Renesas 7028L20PFI

Overview

7028L20PFI from IDT (Integrated Device Technology) is a high-speed, industrial-grade 64K × 16 dual-ported static RAM with independent left/right ports, 20 ns max access time, TTL-compatible 5V ±10% supply, and integrated semaphore/arbiter logic for inter-processor communication in real-time embedded systems.

For engineers reviewing the 7028L20PFI datasheet, 7028L20PFI pinout, 7028L20PFI application, or 7028L20PFI equivalent, this device supports simultaneous asynchronous reads/writes across two ports, hardware BUSY arbitration, interrupt flag signaling, and byte-selectable I/O - critical for deterministic multi-CPU memory sharing in telecom line cards and industrial motion controllers.

Technical Context

The 7028L20PFI implements fully asynchronous dual-port operation with separate address, control, and bidirectional I/O buses per port. Its on-chip arbitration logic uses push-pull BUSY outputs (not open-drain) to stall conflicting writes when address matches occur, with tBDD ≤ 17 ns propagation delay from BUSY assertion to valid read data.

It integrates eight dedicated semaphore latches accessible via A0–A2 and controlled by SEM pins, enabling token-passing resource locking without software overhead. Interrupt flags (INTL/INTR) are triggered by writes to fixed addresses FFFE_H (left port sets right INTR) and FFFF_H (right port sets left INTL), supporting mailbox-style inter-processor messaging.

Key Specifications

Pinout & Package

7028L20PFI 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 connected per layout guidelines; NC pins are no-connect and 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-20AC and IS61WV6416BLL-20NLI, the 7028L20PFI uniquely delivers hardware-enforced memory coherency, deterministic arbitration, and integrated inter-processor signaling - eliminating external logic and software complexity in tightly coupled multi-CPU architectures.

Availability

7028L20PFI is available at Aetrix Electronics and suitable for telecom infrastructure, industrial motion control, and automotive ADAS applications requiring stable component supply, long-term lifecycle assurance, and industrial temperature qualification.

Supply support for 7028L20PFI 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) was a fabless semiconductor company specializing in high-performance timing, memory, and interface solutions before its acquisition by Renesas Electronics in 2019.

The 7028L20PFI belongs to IDT's legacy dual-port SRAM product line, engineered specifically for deterministic, low-latency inter-processor communication in real-time embedded systems demanding hardware arbitration and semaphore support.

FAQ

What is the maximum operating temperature range for the 7028L20PFI?

The 7028L20PFI is rated for industrial temperature operation from −40°C to +85°C, with all electrical specifications-including 20 ns access time-guaranteed across this full range. This makes it suitable for deployment in harsh environments such as factory floors, outdoor telecom cabinets, and vehicle engine compartments where ambient thermal stability cannot be assured.

How does the BUSY arbitration logic function in the 7028L20PFI?

In Master mode (M/S = VIH), the 7028L20PFI asserts BUSYL or BUSYR when both ports attempt to access the same memory address simultaneously. The BUSY signal gates the write path on the delayed port, preventing data corruption. tBDD ≤ 17 ns ensures valid read data appears within 17 ns after BUSY assertion - enabling tight timing closure in real-time systems.

Can the 7028L20PFI be used in a 32-bit data bus configuration?

Yes - the 7028L20PFI supports 32-bit expansion via MASTER/SLAVE cascading. One device operates as Master (M/S = VIH), the other as Slave (M/S = VIL); CE0/CE1 enables depth expansion, while UBL/LBL and UBR/LBR allow byte-aligned writes across both devices, forming a seamless 32-bit memory space without external decoding logic.

What is the purpose of the SEM pins on the 7028L20PFI?

The SEML and SEMR pins select between RAM array access (SEM = VIH) and semaphore register access (SEM = VIL). When SEM is low, the device routes I/O0–I/O15 and A0–A2 to eight dedicated semaphore latches - enabling hardware-accelerated token passing for resource locking without CPU intervention or software polling overhead.

Does the 7028L20PFI require external pull-up resistors on BUSY or INT pins?

No - the 7028L20PFI features push-pull (totem-pole) outputs on BUSYL, BUSYR, INTL, and INTR pins in Master mode, eliminating the need for external pull-up resistors. In Slave mode, BUSY pins become inputs and must be driven externally; INT pins remain active-low outputs and retain push-pull drive capability regardless of M/S state.