Renesas 71V2556S166PFG

Overview

71V2556S166PFG from IDT (now Renesas) is a 3.3V synchronous ZBT™ SRAM with 128K × 36-bit organization (4.5 Mbit), 166 MHz operation (3.5 ns clock-to-data access), pipelined outputs, and zero-bus-turnaround architecture. It supports 4-word linear/interleaved burst reads/writes, individual byte write control (BW1–BW4), and operates across industrial temperature range (–40°C to +85°C) in a 100-pin TQFP package.

For engineers reviewing the 71V2556S166PFG datasheet, 71V2556S166PFG pinout, 71V2556S166PFG application, or 71V2556S166PFG equivalent, key selection criteria include ZBT timing compliance, 2.5V I/O voltage compatibility, burst counter behavior under ADV/LD control, and support for depth expansion via three chip enables (CE1/CE2/CE2).

Technical Context

This device implements a fully synchronous, clock-edge-triggered interface with address, data, and control registers sampled on the positive CLK edge. Its internal burst counter increments on ADV/LD = HIGH and loads external addresses on ADV/LD = LOW - enabling deterministic linear or interleaved burst sequences selected by LBO.

The ZBT architecture eliminates dead cycles between read/write transitions via internally synchronized OE and pipelined output registers. Clock Enable (CEN) suspends all synchronous operations while preserving register state, and three independent chip enables allow flexible memory depth expansion without bus contention.

Key Specifications

Pinout & Package

Packaged in a JEDEC-standard 100-pin plastic thin quad flatpack (TQFP), 14 mm × 20 mm footprint, with exposed thermal pad (not electrically connected). Pinout validated per IDT 71V2556 PKG100 configuration (Rev. Aug.20.20).

Key Features

Applications

Equivalent & Alternatives

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

Compared with CY7C1356BV18-167AXC and AS7C3256B-167JCIN, the 71V2556S166PFG uniquely combines 2.5V I/O domain separation, LBO-configurable burst order, and three chip enables - making it optimal for complex, multi-device ZBT buffer subsystems requiring signal integrity and flexible expansion.

Availability

71V2556S166PFG 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 temperature ranges and long production lifecycles.

Supply support for 71V2556S166PFG 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, computing, and industrial markets.

The 71V2556S166PFG belongs to IDT's ZBT SRAM product line, designed specifically for zero-latency bus turnaround in high-speed packet-switching, telecom infrastructure, and real-time data acquisition systems.

FAQ

What is the maximum operating frequency of the 71V2556S166PFG?

The 71V2556S166PFG is rated for 166 MHz operation, delivering a guaranteed 3.5 ns clock-to-data access time under industrial temperature and voltage conditions. This frequency is validated per AC Electrical Characteristics in the official IDT datasheet (Rev. Aug.20.20), with timing referenced to the rising edge of CLK and measured with proper load conditions (50 Ω, VDDQ = 2.5 V).

Does the 71V2556S166PFG support both linear and interleaved burst modes?

Yes, the 71V2556S166PFG supports both linear and interleaved 4-word burst sequences, selected by the LBO pin: LBO = VSS configures linear order (A0, A1, A2, A3), while LBO = VDD selects interleaved order (A0, A2, A1, A3). This behavior is defined in the Linear and Interleaved Burst Sequence Tables and confirmed in functional timing diagrams.

What is the function of the ADV/LD pin on the 71V2556S166PFG?

The ADV/LD pin on the 71V2556S166PFG serves a dual role: when LOW, it loads an external address into the internal address latch; when HIGH, it advances the internal burst counter. This pin directly controls burst initiation and sequencing - a defining feature of the ZBT architecture that eliminates external address generation logic.

Can the 71V2556S166PFG operate with only two chip enables asserted?

No - the 71V2556S166PFG requires CE1 = LOW, CE2 = LOW, and CE2 = HIGH to select the device. CE2 is active-high, while CE1 and CE2 are active-low. Any deviation (e.g., CE2 = LOW or CE1 = HIGH) deselects the device, halting new operations though pending transfers complete. This 3-signal enable scheme enables precise depth expansion control.

Is JTAG boundary scan supported on the 71V2556S166PFG?

No - the 71V2556S166PFG does not include JTAG boundary scan. JTAG (TMS, TDI, TCK, TDO, TRST) is only available on the "SA" variant (e.g., 71V2556SA), as explicitly stated in the Features section and Pin Definitions. The "S" suffix denotes the standard version without JTAG functionality.