Renesas 71V65903S85BG

Overview

71V65903S85BG from IDT (now Renesas) is a 3.3V synchronous ZBT™ SRAM organized as 512K x 18 (9,437,184-bit), supporting 100 MHz operation with 7.5 ns clock-to-data access. It implements zero bus turnaround (ZBT) architecture to eliminate dead cycles between read/write transitions, features flow-through outputs, and uses a synchronous burst counter for 4-word interleaved or linear sequences - deployed in high-speed networking packet buffers and telecom baseband subsystems.

For engineers reviewing the 71V65903S85BG datasheet, 71V65903S85BG pinout, 71V65903S85BG application, or 71V65903S85BG equivalent, key selection criteria include its 100 MHz timing compliance, 3.3V core/I/O supply tolerance (±5%), industrial temperature range (–40°C to +85°C), TQFP-100 package footprint, and support for individual byte write control (BW1–BW2) in x18 configuration.

Technical Context

The 71V65903S85BG employs a synchronous dual-register architecture: address/control signals are latched on the rising CLK edge when ADV/LD is low and chip enables are active, while data output follows one cycle later via flow-through path (no output register). Its burst counter advances on ADV/LD high, selecting sequence order via static LBO pin.

Three chip enables (CE1, CE2 active-low; CE2 active-high) enable depth expansion; CEN suspends all synchronous logic without affecting output state; ZZ enables asynchronous sleep mode with guaranteed data retention. OE is asynchronous and can be tied low for simplified read access.

Key Specifications

Pinout & Package

Packaged in JEDEC-standard 100-pin plastic thin quad flatpack (TQFP), 14 mm × 20 mm body, 0.5 mm pitch. Pinout validated per PKG100 configuration for 512K × 18 variant (document 5298 drw 02a).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar synchronous SRAM applications.

Compared with CY7C1355BV18-100BZXI and AS7C35128P-10JCN, the 71V65903S85BG uniquely delivers zero bus turnaround, flow-through outputs, and programmable burst sequencing - making it optimal for real-time packet and sample buffering where deterministic latency and bus efficiency are critical.

Availability

71V65903S85BG is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and test equipment applications requiring stable component supply, long-term lifecycle support, and industrial-grade reliability.

Supply support for 71V65903S85BG 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), now part of Renesas Electronics, is a fabless semiconductor company specializing in high-performance timing, memory interface, and RF solutions for communications and computing markets.

The 71V65903S85BG belongs to IDT's ZBT™ SRAM product line, engineered specifically for zero-turnaround, burst-capable buffering in high-speed data-path applications such as network switches, baseband processors, and instrumentation systems.

FAQ

What is the memory organization and total capacity of the 71V65903S85BG?

The 71V65903S85BG is organized as 512K × 18, delivering 9,437,184 bits (9.4 Mbit) of synchronous SRAM. This configuration provides an 18-bit data bus (16 data + 2 parity bits) and uses 19 address lines (A0–A18) to access the full memory space - optimized for 16-bit microprocessor and DSP interfaces requiring parity protection.

Does the 71V65903S85BG support burst mode, and how is burst order controlled?

Yes, the 71V65903S85BG supports 4-word burst mode using an internal synchronous counter. Burst order is selected by the LBO pin: LBO = VDD enables interleaved sequence; LBO = VSS enables linear sequence. The ADV/LD pin controls counter advancement - low loads a new address, high increments the counter - enabling efficient DMA transfers without external address generation.

What package type and pin count does the 71V65903S85BG use?

The 71V65903S85BG is supplied in a JEDEC-standard 100-pin plastic thin quad flatpack (TQFP), measuring 14 mm × 20 mm with 0.5 mm lead pitch. This package is verified for the 512K × 18 configuration and includes dedicated VDD, VDDQ, and VSS pins distributed for low-noise power delivery - compatible with standard surface-mount assembly processes.

How does the 71V65903S85BG implement zero bus turnaround (ZBT)?

The 71V65903S85BG achieves ZBT by eliminating idle cycles between read and write operations through synchronized control logic and flow-through outputs. When ADV/LD and R/W change states mid-burst, the device transitions seamlessly - for example, a burst read followed immediately by a burst write incurs no dead cycles, maximizing bus bandwidth in high-throughput packet buffering applications.

Can the 71V65903S85BG operate in low-power mode, and how is it activated?

Yes, the 71V65903S85BG supports low-power sleep mode via the asynchronous ZZ pin. When ZZ is driven HIGH, the internal clock is gated and dynamic power drops significantly while retaining all stored data. This mode is fully compliant across the industrial temperature range (–40°C to +85°C) and requires no additional sequencing - making it ideal for power-constrained telecom and portable test equipment.