140LA35J8 uniquely combines SLAVE-specific BUSY input behavior, 2V data retention, and QML Class V qualification-making it irreplaceable in battery-backed, safety-critical MASTER/SLAVE architectures.

Availability

7140LA35J8 is available at Aetrix Electronics and suitable for real-time inter-processor communication, industrial PLC data buffering, and military avionics shared memory applications requiring stable component supply across extended product lifecycles.

Supply support for 7140LA35J8 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, and interface solutions, now part of Renesas Electronics.

The IDT7130/7140 family was designed specifically for deterministic, low-latency dual-processor memory sharing-targeting aerospace, defense, and industrial control systems demanding guaranteed write collision avoidance and battery-backed data integrity.

FAQ

What is the role of BUSYL and BUSYR on the 7140LA35J8?

BUSYL and BUSYR are dedicated input pins on the 7140LA35J8 that, when driven low, inhibit write operations to the left and right ports respectively. Unlike the MASTER IDT7130 which drives BUSY outputs, the 7140LA35J8 relies entirely on external arbitration signals-requiring pull-up resistors and coordination with a MASTER device to prevent memory contention. This SLAVE-specific interface eliminates need for discrete logic in expanded memory systems.

Does the 7140LA35J8 support true 2V data retention, and how is it implemented?

Yes, the 7140LA35J8 supports guaranteed 2.0 V minimum VCC for data retention-confirmed in datasheet Table 7. When main VCC drops below 4.5 V, the device enters data retention mode with ICCDR ≤4 µA (typical) at 2V, preserving stored values indefinitely without refresh. This is enabled by the LA (Low-power Active) variant's optimized CMOS design and does not require external circuitry-making it ideal for battery-backed applications like avionics black boxes or industrial UPS buffers.

Can the 7140LA35J8 operate as a standalone dual-port memory without a MASTER device?

No-the 7140LA35J8 is explicitly designed as a SLAVE device and lacks on-chip arbitration logic. Its BUSY pins are inputs only, and it cannot resolve port conflicts autonomously. Attempting standalone use risks undetected write collisions and data corruption. It must be paired with an IDT7130 MASTER or functionally equivalent controller that drives BUSY outputs and manages priority arbitration per Truth Table III in the datasheet.

What package type is used for the 7140LA35J8, and why does it matter for reliability?

The 7140LA35J8 uses a 48-pin ceramic flatpack (FP48) package with dimensions ~0.75 in × 0.75 in × 0.11 in. Ceramic construction provides superior thermal stability, hermetic sealing against moisture and contaminants, and mechanical robustness under shock/vibration-key for MIL-PRF-38535 QML Class V qualification. This makes it suitable for aerospace, defense, and downhole industrial environments where plastic packages would fail prematurely.

How does the 7140LA35J8 differ from the SA version in power consumption?

The 7140LA35J8 consumes significantly less power than the SA variant: 1 µA typical ISB3 (full standby) versus 15 µA for SA, and 200 µW typical battery-retention draw at 2V versus undefined for SA. This is achieved via optimized transistor sizing and leakage reduction-enabling years of operation on small lithium batteries. The LA version also specifies VDR = 2.0 V minimum, while SA versions omit data retention capability entirely.