Renesas 71421LA20PFG

Overview

IDT71421LA20PFG from Integrated Device Technology is a high-speed 2K × 8 dual-port static RAM configured as a SLAVE device in MASTER/SLAVE memory expansion systems, featuring interrupt flags (INTL/INTR), BUSY input for port arbitration, 20 ns read cycle time, 5 V ±10% supply, and industrial temperature range (–40°C to +85°C). It enables error-free 16-bit-or-wider memory systems without external logic in real-time interprocessor communication applications.

For engineers reviewing the IDT71421LA20PFG datasheet, IDT71421LA20PFG pinout, IDT71421LA20PFG application, or IDT71421LA20PFG equivalent, key selection considerations include its SLAVE-only BUSY input behavior, battery-backed 2 V data retention, dual independent asynchronous ports, and compatibility with IDT71321 MASTER devices in width-expanded configurations.

Technical Context

The IDT71421LA20PFG implements fully asynchronous dual-port operation with separate address, control, and I/O buses per port-no shared timing constraints between left (L) and right (R) sides. Its BUSY pin functions exclusively as an input (not output), enabling write-inhibit arbitration when asserted low by a MASTER device (e.g., IDT71321).

Interrupt logic uses dedicated mailbox addresses: INTL asserts on right-port write to 0x7FE; INTR asserts on left-port write to 0x7FF. Both flags are cleared by reading the same address with OE and CE active-no external interrupt controller required. The LA variant supports 2 V battery backup with ≤100 µA retention current.

Key Specifications

Pinout & Package

Package: 64-pin TQFP (PNG64), 14 mm × 14 mm × 1.4 mm body, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1371D-200BAXI and R1EX24002ASAS0I, IDT71421LA20PFG uniquely delivers integrated hardware arbitration, mailbox interrupts, and 5 V compatibility in a single chip-reducing system-level design effort and validation scope for deterministic dual-CPU architectures.

Availability

IDT71421LA20PFG is available at Aetrix Electronics and suitable for industrial PLC communication, avionics data logging, and railway signaling interfaces requiring stable component supply across extended product lifecycles.

Supply support for IDT71421LA20PFG 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

Integrated Device Technology (IDT), now part of Renesas Electronics, designs high-performance timing, memory, and interface solutions for communications, computing, and industrial markets.

IDT71421LA20PFG belongs to the IDT71321/71421 dual-port SRAM family, engineered specifically for deterministic interprocessor communication in real-time embedded systems requiring hardware-enforced arbitration and low-latency interrupts.

FAQ

What is the role of IDT71421LA20PFG in a MASTER/SLAVE dual-port SRAM configuration?

IDT71421LA20PFG functions exclusively as a SLAVE device: its BUSYR pin is an input (not output) that receives write-inhibit signals from a MASTER IDT71321. It does not generate BUSY flags or perform arbitration-its role is to obey external BUSY assertions and provide synchronized memory expansion without added logic.

Does IDT71421LA20PFG support battery backup, and what are the retention specifications?

Yes, IDT71421LA20PFG supports battery backup with VDR = 2.0 V minimum. At TA = +25°C and VCC = 2.0 V, it retains data with ICCDR ≤ 100 µA (typical) and ≤ 1500 µA (max). This enables reliable nonvolatile storage during main power loss in safety-critical systems.

How do the interrupt flags (INTL and INTR) operate in IDT71421LA20PFG?

INTL asserts when the right port writes to address 0x7FE; INTR asserts when the left port writes to 0x7FF. Both are open-drain outputs requiring external pull-up resistors. Flags clear automatically upon reading the same address with CE and OE active-no register writes or software clearing needed.

What package and pin count does IDT71421LA20PFG use, and is it RoHS-compliant?

IDT71421LA20PFG uses a 64-pin TQFP (PNG64) package measuring 14 mm × 14 mm × 1.4 mm. It is lead-free and RoHS-compliant, with four VCC and four GND pins distributed for optimal power integrity in high-speed digital designs.

Can IDT71421LA20PFG be used standalone, or does it require pairing with IDT71321?

IDT71421LA20PFG can operate as a standalone dual-port SRAM for basic asynchronous memory sharing-but its BUSYR input remains unconnected, and interrupt functionality works independently. For width expansion with hardware arbitration, pairing with IDT71321 MASTER is required to drive BUSYR and enable full feature set.