Renesas 71V3556S166PFG

Overview

71V3556S166PFG from IDT (now Renesas) is a 3.3V synchronous ZBT™ SRAM with 128K × 36-bit organization, 166 MHz clock frequency, 3.5 ns clock-to-data access time, zero bus turnaround architecture, and pipelined outputs. It serves as high-speed buffer memory in network packet processors and telecom line cards requiring deterministic read/write interleaving without dead cycles.

For engineers reviewing the 71V3556S166PFG datasheet, 71V3556S166PFG pinout, 71V3556S166PFG application, or 71V3556S166PFG equivalent, key selection criteria include ZBT™ burst timing compliance, TQFP-100 package compatibility, industrial temperature support (–40°C to +85°C), and 4-word linear/interleaved burst capability with individual byte write control.

Technical Context

The 71V3556S166PFG implements a fully synchronous, positive-edge-triggered register pipeline for address, data, and control signals, with two-cycle latency between address/control registration and data transfer. Its ZBT™ architecture eliminates bus turnaround dead cycles by enabling immediate read-after-write or write-after-read transitions using internal burst counter logic and ADV/LD-controlled address sequencing.

It integrates three chip enables (CE1, CE2 active-low; CE2 active-high), asynchronous OE, synchronous CEN, and static LBO for burst order selection. Optional IEEE 1149.1 JTAG boundary scan is supported in SA variants but not in the "S" suffix version - confirmed by pin function tables showing TRST/TMS/TDI/TCK/TDO as NC on 71V3556S166PFG.

Key Specifications

Pinout & Package

Packaged in JEDEC-standard 100-pin thin quad flatpack (TQFP), 14 mm × 20 mm body, lead-free and RoHS-compliant. Pin 64 supports ZZ (sleep mode) on latest die revision; pins 14/16/66 tolerate VIH-level voltage without direct VDD connection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1362BV166BZC and AS7C33128PFSIG, the 71V3556S166PFG uniquely delivers ZBT™-guaranteed zero bus turnaround and integrated 4-word burst counter - essential for maintaining throughput in packet-processing pipelines without architectural redesign.

Availability

71V3556S166PFG is available at Aetrix Electronics and suitable for network packet buffering, telecom line card memory, baseband processor cache, and industrial PLC data logging requiring stable component supply across extended product lifecycles.

Supply support for 71V3556S166PFG 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, and interface solutions for communications and computing infrastructure.

The 71V3556S166PFG belongs to IDT's ZBT™ SRAM product line, engineered specifically for zero-latency memory subsystems in telecom switches, routers, and base stations where deterministic burst timing and bus efficiency are critical.

FAQ

What is the memory organization and speed grade of the 71V3556S166PFG?

The 71V3556S166PFG is a 128K × 36-bit (4.5 Mbit) synchronous SRAM rated for 166 MHz operation with 3.5 ns clock-to-data access time. It operates exclusively in x36 mode and does not support x18 reconfiguration. This configuration is fixed per the device marking and functional block diagram.

Does the 71V3556S166PFG support JTAG boundary scan?

No, the 71V3556S166PFG does not support JTAG boundary scan. The "S" suffix denotes the standard version; JTAG functionality is only available in "SA" variants (e.g., 71V3556SA), where TMS/TDI/TCK/TDO/TRST pins are assigned. In the 71V3556S166PFG, those pins are marked NC in all package configurations.

How does the ZBT™ feature eliminate bus turnaround dead cycles in the 71V3556S166PFG?

The 71V3556S166PFG achieves zero bus turnaround by decoupling address/control registration from data transfer using pipelined registers and an internal burst counter. When R/W changes between cycles, the device immediately advances the burst counter (via ADV/LD high) instead of inserting idle cycles - enabling back-to-back read/write operations with no bus contention.

What is the function of the ZZ pin on the 71V3556S166PFG, and is it supported in the TQFP package?

The ZZ pin (pin 64) provides synchronous sleep mode control: asserted high to gate the internal clock and minimize power while retaining memory contents. Per the latest die revision documentation, ZZ functionality is implemented and validated on the TQFP-100 package - confirmed by note #2 in the PKG100 pin configuration diagrams.

Can the 71V3556S166PFG operate with different supply voltages for core and I/O rails?

Yes, the 71V3556S166PFG requires separate 3.3 V ±5% supplies: VDD for core logic and VDDQ for I/O drivers. Both rails must be within specification simultaneously, but they may be powered independently to manage noise coupling - a design requirement explicitly stated in the Recommended DC Operating Conditions table.