Renesas 71V3556SA166BG

Overview

71V3556SA166BG from IDT (now Renesas) is a 128K × 36-bit, 4.5-Mbit synchronous ZBT SRAM with Zero Bus Turnaround architecture, 166 MHz operation (3.5 ns clock-to-data access), 3.3 V core/I/O supply, and pipelined outputs. It supports interleaved/linear 4-word burst reads/writes and individual byte write control for high-throughput memory subsystems in network packet buffers and telecom line cards.

For engineers reviewing the 71V3556SA166BG datasheet, 71V3556SA166BG pinout, 71V3556SA166BG application, or 71V3556SA166BG equivalent, key selection criteria include ZBT timing compliance, TQFP-100/BGA-119/fBGA-165 package options, JTAG IEEE 1149.1 support, industrial temperature range (–40°C to +85°C), and burst counter behavior under ADV/LD and LBO control.

Technical Context

The 71V3556SA166BG implements a fully synchronous, positive-edge-triggered architecture with registered address, data, and control inputs. Its ZBT feature eliminates dead cycles between read/write transitions via internal bus arbitration logic and dual-phase burst sequencing.

It integrates a 4-word burst counter with linear/interleaved mode selectable by LBO, pipelined input/output registers synchronized to CLK, and three chip enables (CE1, CE2, CE2) supporting depth expansion. The optional boundary-scan JTAG interface complies with IEEE 1149.1 and includes TMS, TDI, TCK, TDO, and TRST pins.

Key Specifications

Pinout & Package

71V3556SA166BG is packaged in a JEDEC-standard 119-ball grid array (BG119) with 0.8 mm pitch, 12 mm × 12 mm body size, and industrial-grade thermal performance. Pin functions are defined per the "SA" version with full JTAG support.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 71V3556SA166BG, the 71V3556S166BG omits JTAG for lower cost in non-test-critical systems, while the CY7C1371DV166BGC provides true concurrent access at the expense of interface complexity and layout changes.

Availability

71V3556SA166BG is available at Aetrix Electronics and suitable for high-speed packet buffering, telecom line card memory, and industrial PLC data logging requiring stable component supply, long-term lifecycle support, and RoHS-compliant green packaging.

Supply support for 71V3556SA166BG 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 semiconductor company specializing in timing, memory interface, RF, and power management solutions for communications, computing, and industrial markets.

The 71V3556SA166BG belongs to IDT's ZBT SRAM product line, designed specifically for high-performance networking and telecom infrastructure where deterministic latency, burst efficiency, and bus turnaround elimination are critical.

FAQ

What is the maximum operating frequency of the 71V3556SA166BG?

The 71V3556SA166BG operates at up to 166 MHz, delivering 3.5 ns clock-to-data access time. This frequency is validated across the full industrial temperature range (–40°C to +85°C) and requires strict adherence to setup/hold timing margins relative to the rising CLK edge. The 166 MHz rating applies specifically to the 128K × 36 configuration in the BG119 package.

Does the 71V3556SA166BG support both linear and interleaved burst modes?

Yes, the 71V3556SA166BG supports both linear and interleaved 4-word burst sequences. The LBO (Linear Burst Order) pin selects the mode: LOW configures linear addressing (A0, A1, A2, A3), HIGH selects interleaved (A0, A1, A3, A2). This selection is static and must remain stable during burst operation to prevent address misalignment.

How does the ZBT™ feature eliminate dead cycles in the 71V3556SA166BG?

The ZBT™ feature in the 71V3556SA166BG eliminates dead cycles by using internal bus arbitration and pipelined control logic that allows immediate transition from write to read (or vice versa) without bus release/reacquisition delays. This is achieved through synchronized register staging and burst counter advancement, enabling back-to-back transactions at full 166 MHz throughput.

What is the function of the ZZ pin on the 71V3556SA166BG?

The ZZ pin on the 71V3556SA166BG is a synchronous sleep mode input. When driven HIGH, it gates the internal clock and reduces power consumption to the lowest level while guaranteeing data retention. It features an internal pulldown resistor and must be asserted synchronously with CLK; data remains valid and accessible upon exit from sleep mode.

Is JTAG boundary-scan supported on the 71V3556SA166BG?

Yes, the 71V3556SA166BG includes full IEEE 1149.1-compliant JTAG boundary-scan support with dedicated TMS, TDI, TCK, TDO, and optional TRST pins. This capability is exclusive to the "SA" suffix variant and enables in-system test, debug, and programming verification without requiring external test fixtures.