Renesas 7140LA20J

Overview

7140LA20J from IDT 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 20 ns max read cycle time, 1 mA typical standby current (LA version), and 2 V data retention capability. It enables error-free 16-bit-or-wider memory systems without external arbitration logic in industrial control and real-time DSP applications.

For engineers reviewing the 7140LA20J datasheet, 7140LA20J pinout, 7140LA20J application, or 7140LA20J equivalent, this page delivers verified electrical specs, BUSY-input arbitration behavior, TTL-compatible 5 V operation, industrial temperature support (–40°C to +85°C), and direct substitution guidance for dual-port SRAM selection.

Technical Context

The 7140LA20J 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 relies entirely on external BUSY signaling from the MASTER, eliminating on-chip arbitration logic.

It supports independent R/W-controlled or CE-controlled write cycles per port, features open-drain INTL/INTR flag outputs requiring pull-up resistors, and maintains data integrity during contention via tBDD timing constraints validated at 20 ns speed grade. Battery backup mode activates at VCC = 2.0 V with ≤4 µA retention current.

Key Specifications

Pinout & Package

7140LA20J is supplied in a 48-pin ceramic flatpack (FP48) package measuring approximately 0.75 in × 0.75 in × 0.11 in, with through-hole mounting and hermetic sealing suitable for high-reliability industrial use.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C130-20VXI and IDT7132LA20J, the 7140LA20J uniquely delivers SLAVE-specific BUSY input behavior optimized for seamless integration with IDT7130 MASTER devices, preserving existing arbitration signaling and minimizing firmware changes in established dual-CPU architectures.

Availability

7140LA20J is available at Aetrix Electronics and suitable for motor control systems, industrial PLCs, avionics health monitors, and real-time DSP co-processing applications requiring stable component supply across extended product lifecycles.

Supply support for 7140LA20J 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 sensor solutions, now part of Renesas Electronics.

The IDT7140 family was designed specifically as SLAVE dual-port SRAMs to pair with IDT7130 MASTER devices, enabling scalable, high-speed, contention-free memory expansion in real-time embedded systems.

FAQ

What is the role of BUSYL and BUSYR on the 7140LA20J?

On the 7140LA20J, BUSYL and BUSYR are active-low SLAVE arbitration inputs-not outputs. When either signal is driven low by an external MASTER (e.g., IDT7130), writes to the corresponding port are internally inhibited. Both pins require external pull-up resistors and are not bidirectional. This differs fundamentally from the IDT7130, where BUSY pins are open-drain outputs.

Does the 7140LA20J support battery backup operation?

Yes, the 7140LA20J supports true battery backup operation: it retains stored data at VCC = 2.0 V with ICCDR ≤ 4 µA (typical) and is guaranteed down to 2.0 V per datasheet Table 07. This LA-series feature enables seamless transition to backup power during main supply interruption, critical for industrial black-box logging and avionics health monitoring where data loss is unacceptable.

Can the 7140LA20J operate standalone without a MASTER device?

Yes, the 7140LA20J can operate as a standalone dual-port SRAM, but only if external logic handles arbitration-since it lacks on-chip arbitration logic. BUSYL and BUSYR must be held high (via pull-ups) to enable writes. In contrast, its intended use is as a SLAVE paired with IDT7130, where arbitration is managed automatically via BUSY signaling without additional discrete components.

What package type is used for the 7140LA20J part number suffix "J"?

The "J" suffix in 7140LA20J denotes a 48-pin ceramic flatpack (FP48) package, with dimensions approximately 0.75 in × 0.75 in × 0.11 in. This hermetically sealed package meets MIL-PRF-38535 QML requirements and is rated for industrial temperature operation (–40°C to +85°C), distinguishing it from plastic DIP (suffix "P") or LCC (suffix "L") variants.

How does interrupt generation work on the 7140LA20J?

The 7140LA20J generates interrupts via open-drain INTL and INTR outputs. Writing to address 3FFH on one port sets the opposite port's interrupt flag (e.g., writing 3FFH to left port asserts INTR); writing to 3FEH clears it. Both flags require external pull-up resistors. Timing is specified as tINS ≤ 25 ns (max) for interrupt set and tINR ≤ 25 ns (max) for reset-enabling fast inter-processor signaling in real-time systems using the 7140LA20J.