Renesas Electronics America Inc IDT71V2558S166PF

Product Summary IDT71V2558S166PF Synchronous ZBT SRAM

The IDT71V2558S166PF, manufactured by Renesas Electronics Corporation, is a high-performance 4.5 Mbit synchronous static random-access memory (SRAM) designed for high-bandwidth, latency-sensitive systems. As a member of the IDT71V2558 family, this device offers Zero Bus Turnaround™ (ZBT™) architecture to eliminate dead bus cycles and maximize memory throughput—attributes crucial in networking, telecommunications, cache memory, and other real-time embedded applications.

Packaged in a standard 100-pin thin quad flat pack (TQFP) measuring 14×14 mm, the IDT71V2558S166PF provides 128K x 36-bit or 256K x 18-bit configurations, running at speeds up to 166 MHz. Its combination of high frequency operation, pipelined and burst access, and flexible I/O voltage support make it suitable for engineers looking to maintain maximum data throughput without compromising system design flexibility.

Main Features and Operational Benefits of the IDT71V2558S166PF

A comprehensive suite of features underscores the IDT71V2558S166PF’s appeal for advanced system designs:

True synchronous operation, including all address, control, and data signals registered on the rising clock edge for predictable, pipelined access and easy system integration.

Zero Bus Turnaround™ (ZBT™) implementation—virtually eliminating dead bus cycles during reads and writes, allowing for seamless switching between memory operations.

Maximum operating frequency up to 200 MHz and clock-to-data access times as fast as 3.2 ns (typical performance at 166 MHz and 3.5 ns).

4-word burst capability, selectable as either interleaved or linear, supporting high bandwidth and sequential access use cases.

Byte write control with individual byte write enable signals, facilitating partial word updates or more granular write functionalities.

Multiple chip enables (three per chip) for straightforward memory array depth expansion or bank selection in high-density designs.

Support for both commercial and industrial temperature ranges, making the IDT71V2558S166PF suitable for a broad spectrum of operational environments.

Engineers can leverage these advanced features to address the challenges of high-performance data buffering, packet processing, look-up tables, and cache requirements in networking chips, routers, and high-speed acquisition systems.

Memory Structure and Configuration Choices for the IDT71V2558S166PF

The IDT71V2558S166PF supports two primary memory organizations: 128K x 36-bit and 256K x 18-bit, each optimized to match different system data bus widths. The flexible organization allows direct interfacing with a variety of processors, FPGAs, and ASICs.

Its synchronous, pipelined structure means addresses and control inputs are registered on the clock’s rising edge, and, thanks to the ZBT™ innovation, read and write operations can be transitioned with no bus turnaround delays. Address, data input/output, and control signal registers are all included, while the sole asynchronous input—output enable (OE)—permits rapid tri-stating of data outputs for multi-device buses. A clock enable (CEN) signal can suspend device operation, holding data and control states as long as needed, which is useful for power management or bus contention avoidance.

Pin Assignment and Packaging Variants for the IDT71V2558S166PF

Designed for design flexibility and compliance with industry standards, the IDT71V2558S166PF is offered in several package choices:

100-pin Thin Quad Flatpack (TQFP) – 14x14mm body

119-ball Ball Grid Array (BGA)

165-ball Fine Pitch Ball Grid Array (fBGA)

All packages conform to JEDEC standards and are well-suited for automated board assembly. The pinout layouts reflect memory configuration (x36 or x18), with reserved pins for future JTAG support and higher density product migration, ensuring design scalability for next-generation systems.

Key pin assignments include multiple chip-selects, clock, address, data, byte write enables, command pins (adv/ld, R/W, LBO), and separate power supplies for the core (3.3V) and I/O cells (2.5V VDDQ). Proper connection of control pins is crucial to maximizing device capability, and system designers should note reserved pins to guarantee compatibility with future device revisions.

Comprehensive Functional Description of the IDT71V2558S166PF

The functional essence of the IDT71V2558S166PF centers on its ZBT™ SRAM architecture—an approach removing the dead time often associated with switching between read and write cycles in traditional synchronous SRAMs. By synchronizing all operational signals, it ensures data and control flow seamlessly in pipelined bus architectures.

