Renesas 7009L20PFGI8

Overview

7009L20PFGI8 from IDT is a high-speed 128K × 8 true dual-ported static RAM with independent left/right ports, 20 ns max access time (industrial grade), TTL-compatible 5V ±10% supply, and integrated hardware semaphore/INT/BUSY arbitration logic. It enables simultaneous asynchronous reads of the same memory location in real-time interprocessor communication systems.

For engineers reviewing the 7009L20PFGI8 datasheet, 7009L20PFGI8 pinout, 7009L20PFGI8 application, or 7009L20PFGI8 equivalent, key selection considerations include dual-port contention handling via BUSY flag timing (tBDD ≤17 ns), semaphore address mapping (A0–A2), M/S master/slave configuration, and industrial temperature support (–40°C to +85°C).

Technical Context

The 7009L20PFGI8 implements fully asynchronous dual-port operation with separate CE0/CE1, R/W, OE, and address buses per port. Its on-chip arbitration logic resolves port-to-port conflicts using push-pull BUSY outputs (not open-drain) and supports both master (BUSY output) and slave (BUSY input) modes via the M/S pin.

Hardware semaphore functionality uses eight dedicated latches addressed by A0–A2 and controlled by SEM/CE high-level enable; interrupt flags (INTL/INTR) are triggered by writes to fixed mailbox addresses (1FFFEh/1FFFFh), with set/reset timing tINS/tINR ≤20 ns.

Key Specifications

Pinout & Package

7009L20PFGI8 is housed in a 100-pin Thin Quad Flatpack (TQFP) with 14 mm × 14 mm body and 1.4 mm height; pin 1 located at top-left corner (notch-marked side).

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1370D-200BZXI and AS7C3128A-20JIN, the 7009L20PFGI8 uniquely integrates hardware semaphore, BUSY arbitration, and true dual-port timing in a single 5V TQFP device - eliminating external logic and enabling deterministic real-time interprocessor communication without software overhead.

Availability

7009L20PFGI8 is available at Aetrix Electronics and suitable for real-time interprocessor communication, industrial motion control, avionics data concentrators, and medical imaging subsystems requiring stable component supply across extended temperature ranges.

Supply support for 7009L20PFGI8 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, RF, and real-time interconnect solutions for communications, computing, and industrial markets.

The 7009L20PFGI8 belongs to IDT's high-speed dual-port SRAM product line, designed specifically for deterministic, low-latency interprocessor communication in industrial, avionics, and medical systems requiring hardware arbitration and mailbox-style signaling.

FAQ

What is the maximum operating temperature range supported by the 7009L20PFGI8?

The 7009L20PFGI8 is qualified for industrial temperature operation from –40°C to +85°C. This rating applies across all specified DC and AC electrical characteristics, including 20 ns access time, BUSY arbitration timing (tBDD ≤17 ns), and semaphore functionality. The device maintains full functionality without derating within this range and does not support extended military-grade temperatures.

How does the BUSY arbitration logic function in master versus slave configuration for the 7009L20PFGI8?

In master mode (M/S = VIH), BUSYL and BUSYR are push-pull outputs that assert LOW when port-to-port address contention occurs, inhibiting writes on the contending port. In slave mode (M/S = VIL), BUSYL and BUSYR become inputs; a LOW level externally applied disables writes. The 7009L20PFGI8 uses this dual-role capability to support scalable width-expanded arrays with one master managing arbitration and multiple slaves responding to its BUSY signal.

What memory addresses are used for interrupt flag generation in the 7009L20PFGI8?

The 7009L20PFGI8 uses fixed SRAM addresses for interrupt mailbox functionality: writing to address 1FFFEh (hex) asserts the left-port interrupt flag (INTL), and writing to 1FFFFh (hex) asserts the right-port flag (INTR). Clearing is performed by reading those same addresses. These locations remain fully accessible as general-purpose RAM when interrupt functionality is unused, and timing parameters tINS/tINR are guaranteed ≤20 ns across the industrial temperature range.

Can the 7009L20PFGI8 support depth expansion without external logic, and how is it implemented?

Yes, the 7009L20PFGI8 supports depth expansion using its dual chip-enable inputs (CE0 and CE1) per port. By asserting CE0L/CE1L or CE0R/CE1R in complementary combinations, multiple devices can be stacked to increase memory depth while maintaining full-speed operation. No external decoding logic is required because the internal CE truth table defines four discrete enable states (e.g., CE0L = VIL & CE1L = VIH selects left port), enabling seamless 2× or 4× depth scaling.

What is the role of the SEM pin in the 7009L20PFGI8, and how does it interact with CE for semaphore access?

The SEM pin enables access to the eight hardware semaphore latches. Semaphore operation requires SEM = VIL *and* CE = VIH - a deliberate inverted enable scheme that electrically isolates semaphore and main RAM address spaces. When active, A0–A2 select one of eight semaphores, and I/O0 carries the token value (I/O1–I/O7 reflect it). This separation prevents accidental semaphore writes during normal RAM access and ensures atomic token-passing critical for real-time resource allocation.