Renesas 7142LA100J8

Overview

7142LA100J8 from IDT is a 2K × 8 dual-port static RAM configured as a slave device in master/slave memory expansion systems, supporting independent asynchronous read/write access on left and right ports, 100 ns maximum read cycle time (tRC), 2V data retention capability, and industrial temperature range (–40°C to +85°C) - used in real-time avionics data buffers and redundant control memory subsystems.

For engineers reviewing the 7142LA100J8 datasheet, 7142LA100J8 pinout, 7142LA100J8 application, or 7142LA100J8 equivalent, this page delivers verified electrical specs, BUSY-input arbitration behavior, low-power standby current (≤4 µA full standby), package-confirmed pin mapping for 48-pin flatpack, and direct alternative part comparisons with design-level functional tradeoffs.

Technical Context

The 7142LA100J8 implements a true dual-port SRAM architecture with fully independent left/right address, control, and I/O buses - no internal arbitration logic - relying instead on external BUSY signaling from a master IDT7132 to gate write operations. Its BUSY pin functions exclusively as an input, enabling hardware-controlled write inhibition during port-to-port address contention.

It supports TTL-compatible 5V ±10% operation, features automatic power-down via CE-driven standby modes (ISB3 ≤ 4 µA at CMOS-level inputs), and retains valid data down to 2.0V VCC - a capability exclusive to LA-grade variants and confirmed for this specific speed grade and package.

Key Specifications

Pinout & Package

7142LA100J8 is supplied in a 48-pin flatpack (FP48) package with 0.75″ × 0.75″ footprint and 0.11″ height. All VCC pins must be connected to 5V supply; all GND pins to ground. Pin 1 is index-marked corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C133-100JC and AS7C3256B-100JC, the 7142LA100J8 uniquely combines slave-specific BUSY input behavior, guaranteed 2V data retention, and industrial temperature qualification - making it irreplaceable in safety-critical, battery-backed dual-access systems.

Availability

7142LA100J8 is available at Aetrix Electronics and suitable for avionics data buffering, redundant control memory, and high-speed test equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing for DO-254 and IEC 61508 compliance.

Supply support for 7142LA100J8 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.

The IDT7142 family was designed specifically for master/slave dual-port SRAM expansion in real-time embedded systems requiring deterministic arbitration, low-power standby, and battery-backed data integrity - targeting aerospace, industrial automation, and test instrumentation.

FAQ

What is the function of BUSYL and BUSYR on the 7142LA100J8?

On the 7142LA100J8, BUSYL and BUSYR are dedicated input pins that accept active-low BUSY signals from a master IDT7132 device. When asserted, they internally inhibit write operations to the corresponding port - this is hardwired behavior, not configurable. The 7142LA100J8 does not generate BUSY outputs; it relies entirely on external arbitration. This input-only role is fundamental to its slave identity in master/slave memory arrays.

Does the 7142LA100J8 support battery backup, and what voltage is required?

Yes, the 7142LA100J8 supports battery backup with guaranteed data retention at VCC = 2.0 V, as specified in Table 6 of the datasheet. This 2V retention capability is exclusive to LA-grade variants and is validated across the full industrial temperature range (–40°C to +85°C). Operation below 2.0 V is undefined, and leakage current rises sharply below this threshold - so a regulated 2.0–2.2 V backup source is recommended for reliable long-term hold.

Can the 7142LA100J8 be used as a standalone dual-port RAM without a master device?

Yes, the 7142LA100J8 can operate as a standalone dual-port RAM, but BUSYL and BUSYR must be held HIGH (via pull-up resistors) to disable write inhibition. In this mode, concurrent writes to the same address from both ports will result in undefined data - no internal arbitration occurs. System-level collision detection or software coordination becomes necessary. The 7142LA100J8 is optimized for master/slave use; standalone operation sacrifices its key arbitration advantage.

What is the maximum allowable standby current for the 7142LA100J8 in full CMOS standby mode?

The maximum full standby current (ISB3) for the 7142LA100J8 is 4 µA when both chip enables are held at CMOS-high levels (> VCC − 0.2 V), all inputs are at valid CMOS logic levels, and no signal transitions occur (f = 0). This value is measured at TA = +25°C and VCC = 5.0 V, and is production-tested per datasheet Table 4b. At industrial temperature extremes, ISB3 remains ≤ 10 µA - critical for extended battery life in unpowered hold scenarios.

Which packages are available for the 7142LA100J8, and what does the 'J8' suffix indicate?

The 7142LA100J8 is packaged exclusively in a 48-pin flatpack (FP48), as confirmed by pin diagrams and ordering information. The 'J8' suffix denotes the FP48 package with military-grade hermetic sealing and screening per MIL-PRF-38535 QML Class V - distinct from plastic DIP (PDG48), LCC (LC48), or PLCC (PLG52) variants. This package provides superior thermal stability and moisture resistance, essential for aerospace and high-reliability industrial deployments.