Renesas 7024S20J

Overview

7024S20J from IDT is a high-speed 4K × 16 true dual-port static RAM with independent asynchronous left/right ports, 20 ns max access time (commercial/industrial), TTL-compatible 5V ±10% supply, and on-chip semaphore arbitration logic - used in real-time interprocessor communication systems requiring simultaneous read/write to shared memory locations.

For engineers reviewing the 7024S20J datasheet, 7024S20J pinout, 7024S20J application, or 7024S20J equivalent, key selection considerations include BUSY flag timing (tBAA ≤ 20 ns), dual-port arbitration behavior, battery-backed data retention (2V, 100–4000 µA), and compatibility with master/slave cascading for 32-bit+ bus expansion.

Technical Context

The 7024S20J implements full hardware port arbitration with dedicated BUSY output (master) or input (slave) via M/S pin, enabling deterministic conflict resolution during simultaneous access to identical addresses. Its semaphore logic supports eight software-managed flags accessed via A0–A2 and I/O0–I/O15, with tSPS = 5 ns contention window and tSWRD = 5 ns write-to-read latency.

It operates fully asynchronously per port: reads and writes require no clock; timing depends only on CE, R/W, OE, UB/LB, and SEM assertion/deassertion sequences. The device supports two distinct power modes - active (750 mW typ.) and standby (5 mW typ. for S version) - with automatic power-down controlled by chip enable.

Key Specifications

Pinout & Package

7024S20J 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 suitable for automated assembly and thermal cycling reliability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C024AV-20AXC and IDT70V24S20PF, the 7024S20J uniquely supports 5V-only operation with guaranteed 2V data retention and PLCC packaging - making it the sole option for industrial retrofits requiring drop-in replacement in existing 5V, battery-backed, through-hole-or-SMT hybrid assemblies.

Availability

7024S20J is available at Aetrix Electronics and suitable for real-time interprocessor communication, redundant control systems, DSP co-processing, and legacy bus expansion applications requiring stable component supply across extended product lifecycles.

Supply support for 7024S20J 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 high-performance silicon solutions, now part of Renesas Electronics.

The 7024S20J belongs to IDT's legacy dual-port SRAM family designed specifically for deterministic, low-latency interprocessor communication in industrial, military, and telecom infrastructure - emphasizing hardware arbitration, battery backup, and ruggedized packaging.

FAQ

What is the maximum operating frequency supported by the 7024S20J?

The 7024S20J does not operate on a clock; it is a fully asynchronous SRAM. Its performance is defined by access timing parameters - notably tRC (read cycle time) and tAA (address access time), both rated at 20 ns maximum for this variant. This enables reliable operation in systems where read/write cycles occur at up to ~50 MHz effective bandwidth, assuming optimal control signal timing and no bus turnaround delays.

Does the 7024S20J support true simultaneous read operations from both ports to the same memory address?

Yes, the 7024S20J features true dual-port memory cells that allow concurrent reads from both left and right ports to identical addresses without contention or delay. This capability is explicitly confirmed in the datasheet's "Features" section and functional block diagram - enabling lock-free data broadcast and synchronization-free status monitoring in multi-CPU architectures.

How does the BUSY flag function in master versus slave configuration for the 7024S20J?

When M/S = H (master), BUSYL/BUSYR are outputs indicating port contention; when M/S = L (slave), BUSYL/BUSYR become inputs accepting BUSY signals from a master device. In master/slave cascades, this enables hardware-enforced priority: the slave halts its write if BUSY is asserted, ensuring deterministic arbitration without software overhead - a core feature of the 7024S20J's system-level design.

Can the 7024S20J retain data during complete power loss, and what voltage is required?

Yes, the 7024S20J supports data retention at VCC = 2.0 V minimum, as specified in Table 10 (Data Retention Characteristics). At this voltage, ICCDR is characterized up to 4000 µA (industrial grade), allowing operation from a backup battery or capacitor. Retention is guaranteed - not just characterized - and applies across the full –40°C to +85°C industrial temperature range.

What package type is used for the 7024S20J, and are there thermal or mounting considerations?

The 7024S20J uses an 84-pin Plastic Leaded Chip Carrier (PLCC) package with body dimensions approximately 1.15 in × 1.15 in × 0.17 in. It requires standard PLCC socket or reflow soldering per IPC-7095 guidelines. Thermal resistance (θJA) is not published, but the device's 750 mW typical active power and multiple VCC/GND pins provide robust thermal performance in natural-convection industrial enclosures.