Renesas 70V24S55PFG

Overview

70V24S55PFG from Integrated Device Technology (IDT) is a high-speed 4K x 16 true dual-port static RAM with independent left/right asynchronous ports, 55 ns maximum read cycle time, 3.3 V single-supply operation, and integrated semaphore arbitration logic - used in real-time inter-processor communication systems requiring concurrent memory access without bus contention.

For engineers reviewing the 70V24S55PFG datasheet, 70V24S55PFG pinout, 70V24S55PFG application, or 70V24S55PFG equivalent, key selection criteria include its 84-pin PLCC package, industrial temperature range (–40°C to +85°C), dual-port arbitration timing (tSPS = 5 ns), and low-power standby current of 65 mA (typ.) under TTL-level inputs.

Technical Context

The 70V24S55PFG implements fully asynchronous dual-port architecture with separate address, control, and I/O buses per port, enabling simultaneous read/write operations to the same memory location. It integrates on-chip hardware semaphore logic (8 flags, addressed via A0–A2) and automatic port arbitration with BUSY flag signaling for master/slave configurations.

It supports multiplexed bus compatibility via independent upper-byte (UBR/UBL) and lower-byte (LBR/LBL) enables, and expands data width beyond 16 bits using cascaded master/slave mode - where M/S = VIH configures BUSY as output (master), and M/S = VIL configures BUSY as input (slave).

Key Specifications

Pinout & Package

70V24S55PFG is housed in an 84-pin Plastic Leaded Chip Carrier (PLCC, package code PLG84), with all VDD pins requiring connection to 3.3 V and all VSS pins tied to ground. Pin 1 is located at the index corner; pin numbering proceeds counterclockwise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV33-55AXC and IDT70V24L15PF, the 70V24S55PFG uniquely combines PLCC mechanical compatibility, built-in master/slave BUSY signaling, and precisely matched 55 ns timing - making it the sole option for retrofitting legacy industrial controllers without PCB redesign.

Availability

70V24S55PFG is available at Aetrix Electronics and suitable for industrial PLC communication modules, avionics flight control interfaces, and medical imaging data buffers requiring stable component supply across extended product lifecycles.

Supply support for 70V24S55PFG 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

Integrated Device Technology (IDT), now part of Renesas Electronics, is a fabless semiconductor company specializing in timing, memory interface, RF, and sensor signal conditioning ICs for communications, computing, and industrial markets.

The IDT70V24 family was designed specifically for real-time inter-processor communication in ruggedized embedded systems - emphasizing deterministic latency, hardware arbitration, and industrial-grade reliability over raw density or cost-per-bit.

FAQ

What is the maximum operating temperature range for the 70V24S55PFG?

The 70V24S55PFG is rated for industrial temperature operation from –40°C to +85°C. This specification is validated per the Absolute Maximum Ratings table and confirmed in the DC Electrical Characteristics section for the "Ind" grade. The device maintains full functionality-including 55 ns access timing and semaphore arbitration-across this entire range without derating. Thermal design must ensure junction temperature remains below +150°C under worst-case power dissipation.

Does the 70V24S55PFG support true simultaneous read operations on both ports?

Yes, the 70V24S55PFG implements true dual-port SRAM cells that allow concurrent reads from the same memory location on left and right ports without contention or timing penalty. This is explicitly stated in the Features section ("True Dual-Ported memory cells which allow simultaneous reads of the same memory location") and enabled by fully independent address/control/I/O paths. No arbitration delay or BUSY assertion occurs during dual-read scenarios.

How is semaphore functionality implemented in the 70V24S55PFG?

The 70V24S55PFG integrates eight hardware semaphore flags accessible via I/O0–I/O15 pins and addressed by A0–A2. Semaphore access is enabled by asserting SEM = VIL while holding CE = VIH or UB & LB = VIH. Each flag can be written (via I/O0) and read (via all I/O lines), with tSWRD = 5 ns write-to-read delay and tSPS = 5 ns contention window - ensuring deterministic lock acquisition in multi-processor systems.

Can the 70V24S55PFG be used in a master/slave configuration without external logic?

Yes, the 70V24S55PFG supports native master/slave cascading using the M/S pin: when M/S = VIH, BUSY is driven as an output (master); when M/S = VIL, BUSY is accepted as an input (slave). This allows expansion to 32-bit+ data width using multiple devices, with automatic port arbitration - no external gates or latches are required, as confirmed in the Functional Block Diagram and Truth Table II notes.

What is the pin-compatible replacement for the 70V24S55PFG if longer access time is acceptable?

No pin-compatible replacement exists for the 70V24S55PFG in the same 84-pin PLCC package with identical pinout and function. Alternative parts like CY7C1362BV33-55AXC use 100-pin TQFP and lack M/S logic, while IDT70V24L15PF shares the PLCC package but targets 15 ns timing - making it incompatible for 55 ns–constrained designs. Migration requires PCB redesign or system-level timing revalidation.