Key operational aspects include:

Synchronous loading of addresses and control signals for every cycle; data transfer commences two cycles after address/control register loading.

On-chip burst counter: supports automatic four-cycle burst access after a single address load, greatly increasing memory bandwidth for sequential data streams.

Burst sequence control: the LBO input selects linear (A0, A1, A2, A3) or interleaved (A0, A2, A1, A3) address ordering, optimizing for different topologies and cache mapping strategies.

Clock enable (CEN) and chip enable controls allow dynamic suspension of memory operation, minimizing switching noise and power when the device is not in use.

Byte write capabilities enable per-byte write masking, advantageous in data manipulation or ECC-protected memory systems.

In practical deployment, these features allow for efficient support of high-speed synchronous designs. For instance, in a network processor where memory access patterns can rapidly switch direction, ZBT™ SRAM like the IDT71V2558S166PF maintains continuous throughput without inserting wait cycles.

Electrical Specifications and Optimal Usage Conditions of the IDT71V2558S166PF

A robust suite of electrical characteristics ensures stable operation across its rated environments:

Core supply voltage (VDD): 3.3V ±5%

I/O supply voltage (VDDQ): 2.5V

Input logic levels: –1.0V to 6.0V (transients), with VIH/VIL defined for robust external interfacing

Operating temperature range: Commercial and Industrial

Input leakage currents, output high/low voltages, and standby currents are all tightly controlled for predictable system power budgets.

System engineers must ensure all synchronous signals meet specified setup and hold times with respect to the main clock. Unused pins, including reserved or future function pins (e.g., JTAG, sleep modes), should be handled according to the datasheet to avoid signal integrity issues.

Timing Characteristics, Burst Operation, and Interface Options for the IDT71V2558S166PF

Timing design is central to high-speed SRAM interface design. The IDT71V2558S166PF offers:

Clock-to-output (read access) time: as low as 3.2–3.5ns at 166MHz, supporting short-latency data delivery.

Fully pipelined operation: new address/command/data can be registered every clock cycle, enabling sustained throughput at the device’s maximum frequency.

4-beat burst access: On assertion of the ADV/LD signal, the device auto-increments the burst counter for sequential data; both linear and interleaved burst sequences are supported.

Data bus contention avoidance: The device ensures data bus is tri-stated two cycles after chip deselect or write initiation, reducing interface errors in multi-drop/multi-device designs.

Multiple truth tables and functional waveforms (provided in the datasheet) illustrate correct setup for singular/burst reads, writes, and the role of control signals (ADV/LD, R/W, BWx, CEN, CE1, CE2, CE3).

Strategic device timing—particularly for integrating with FPGAs, network processors, and custom ASICs—requires close attention to these schemes in board-level simulation and signal integrity checks.

Possible Alternative or Substitute Models for the IDT71V2558S166PF

When considering the IDT71V2558S166PF for new or legacy designs, engineers may also evaluate these related or replacement-class devices:

IDT71V2556 series: Functionally similar to the IDT71V2558 but with capacity options and pin compatibility for easy migration.

SRAMs from alternative vendors implementing Zero Bus Turnaround (ZBT™) architecture, such as devices from Micron Technology or other manufacturers supporting the same memory organization, voltages, and burst/pipelined interfaces.

When selecting replacements, key parameters to compare include memory density (bits x width), maximum operating frequency, ZBT compliance, I/O voltages, package type, and pinout compatibility.

Ensuring suitable replacements involves confirming signal timing, signal integrity, and firmware compatibility, especially when leveraging advanced features like burst modes or byte write masking.

Conclusion

The IDT71V2558S166PF Synchronous ZBT SRAM by Renesas addresses the ever-increasing demand for zero-wait-state, high-speed memory in network infrastructure, embedded, and data-intensive environments. Its combination of synchronous pipelining, 4.5Mbit density, 166MHz operation, and advanced interface controls makes it a robust choice for both new designs and legacy system maintenance. With its flexibility in configuration, robust package options, and futureproof pin assignments, the IDT71V2558S166PF ensures engineers and procurement specialists can maintain both performance and supply longevity in next-generation electronic systems.