Diodes Incorporated PI6C20800SIAEX

Overview

PI6C20800SIAEX 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), and SMBus programmable control. It operates at 3.3V, supports industrial temperature range (–40°C to +85°C), and serves as a companion to PI6C410BS clock generators in Intel server chipset applications.

For engineers reviewing the PI6C20800SIAEX datasheet, PI6C20800SIAEX pinout, PI6C20800SIAEX application, or PI6C20800SIAEX equivalent, key selection criteria include differential output current programmability via IREF, tristate control per output group, PLL bandwidth selection, SRC clock division capability, and lock status indication via LOCK pin.

Technical Context

The PI6C20800SIAEX implements a dual-mode clock distribution architecture: PLL mode for jitter filtering (PCIe® 2.0 additive phase jitter <1 ps) and bypass mode for low-latency fanout (up to 400 MHz input). Its current-mode HCSL outputs deliver 0.7 V differential swing into 100 Ω loads with ±12% current accuracy when configured with 475 Ω IREF.

Control is implemented via dedicated LVTTL pins (SRC_STOP#, PWRDWN#, OE[0:7], OE_INV) and an SMBus slave interface supporting indexed block read/write. The device latches PLL lock status on the LOCK pin and allows independent enable/disable of each output pair through register-controlled OE bits and hardware pins.

Key Specifications

Pinout & Package

PI6C20800SIAEX is packaged in a 48-pin TSSOP (Package Code A), 240-mil wide, RoHS-compliant and halogen-free "Green" package with exposed thermal pad not present. Pin layout supports differential signal routing with dedicated VDD/VSS pairs per output quadrant and isolated PLL supply (VDD_A/VSS_A).

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT8T49N242A and NB3N551, PI6C20800SIAEX uniquely balances PCIe-compliant jitter performance, per-output control granularity, and dual-mode (PLL/bypass) flexibility-making it optimal for scalable, firmware-managed server clock architectures.

Availability

PI6C20800SIAEX is available at Aetrix Electronics and suitable for enterprise SSD controllers, Intel server chipset clock distribution, industrial storage arrays, and high-density PCIe expansion chassis requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for PI6C20800SIAEX 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 integrated circuits, specializing in high-performance analog, logic, and timing solutions for computing, industrial, and communications markets.

The PI6C product line delivers PCIe-optimized clock buffers and generators designed specifically for Intel and AMD server platforms, emphasizing low jitter, industrial temperature support, and compatibility with PI6C410BS and other Pericom-originated timing ICs.

FAQ

What is the function of the IREF pin on PI6C20800SIAEX?

The IREF pin connects to an external 475 Ω 1% resistor to set the nominal differential output current (2.32 mA), directly determining the 0.7 V HCSL output swing into 100 Ω loads. This enables precise calibration across voltage and temperature variations without trimming components on the PCB.

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

The LOCK pin is an open-drain 3.3 V LVTTL output that remains low until PLL lock is achieved, then transitions high and latches in that state. It stays asserted even if the input clock is later removed, providing a reliable hardware-ready signal for system boot sequencing without requiring continuous polling.

Can PI6C20800SIAEX operate in both PLL and bypass modes simultaneously?

No. PLL/BYPASS# is a single LVTTL input that selects global operation mode: logic low enables PLL mode (jitter filtering), logic high enables bypass mode (direct fanout). Mode switching requires deasserting PWRDWN# and waiting for LOCK assertion in PLL mode or stable output edges in bypass mode.

What is the maximum allowed input frequency in bypass mode, and what limits it?

The maximum input frequency in bypass mode is 400 MHz, specified under AC switching characteristics. This limit arises from internal signal path propagation delay and output driver bandwidth constraints-not from PLL circuitry-as bypass mode routes the input directly to outputs without phase detection or feedback.