Renesas 70T631S15BF8

Overview

70T631S15BF8 from Integrated Device Technology is a high-speed 256K × 18 asynchronous dual-port static RAM with true simultaneous access, 15 ns max access time, single 2.5 V core supply, and selectable 2.5 V/3.3 V I/O interface per port. It supports RapidWrite Mode for back-to-back writes and on-chip semaphore arbitration-used in real-time embedded systems requiring deterministic inter-processor communication.

For engineers reviewing the 70T631S15BF8 datasheet, 70T631S15BF8 pinout, 70T631S15BF8 application, or 70T631S15BF8 equivalent, key selection criteria include dual-port timing integrity, BUSY/INT flag behavior in MASTER/SLAVE configurations, JTAG-compliant testability in BGA-208, and voltage-flexible I/O operation via OPTL/OPTR pins.

Technical Context

This device implements fully asynchronous dual-port architecture with independent address/control/I/O buses per port, enabling concurrent read/write to identical memory locations without external arbitration logic. Its on-chip port arbitration resolves contention using BUSY flags and semaphore registers addressed via A0–A2.

RapidWrite Mode eliminates R/W toggling between consecutive writes by defining cycle end on address transition-reducing control timing complexity at 15 ns cycle times. Sleep mode (ZZL/ZZR) disables dynamic inputs while preserving JTAG accessibility and M/S/INT/SEM functionality.

Key Specifications

Pinout & Package

208-ball fine-pitch BGA (BF208) package with 0.8 mm ball pitch, 15 mm × 15 mm body size, and thermal pad-compatible layout. Pin functions follow left/right port symmetry with dedicated chip enables (CE0L/CE1L, CE0R/CE1R), byte controls (LBL/LBR, UBL/UBR), and dual-voltage I/O supplies (VDDQL/VDDQR).

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV18 and IDT70V27L15PF8, the 70T631S15BF8 uniquely delivers true dual-port concurrency with integrated arbitration, voltage-flexible I/O, and RapidWrite Mode-making it irreplaceable in deterministic real-time inter-processor communication architectures.

Availability

70T631S15BF8 is available at Aetrix Electronics and suitable for real-time inter-processor communication, digital signal processing buffering, and industrial PLC data exchange requiring stable component supply across commercial temperature range and long-term production continuity.

Supply support for 70T631S15BF8 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, and interface solutions for communications, computing, and industrial markets.

The IDT70T63x family targets deterministic, low-latency memory sharing between heterogeneous processors-optimized for applications demanding hardware-enforced arbitration, voltage flexibility, and JTAG-testable BGA packaging.

FAQ

What is the memory organization of the 70T631S15BF8?

The 70T631S15BF8 implements a 256K × 18 (4.608 Mbit) asynchronous dual-port SRAM configuration. Address line A18 is designated No Connect (NC) for this variant, confirming its 256K depth rather than 512K. Both left and right ports share identical 18-bit data width and independent 18-bit addressing, enabling full-word parallel access without data multiplexing.

Does the 70T631S15BF8 support RapidWrite Mode, and how does it affect timing?

Yes, the 70T631S15BF8 supports RapidWrite Mode, allowing consecutive write operations without pulsing R/W, CE, or byte enables between cycles. In this mode, the write cycle ends on address transition rather than R/W deassertion-reducing control complexity at 15 ns timing. Designers must meet tAAS (≤1 ns address skew) and tARF (≥1.5 V/ns rise/fall) to prevent spurious writes, per datasheet Table 14.

How does the BUSY flag operate in MASTER versus SLAVE configuration on the 70T631S15BF8?

On the 70T631S15BF8, BUSYL and BUSYR function as outputs when M/S = VIH (Master mode), indicating port contention during simultaneous access to the same address. When M/S = VIL (Slave mode), BUSY pins become inputs-allowing the Master to drive BUSY and coordinate access. This hardware handshake eliminates software polling and ensures deterministic arbitration in multi-processor systems.

What voltage levels are supported on the I/O ports of the 70T631S15BF8?

The 70T631S15BF8 supports selectable 2.5 V or 3.3 V I/O operation per port via independent OPTL and OPTR pins. When OPTX = VSS (0 V), the corresponding port operates at 2.5 V levels with VDDQX = 2.5 V; when OPTX = VDD (2.5 V), it operates at 3.3 V levels with VDDQX = 3.3 V. Core VDD remains fixed at 2.5 V ±100 mV regardless of I/O selection.

Is JTAG boundary scan supported on the 70T631S15BF8, and which package options include it?

Yes, the 70T631S15BF8 supports IEEE 1149.1 JTAG boundary scan with dedicated TDI, TDO, TCK, TMS, and TRST pins. This feature is explicitly confirmed for the BGA-208 (BF208) and BGA-256 packages per datasheet Feature list. JTAG remains functional during sleep mode (ZZ asserted), though boundary scan is not recommended in that state per datasheet Note 4.