Renesas 7140LA25J8

Overview

7140LA25J8 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 25 ns maximum read cycle time, 1 mA typical standby current, 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 7140LA25J8 datasheet, 7140LA25J8 pinout, 7140LA25J8 application, or 7140LA25J8 equivalent, key selection criteria include BUSY input timing compatibility with IDT7130 master devices, dual-port arbitration behavior under address contention, low-power battery backup operation, and ceramic flatpack packaging for thermal stability in extended temperature environments.

Technical Context

The 7140LA25J8 operates as a SLAVE dual-port SRAM with dedicated BUSY inputs (BUSYL, BUSYR) that inhibit writes when asserted low-unlike the MASTER IDT7130 which drives open-drain BUSY outputs. Its arbitration logic responds solely to address match detection between ports, requiring tAPS ≥ 5 ns setup to guarantee deterministic BUSY assertion.

It supports independent TTL-compatible control per port (CEL/OEL/R/WL and CER/OER/R/WR), full CMOS-level standby modes (ISB3 ≤ 0.2 mA), and retains data at VCC = 2.0 V across –40°C to +85°C. The device lacks on-chip arbitration logic-relying entirely on external or MASTER-driven BUSY signaling for conflict resolution.

Key Specifications

Pinout & Package

7140LA25J8 is supplied in a 48-pin ceramic flatpack (FP48) package with 0.75″ × 0.75″ body size and side-brazed leads. Pin 1 is index-marked; all VCC pins (14, 27, 48) require local decoupling; all GND pins (1, 26, 31) must be solidly connected to ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1371BV25 and AS7C31026B-25JCIN, the 7140LA25J8 uniquely delivers deterministic arbitration, 2 V data retention, and industrial temperature support in a proven MASTER/SLAVE topology-making it irreplaceable for legacy real-time systems requiring drop-in compatibility with IDT7130-based memory subsystems.

Availability

7140LA25J8 is available at Aetrix Electronics and suitable for industrial programmable logic controllers, avionics data acquisition units, real-time digital signal processing systems, and medical imaging front-end buffers requiring stable component supply across extended lifecycle programs.

Supply support for 7140LA25J8 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 IDT7140 product line was engineered specifically for MASTER/SLAVE dual-port SRAM expansion in real-time embedded systems, delivering deterministic arbitration, low-power battery backup, and industrial temperature resilience without external logic.

FAQ

What is the function of BUSYL and BUSYR on the 7140LA25J8?

On the 7140LA25J8, BUSYL and BUSYR are dedicated input pins-not outputs-that receive arbitration signals from an external MASTER device (e.g., IDT7130). When either pin is driven low, the corresponding port's write operations are internally inhibited. This behavior is fundamental to the SLAVE role of the 7140LA25J8 and differs from the MASTER's open-drain BUSY outputs.

Does the 7140LA25J8 support true simultaneous read/write across ports?

Yes-the 7140LA25J8 supports fully asynchronous, independent read and write operations on left and right ports. However, simultaneous writes to the same memory address trigger BUSY arbitration: the 7140LA25J8 relies on external BUSY signaling (typically from an IDT7130 MASTER) to resolve contention. No internal arbitration logic exists on the 7140LA25J8 itself.

Can the 7140LA25J8 operate without a MASTER device like the IDT7130?

Yes-the 7140LA25J8 can function as a standalone dual-port SRAM if BUSYL and BUSYR are held high (via pull-up resistors) and external arbitration logic manages address contention. However, its design intent and full feature set-including seamless 16-bit expansion-are realized only in coordinated MASTER/SLAVE configurations with IDT7130 devices.

What does "LA" signify in the 7140LA25J8 part number?

The "LA" suffix in 7140LA25J8 denotes Low-power Active/Standby operation with Battery Backup capability. Specifically, it guarantees 2 V data retention and ultra-low ISB3 standby current (0.2 mA typ.), distinguishing it from the "SA" variant (standard active power, no retention spec) and enabling use in systems requiring non-volatile memory persistence during main power loss.

Is the 7140LA25J8 pin-compatible with other IDT7140 variants such as 7140SA25J8?

Yes-7140LA25J8 and 7140SA25J8 share identical pinout, package (FP48), and AC/DC specifications except for standby current and data retention. Both meet the same 25 ns access time and industrial temperature range. The LA variant substitutes lower ISB3/ISB4 currents and adds VDR = 2.0 V specification, with no layout or schematic changes required for migration.