Renesas IDT71P71804S250BQ

Overview

IDT71P71804S250BQ from Integrated Device Technology is a 1M × 18-bit, 18 Mb pipelined DDR II SRAM with burst-of-2 operation, 250 MHz clock frequency (4 ns K,K cycle time), HSTL-compatible 1.5 V I/O interface (VDDQ), and 1.8 V core supply (VDD). It delivers double-data-rate bandwidth via dual-edge-aligned echo clocks (CQ/CQ) and supports scalable output impedance (35–70 Ω) for signal integrity in high-speed memory subsystems used in network packet buffers and baseband processors.

For engineers reviewing the IDT71P71804S250BQ datasheet, IDT71P71804S250BQ pinout, IDT71P71804S250BQ application, or IDT71P71804S250BQ equivalent, key selection criteria include its 1M×18 organization, 165-ball fBGA package, programmable ZQ impedance calibration, DLL-enabled tight data-to-clock alignment, and support for SA0-controlled burst reversal in x18 mode.

Technical Context

The IDT71P71804S250BQ implements a synchronous, pipelined DDR II architecture with two independent clock domains: K/K for address/control/data capture and C/C for read data output timing. Its internal DLL aligns DQ outputs to C/C edges with sub-0.5 ns jitter tolerance, enabling reliable 250 MHz operation (tKHKH = 4.0 ns min).

It features multiplexed address inputs, common read/write data port (DQ[17:0]), dual echo clocks (CQ/CQ), and byte write control (BW0/BW1) for selective 9-bit word updates. The device uses HSTL Class I inputs with VREF reference and supports voltage scaling from 1.4 V to 1.9 V on VDDQ while maintaining 1.8 V core logic.

Key Specifications

Pinout & Package

Package: 165-ball fBGA (13 mm × 15 mm, 1.0 mm pitch), RoHS-compliant, moisture sensitivity level 3.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed synchronous memory applications.

Compared with CY7C1551KV18 and MT46V16M18, the IDT71P71804S250BQ uniquely combines burst-order flexibility (SA0), sub-0.3 ns DLL alignment, and true SRAM simplicity-making it optimal for deterministic, low-jitter memory subsystems in telecom and industrial control.

Availability

IDT71P71804S250BQ is available at Aetrix Electronics and suitable for network packet buffering, baseband signal processing, high-performance computing cache, and industrial motion controller memory requiring stable component supply and long-term obsolescence management.

Supply support for IDT71P71804S250BQ 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

Integrated Device Technology (IDT), now part of Renesas Electronics, designs high-performance timing, memory interface, and RF solutions for communications, computing, and industrial markets.

The IDT71P71804S250BQ belongs to IDT's QDR™ II SRAM family, engineered specifically for bandwidth-intensive, low-latency applications such as network switches, routers, and baseband processors where DDR II's burst-of-2 and echo-clock architecture maximizes data throughput without increasing clock frequency.

FAQ

What is the maximum operating frequency of the IDT71P71804S250BQ?

The IDT71P71804S250BQ is rated for 250 MHz operation, corresponding to a minimum K,K clock cycle time (tKHKH) of 4.0 ns. This enables a sustained 500 MT/s data rate on its 18-bit DDR bus. The device supports lower frequencies (200 MHz, 167 MHz) with relaxed timing margins, but 250 MHz represents its highest validated speed grade per the advance information datasheet.

Does the IDT71P71804S250BQ require an external termination resistor?

No, the IDT71P71804S250BQ does not require external series termination resistors on its DQ or CQ lines. Its programmable output impedance (35–70 Ω) is calibrated via the ZQ pin and an external RQ resistor (175–350 Ω to ground), allowing precise matching to PCB trace impedance and eliminating discrete components.

How does the SA0 pin affect memory access in the IDT71P71804S250BQ?

In the IDT71P71804S250BQ, the SA0 pin controls burst sequence order for 18-bit words: when SA0 = 0, the burst reads/writes words in linear order (a then b); when SA0 = 1, it reverses the order (b then a). This feature supports efficient handling of interleaved data structures like packet headers and payloads without software reordering.

Can the IDT71P71804S250BQ operate with only the K,K clocks, without C,C?

Yes, the IDT71P71804S250BQ supports single-clock mode: tying C and C high disables their function, causing K,K to control both input latching and output timing. In this mode, DQ outputs align to K,K edges instead of C,C, and echo clocks CQ/CQ are generated from K,K - simplifying clock distribution at the cost of reduced timing margin.

What is the purpose of the Doff pin on the IDT71P71804S250BQ?

The Doff pin disables the internal delay-locked loop (DLL) when pulled low. With DLL off, DQ output timing follows K,K or C,C propagation delay directly (no active deskew), increasing tCHQV/tCHQX by ~0.5 ns. This mode is useful for debug, low-power states, or systems where DLL lock instability occurs - but sacrifices the tight data-to-clock alignment critical for 250 MHz operation.