Renesas 70261L20PFI8

Overview

70261L20PFI8 from IDT (now Renesas) is a high-speed 16K × 16 true dual-port static RAM with interrupt and semaphore logic, operating at 20 ns max access time over industrial temperature (−40°C to +85°C), powered by single 5V ±10% supply, and packaged in 100-pin TQFP. It enables simultaneous asynchronous read/write access from independent left/right ports in real-time interprocessor communication systems.

For engineers reviewing the 70261L20PFI8 datasheet, 70261L20PFI8 pinout, 70261L20PFI8 application, or 70261L20PFI8 equivalent, key selection criteria include bus arbitration timing (tBDD ≤ 30 ns), low standby power (ISB3 = 0.2 mA typ.), interrupt mailbox addressing (3FFE/3FFF), and Master/Slave cascading support for 32-bit+ memory expansion.

Technical Context

The 70261L20PFI8 implements fully asynchronous dual-port architecture with separate address, control, and I/O buses per port, enabling concurrent access without external arbitration logic. Its on-chip hardware supports semaphore signaling across eight flags (A0–A2 addressed), BUSY flag arbitration (M/S = H for Master output, M/S = L for Slave input), and interrupt generation via dedicated mailbox addresses (3FFE for INTL, 3FFF for INTR).

It features byte-selectable upper/lower data paths (UBL/LBL, UBR/LBR), TTL-compatible I/Os, and automatic power-down via CE-driven standby modes - ISB3 = 0.2 mA (typ.) when both ports are fully disabled with CMOS-level inputs. Fabricated in high-performance CMOS, it delivers 750 mW active power (typ.) at 5 V.

Key Specifications

Pinout & Package

70261L20PFI8 is housed in a 100-pin TQFP (PNG100) package with 0.5 mm pitch, body size 14 mm × 14 mm × 1.4 mm. All VCC and GND pins must be connected per datasheet layout guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV33-200BZI and IDT70V261S20PFI, the 70261L20PFI8 uniquely integrates interrupt mailboxes and hardware semaphores within an industrial-grade 5V dual-port SRAM, eliminating external logic while ensuring deterministic timing in harsh environments.

Availability

70261L20PFI8 is available at Aetrix Electronics and suitable for real-time interprocessor communication, industrial PLC memory buffering, aerospace avionics data logging, and medical imaging frame buffer applications requiring stable component supply and long-term industrial temperature reliability.

Supply support for 70261L20PFI8 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

Renesas Electronics (formerly Integrated Device Technology) is a global semiconductor leader specializing in microcontrollers, analog, power management, and memory solutions for industrial, automotive, and communications markets.

The IDT70261 product line was designed specifically for deterministic, low-latency interprocessor communication in embedded systems requiring hardware-enforced memory coherency, interrupt signaling, and scalable memory width expansion.

FAQ

What is the maximum access time specification for the 70261L20PFI8 under industrial temperature conditions?

The 70261L20PFI8 has a maximum access time (tAA) of 20 ns over the full industrial temperature range (−40°C to +85°C), as guaranteed in the AC Electrical Characteristics table for the "70261X20" speed grade. This value applies to both read and write cycles when operating at VCC = 5.0 V ±10% and defines the worst-case delay from address valid to valid data output or data setup completion.

How does the 70261L20PFI8 implement hardware semaphore functionality?

The 70261L20PFI8 provides eight dedicated semaphore flags accessed via address bits A0–A2. To use them, CE must be high and SEM low (CE = VIH, SEM = VIL). Writing to I/O0 sets the selected semaphore; reading returns the flag state on all I/O lines (I/O0–I/O15). This enables lock-free mutual exclusion between ports without software polling or external logic.

Can the 70261L20PFI8 be used in a Master/Slave configuration for 32-bit memory expansion?

Yes - the 70261L20PFI8 supports Master/Slave cascading via the M/S pin. When M/S = H, BUSY is an output (Master); when M/S = L, BUSY is an input (Slave). Multiple devices can be connected to form wider data paths (e.g., two 16-bit devices yield 32-bit width), with automatic port arbitration and no additional discrete logic required per the IDT MASTER/SLAVE Dual-Port RAM approach.

What are the interrupt mailbox addresses for the 70261L20PFI8 and how do they operate?

The 70261L20PFI8 uses fixed addresses 3FFE_H (for INTL) and 3FFF_H (for INTR) as interrupt mailboxes. Writing to 3FFF_H from the left port asserts INTR; reading 3FFF_H from the right port clears it. Similarly, writing to 3FFE_H from the right port asserts INTL, and reading it from the left port clears the flag. These locations are standard SRAM cells - user-defined data may be stored alongside the interrupt trigger.

What is the minimum standby current consumption of the 70261L20PFI8 in full shutdown mode?

In full standby mode (ISB3), where both ports are disabled with CMOS-level inputs (CE > VCC − 0.2 V, all inputs > VCC − 0.2 V or < 0.2 V, f = 0), the 70261L20PFI8 consumes 0.2 mA typical current. This ultra-low quiescent current enables energy-efficient sleep states in battery-backed or thermally constrained industrial systems.