Renesas UPD44647366AF5-E25-FQ1-A

Overview

UPD44647366AF5-E25-FQ1-A from Renesas Electronics is a 2,097,152-word × 36-bit synchronous Quad Data Rate II+ (QDR II+) SRAM with 2.5 clock cycles read latency, 400 MHz operation, HSTL interface, and 165-pin plastic BGA (15 × 17 mm) packaging. It delivers concurrent read/write ports, on-die termination (ODT), QVLD data-valid signaling, and DLL/PLL-based timing control for high-bandwidth networking and packet buffering applications.

For engineers reviewing the UPD44647366AF5-E25-FQ1-A datasheet, UPD44647366AF5-E25-FQ1-A pinout, UPD44647366AF5-E25-FQ1-A application, or UPD44647366AF5-E25-FQ1-A equivalent, key selection considerations include its 2M × 36 organization, 2.5-cycle read latency at 400 MHz, HSTL I/O compatibility, ODT enablement via dedicated ODT pin, and strict power-on sequencing requirements for DLL/PLL lock and impedance calibration.

Technical Context

This QDR II+ SRAM implements dual-edge-triggered synchronous architecture using K/K# input clocks and CQ/CQ# echo clocks to align output data valid windows. Its internal burst counter supports fixed 4-word bursts, enabling full bus utilization without address toggling between transfers.

The device integrates independent read and write data paths, user-programmable output impedance (35–70 Ω), and JTAG 1149.1 test access. Read latency is fixed at 2.5 clock cycles - not user-selectable - and write latency remains constant at 1.0 cycle regardless of read latency mode.

Key Specifications

Pinout & Package

UPD44647366AF5-E25-FQ1-A is housed in a 165-pin plastic BGA (15 × 17 mm, 1.0 mm pitch) with standard ball layout per Renesas datasheet M19962EJ2V0DS. Pin functions are defined for the 2M × 36 configuration, including 19 address inputs (A), 36 bidirectional data I/Os (D0–D35/Q0–Q35), four byte-write enables (BW0#–BW3#), and dedicated control signals (R#, W#, K/K#, CQ/CQ#, QVLD, ODT, ZQ, DLL#, VREF, TMS/TCK/TDI/TDO).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar QDR II+ SRAM applications.

Compared with CY7C2665KV18-400BZXC and AS7C3256A-20JC, UPD44647366AF5-E25-FQ1-A provides superior signal integrity via QVLD timing assurance and programmable output impedance, while its integrated DLL/PLL ensures stable 400 MHz operation across voltage/temperature - making it optimal for high-reliability networking and test equipment.

Availability

UPD44647366AF5-E25-FQ1-A is available at Aetrix Electronics and suitable for networking packet buffering, telecom line card memory, test equipment waveform storage, and industrial real-time controller cache requiring stable component supply, long-lifecycle support, and lead-free RoHS-compliant packaging.

Supply support for UPD44647366AF5-E25-FQ1-A 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

Renesas Electronics Corporation is a global semiconductor leader specializing in microcontrollers, analog, power, and memory solutions for automotive, industrial, and infrastructure markets.

UPD44647366AF5-E25-FQ1-A belongs to Renesas' QDR II+ SRAM product line, engineered specifically for high-bandwidth, low-latency applications in networking equipment, base stations, and high-end test instrumentation where deterministic timing and signal integrity are critical.

FAQ

What is the read latency of UPD44647366AF5-E25-FQ1-A, and is it configurable?

UPD44647366AF5-E25-FQ1-A has a fixed 2.5 clock cycles read latency - it is not user-configurable. This value is hardwired per device variant and corresponds to the "2.5" suffix in the part number. The datasheet confirms latency is determined at manufacturing and cannot be altered via register settings or pin strapping. For designs requiring 2.0-cycle latency, UPD44647364AF5-E25-FQ1-A must be selected instead.

Does UPD44647366AF5-E25-FQ1-A support on-die termination (ODT), and how is it enabled?

Yes, UPD44647366AF5-E25-FQ1-A supports ODT on D0–D35 and BW0#–BW3# pins. ODT is enabled by holding the ODT pin HIGH during power-on initialization - the state is latched and cannot be changed afterward. When active, ODT sets termination resistance to 0.6 × RQ (105–210 Ω), where RQ is the external resistor connected from ZQ to ground (175–350 Ω). The ODT pin must be tied to VDDQ via ≤10 kΩ resistor for reliable activation.

What is the function of the QVLD pin on UPD44647366AF5-E25-FQ1-A, and how does it differ from CQ/CQ#?

The QVLD pin on UPD44647364AF5-E25-FQ1-A (and thus UPD44647366AF5-E25-FQ1-A) indicates validity of output data Q0–Q35 and is edge-aligned with CQ/CQ#. Unlike CQ/CQ#, which run freely and stop only when K/K# halt, QVLD asserts only during active read bursts and provides unambiguous data-ready signaling without requiring echo-clock routing to the receiver. This reduces PCB routing complexity and improves timing margin in high-speed systems.

What are the power sequencing requirements for UPD44647366AF5-E25-FQ1-A during startup?

UPD44647366AF5-E25-FQ1-A requires strict power-on sequencing: VSS first, then VDD, followed by VDDQ (simultaneous with or after VDD, but VDDQ must not exceed VDD by >0.5 V), then VREF, and finally stable K/K# clock for ≥20 μs to lock the DLL/PLL. Failure to follow this sequence risks undefined behavior, failed impedance calibration, or inability to achieve specified AC performance. The DLL# pin must be held HIGH throughout startup.

Can UPD44647366AF5-E25-FQ1-A operate with a 1.5 V VDDQ supply, and what are the implications?

Yes, UPD44647366AF5-E25-FQ1-A supports VDDQ = 1.5 ± 0.1 V (or 1.8 ± 0.1 V) per its datasheet. Using 1.5 V reduces I/O power consumption and heat generation but requires compatible HSTL Class I drivers/receivers rated for 1.5 V operation. VREF must be set to VDDQ/2 (i.e., 0.75 V), and ZQ calibration remains valid as long as the external RQ resistor matches the 1.5 V VDDQ condition per the ODT DC parameter table.