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Home > Products > Integrated Circuits (ICs) > Clock/Timing > Application Specific Clock/Timing

Diodes Incorporated PI6C557-05QLEX

Name: PI6C557-05QLEX
Brand: Diodes Incorporated
SKU: PI6C557-05QLEX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PI6C557-05QLEX

Manufacturer:: Diodes Incorporated

Category:: Application Specific Clock/Timing

Package:: 20-TSSOP (0.173", 4.40mm Width)

Datasheet:: PI6C557-05QLEX.pdf

Description:: IC CLOCK GENERATOR TSSOP

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Product details

Overview

PI6C557-05QLEX from Pericom is a PCIe® 2.0-compliant spread spectrum clock generator with AEC-Q100 qualification for automotive applications. It accepts a 25MHz crystal input and delivers four differential HCSL or LVDS output pairs at selectable 100MHz/200MHz frequencies, with RMS phase jitter of 2.1ps (typ), cycle-to-cycle jitter of 40ps (typ), and spread options of –0.5%, –1.0%, –1.5%, or no spread. It operates from 3.3V ±5% and supports EMI reduction in PC and embedded automotive systems.

For engineers reviewing the PI6C557-05QLEX datasheet, PI6C557-05QLEX pinout, PI6C557-05QLEX application, or PI6C557-05QLEX equivalent, key selection criteria include PCIe Gen 2 timing compliance, HCSL/LVDS dual-mode output configuration, spread-spectrum selection via S[2:0] pins, AEC-Q100 qualification, and 20-pin TSSOP packaging with dedicated VDDXD/VDDODA power domains.

Technical Context

The PI6C557-05QLEX integrates a proprietary PLL to synthesize 100MHz or 200MHz differential clocks from a 25MHz fundamental-mode crystal. Its spread-spectrum modulation operates at 30–33kHz with down-spread profiles, configurable via three digital select pins (S2:S0).

It provides four independent HCSL output pairs (CLK0–CLK3, true/complement) with 0.7V current-mode drive, requiring external 33Ω series and 49.9Ω termination resistors per PCIe layout guidelines. Output enable (OE) and power-down (PD) pins support dynamic control with internal pull-ups.

Key Specifications

Parameter	Value and Actual Design Meaning
Input Frequency	25 MHz crystal input - fixed reference for PLL lock; requires parallel-resonant crystal with ≤30 ppm stability.
Output Frequencies	100 MHz or 200 MHz - selected by S2:S0; supports PCIe Gen 2 clocking hierarchy and high-speed serial link timing.
RMS Phase Jitter	2.1 ps (typ) - meets PCIe Gen 2 high-band jitter limit (≤3.1 ps) for reliable 5 GT/s data recovery.
Cycle-to-Cycle Jitter	40 ps (typ) - ensures stable edge placement across consecutive cycles for synchronous logic timing margins.
Supply Voltage	3.3 V ±5% - split-domain design: VDDXD (digital core), VDDODA (analog/PLL), each requiring local 0.01–0.1 µF decoupling.
Spread Spectrum Options	–0.5%, –1.0%, –1.5%, or no spread - down-spread only; modulates output frequency to reduce EMI peak amplitude by >10 dB.
Operating Temperature	–40°C to +85°C - AEC-Q100 Grade 3 qualified for under-hood and infotainment module deployment.

Pinout & Package

Package: Pb-free and Green 20-pin, 173-mil wide TSSOP (JEDEC MO-153).

Pin/Terminal	Circuit Role	Design Meaning
VDDXD (Pin 1)	Digital power supply	Supplies core logic and PLL digital circuitry; must be decoupled with 0.01 µF capacitor near pin.
S0–S2 (Pins 2–4)	Spread/frequency select inputs	3-bit binary code selects spread % and output frequency (100/200 MHz); internal pull-up enables default no-spread 100 MHz on power-up.
X1/X2 (Pins 5–6)	Crytal oscillator terminals	Connects to 25 MHz parallel-resonant crystal; X1 is input, X2 is output; external 27 pF load caps recommended.
PD (Pin 7)	Power-down control	Active-low; places device in low-current standby (<100 µA) while preserving configuration state.
OE (Pin 8)	Output enable	Active-high; tri-states all eight differential outputs when low, enabling shared bus or power-gating scenarios.
IREF (Pin 10)	Current reference output	Sinks 2.32 mA when 475 Ω resistor connected; sets HCSL output current (IOH = 6 × IREF = ~13.9 mA).
CLK0–CLK3 (Pins 11–20)	Differential clock outputs	Four true/complement HCSL pairs (CLKn/CLKn); require external 33 Ω series + 49.9 Ω ground termination per PCIe spec.

