Renesas 70V639S12PRF

Overview

IDT70V639S12PRF from Integrated Device Technology is a high-speed 128K × 18 asynchronous dual-port static RAM with fully independent left/right ports, 12 ns max access time (industrial grade), LVTTL-compatible 3.3 V core supply, and selectable 3.3 V/2.5 V I/O voltage per port via OPTL/OPTR pins. It enables simultaneous read/write access to the same memory location in real-time embedded systems requiring deterministic inter-processor communication.

For engineers reviewing the IDT70V639S12PRF datasheet, IDT70V639S12PRF pinout, IDT70V639S12PRF application, or IDT70V639S12PRF equivalent, this page delivers verified package mapping (128-pin TQFP), confirmed dual-port arbitration logic, true dual-port timing behavior, and industrial-grade (-40°C to +85°C) operation - all validated against IDT DSC-5621/8 (June 2018).

Technical Context

The IDT70V639S12PRF implements true dual-port SRAM cells with on-chip port arbitration, semaphore signaling, and BUSY flag logic for conflict resolution between left and right ports. It supports both CE-controlled and R/W-controlled write cycles, with separate byte enables (UBL/LBR, UBR/LBL) enabling 9-bit sub-word access per port.

Its Master/Slave (M/S) configuration allows cascading for 36-bit+ word systems without external logic; when M/S = VIH, BUSYR/BUSYL are outputs indicating port contention; when M/S = VIL, BUSYR/BUSYL become inputs for slave-side synchronization. JTAG is explicitly excluded in the PK128 package per datasheet note.

Key Specifications

Pinout & Package

Package: 128-pin TQFP (PK128), RoHS-compliant, lead-finish SnPb (EOL as of June 15, 2018). All VDD pins require 3.3 V; VDDQL/VDDQR must match OPTL/OPTR selection (3.3 V if VIH, 2.5 V if VIL); all VSS pins grounded.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1375DV33 and R1EX24016AS, the IDT70V639S12PRF uniquely delivers industrial-grade 12 ns dual-port performance with integrated semaphore and Master/Slave expansion - making it irreplaceable in deterministic multi-processor architectures.

Availability

IDT70V639S12PRF is available at Aetrix Electronics and suitable for real-time inter-processor communication, digital signal processing buffering, and industrial motion controller memory requiring stable component supply across extended temperature ranges.

Supply support for IDT70V639S12PRF 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, is a fabless semiconductor company specializing in timing, memory interface, RF, and power management ICs for communications, computing, and industrial markets.

The IDT70V639S product line was engineered for high-reliability, low-latency shared memory in multi-processor systems - targeting aerospace avionics, industrial automation, and telecom infrastructure where deterministic arbitration is critical.

FAQ

What is the maximum guaranteed access time for IDT70V639S12PRF over its full industrial temperature range?

IDT70V639S12PRF guarantees a maximum access time of 12 ns across the full industrial temperature range of -40°C to +85°C, with VDD = 3.3 V ±150 mV. This value is specified in Table 12 of the official datasheet (DSC-5621/8) and applies to tAA, tACE, and tAOE parameters under worst-case conditions - not a typical or commercial-grade specification.

Does IDT70V639S12PRF support JTAG boundary scan testing?

No, IDT70V639S12PRF does not support JTAG boundary scan. The datasheet explicitly states: "Due to limited pin count, JTAG is not supported on the 128-pin TQFP package" (page 1, Features section). While JTAG pins (TMS, TCK, TRST, TDI, TDO) appear in the 208-ball and 256-ball BGA variants, they are omitted in the PK128 footprint used by IDT70V639S12PRF.

How does the Master/Slave (M/S) pin affect BUSY signal behavior in IDT70V639S12PRF?

When M/S = VIH, IDT70V639S12PRF operates as a Master: BUSYL and BUSYR are active outputs asserting during port contention. When M/S = VIL, it operates as a Slave: BUSYL and BUSYR become inputs, allowing external coordination of write sequencing. This dual-mode behavior is defined in Note 1 on page 2 and timing diagrams on pages 15–16 of the datasheet.

Can IDT70V639S12PRF operate with different I/O voltages on left and right ports simultaneously?

Yes, IDT70V639S12PRF supports independent I/O voltage selection per port: OPTL sets VDDQL (left port), and OPTR sets VDDQR (right port). Either can be configured for 3.3 V (OPT = VIH) or 2.5 V (OPT = VIL), enabling mixed-voltage interfacing - e.g., left port to a 2.5 V FPGA and right port to a 3.3 V microcontroller - as confirmed in Table 1 and Pin Names section (page 5).

What memory address range is used for semaphore register access in IDT70V639S12PRF?

Semaphore register access in IDT70V639S12PRF occurs at addresses A2–A0 only, with CE = VIH and SEM = VIL (Truth Table II, page 6). The eight semaphore flags reside in a dedicated 8-bit register mapped to A0–A2; higher address bits (A3–A16) are ignored during semaphore access. This is distinct from main memory access, which requires CE = VIL and SEM = VIH.