Renesas 71V3559S85BG

Overview

71V3559S85BG 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 or interleaved), and zero bus turnaround for seamless read/write transitions. It operates at 100 MHz with 7.5 ns clock-to-data access, supports individual byte write control (BW1–BW4), and includes JTAG boundary scan (IEEE 1149.1) for system-level testability in high-speed networking and packet buffering applications.

For engineers reviewing the 71V3559S85BG datasheet, 71V3559S85BG pinout, 71V3559S85BG application, or 71V3559S85BG equivalent, this device delivers deterministic timing, synchronous burst addressing via ADV/LD, low-latency memory access without dead cycles, and industrial-temperature operation (–40°C to +85°C) in a JEDEC-standard 100-pin TQFP package.

Technical Context

The 71V3559S85BG implements a synchronous dual-edge-triggered architecture where address, control, and data-in are registered on the rising edge of CLK, while output data flows through without an output register-enabling immediate availability one cycle after read initiation. Its internal burst counter advances on ADV/LD = HIGH, with sequence order selected by static LBO pin (VSS = linear, VDD = interleaved).

Three chip enables (CE1, CE2 active-low; CE2 active-high) provide flexible depth expansion, while CEN suspends all synchronous logic without affecting output state. The optional JTAG interface (TMS/TDI/TCK/TDO/TRST) supports IEEE 1149.1 compliance, and ZZ pin enables synchronous sleep mode with guaranteed data retention.

Key Specifications

Pinout & Package

71V3559S85BG is packaged in a JEDEC-standard 100-pin thin quad flatpack (TQFP), 14 mm × 20 mm body, with 0.5 mm pitch. Pin 64 supports ZZ (sleep mode) on latest die revisions; pins 83–84 are reserved for future density extensions.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1355BV18-100BZI and AS7C3256A-10JIN, the 71V3559S85BG uniquely delivers ZBT™ zero-turnaround, integrated burst counter, and IEEE 1149.1 JTAG in a single industrial-grade 100-pin TQFP-making it optimal for deterministic, high-throughput packet buffering where bus efficiency and testability are co-primary requirements.

Availability

71V3559S85BG is available at Aetrix Electronics and suitable for high-speed networking equipment, industrial programmable logic controllers, and wireless infrastructure requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for 71V3559S85BG 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 and computing markets.

The 71V3559S85BG belongs to IDT's ZBT™ SRAM product line, engineered specifically for high-bandwidth, low-latency applications in networking switches, routers, and baseband processing where deterministic burst access and zero bus turnaround are essential.

FAQ

What is the memory organization and total capacity of the 71V3559S85BG?

The 71V3559S85BG is organized as 256K × 18, delivering 4,718,592 bits (4.5 Mbit) of synchronous SRAM. It provides an 18-bit data bus with two dedicated parity bits (I/OP1 and I/OP2), supporting error detection in mission-critical communication systems. This configuration matches standard 18-bit bus widths used in many packet processors and FPGA-based datapaths.

Does the 71V3559S85BG support burst mode, and how is it configured?

Yes, the 71V3559S85BG supports a 4-word synchronous burst mode controlled by the ADV/LD and LBO pins. When ADV/LD is HIGH, the internal burst counter increments; LBO selects linear (LBO = LOW) or interleaved (LBO = HIGH) sequence order. Burst operation reduces address bus toggling and improves throughput for sequential memory accesses common in packet buffering and video streaming.

What is the role of the ZZ pin on the 71V3559S85BG, and does it retain data in sleep mode?

The ZZ pin on the 71V3559S85BG is a synchronous sleep mode input (active HIGH). When asserted, it gates the internal clock and reduces power consumption to its minimum level while guaranteeing full data retention-critical for energy-constrained base station radios and industrial controllers needing rapid wake-up without data reload.

Is JTAG boundary scan supported on the 71V3559S85BG, and which pins implement it?

Yes, the 71V3559S85BG includes optional IEEE 1149.1-compliant JTAG boundary scan. Pins TMS, TDI, TCK, TDO, and TRST (optional reset) are dedicated to the JTAG interface and appear on the 100-pin TQFP package (pins U16, U15, U14, U13, and U12 respectively). This enables structural testing of PCB interconnects during manufacturing and field diagnostics.

How does the 71V3559S85BG achieve zero bus turnaround (ZBT™), and what benefit does it provide?

The 71V3559S85BG achieves ZBT™ via synchronized control logic that eliminates dead cycles between read and write operations: the last word of a read burst can be immediately followed by the first word of a write burst without bus idle time. This enables sustained 100% bus utilization in high-throughput packet forwarding engines, directly improving system-level throughput and reducing average packet latency.