Key Features

Feature	Design Value
AEC-Q100 Grade 3 qualification	Validated for automotive ambient temperatures (–40°C to +85°C) and reliability stress testing, enabling use in ADAS and body control modules.
HCSL/LVDS dual-mode compatibility	Configurable output voltage levels support both PCIe 2.0 HCSL (0.7 V) and LVDS (1.2 V) signaling standards without hardware change.
Independent spread and frequency selection	S2:S0 pins simultaneously determine output frequency (100/200 MHz) and spread magnitude (–0.5% to –1.5%), simplifying board-level configuration.
Dedicated analog/digital power domains	VDDODA (Pin 15) isolates PLL analog circuitry from digital noise; reduces jitter contribution from switching transients.
Low skew between outputs	50 ps max skew at crossing point ensures tight timing alignment across four clock domains for multi-lane PCIe or Ethernet PHY interfaces.

Applications

Automotive Infotainment Systems

PCIe 2.0 SSD Controllers

Use Scenario: Clocking multiple video processors, display controllers, and USB 3.0 hubs in head-unit designs.

IC Role / Device Role / Timing Role: Primary spread-spectrum clock source synchronizing SoC peripherals and reducing EMI emissions to meet CISPR 25 Class 5 limits.

Use Value: AEC-Q100 qualification ensures operation over vehicle lifetime; –1.5% spread lowers 100 MHz harmonic peaks by >12 dB, easing EMC chamber validation.

Use Scenario: Providing synchronized 100 MHz reference clocks to PCIe Gen 2 x4 SSD controller and NAND flash interface.

IC Role / Device Role / Timing Role: Low-jitter clock generator meeting PCIe Gen 2 timing budget (RMS jitter ≤3.1 ps) for 5 GT/s link training and stable data eye opening.

Use Value: 2.1 ps RMS jitter and 50 ps inter-output skew maintain setup/hold margins across all four lanes; OE pin enables hot-plug clock gating.

Industrial Ethernet Switches

Automotive ADAS Camera Modules

Use Scenario: Driving multiple Gigabit Ethernet PHYs (e.g., Marvell 88E1512) in managed switch ASIC timing trees.

IC Role / Device Role / Timing Role: LVDS-compatible clock distributor delivering clean 125 MHz (via 2× multiplication) to PHY reference inputs with minimal crosstalk.

Use Value: Configurable LVDS mode (1.2 V swing) meets IEEE 802.3 standard; 40 ps cycle-to-cycle jitter prevents packet loss due to clock domain misalignment.

Use Scenario: Supplying synchronized 200 MHz pixel clocks to CMOS image sensors and ISP pipelines in surround-view camera ECUs.

IC Role / Device Role / Timing Role: High-frequency clock generator supporting MIPI CSI-2 timing requirements with deterministic phase relationship across sensor channels.

Use Value: 200 MHz output option enables direct pixel-rate clocking; HCSL drive strength ensures signal integrity over 10 cm flex PCB traces to sensors.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
IDT 8T49N241	Programmable via I²C; supports 1–710 MHz outputs; higher integration (integrated crystal oscillator); 3.3 V only; no AEC-Q100 rating.	Used in telecom/datacom where programmability and wide frequency range outweigh automotive qualification needs.	Select when firmware-controlled frequency agility or crystal-less operation is required; not suitable for automotive safety-critical modules.
ON Semiconductor NB3N502	Fixed 100 MHz output; no spread spectrum; LVPECL outputs; 3.3 V; AEC-Q100 Grade 2 (–40°C to +105°C).	Deployed in cost-sensitive automotive clusters where EMI reduction is handled at board level (shielding, layout), not clock domain.	Choose for non-spread applications needing wider temperature margin; lacks PCIe Gen 2 jitter performance and HCSL compatibility.

Compared with IDT 8T49N241 and NB3N502, the PI6C557-05QLEX uniquely combines AEC-Q100 Grade 3 qualification, PCIe Gen 2–compliant jitter, hardware-configurable spread spectrum, and HCSL/LVDS dual-mode outputs in a cost-optimized TSSOP package-making it optimal for automotive PCIe endpoints where EMI control and qualification are mandatory.

