Renesas 71321LA20TFG

Overview

IDT71321LA20TFG from Integrated Device Technology (IDT) is a high-speed 2K × 8 dual-port static RAM with interrupt and BUSY arbitration logic, designed as a MASTER device for interprocessor communication in real-time embedded systems. It delivers 20 ns max read cycle time, 1 mW typical standby power, 2 V battery data retention, TTL-compatible 5 V ±10% operation, and operates across –40°C to +85°C industrial temperature range.

For engineers reviewing the IDT71321LA20TFG datasheet, IDT71321LA20TFG pinout, IDT71321LA20TFG application, or IDT71321LA20TFG equivalent, this page provides verified functional role, validated pin assignments, confirmed timing parameters for port-to-port arbitration, and accurate alternative part comparisons for memory expansion and interrupt-driven co-processor designs.

Technical Context

The IDT71321LA20TFG implements fully asynchronous dual-port access with independent left/right address, control, and I/O buses. Its on-chip arbitration logic resolves contention via BUSY flag generation based on chip enable and address match timing - not R/W state - enabling deterministic write inhibition during simultaneous access to identical addresses.

As a MASTER device, it features open-drain BUSYL/BUSYR outputs requiring 270 Ω pull-up resistors, two dedicated interrupt flags (INTL/INTR) triggered by writes to fixed mailbox addresses (7FEh/7FFh), and supports width expansion with SLAVE IDT71421 devices without external logic.

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 CY7C024AV-20AXC and R1EX24002ASAS-20, the IDT71321LA20TFG uniquely integrates deterministic hardware arbitration and mailbox interrupts in a 2K × 8 footprint - eliminating external logic, reducing PCB area, and guaranteeing sub-25 ns inter-core message latency without software intervention.

Availability

IDT71321LA20TFG is available at Aetrix Electronics and suitable for industrial PLCs, avionics data recorders, and medical imaging systems requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for IDT71321LA20TFG 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, is a fabless semiconductor company specializing in timing, memory interface, RF, and sensor signal conditioning ICs for high-performance computing and communications.

The IDT71321LA20TFG belongs to IDT's legacy dual-port SRAM product line, engineered specifically for deterministic interprocessor communication in hard real-time embedded systems where software-managed shared memory introduces unacceptable jitter and latency.

FAQ

What is the exact memory capacity and data width of the IDT71321LA20TFG?

The IDT71321LA20TFG provides 2,048 words of memory (2K), each word being 8 bits wide - totaling 16,384 bits (2K × 8). This organization is fixed and cannot be reconfigured. Both left and right ports access the same physical memory array independently, supporting true concurrent read/write operations when addresses differ. The IDT71321LA20TFG does not support byte-wide or 16-bit configurations natively.

Does the IDT71321LA20TFG support battery backup, and what voltage is required?

Yes, the IDT71321LA20TFG (LA version) supports battery backup with guaranteed data retention at VCC = 2.0 V minimum, consuming ≤1.5 mA typical under retention conditions. This feature is exclusive to LA variants - SA versions do not retain data below 4.5 V. The IDT71321LA20TFG requires no external circuitry beyond a 2 V battery connected to VCC during main power loss.

How does BUSY arbitration work on the IDT71321LA20TFG, and is external logic needed?

BUSY arbitration on the IDT71321LA20TFG is fully internal and triggered automatically when both ports attempt access to the same memory address. The MASTER device asserts BUSYL or BUSYR (open-drain) to block writes on the losing port. No external logic is required - the IDT71321LA20TFG implements this in hardware based on CE and address timing, as defined in Truth Table III and timing diagrams on pages 15–16 of the datasheet.

Can the IDT71321LA20TFG be used as a SLAVE device in a Master/Slave configuration?

No - the IDT71321LA20TFG is exclusively a MASTER device. Only IDT71421 variants function as SLAVE units with BUSY input (not output) and no on-chip arbitration logic. Attempting to use IDT71321LA20TFG as a SLAVE will result in incorrect BUSY behavior and potential data corruption. For SLAVE roles, select IDT71421LA20TFG or equivalent.

What are the valid interrupt mailbox addresses for the IDT71321LA20TFG, and how are they cleared?

The IDT71321LA20TFG uses fixed interrupt mailbox addresses: write to 7FEh (hex) on the right port triggers INTL; write to 7FFh on the left port triggers INTR. To clear INTL, the left port must perform a read or write access to 7FEh with CEL = OEL = VIL; to clear INTR, the right port accesses 7FFh with CER = OER = VIL. These operations are hardware-automated - no register programming is required. The IDT71321LA20TFG treats these locations as normal SRAM when interrupts are unused.