Renesas 71342SA25PFI

Overview

IDT71342SA25PFI from Integrated Device Technology is a high-speed 4K × 8 dual-port static RAM with on-chip semaphore logic, operating at 25 ns (max) access time over –40°C to +85°C industrial temperature range, powered by single 5V ±10% supply, and packaged in 52-pin PLCC. It enables concurrent asynchronous read/write access from left and right ports for real-time interprocessor communication in embedded control systems.

For engineers reviewing the 71342SA25PFI datasheet, 71342SA25PFI pinout, 71342SA25PFI application, or 71342SA25PFI equivalent, this device delivers deterministic port-to-port arbitration via hardware semaphores, supports battery-backed data retention (LA variant only), and requires precise CE/SEM timing coordination for SRAM vs. semaphore address space selection.

Technical Context

The 71342SA25PFI implements fully independent left/right ports with separate address (A0L–A11L / A0R–A11R), data (I/O0L–I/O7L / I/O0R–I/O7R), and control lines (CEL/CER, OEL/OER, R/WL/R/WR), enabling true asynchronous dual-port operation without bus contention. Its dedicated semaphore logic block uses eight latches addressed via A0–A2 under SEM = VIL, with active-low token semantics and automatic contention resolution.

Access to SRAM memory space requires CE = VIL and SEM = VIH; semaphore register access requires CE = VIH and SEM = VIL - a strict functional partition enforced by internal decode logic. Power management is controlled per-port via CE and SEM high states, enabling TTL-level or CMOS-level standby modes with ISB3 as low as 0.2 mA (typ) for full standby.

Key Specifications

Pinout & Package

71342SA25PFI is housed in a 52-pin Plastic Leaded Chip Carrier (PLCC) package measuring approximately 20.07 mm × 20.07 mm × 4.32 mm (0.79 in × 0.79 in × 0.17 in), with gull-wing leads and body cavity for thermal relief. All VCC pins must be decoupled locally; all GND pins require low-impedance grounding.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1355BV25 and IDT71322SA25PFI, the 71342SA25PFI uniquely balances 4K depth, hardware semaphore integration, and industrial-qualified 25 ns performance in a compact PLCC package - making it optimal for latency-critical, safety-aware dual-processor systems where external arbitration is undesirable.

Availability

71342SA25PFI is available at Aetrix Electronics and suitable for industrial motion control, avionics data concentration, and railway signaling interlocking requiring stable component supply across extended product lifecycles.

Supply support for 71342SA25PFI 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, specialized in high-performance timing, memory, and interface ICs for communications, computing, and industrial markets.

The IDT71342 product line was designed specifically for deterministic interprocessor communication in real-time embedded systems, emphasizing hardware-accelerated resource arbitration and industrial-grade reliability.

FAQ

What is the difference between SEM and SEML/SEMR pins on the 71342SA25PFI?

The SEM pin is an active-low input that selects the semaphore register address space (A0–A2 only) when driven low; SEML and SEMR are open-drain output pins reflecting the current token ownership status of each port - SEML goes low when the left port holds a semaphore flag, and SEMR goes low when the right port holds it. The 71342SA25PFI uses this separation to enable both configuration (SEM) and real-time status monitoring (SEML/SEMR) without contention.

Can the 71342SA25PFI operate with a 3.3 V supply?

No, the 71342SA25PFI is specified exclusively for 5.0 V ±10% operation (4.5 V to 5.5 V). Its input thresholds (VIH = 2.2 V min), output drive strength, and internal CMOS logic are characterized only at 5 V. Applying 3.3 V will result in undefined behavior, failed reads/writes, and potential damage due to improper biasing of protection diodes. The 71342SA25PFI does not support mixed-voltage or level-shifting interfaces internally.

How does the 71342SA25PFI handle simultaneous semaphore requests from both ports?

The 71342SA25PFI employs dedicated hardware arbitration logic that guarantees exactly one port receives the semaphore token on simultaneous requests - never both or neither. If timing skew is <1 ns, assignment is deterministic based on internal propagation delay; otherwise, it resolves arbitrarily but always atomically. This behavior is verified in Truth Table II and timing diagram 2721 drw 13, ensuring no system deadlock occurs. The 71342SA25PFI makes no software assumptions about fairness - only atomicity.

Is battery backup supported on the 71342SA25PFI?

No, battery backup and 2 V data retention are exclusive to the LA variant (e.g., 71342LA25PFI). The 71342SA25PFI is the standard-power version optimized for higher-speed operation and lower standby current in active systems; it lacks the internal circuitry for low-voltage retention mode. Data retention below 4.5 V is not guaranteed, and VCC < 4.5 V may cause spontaneous bit corruption. Use 71342SA25PFI only in systems with stable 5 V regulation.

What happens if both CE and SEM are high simultaneously on the 71342SA25PFI?

When both CEL/CER and SEM are high, the 71342SA25PFI enters full standby mode (ISB3), drawing only 0.2 mA (typ) - the lowest power state. In this condition, all I/O pins go high-impedance, internal memory cells retain data, and semaphore latches maintain their last state. The 71342SA25PFI remains responsive to CE/SEM transitions; no reset or initialization is required upon wake-up. This mode is ideal for periodic wake-and-check architectures in energy-constrained industrial nodes.