Renesas 71V2556S100PFG

Overview

71V2556S100PFG from IDT (now Renesas) is a 3.3V synchronous ZBT™ SRAM with 128K × 36-bit (4.5 Mbit) organization, 100-pin TQFP package, and pipelined outputs enabling 166 MHz operation (3.5 ns clock-to-data access). It supports zero-bus-turnaround (ZBT) for dead-cycle-free read/write transitions and features individual byte write control (BW1–BW4), burst counter, and industrial temperature range (–40°C to +85°C).

For engineers reviewing the 71V2556S100PFG datasheet, 71V2556S100PFG pinout, 71V2556S100PFG application, or 71V2556S100PFG equivalent, key selection considerations include its 2.5V I/O supply (VDDQ), JEDEC-standard 100-pin TQFP footprint, synchronous burst capability (linear/interleaved), and support for high-throughput memory subsystems in networking and telecom infrastructure.

Technical Context

The 71V2556S100PFG implements a fully synchronous, clock-edge-triggered architecture with input/output registers aligned to the rising edge of CLK. Its internal burst counter and ADV/LD control enable single-address-initiated 4-word bursts, with LBO selecting linear or interleaved sequence order.

ZBT functionality eliminates bus turnaround latency by allowing immediate read-after-write or write-after-read transitions without wait states. The device uses three chip enables (CE1, CE2, CE2) for depth expansion and includes optional IEEE 1149.1 JTAG boundary scan (not implemented on "S" version per pin definitions).

Key Specifications

Pinout & Package

71V2556S100PFG is packaged in a JEDEC-standard 100-pin plastic thin quad flatpack (TQFP), 14 mm × 20 mm body size, with 0.5 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1355BV18 and AS7C3256B, the 71V2556S100PFG uniquely delivers ZBT-optimized 166 MHz synchronous operation in a 100-pin TQFP with 2.5V I/O-making it the only choice for legacy-compatible, high-throughput, industrial-grade packet buffering where pinout, voltage, and timing are jointly constrained.

Availability

71V2556S100PFG is available at Aetrix Electronics and suitable for network packet buffering, telecom line card memory, high-speed test equipment memory, and industrial PLC data logging requiring stable component supply across extended product lifecycles.

Supply support for 71V2556S100PFG 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 71V2556S100PFG belongs to IDT's ZBT SRAM product line, designed specifically for zero-latency memory subsystems in high-speed networking, telecom, and test equipment where deterministic burst access and bus turnaround elimination are critical.

FAQ

What is the maximum operating frequency of the 71V2556S100PFG?

The 71V2556S100PFG is rated for a maximum clock frequency of 166 MHz, corresponding to a 3.5 ns clock-to-data access time under specified operating conditions (VDD = 3.3 V ±5%, VDDQ = 2.5 V, TA = –40°C to +85°C). This specification is guaranteed across the full industrial temperature range and applies to both read and write burst operations.

Does the 71V2556S100PFG support JTAG boundary scan?

No, the 71V2556S100PFG does not implement JTAG boundary scan. While the datasheet notes optional IEEE 1149.1 support for the "SA" variant, the "S" suffix (as in 71V2556S100PFG) explicitly denotes the non-JTAG version-confirmed by pin definitions showing TMS/TDI/TCK/TDO/TRST as NC (no connect) on the 100-pin TQFP package.

What is the function of the LBO pin on the 71V2556S100PFG?

The LBO (Linear/Interleaved Burst Order) pin on the 71V2556S100PFG selects the burst sequence mode: when pulled to VSS (low), it enables linear burst order (A0, A1, A2, A3); when pulled to VDD (high), it enables interleaved burst order (A0, A2, A1, A3). This setting is sampled at the rising edge of CLK during burst initiation and remains active for the entire 4-word burst.

Can the 71V2556S100PFG operate with only VDD powered and VDDQ unconnected?

No. The 71V2556S100PFG requires both VDD (3.3 V ±5%) and VDDQ (2.5 V) to be actively supplied within specification. VDDQ powers all I/O buffers and must be present before or simultaneously with VDD; the datasheet explicitly states that I/O pins cannot exceed VDDQ during power-up ramp, and operation with missing VDDQ will result in undefined or nonfunctional I/O behavior.

How many chip enable signals does the 71V2556S100PFG have, and how do they interact?

The 71V2556S100PFG has three chip enable signals: CE1, CE2, and CE2. The device is selected only when CE1 = L, CE2 = L, and CE2 = H. Deselection occurs if any one of these conditions fails while ADV/LD is low. Pending read/write transfers complete before outputs tri-state two cycles after deselect, ensuring data integrity during bank switching.