Renesas 7025S55JI8

Overview

7025S55JI8 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 supports simultaneous reads of the same memory location, on-chip semaphore arbitration, and battery backup data retention down to 2 V.

For engineers reviewing the 7025S55JI8 datasheet, 7025S55JI8 pinout, 7025S55JI8 application, or 7025S55JI8 equivalent, key selection criteria include dual-port contention resolution timing (tBDD ≤ 30 ns), BUSY flag arbitration (M/S = VIH/VIL), byte-selectable I/O (UBL/LBL), and 84-pin PLCC package compatibility in real-time embedded systems requiring deterministic memory access.

Technical Context

The 7025S55JI8 implements fully asynchronous dual-port operation with separate address, control, and bidirectional I/O buses per port. Its on-chip arbitration logic resolves port contention via BUSY flag assertion-either through chip-enable (CE) or address-match detection-and supports master/slave cascading for 32-bit+ word expansion using M/S pin configuration.

It integrates full hardware semaphore signaling (8 flags addressed by A0–A2), interrupt flag generation (INTL/INTR), and separate upper- and lower-byte enables (UBL/LBL, UBR/LBR) to support multiplexed bus interfaces. Data retention at 2 V is guaranteed only for the L-version; the S-version (as indicated by 'S' in 7025S55JI8) specifies active power at 750 mW (typ.) and standby at 5 mW (typ.) under industrial conditions.

Key Specifications

Pinout & Package

7025S55JI8 is housed in an 84-pin Plastic Leaded Chip Carrier (PLCC) package with J-lead geometry, body size ≈ 1.12 in × 1.12 in × 0.16 in, and lead pitch of 0.05 in. Pin 1 is marked by a notch or dot; orientation follows standard PLCC top-view convention.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C136-55JC and AS7C3256A-55JC, the 7025S55JI8 uniquely delivers integrated BUSY arbitration, hardware semaphores, and M/S-configurable cascading - reducing BOM count and PCB area in tightly coupled dual-processor architectures.

Availability

7025S55JI8 is available at Aetrix Electronics and suitable for motor control systems, digital signal processing platforms, telecom line cards, and avionics data recorders requiring stable component supply across extended industrial temperature ranges and long production lifecycles.

Supply support for 7025S55JI8 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 7025S55JI8 belongs to IDT's legacy high-speed dual-port SRAM product line, designed specifically for deterministic, low-latency shared memory in real-time embedded systems with asymmetric processing requirements.

FAQ

What is the maximum operating temperature range for the 7025S55JI8?

The 7025S55JI8 is rated for industrial temperature operation from –40°C to +85°C. This specification is confirmed in the "Recommended DC Operating Conditions" table (Table 5) of the official datasheet, and applies to all speed grades including the 55 ns variant. The device maintains full 55 ns timing performance across this entire range without derating.

Does the 7025S55JI8 support battery backup data retention?

No - the 7025S55JI8 is the 'S' (standard power) version and does not support battery backup data retention. Only the 'L' (low-power) variant (e.g., 7025L55JI8) guarantees data retention at 2 V per Table 10. The 7025S55JI8 specifies typical active power at 750 mW and standby at 5 mW, but lacks the sub-1 µA full-standby current required for reliable battery hold-up.

How does the M/S pin affect BUSY functionality in the 7025S55JI8?

When M/S = H (high), the 7025S55JI8 operates as a Master: BUSYL and BUSYR become outputs that assert during port contention. When M/S = L (low), it operates as a Slave: BUSYL and BUSYR become inputs used to receive BUSY signals from a Master device. This configuration enables hardware-controlled arbitration in cascaded multi-chip systems without external logic, as defined in the Functional Block Diagram and Truth Table II.

Can the 7025S55JI8 perform simultaneous reads from both ports to the same memory address?

Yes - the 7025S55JI8 features true dual-port memory cells that allow simultaneous reads of the same memory location from both ports without contention or timing penalty. This capability is explicitly stated in the "Features" section and verified by the "Truth Table I" which shows valid DATAOUT on both I/O buses when CE and OE are asserted concurrently on matching addresses.

What package type is used for the 7025S55JI8, and are there pin-compatible alternatives?

The 7025S55JI8 uses an 84-pin Plastic Leaded Chip Carrier (PLCC) package, as confirmed by the "Pin Configurations" diagram (Drawing 02) and ordering information footnote. While other variants (e.g., 7025S55JG8) use 84-pin PGA or 100-pin TQFP, the PLCC version is not pin-compatible with those due to differing pin counts, spacing, and signal mapping - direct substitution requires PCB layout revision.