Renesas 71V3559S85BQI

Overview

71V3559S85BQI from Integrated Device Technology is a 3.3V synchronous ZBT™ SRAM organized as 256K x 18 (4.5 Mbit), featuring flow-through outputs, 4-word burst capability (linear/interleaved), zero bus turnaround, and JTAG IEEE 1149.1 support. It operates at 100 MHz with 7.5 ns clock-to-data access and targets high-speed cache and buffer applications in networking and telecom systems.

For engineers reviewing the 71V3559S85BQI datasheet, 71V3559S85BQI pinout, 71V3559S85BQI application, or 71V3559S85BQI equivalent, key selection criteria include burst mode control via ADV/LD and LBO, individual byte write enables (BW1–BW4), synchronous chip enables (CE1/CE2/CE2), sleep mode (ZZ), and TQFP-100 packaging with industrial temperature range (–40°C to +85°C).

Technical Context

The 71V3559S85BQI implements a synchronous dual-edge-triggered architecture where address/control inputs are registered on the rising CLK edge, and data transfers occur one cycle later. Its internal burst counter advances on ADV/LD = HIGH, enabling four consecutive accesses per address load without dead cycles between reads/writes.

It supports two memory configurations (128K × 36 and 256K × 18); the 71V3559S85BQI variant is specifically the 256K × 18 configuration in 100-pin TQFP. The device uses flow-through output buffering (no output register), asynchronous OE for tri-state control, and optional JTAG boundary scan with TMS/TDI/TCK/TDO/TRST pins.

Key Specifications

Pinout & Package

71V3559S85BQI is packaged in a JEDEC-standard 100-pin thin quad flatpack (TQFP), 14 mm × 20 mm body size, with 0.5 mm pitch. Pin 1 is located at top-left corner (marked by dot or notch). The package supports industrial temperature operation and includes dedicated VDD/VDDQ/VSS rails for core and I/O power separation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1371DV33-100AXC and AS7C3256A-10JIN, the 71V3559S85BQI uniquely delivers zero bus turnaround, integrated burst counter, and JTAG testability-making it optimal for high-clock-rate, burst-intensive telecom and networking buffers where deterministic latency and debug visibility are essential.

Availability

71V3559S85BQI is available at Aetrix Electronics and suitable for packet buffering, telecom caching, backplane interfacing, and industrial PLC data exchange requiring stable component supply across extended product lifecycles.

Supply support for 71V3559S85BQI 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 sensor solutions for communications, computing, and industrial markets.

The 71V3559S85BQI belongs to IDT's ZBT™ SRAM product line, engineered specifically for high-speed, low-latency buffer and cache applications in networking infrastructure where zero bus turnaround and deterministic burst timing are critical.

FAQ

What is the memory organization and total capacity of the 71V3559S85BQI?

The 71V3559S85BQI is organized as 256K × 18, delivering 4,718,592 bits (4.5 Mbit) of synchronous SRAM. This configuration provides an 18-bit data bus width optimized for packet payload alignment and telecom framing standards, with address lines A0–A17 supporting full 256K-depth addressing.

Does the 71V3559S85BQI support burst mode, and how is it configured?

Yes, the 71V3559S85BQI supports 4-word burst mode controlled by the ADV/LD and LBO pins. When ADV/LD is HIGH, the internal burst counter advances; LBO selects linear (LOW) or interleaved (HIGH) sequence. Burst operation eliminates repeated address loading, improving effective bandwidth by up to 4× over single-word access.

What is the role of the ZZ pin on the 71V3559S85BQI, and how does it affect power consumption?

The ZZ pin is a synchronous active-high sleep mode input. When asserted, it gates the internal clock and places the 71V3559S85BQI into its lowest power state while guaranteeing data retention. This feature enables dynamic power management in systems with intermittent traffic, such as burst-mode packet processors or duty-cycled industrial controllers.

How many chip enable signals does the 71V3559S85BQI have, and what is their polarity?

The 71V3559S85BQI has three chip enable signals: CE1 and CE2 are active-low, while CE2 is active-high. All three must be simultaneously asserted (CE1 = LOW, CE2 = LOW, CE2 = HIGH) to select the device. This triple-enable scheme allows flexible depth expansion and hierarchical memory decoding without external logic.

Is JTAG boundary scan supported on the 71V3559S85BQI, and which pins are used?

Yes, the 71V3559S85BQI includes optional IEEE 1149.1-compliant JTAG boundary scan. Pins TMS, TDI, TCK, TDO, and TRST (optional reset) are dedicated to this function. These signals are multiplexed on specific TQFP pins and support production testing, in-system verification, and debug trace capabilities in complex PCB assemblies.