Renesas 7140LA35L48B

Overview

7140LA35L48B 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 max read cycle time, 1 µA typical full-standby current (CMOS-level inputs), and battery-backed data retention at 2 V - used in real-time embedded controllers requiring concurrent CPU/DSP memory access.

For engineers reviewing the 7140LA35L48B datasheet, 7140LA35L48B pinout, 7140LA35L48B application, or 7140LA35L48B equivalent, key selection criteria include BUSY input timing (tWB = 0 ns), dual-port arbitration compatibility with IDT7130 MASTER, industrial temperature support (–40°C to +85°C), and ceramic flatpack (FP48) package mechanical compatibility.

Technical Context

The 7140LA35L48B implements a true dual-port SRAM architecture with independent address, control, and I/O buses for left (L) and right (R) ports. It lacks on-chip arbitration logic - instead accepting BUSYL/BUSYR as active-low inputs to inhibit writes during contention, per IDT7130 MASTER-generated BUSY signals.

It supports R/W-controlled and CE-controlled write cycles, features open-drain INTL/INTR flags for inter-port communication, and enables battery backup via V_CC = 2 V with guaranteed data retention (V_DR = 2.0 V min), while operating from a single 5.0 V ±10% supply across industrial temperature range.

Key Specifications

Pinout & Package

7140LA35L48B is housed in a 48-pin ceramic flatpack (FP48) package with 0.75″ × 0.75″ footprint and 0.11″ height, featuring hermetic construction and gold-plated leads 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 CY7C1352BV-35AC and IDT7134LA35JG, the 7140LA35L48B uniquely satisfies 5 V operation, FP48 hermetic packaging, and SLAVE-only arbitration interface - making it irreplaceable in fielded industrial systems requiring drop-in compatibility and battery-retained state.

Availability

7140LA35L48B is available at Aetrix Electronics and suitable for motor control co-processors, redundant PLCs, avionics sensor buffers, and DSP/microcontroller shared-memory systems requiring stable component supply across extended product lifecycles.

Supply support for 7140LA35L48B 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 signal conditioning ICs, acquired by Renesas Electronics in 2019.

The IDT7140LA family was designed specifically as SLAVE dual-port SRAMs to complement the IDT7130 MASTER in high-reliability, asynchronous 16-bit+ memory expansion - targeting industrial control, test equipment, and military computing where deterministic latency and data integrity are critical.

FAQ

What is the function of BUSYL and BUSYR on the 7140LA35L48B?

BUSYL and BUSYR are active-low arbitration inputs on the 7140LA35L48B. When asserted (LOW), they inhibit write operations to the corresponding left or right port - a mechanism used exclusively in MASTER/SLAVE configurations where the IDT7130 MASTER generates these signals to prevent memory contention. Unlike the IDT7130, the 7140LA35L48B does not drive BUSY outputs.

Does the 7140LA35L48B support battery backup operation?

Yes, the 7140LA35L48B supports battery backup operation with guaranteed data retention at V_CC = 2.0 V minimum. This LA-grade feature allows the device to retain memory contents during main power loss, consuming only 100–4000 µA depending on grade and temperature - enabling maintenance-free operation in field instruments and avionics systems.

Can the 7140LA35L48B be used as a standalone dual-port RAM without an IDT7130 MASTER?

Yes, the 7140LA35L48B can operate as a standalone dual-port RAM. Its left and right ports function fully asynchronously with independent control lines. However, BUSY inputs must be held HIGH (via pull-up resistors) to enable writes, and inter-port contention must be managed externally - unlike the IDT7130, it lacks on-chip arbitration logic.

What is the meaning of "L48B" in the part number 7140LA35L48B?

In 7140LA35L48B, "L48B" denotes the package variant: "L" indicates ceramic flatpack (FP48), "48" specifies 48 pins, and "B" identifies the revision or process variant per IDT's internal ordering code - consistent with FP48 mechanical dimensions (0.75″ × 0.75″ × 0.11″) and pinout shown in datasheet drawing 2689 drw 03F.

How does the 7140LA35L48B handle simultaneous access to the same memory location from both ports?

The 7140LA35L48B relies on external arbitration: when both ports attempt access to the same address, the IDT7130 MASTER asserts BUSYL or BUSYR to block the losing port's write. The 7140LA35L48B itself has no priority resolution - it simply honors the BUSY input state. Read operations remain valid; only writes are inhibited, preserving data integrity without internal conflict resolution logic.