Renesas 7025S55G

Overview

7025S55G from IDT is a high-speed 8K × 16 (128 Kbit) true dual-port static RAM with independent asynchronous left/right ports, 55 ns maximum read cycle time, TTL-compatible 5 V ±10% supply, and industrial temperature range (–40°C to +85°C). It enables simultaneous read access to the same memory location and supports master/slave cascading for 32-bit+ bus expansion in real-time embedded control systems.

For engineers reviewing the 7025S55G datasheet, 7025S55G pinout, 7025S55G application, or 7025S55G equivalent, key selection considerations include BUSY arbitration timing (tBDD ≤ 30 ns), semaphore flag support (8 flags via A0–A2), byte-selectable I/O (UBL/LBL), and low-power standby (ISB1 = 13 mA typ. at 55 ns speed).

Technical Context

The 7025S55G implements full hardware port arbitration with dedicated BUSY flag logic and on-chip semaphore signaling-enabling deterministic contention resolution between ports without external logic. Its dual independent address/data/control paths allow fully asynchronous operation: one port can read while the other writes, even to overlapping addresses, with BUSY assertion only when actual conflict occurs.

It supports two distinct operational modes: as a stand-alone 128 Kbit dual-port RAM, or in MASTER/SLAVE configuration using the M/S pin-where the master asserts BUSYL/BUSYR as output and the slave accepts BUSY as input to gate write cycles during arbitration. Semaphore access uses separate CE/SEM control and shares I/O0–I/O15 for flag data transfer.

Key Specifications

Pinout & Package

7025S55G is packaged in an 84-pin ceramic PGA (PLG84) with 1.15″ × 1.15″ footprint and 0.17″ height. Pin assignments are symmetric for left/right ports, supporting identical PCB layout for both sides in master/slave configurations.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C028V-55AXC and IDT70V25S55PF, the 7025S55G offers superior thermal stability in extended industrial temperature ranges, native 5 V compatibility without level shifters, and proven ceramic PGA reliability in high-vibration avionics deployments-making it optimal for mission-critical deterministic systems.

Availability

7025S55G is available at Aetrix Electronics and suitable for industrial motion controllers, avionics display systems, and redundant flight control units requiring stable component supply across extended product lifecycles.

Supply support for 7025S55G 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 7025S55G belongs to IDT's legacy high-speed dual-port SRAM family, designed specifically for deterministic real-time systems requiring hardware-enforced memory coherency between multiple processors or ASICs.

FAQ

What is the maximum operating frequency supported by the 7025S55G?

The 7025S55G does not operate on a clock signal-it is fully asynchronous. Its performance is specified by timing parameters: maximum read cycle time (tRC) is 55 ns, corresponding to an effective throughput of up to 18.2 million 16-bit words per second per port under ideal conditions. Actual system bandwidth depends on address/data setup/hold times and bus protocol overhead.

Does the 7025S55G support battery backup for data retention?

No-the 7025S55G is the standard-power "S" variant and is not rated for battery backup operation. Only the "L" variant (e.g., 7025L55G) guarantees data retention at 2 V. The 7025S55G requires continuous 5 V ±10% supply to maintain memory state; removal of VCC results in immediate data loss.

How does the BUSY arbitration logic work when M/S = HIGH on the 7025S55G?

When M/S = HIGH, the 7025S55G operates as a master: BUSYL and BUSYR become outputs. If both ports attempt simultaneous write access to the same address, the port asserting R/W first wins arbitration, and the losing port's BUSY signal goes HIGH within tBAA ≤ 20 ns, blocking its write cycle until BUSY deasserts after tBDA ≤ 20 ns-ensuring atomic memory updates.

Can the 7025S55G be used in a 32-bit data bus configuration?

Yes-the 7025S55G supports 32-bit expansion via master/slave cascading. Two devices are connected with M/S = HIGH on the master and M/S = LOW on the slave; the master's BUSY output connects to the slave's BUSY input. This configuration allows full-speed 32-bit access without external glue logic, as described in the functional block diagram and pin configuration notes.

What is the purpose of the SEM pin on the 7025S55G?

The SEM (Semaphore Enable) pin controls access to the internal 8-flag semaphore register. When SEM = LOW and CE = HIGH (or UB & LB = HIGH), the device enters semaphore mode: A0–A2 select one of eight flags, and I/O0–I/O15 transfer flag state. This provides hardware-accelerated mutual exclusion for multi-processor systems-eliminating software-based spinlocks and reducing inter-CPU latency.