Diodes Incorporated PI6C20800SVEX

Overview

PI6C20800SVEX from Diodes Incorporated is a PCIe®-compliant 1:8 HCSL differential clock buffer with PLL/fanout mode selection, 8 differential output pairs, <50ps output-to-output skew (PI6C20800S grade), and SMBus programmable control. It operates at 3.3V, supports SRC clock division-by-2, and targets Intel server chipset clock distribution systems requiring low additive jitter (<1ps RMS for PCIe 2.0) and industrial-grade reliability.

For engineers reviewing the PI6C20800SVEX datasheet, PI6C20800SVEX pinout, PI6C20800SVEX application, or PI6C20800SVEX equivalent, key selection criteria include differential output current programmability via IREF, tristate control per output via OE[0:7], PLL bandwidth selection, and lock status monitoring via LOCK pin - all critical for PCIe Gen2/Gen3 timing integrity in high-density server backplanes.

Technical Context

The PI6C20800SVEX implements a dual-mode architecture: PLL mode (95–105 MHz input) for jitter filtering and fanout mode (95–400 MHz) for low-latency distribution. Its current-mode HCSL outputs deliver 0.7V differential swing into 100Ω loads with ±12% current accuracy (IREF = 2.32 mA, RREF = 475 Ω).

Control is implemented via three independent LVTTL interfaces (SRC_STOP#, PWRDWN#, OE_INV) plus an SMBus slave interface (7-bit address 0x6E) supporting indexed block read/write for register-level configuration of PLL bandwidth, bypass mode, output enable states, and SRC_STOP# behavior - enabling dynamic power management and system-level synchronization.

Key Specifications

Pinout & Package

PI6C20800SVEX is housed in a 48-pin SSOP (V package), 300-mil wide, JEDEC MO-118 AA compliant. Pin pitch is 0.025", body width 0.300", and lead finish is Pb-free & RoHS-compliant green plating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT 8V19N408A and ON Semi NB3N502HG, the PI6C20800SVEX uniquely balances PCIe Gen2/Gen3 jitter compliance, per-output control, and industrial-grade scalability - making it optimal for server OEMs needing field-upgradable thermal performance without hardware revision.

Availability

PI6C20800SVEX is available at Aetrix Electronics and suitable for PCIe server backplanes, Intel chipset companion clocking, and high-density NVMe storage controllers requiring stable component supply, long-term lifecycle support, and RoHS-compliant green packaging.

Supply support for PI6C20800SVEX 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-performance timing, power management, and signal integrity solutions for enterprise, industrial, and automotive markets.

The PI6C20800S belongs to Diodes' Pericom-branded PCIe timing portfolio, designed specifically to support Intel server platform clock tree architectures with low-jitter distribution, flexible power management, and robust manufacturability.

FAQ

What is the function of the IREF pin, and how is it configured?

The IREF pin sets the nominal output current for all eight HCSL differential outputs using an external 475Ω ±1% resistor connected to VSS. This establishes IREF = 2.32 mA, resulting in 6 × IREF ≈ 13.9 mA drive strength - calibrated to deliver 0.7V differential swing into 100Ω loads. No internal current source is used; accuracy depends solely on resistor tolerance and layout symmetry.

How does the LOCK pin behave during power-up and PLL lock acquisition?

The LOCK pin is a latched 3.3V LVTTL output that remains LOW until the internal PLL achieves frequency and phase lock, then transitions HIGH and holds that state until reset or power cycle. It does not toggle during normal operation. BIOS firmware typically polls LOCK before initializing PCIe root ports - ensuring clock stability prior to enumeration.

Can PI6C20800SVEX operate in fanout mode with a 250 MHz input clock?

Yes - in fanout (bypass) mode, the device accepts SRC/SRC# inputs from 95 MHz to 400 MHz, including 250 MHz. The AC specification confirms Tpd variation of ±6 ns across this range for PI6C20800S grade. However, PLL mode is restricted to 95–105 MHz; using 250 MHz in PLL mode will prevent lock and force fallback to bypass behavior.

What is the SMBus address, and which registers control output enable states?

The PI6C20800SVEX uses a fixed 7-bit SMBus slave address of 0x6E (1101110). Output enable states are controlled via Data Byte 1 (register offset 0x01), where bits 0–7 correspond directly to OE[0] through OE[7]. Writing 0x00 disables all outputs; writing 0xFF enables all. This register is writable in real time without disrupting ongoing clock distribution.