Renesas 7028L20PFI8

Overview

7028L20PFI8 from IDT (now Renesas) is a high-speed 64K × 16 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/arbiter logic. It enables simultaneous read/write to the same memory location and supports master/slave cascading for 32-bit+ bus expansion in real-time multiprocessor systems.

For engineers reviewing the 7028L20PFI8 datasheet, 7028L20PFI8 pinout, 7028L20PFI8 application, or 7028L20PFI8 equivalent, key selection criteria include BUSY arbitration timing (tBDD ≤ 17 ns), dual-port semaphore flag latency (tSAA ≤ 20 ns), industrial temperature support (–40°C to +85°C), and 100-pin TQFP package compatibility with board-level signal integrity constraints.

Technical Context

The 7028L20PFI8 implements fully asynchronous dual-port operation with separate address, control, and I/O buses per port - enabling concurrent reads/writes without internal clocking. Its on-chip arbitration logic uses push-pull BUSY outputs (not open-drain) and supports both master-mode (BUSY as output) and slave-mode (BUSY as write-inhibit input) via the M/S pin.

Hardware semaphore functionality is implemented via eight dedicated latches addressed by A0–A2, accessible only when CE = VIH and SEM = VIL. Interrupt flags (INTL/INTR) are software-triggered by writes to fixed addresses FFFE_H (left port sets right INTR) and FFFF_H (right port sets left INTL), with tINS/tINR ≤ 20 ns.

Key Specifications

Pinout & Package

7028L20PFI8 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 VCC and GND pins must be individually decoupled; NC pins are not internally connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C028V-20AXC and AS7C362000B-20TIN, the 7028L20PFI8 uniquely integrates hardware semaphore, BUSY arbitration, and interrupt signaling in a single 5V device - eliminating external logic and guaranteeing sub-20 ns deterministic response for safety-critical multiprocessor coordination.

Availability

7028L20PFI8 is available at Aetrix Electronics and suitable for industrial motion control, telecom line card design, avionics data concentrators, and medical imaging subsystems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 7028L20PFI8 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), now part of Renesas Electronics, is a semiconductor leader specializing in high-performance timing, memory, and interface solutions for communications, computing, and industrial markets.

The 7028L20PFI8 belongs to IDT's legacy high-speed dual-port SRAM product line, engineered specifically for deterministic, low-latency inter-processor communication in real-time embedded systems with strict timing and reliability requirements.

FAQ

What is the guaranteed maximum access time for 7028L20PFI8 over its full industrial temperature range?

The 7028L20PFI8 guarantees a maximum access time of 20 ns across the full industrial temperature range (–40°C to +85°C) and supply voltage range (4.5 V to 5.5 V). This value is production-tested and specified in the AC Electrical Characteristics table (Table 12) under the 7028L20 column for parameters tAA, tACE, and tAOE. It reflects worst-case propagation delay from address/control assertion to valid output data under defined load conditions.

How does the BUSY arbitration logic function in master versus slave mode for 7028L20PFI8?

In master mode (M/S = VIH), BUSYL and BUSYR are push-pull outputs that assert low when address contention occurs, automatically inhibiting writes on the contending port. In slave mode (M/S = VIL), BUSYL and BUSYR become inputs - an external low signal blocks writes to that port. The 7028L20PFI8 requires no pull-up resistors in master mode due to its totem-pole driver structure, unlike open-drain alternatives.

Can 7028L20PFI8 support true simultaneous read operations from both ports to the same memory address?

Yes, the 7028L20PFI8 supports true simultaneous reads from both ports to the same memory address without contention or timing penalty. Its true dual-ported memory cell architecture allows independent, asynchronous access - confirmed in the Functional Description section and Truth Table II. BUSY signals are inactive during concurrent reads, and tBDD timing applies only to read/write or write/write contention scenarios.

What are the electrical requirements for using the semaphore function on 7028L20PFI8?

To access the eight semaphore latches on the 7028L20PFI8, CE must be high (VIH) and SEM must be low (VIL) - a distinct enable condition separate from RAM access. Semaphore reads/writes use A0–A2 for addressing and I/O0 for data; all 16 I/O lines reflect the semaphore value during reads. Timing parameters tSAA (≤20 ns) and tSOP (10 ns) govern semaphore access, and tSPS (5 ns) defines the minimum separation between competing semaphore requests.

Is 7028L20PFI8 pin-compatible with earlier speed grades like 7028L15?

Yes, the 7028L20PFI8 is pin-compatible and footprint-compatible with the 7028L15 series (e.g., 7028L15PFI8), sharing identical 100-pin TQFP packaging, pinout, and DC/AC interface specifications. The primary difference is guaranteed access time (20 ns vs. 15 ns) and extended industrial temperature qualification - allowing drop-in replacement in designs where 20 ns timing suffices and thermal margin is required.