Diodes Incorporated PI6LC4830ZHEX

Overview

PI6LC4830ZHEX from Pericom Semiconductor is a low-phase-noise LC-VCO-based clock generator optimized for PCIe® 2.0 timing systems, delivering three 100MHz HCSL outputs, one selectable 100/50MHz LVCMOS output, and one 25MHz LVPECL reference output. It supports 25MHz crystal or differential input, operates at 3.3V, and features PLL bypass mode for testability.

For engineers reviewing the PI6LC4830ZHEX datasheet, PI6LC4830ZHEX pinout, PI6LC4830ZHEX application, or PI6LC4830ZHEX equivalent, key selection criteria include RMS phase jitter (≤1ps), HCSL/LVCMOS/LVPECL output flexibility, integrated crystal oscillator support, and 32-pin 5×5mm TQFN packaging for high-density server and storage board designs.

Technical Context

The PI6LC4830ZHEX implements an LC-based VCO architecture to achieve ultra-low integrated phase noise (≤1ps RMS, 12kHz–20MHz), significantly exceeding standard ring-oscillator PLLs in PCIe 2.0 jitter compliance. Its dual-input mux (crystal X1/X2 or differential IN+/IN−) and programmable IN_SEL pin enable flexible clock source selection without external switching.

It integrates independent power domains-VDDA_PLL for analog PLL core, VDD_OSC for crystal oscillator, VDD_OutA/B_SE for LVCMOS banks, and VDD_Out for HCSL buffers-enabling precise noise isolation and supply rejection (PSR = −46 dBc). The PLL_Byps pin allows direct signal routing from input to outputs, supporting functional test modes independent of PLL lock.

Key Specifications

Pinout & Package

Package: 32-pin Thin Quad Flat No-Lead (TQFN), 5×5mm body, 0.5mm pitch, exposed thermal pad (ZH code). Designed for high thermal conductivity and minimal parasitic inductance in dense PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5332A-D-GM and ICS8430I-01T, the PI6LC4830ZHEX offers superior jitter performance (≤1ps vs. ≥1.5ps), integrated crystal oscillator, and native multi-standard output support-making it optimal for cost-sensitive, fixed-frequency PCIe 2.0 and storage applications where simplicity and noise immunity are prioritized over programmability.

Availability

PI6LC4830ZHEX is available at Aetrix Electronics and suitable for PCIe 2.0 server motherboards, enterprise NVMe SSD modules, and high-density network switch line cards requiring stable component supply, long-lifecycle availability, and guaranteed RoHS-compliant sourcing.

Supply support for PI6LC4830ZHEX 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 (acquired by Diodes Incorporated in 2016) specialized in high-performance timing, interface, and signal-integrity solutions for datacenter, networking, and storage applications.

The PI6LC4830 belongs to Pericom's HiFlex™ clock generator family, engineered specifically for PCIe 2.0 and enterprise storage timing with emphasis on ultra-low jitter, multi-standard output compatibility, and crystal integration to reduce system-level BOM and layout complexity.

FAQ

What crystal specifications are required for the PI6LC4830ZHEX?

The PI6LC4830ZHEX requires a 25MHz fundamental-mode parallel-resonant crystal with 18pF load capacitance (CL), ≤50Ω ESR, and ±20ppm to ±30ppm tolerance. Recommended parts include FL2500047 (3.2×2.5mm, ±20ppm) and GC2500003 (4.0mm HC-49/SMD, ±30ppm). C1/C2 load capacitors (27pF/33pF typical) must be tuned per board layout to meet ppm accuracy.

How is HCSL output current calibrated using the IREF pin?

HCSL output current is set by connecting a precision 475Ω ±1% resistor between IREF (Pin 28) and GND. This establishes a nominal 2.32mA reference current, which scales the HCSL driver strength to deliver VOH = 660–900mV and VOL = 150mV into 100Ω differential loads. Current accuracy is ±12% over voltage/temperature per datasheet Section 7.

Can the PI6LC4830ZHEX operate without an external crystal?

Yes-the PI6LC4830ZHEX supports differential clock inputs (IN+/IN−) at 25MHz, allowing replacement of the crystal with an external LVDS/HCSL/LVPECL source. When IN_SEL is high, the internal mux selects IN+/IN−; the crystal pins (X1/X2) become inactive. PLL lock time remains 5ms, and all output specifications are maintained.

What is the purpose of the separate VDDA_PLL and VDD_OSC supply pins?

VDDA_PLL powers the analog core of the LC-VCO and phase detector, while VDD_OSC powers the crystal oscillator circuitry. Separating these rails prevents digital switching noise from VDD_Out or VDD_PLL from modulating the VCO or crystal gain stage-directly enabling the ≤1ps RMS phase jitter performance critical for PCIe 2.0 compliance.