71421SA25PFI8

Overview

The 71421SA25PFI8 is a 16Kb (2K x 8) dual-port static RAM manufactured by Renesas Electronics Corporation. It features asynchronous parallel interface operation with a 20 ns access time and write cycle time. The device operates on a single 5V ±10% power supply within a voltage range of 4.5V to 5.5V. It is housed in a 64-TQFP (14x14) surface-mount package. The component supports industrial temperature ranges and includes internal interrupt logic for interprocessor communications.

Feature Summary

• True dual-ported memory cells enabling simultaneous independent access to the same memory location from both ports.
• Integrated internal interrupt logic providing two INT flags for efficient port-to-port communication without external discrete logic.
• Fully asynchronous operation from either port, supporting battery backup data retention down to 2V.
• TTL-compatible inputs and outputs with automatic power-down mode controlled by chip enable signals.

Applications

• Interprocessor communication in multi-CPU systems
• High-speed data buffering between processors
• Master/Slave dual-port configurations expanding bus width to 16 bits or more

Procurement Notes

Verify RoHS compliance status as the component may not meet current environmental regulations. Confirm lead availability as the part is marked obsolete. Ensure replacement packages match the original footprint requirements. Validate that the substitute component maintains identical pinout and electrical characteristics for seamless integration into existing designs.

Selection Notes

Select this component for applications requiring high-speed, non-blocking concurrent access to shared memory resources. It is suitable for systems needing direct processor-to-processor signaling via internal interrupts. Consider the 64-TQFP package constraints for PCB layout. Verify that the 5V supply voltage aligns with the system's power architecture and that the operating temperature range meets environmental specifications.

Part Context

This device belongs to the 71321/71421 series of dual-port SRAMs. It functions as a standalone 8-bit memory or as a master unit in wider bus configurations. The series is designed to eliminate the need for external arbitration logic, simplifying system design while maintaining full-speed error-free operation across multiple processing units.

Replacement Considerations

• 71421LA25PFGI8

FAQ

Can the 71421SA25PFI8 be used to expand data bus width?

Yes, it can function as a MASTER dual-port RAM to expand data bus width to 16 bits or more when paired with a SLAVE dual-port RAM like the 71421.

What is the data retention capability during low voltage conditions?

The device supports battery backup operation with data retention down to 2V, although this feature is specifically noted for the LA variant in some documentation.