Renesas 7025S55PF8

Overview

7025S55PF8 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 5V ±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 7025S55PF8 datasheet, 7025S55PF8 pinout, 7025S55PF8 application, or 7025S55PF8 equivalent, key selection criteria include dual-port arbitration latency, BUSY flag timing under address/CE contention, semaphore update pulse width, battery-backed data retention at 2V, and compatibility with 84-pin PLCC packaging for legacy board reuse.

Technical Context

The 7025S55PF8 implements full hardware port arbitration with dedicated BUSY output (master) or input (slave), enabling deterministic conflict resolution without external logic. Its on-chip semaphore logic uses A0–A2 addressing to manage eight shared flags via I/O0–I/O15, supporting inter-processor synchronization in tightly coupled dual-CPU architectures.

It operates fully asynchronously from either port: reads require only CE, OE, UB/LB, and address assertion; writes are controlled by R/W, CE, and byte enables. The device enters low-power standby (<5 mA typ.) when both chip enables are high, and retains data down to 2V for battery backup operation.

Key Specifications

Pinout & Package

7025S55PF8 is housed in an 84-pin Plastic Leaded Chip Carrier (PLCC) package with 0.050" lead pitch, body size ≈ 1.15 in × 1.15 in × 0.17 in, and standard PLCC land pattern. Pin 1 is marked by a corner notch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C136-55JC and IDT70V25S55PF8, the 7025S55PF8 offers tighter BUSY arbitration timing (5 ns tAPS) and guaranteed 5V TTL compatibility without level shifters-critical for maintaining timing closure in legacy industrial designs where voltage and timing margins are constrained.

Availability

7025S55PF8 is available at Aetrix Electronics and suitable for industrial automation, avionics subsystems, and test equipment requiring stable component supply with long-term obsolescence management.

Supply support for 7025S55PF8 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 sensor solutions, now part of Renesas Electronics since 2019.

The IDT7025 family was designed specifically for high-reliability dual-processor systems requiring deterministic memory sharing, targeting industrial control, military computing, and telecommunications infrastructure where hardware-enforced arbitration and battery backup are mandatory.

FAQ

What is the maximum operating temperature range for the 7025S55PF8?

The 7025S55PF8 is rated for industrial temperature operation from –40°C to +85°C. This specification is validated per the datasheet's recommended DC operating conditions and applies across all speed grades including the 55 ns variant. The device maintains full functionality-including 55 ns access time, semaphore operation, and BUSY arbitration-within this full range without derating.

Does the 7025S55PF8 support battery backup operation, and what voltage is required?

Yes, the 7025S55PF8 supports battery backup operation with guaranteed data retention at VCC = 2.0 V. This is explicitly specified in the "Data Retention Characteristics" table (tCDR and VDR parameters), and applies to the 'L' (low-power) version-confirmed by the 'S' suffix in 7025S55PF8 indicating standard power, yet retaining the 2V retention capability common to the IDT7025S/L family.

How does the M/S pin configure master/slave behavior in the 7025S55PF8?

When M/S = HIGH, the 7025S55PF8 operates as a master: BUSYR becomes an output that asserts during port contention to block writes on the slave device. When M/S = LOW, it operates as a slave: BUSYR becomes an input monitored by the device to gate its own write operations. This configuration enables daisy-chained dual-port expansion without external arbitration logic.

What is the purpose of the semaphore feature in the 7025S55PF8, and how is it accessed?

The 7025S55PF8 includes eight hardware semaphore flags for inter-processor synchronization. They are accessed by setting SEM = LOW while keeping CE and byte enables HIGH, then using A0–A2 to select the flag and I/O0–I/O15 to read/write its state. This eliminates software-based locking and reduces cross-core latency to ≤5 ns (tSOP), as confirmed in the AC Electrical Characteristics tables.

Is the 7025S55PF8 pin-compatible with other members of the IDT7025 family, such as the 7025S20PF8?

Yes, all IDT7025S/L variants-including 7025S55PF8, 7025S20PF8, and 7025L25PF8-share identical 84-pin PLCC pinouts and signal assignments. Speed grade differences (e.g., 20 ns vs. 55 ns) affect only timing parameters and power consumption, not connectivity or logic behavior, enabling direct replacement in existing layouts where timing margins allow.