Renesas 70V28L15PF

Overview

70V28L15PF from Integrated Device Technology is a high-speed 3.3V 64K × 16 true dual-ported static RAM with independent left/right ports, 15 ns max access time (commercial grade), LVTTL-compatible I/O, and on-chip semaphore/arbiration logic for multiprocessor synchronization. It operates across –40°C to +85°C and supports master/slave cascading for 32-bit+ bus expansion in real-time embedded control systems.

For engineers reviewing the 70V28L15PF datasheet, 70V28L15PF pinout, 70V28L15PF application, or 70V28L15PF equivalent, key selection considerations include simultaneous port arbitration timing (tAPS = 5 ns), BUSY flag behavior under M/S configuration, dual CE-controlled power-down modes, and semaphore flag update latency (tSOP = 10 ns).

Technical Context

The 70V28L15PF implements fully asynchronous dual-port architecture with separate address, control, and bidirectional I/O buses per port-enabling concurrent read/write to any memory location without internal contention. Its hardware semaphore logic uses dedicated A0–A2-addressed latches (8 flags) accessed via SEM = VIL and CE = VIH, independent of main memory array operation.

Busy arbitration is implemented via push-pull BUSY outputs (not open-drain) that assert when address matches occur between ports; M/S pin configures BUSY as output (master) or input (slave), directly gating write paths. Port-to-port delay (tWDD ≤ 30 ns) and semaphore contention window (tSPS = 5 ns) are guaranteed timing parameters critical for deterministic interprocessor handshaking.

Key Specifications

Pinout & Package

70V28L15PF is housed in a 100-pin Thin Quad Flatpack (TQFP) with 0.5 mm pitch, 14 mm × 14 mm footprint, and 1.4 mm height. Pin 1 is located at top-left corner (marking dot adjacent), with pins numbered counter-clockwise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C028V-15AXC and AS7C364096B-15TIN, the 70V28L15PF delivers native 3.3V dual-port operation with hardware semaphore and arbitration - reducing BOM count by up to 7 components and eliminating timing-critical external logic design.

Availability

70V28L15PF is available at Aetrix Electronics and suitable for industrial motion controllers, avionics data concentrators, medical imaging subsystems, and test & measurement instruments requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 70V28L15PF 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 interface, and RF solutions for communications, computing, and industrial markets.

The 70V28L15PF belongs to IDT's high-speed dual-port SRAM product line, engineered specifically for deterministic interprocessor communication in real-time embedded systems requiring hardware-enforced resource sharing.

FAQ

What is the maximum operating temperature range supported by the 70V28L15PF?

The 70V28L15PF is rated for industrial temperature operation from –40°C to +85°C. This specification is explicitly confirmed in the datasheet's "Recommended DC Operating Conditions" table (4849 tbl 03) and applies to the 70V28L15PF variant, not just the generic 70V28 family. The device maintains full 15 ns access time compliance across this full range under 3.3 V ± 0.3 V supply conditions.

How does the BUSY signal behave when the 70V28L15PF is configured as a slave?

When M/S = VIL, the 70V28L15PF operates in slave mode and BUSYL/BUSYR become inputs-not outputs. In this configuration, asserting BUSYL or BUSYR low internally inhibits writes to the corresponding port, regardless of R/W state. The datasheet confirms this behavior in Note 1 of the Functional Block Diagram and Section "Busy Logic": "If the write inhibit function of BUSY logic is not desirable, the BUSY logic can be disabled by placing the part in slave mode with the M/S pin."

Can the 70V28L15PF support 32-bit data bus expansion, and how is it implemented?

Yes, the 70V28L15PF supports 32-bit expansion via master/slave cascading using the M/S pin and BUSY chaining. As stated in the datasheet description: "IDT70V28 easily expands data bus width to 32 bits or more using the Master/Slave select when cascading more than one device." Two 70V28L15PF devices operate in lockstep-one as master (M/S = VIH), the other as slave (M/S = VIL)-with BUSY outputs wired to BUSY inputs to maintain atomic access across the combined 32-bit word.

What is the purpose of the SEM pin, and how is it used to access semaphore flags?

The SEM pin (semaphore enable) is an active-low control that selects semaphore register access instead of main memory. To read or write a semaphore flag, CE must be high (VIH) and SEM low (VIL), as defined in Truth Table III. The eight flags are addressed by A0–A2, and data is written via I/O0 (input) and read from all I/O0–I/O15 (output). This separation ensures semaphore operations do not interfere with main memory transactions.

Does the 70V28L15PF require external pull-up resistors on BUSY or INT pins?

No, the 70V28L15PF does not require external pull-up resistors on BUSY or INT pins. The datasheet explicitly states: "The BUSY outputs on the IDT70V28 RAM in master mode, are push-pull type outputs and do not require pull up resistors to operate." Similarly, INTL and INTR are specified as totem-pole outputs (Note 2 in Functional Block Diagram), confirming active drive capability in both high and low states.