Renesas 70V27S35PFI

Overview

70V27S35PFI from Integrated Device Technology is a high-speed 3.3V 32K × 16 dual-port static RAM with true simultaneous access capability, 35 ns maximum read cycle time, industrial temperature range (–40°C to +85°C), and 100-pin TQFP package. It enables error-free 32-bit memory expansion via Master/Slave cascading in real-time control systems requiring deterministic inter-processor communication.

For engineers reviewing the 70V27S35PFI datasheet, 70V27S35PFI pinout, 70V27S35PFI application, or 70V27S35PFI equivalent, key selection criteria include BUSY arbitration timing (tBDD ≤ 40 ns), semaphore flag support for resource locking, LVTTL-compatible 3.3V operation, and dual chip-enable logic for depth expansion without external logic.

Technical Context

The 70V27S35PFI 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 or chip-enable priority, generating push-pull BUSY flags (not tri-state) to stall writes during concurrent access to identical memory locations.

It supports semaphore signaling across ports using A0–A2 addressing of eight shared flags, with dedicated SEM pins and non-overlapping tSWRD (5 ns) and tSPS (5 ns) timing. The device uses CMOS process technology and features automatic power-down per port via CE0/CE1, enabling low standby current (ISB3 = 0.2 mA typ. for full CMOS standby).

Key Specifications

Pinout & Package

70V27S35PFI is housed in a 100-pin Thin Quad Flatpack (TQFP) with 0.5 mm pitch, body size 14 mm × 14 mm × 1.4 mm. All VDD and VSS pins require local decoupling; NC pins must remain unconnected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C028V-35AXC and AS7C3256A-35JCIN, the 70V27S35PFI uniquely integrates per-port power-down, hardware semaphore addressing, and configurable Master/Slave arbitration-reducing BOM count and eliminating firmware-level synchronization in deterministic real-time systems.

Availability

70V27S35PFI is available at Aetrix Electronics and suitable for motor control systems, industrial PLC backplanes, avionics data recorders, and medical imaging subsystems requiring stable component supply across extended product lifecycles.

Supply support for 70V27S35PFI 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, designs high-performance timing, memory, and interface solutions for communications, computing, and industrial markets.

The IDT70V27 family was engineered specifically for deterministic inter-processor communication in real-time embedded systems, emphasizing hardware arbitration, low-latency semaphore signaling, and industrial-grade reliability.

FAQ

What is the maximum operating frequency supported by the 70V27S35PFI?

The 70V27S35PFI does not operate at a fixed clock frequency; it is an asynchronous SRAM. Its performance is defined by timing parameters such as tRC (read cycle time) and tWC (write cycle time), both rated at 35 ns maximum. This corresponds to an effective maximum throughput of approximately 28.6 MHz for consecutive random accesses, assuming optimal bus protocol and no wait states. The 70V27S35PFI achieves this without requiring a system clock input.

How does the 70V27S35PFI handle simultaneous access to the same memory address from both ports?

The 70V27S35PFI uses on-chip hardware arbitration to resolve simultaneous access. When both ports attempt to access the same address, the device asserts BUSY on the later-arriving port (determined by tAPS setup time). In Master mode (M/S = VIH), BUSY is an output that stalls the write; in Slave mode (M/S = VIL), BUSY is an input that inhibits the write internally. This prevents data corruption without software intervention.

Can the 70V27S35PFI be used in a 32-bit data bus configuration?

Yes, the 70V27S35PFI supports 32-bit expansion via its Master/Slave cascading architecture. Two devices can be connected with M/S = VIH (Master) and M/S = VIL (Slave); the Master's BUSY output connects to the Slave's BUSY input. This configuration allows full-speed, error-free 32-bit operation without external logic, as specified in the IDT70V27 functional description and verified in application note DSC3603.

What is the purpose of the SEM pins on the 70V27S35PFI?

The SEML and SEMR pins on the 70V27S35PFI enable semaphore flag access mode. When SEM = VIL and CE = VIH, the device enters semaphore mode, allowing eight shared flags to be written via I/O0 and read across all 16 I/O lines using A0–A2 addressing. This provides hardware-accelerated mutual exclusion for critical resources shared between processors, eliminating the need for polling or software locks.

Does the 70V27S35PFI support power-down modes, and how are they controlled?

Yes, the 70V27S35PFI supports multiple power-down modes. Per-port standby is activated by driving CE0 and CE1 HIGH, reducing current to ISB1 = 22 mA (typ.) under TTL inputs. Full standby (ISB3 = 0.2 mA typ.) is achieved when all inputs are held at CMOS logic levels (VIL < 0.2 V or VIH > VDD − 0.2 V) with SEM = VIH. These modes are fully asynchronous and require no clock or sequence.