Renesas 7024S55J

Overview

7024S55J from IDT is a high-speed 4K × 16 true dual-port static RAM with independent left/right ports, 55 ns max read cycle time (commercial grade), TTL-compatible 5V ±10% supply, and on-chip semaphore arbitration logic - deployed in real-time DSP co-processing systems requiring simultaneous memory access without external logic.

For engineers reviewing the 7024S55J datasheet, 7024S55J pinout, 7024S55J application, or 7024S55J equivalent, this page delivers verified timing specs, master/slave BUSY flag behavior, battery-backed data retention at 2V, and precise PLCC-84 pin mapping for PCB layout and system-level arbitration design.

Technical Context

The 7024S55J implements fully asynchronous dual-port operation with separate address, control, and I/O buses per port, enabling concurrent reads/writes to any memory location - including simultaneous reads of the same address. Its on-chip arbitration logic resolves port contention via BUSY flag signaling and supports both master (BUSY output) and slave (BUSY input) configurations using the M/S pin.

It integrates full hardware semaphore support across eight flags (addressed by A0–A2), with dedicated SEM, INT, and BUSY signals per port. The device operates in three power states: active (750 mW typ.), standby (5 mW typ. for S version), and data retention (2V, ≤4 mA), all managed by CE-driven automatic power-down.

Key Specifications

Pinout & Package

7024S55J is packaged in an 84-pin Plastic Leaded Chip Carrier (PLCC), body size ≈ 1.15 in × 1.15 in × 0.17 in, with gull-wing leads and standard JEDEC MO-047 footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C133-55JC and IDT70V24S55PF, the 7024S55J uniquely combines 5V TTL compatibility, on-die semaphore logic, and 2V data retention in a compact PLCC-84 package - making it irreplaceable in retrofit 5V industrial and avionics applications demanding hardware-level concurrency control and fail-safe memory hold.

Availability

7024S55J is available at Aetrix Electronics and suitable for telecom line card buffering, DSP co-processor memory, and industrial PLC I/O mapping requiring stable component supply across extended product lifecycles.

Supply support for 7024S55J 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 timing, memory, and interface solutions for communications, computing, and industrial markets.

The 7024S55J belongs to IDT's legacy dual-port SRAM family designed specifically for real-time embedded systems requiring deterministic, contention-free memory access between heterogeneous processors or peripherals.

FAQ

What is the maximum operating frequency supported by the 7024S55J?

The 7024S55J does not operate on a clock; it is fully asynchronous. Its performance is specified by timing parameters - the maximum read cycle time is 55 ns, meaning it supports effective throughput up to approximately 18.2 MHz in continuous read cycles. Write cycle time is also 55 ns, and all access times (tAA, tACE, tABE) are guaranteed ≤55 ns under commercial temperature and voltage conditions. This enables integration into systems with tight timing budgets without clock domain constraints.

Does the 7024S55J support battery backup operation, and what voltage is required?

Yes, the 7024S55J supports battery backup operation with guaranteed data retention down to 2.0 V (VDR). In data retention mode, the device maintains stored memory contents while drawing ≤4 mA - verified across the commercial temperature range (0°C to +70°C). This feature is intrinsic to the "S" variant and does not require external circuitry beyond a 2V backup source connected to VCC during main supply dropout.

How does the M/S pin affect BUSY signal behavior on the 7024S55J?

When M/S = HIGH, the 7024S55J operates as a Master: BUSYL and BUSYR become push-pull outputs that assert when port contention occurs (e.g., simultaneous writes to same address). When M/S = LOW, it operates as a Slave: BUSYL and BUSYR become inputs - the device waits for external BUSY assertion before initiating writes. This configuration enables hierarchical arbitration in multi-device systems without external logic.

Can the 7024S55J perform simultaneous reads of the same memory location from both ports?

Yes, the 7024S55J features true dual-ported memory cells that allow completely independent, simultaneous reads of identical addresses from left and right ports - with no timing penalty or arbitration delay. This capability is fundamental to its architecture and is explicitly confirmed in the datasheet's "Features" section, enabling coherent data sharing in lock-step processing applications like digital oscilloscope waveform capture and replay.

What package type is used for the 7024S55J, and is it RoHS-compliant?

The 7024S55J is supplied in an 84-pin Plastic Leaded Chip Carrier (PLCC) package, with body dimensions approximately 1.15 in × 1.15 in × 0.17 in. Per IDT's ordering information and green parts documentation, the 7024S55J is RoHS-compliant and lead-free - meeting JEDEC J-STD-609 Category 1 marking requirements and suitable for modern environmentally regulated production environments.