Renesas 7130SA55J

Overview

7130SA55J from IDT is a high-speed 1K × 8 dual-port static RAM configured as a MASTER device with on-chip arbitration logic, 55 ns maximum read/write cycle time, open-drain BUSY outputs requiring external pull-up resistors, and TTL-compatible 5V ±10% operation - used in real-time inter-processor communication systems requiring concurrent memory access without external logic.

For engineers reviewing the 7130SA55J datasheet, 7130SA55J pinout, 7130SA55J application, or 7130SA55J equivalent, key selection criteria include port-to-port arbitration timing (tBDD ≤ 55 ns), BUSY flag behavior (open-drain, active-low), industrial temperature support (–40°C to +85°C), and compatibility with IDT7140SLAVE devices for 16-bit expansion.

Technical Context

The 7130SA55J implements fully asynchronous dual-port architecture with independent left/right address, control, and I/O buses. Its on-chip arbitration logic resolves contention via address-match detection and priority setup (tAPS = 5 ns), asserting BUSYL/BUSYR to inhibit writes during simultaneous access to identical addresses.

It supports R/W-controlled and CE-controlled write cycles, features INTL/INTR interrupt flags for port-to-port signaling, and maintains data integrity during contention using tWDD (≤80 ns) and tDDD (≤55 ns) timing margins - all validated for 55 ns speed grade across industrial temperature range.

Key Specifications

Pinout & Package

7130SA55J is packaged in a 48-pin ceramic flatpack (FP48) with 0.75″ × 0.75″ body size and side-brazed leads. Pin assignments are electrically identical across FP48, LC48, and PDG48 variants per datasheet revision Jul.12.21.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C131-55JC and IDT7140SA55J, the 7130SA55J uniquely integrates arbitration, BUSY signaling, and inter-port interrupts - making it the only choice for autonomous dual-master memory sharing without external logic.

Availability

7130SA55J is available at Aetrix Electronics and suitable for real-time inter-processor communication, redundant control systems, high-speed data acquisition buffering, and legacy bus interface bridging requiring stable component supply across extended product lifecycles.

Supply support for 7130SA55J 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, and RF solutions, now part of Renesas Electronics.

The IDT7130 product line was designed specifically for deterministic, low-latency dual-processor memory sharing in industrial control, avionics, and telecommunications infrastructure - emphasizing hardware arbitration and interrupt-driven synchronization.

FAQ

What is the function of BUSYL and BUSYR on the 7130SA55J?

BUSYL and BUSYR are open-drain arbitration flag outputs on the 7130SA55J. When asserted LOW, they indicate that the opposite port is accessing the same memory address - blocking writes on the flagged port. Each requires an external pull-up resistor (typically 4.7 kΩ) to VCC. This hardware-level mechanism prevents data corruption during simultaneous access, eliminating need for software locks or external arbitration logic in the 7130SA55J design.

Can the 7130SA55J operate in a standalone configuration without a SLAVE device?

Yes, the 7130SA55J functions fully as a standalone 8-bit dual-port SRAM. Its on-chip arbitration logic, BUSY outputs, and INTL/INTR flags operate independently. The SLAVE IDT7140 is optional and only required when expanding to 16-bit or wider data paths. In standalone use, both left and right ports remain fully functional for concurrent read/write operations with hardware-enforced collision avoidance - no external components needed for basic dual-port operation of the 7130SA55J.

What temperature range is guaranteed for the 7130SA55J?

The 7130SA55J is specified for industrial temperature operation from –40°C to +85°C. This rating is validated across all electrical parameters including 55 ns access time, standby current (ISB1 ≤ 20 mA), and BUSY arbitration timing (tBDD ≤ 55 ns). It is not rated for commercial (0°C to +70°C) or military (–55°C to +125°C) grades - the 'I' suffix in the full ordering code confirms industrial qualification, ensuring reliability in factory automation, transportation, and outdoor embedded systems using the 7130SA55J.

How does the 7130SA55J handle simultaneous writes to the same address from both ports?

The 7130SA55J uses on-chip arbitration logic to resolve simultaneous writes: when address match occurs, it asserts BUSYL or BUSYR within tBAA ≤ 30 ns (55 ns grade), forcing the delayed port into write-inhibit state. The winning port completes its write; the losing port's data is discarded. Priority is determined by which port meets tAPS ≥ 5 ns setup - no external logic required. This deterministic hardware arbitration ensures data integrity and eliminates race conditions in the 7130SA55J without firmware intervention.

Is the 7130SA55J pin-compatible with other speed grades in the IDT7130SA family?

Yes, the 7130SA55J is pin-compatible with all IDT7130SA variants (e.g., 7130SA25J, 7130SA35J) in the same package type (FP48, LC48, PDG48). All share identical pinout, voltage levels, and control signal definitions. Speed grade differences affect only timing parameters (e.g., tRC, tAA) - not pin function or electrical interface. System designs can scale performance by substituting speed grades without PCB layout changes, provided timing margins and load capacitance remain within spec for the 7130SA55J's 55 ns operation.