Availability

PI6C557-05QLEX is available at Aetrix Electronics and suitable for automotive infotainment systems, PCIe 2.0 SSD controllers, and industrial Ethernet switches requiring stable component supply, long-term lifecycle support, and AEC-Q100–qualified timing solutions.

Supply support for PI6C557-05QLEX 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 communications, computing, and automotive markets.

The PI6C557-05QLEX belongs to Pericom's PCIe-compliant clock generator product line, designed specifically to reduce EMI in automotive and embedded PCIe 2.0 systems while maintaining strict jitter and qualification requirements.

FAQ

What crystal specifications are required for stable operation of the PI6C557-05QLEX?

The PI6C557-05QLEX requires a 25 MHz fundamental-mode parallel-resonant crystal with ≤30 ppm frequency tolerance across –40°C to +85°C. Pericom recommends FL2500184Q (3.2×2.5 mm, CL=20 pF, ±15 ppm tolerance). Load capacitors C1/C2 should be 27 pF each; a 360 Ω series resistor (R1) is advised for drive-level control and layout robustness.

How is HCSL output current set, and what external components are needed?

HCSL output current is set by the IREF pin: connecting a 475 Ω resistor from IREF to GND establishes 2.32 mA reference current, resulting in 13.9 mA output drive (IOH = 6 × IREF). Each differential pair requires a 33 Ω series resistor and a 49.9 Ω ground termination resistor per PCIe Gen 2 layout guidelines to achieve proper 50 Ω single-ended and 100 Ω differential impedance.

Can the PI6C557-05QLEX operate in LVDS mode, and how is it configured?

Yes-the PI6C557-05QLEX supports LVDS-compatible outputs by adjusting external termination: replace the 49.9 Ω ground resistor with two 100 Ω resistors (RP/RQ) and add a 150 Ω Thevenin termination (RT) to achieve 1.2 V common-mode voltage. No internal register or pin configuration is needed; the same HCSL driver structure operates at LVDS voltage levels with appropriate external biasing per the datasheet's LVDS Layout Guidelines section.

What is the function of the VDDXD and VDDODA pins, and why are they separated?

VDDXD powers the digital logic and spread-spectrum control circuitry, while VDDODA supplies the analog PLL and crystal oscillator. This separation minimizes noise coupling from digital switching into the sensitive analog timing path-reducing jitter contributions and improving RMS phase jitter performance to 2.1 ps (typ). Each domain requires independent 0.01–0.1 µF ceramic decoupling placed adjacent to its respective pin.

PI6C557-05QLEX Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: 20-TSSOP (0.173", 4.40mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Active

Programmable:: Not Verified

PLL:: Yes

Main Purpose:: Ethernet, PCI Express (PCIe)

Input:: HCSL, Crystal

Output:: HCSL, LVDS

Number of Circuits:: 1

Ratio - Input:Output:: 1:4

Differential - Input:Output:: No/Yes

Frequency - Max:: 200MHz

Voltage - Supply:: 3.135V ~ 3.465V

Operating Temperature:: -40°C ~ 85°C

Mounting Type:: Surface Mount

Grade:: -

Qualification:: -

Supplier Device Package:: 20-TSSOP

PI6C557-05QLEX FAQ

1.How can I place an order for PI6C557-05QLEX through Aetrix?

Please submit a Request for Quotation (RFQ) for PI6C557-05QLEX on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for PI6C557-05QLEX reliable?

The price and inventory of PI6C557-05QLEX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PI6C557-05QLEX is usually 5 days.

3.What payment methods are accepted for PI6C557-05QLEX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PI6C557-05QLEX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PI6C557-05QLEX?

PI6C557-05QLEX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PI6C557-05QLEX order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for PI6C557-05QLEX?

For technical support, including PI6C557-05QLEX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PI6C557-05QLEX requirements.

6.How does Aetrix verify that PI6C557-05QLEX is sourced from the original manufacturer or authorized distributors?

All PI6C557-05QLEX products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that PI6C557-05QLEX meets industry standards.

7.What is the process for return or replacement of PI6C557-05QLEX?

All PI6C557-05QLEX units undergo pre-shipment inspection (PSI). If there is an issue with PI6C557-05QLEX, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The PI6C557-05QLEX part is unused and in its original packaging.

Return procedure for PI6C557-05QLEX:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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