Diodes Incorporated PI6CV857LAE

Overview

PI6CV857LAE from Pericom Semiconductor is a 48-pin TSSOP zero-delay PLL clock buffer optimized for registered DDR SDRAM DIMM applications. It distributes one differential SSTL-2 clock input pair (CLK, CLK) to ten matched differential SSTL-2 output pairs (Y0–Y9) and one feedback pair (FBOUT, FBOUT), operating at AVDD = 2.5 V and VDDQ = 2.5 V with spread-spectrum clocking support for EMI reduction in memory subsystems.

For engineers reviewing the PI6CV857LAE datasheet, PI6CV857LAE pinout, PI6CV857LAE application, or PI6CV857LAE equivalent, key selection criteria include its 10-output fanout, 2.5 V SSTL-2 I/O compatibility, PLL lock range of 100–170 MHz, cycle-to-cycle jitter ≤75 ps, and power-down control via LVCMOS PWRDWN input.

Technical Context

The PI6CV857LAE implements a phase-locked loop using differential reference inputs (CLK/CLK) and external feedback (FBIN/FBIN) to achieve low-skew, low-jitter clock distribution across all ten outputs. Its PLL architecture supports dynamic tracking of spread-spectrum clocking up to ±0.5% modulation depth at 30 kHz, meeting Intel PC100 Registered DIMM specifications.

Internal power domains separate analog core (AVDD = 2.5 V) from output drivers (VDDQ = 2.5 V), enabling independent biasing and noise isolation. The device enters low-power mode when input frequency drops below 20 MHz or when PWRDWN is asserted low, tri-stating all outputs while maintaining PLL bypass functionality when AVDD is strapped low.

Key Specifications

Pinout & Package

Package: 48-pin Pb-free & Green TSSOP (240-mil wide), JEDEC MO-153F compliant, thermal pad not present.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar PLL clock buffer applications.

Compared with IDT72V2231L and NB3N502M, the PI6CV857LAE uniquely delivers 10-output SSTL-2 differential fanout with integrated feedback, SSC tracking, and zero-delay operation - making it the only drop-in solution for DDR2 RDIMM clock trees requiring EMI reduction and tight skew control.

Availability

PI6CV857LAE is available at Aetrix Electronics and suitable for registered DDR2 DIMM modules, server memory subsystems, and industrial embedded DDR2 applications requiring stable component supply, long-term lifecycle support, and Pb-free/Green compliance.

Supply support for PI6CV857LAE 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

Pericom Semiconductor (now part of Diodes Incorporated) is a fabless provider of high-performance interface, timing, and signal integrity solutions, specializing in clock management ICs for memory and computing infrastructure.

The PI6CV857LAE belongs to Pericom's DDR clock buffer product line, engineered specifically to meet Intel PC100/PC2100 Registered DIMM timing, skew, and EMI requirements in high-density memory modules.

FAQ

What is the minimum input clock frequency that maintains PLL lock?

The PI6CV857LAE maintains PLL lock down to 20 MHz under recommended operating conditions. Below this frequency, the device automatically enters low-power mode, tri-stating outputs and disabling the PLL. This threshold is fixed and not user-adjustable; it ensures reliable startup and stable operation across DDR2's valid frequency range (100–200 MHz).

Can FBIN and FBOUT be left unconnected in non-feedback configurations?

No - FBIN and FBOUT must be connected externally in a closed loop for zero-delay operation. Leaving FBIN unconnected prevents PLL lock and results in undefined output behavior. The device does not support open-loop or buffered-only modes; feedback is mandatory for functional clock distribution.

How does the device handle power supply sequencing between AVDD and VDDQ?

AVDD must be stable before or simultaneously with VDDQ. If VDDQ rises significantly before AVDD, output drivers may become active before the PLL locks, causing unstable or uncontrolled clock edges. Recommended sequencing is AVDD ≥ VDDQ within 100 ms, with both supplies ramping monotonically and settling fully before asserting PWRDWN high.

Is the PI6CV857LAE compatible with DDR3 memory interfaces?

No - the PI6CV857LAE is specified only for 2.5 V SSTL-2 signaling used in DDR2. DDR3 requires 1.5 V SSTL-15 I/O levels, different termination schemes, and tighter jitter specs (e.g., <30 ps cycle-to-cycle). Using this device with DDR3 violates voltage and timing specifications and is not supported.