Diodes Incorporated PI6CG18401ZHIEX

Overview

PI6CG18401 from Diodes Incorporated is a 4-output PCIe Gen1–Gen4 clock generator with integrated HCSL drivers, 1.8V supply, 25MHz crystal/CMOS input, and on-chip 50Ω termination per differential output. It delivers 100MHz low-power HCSL clocks with <50ps cycle-to-cycle jitter and supports spread-spectrum options (0%, –0.25%, –0.5%) for EMI reduction in high-speed server and storage platforms.

For engineers reviewing the PI6CG18401 datasheet, PI6CG18401 pinout, PI6CG18401 application, or PI6CG18401 equivalent, key selection criteria include PCIe Gen4 phase jitter compliance (≤0.5ps RMS), individual output enable control via OE# pins, SMBus- or strapping-based configuration, and power-down current as low as 0.6mA total.

Technical Context

The PI6CG18401 employs a proprietary PLL architecture optimized for PCIe timing budgets, achieving <0.5ps RMS integrated phase jitter at PCIe Gen4 (100MHz) with 2–5MHz PLL bandwidth and 10MHz CDR reference. Its analog PLL core uses a 25MHz fundamental-mode crystal input and generates four synchronized, independently enabled HCSL outputs with programmable slew rate and amplitude.

Configuration is supported via tri-level SS_SEL_TRI pin for spread-spectrum selection at power-up or through a 3.3V-tolerant SMBus interface (7-bit address 0x68/0x6A), enabling dynamic register writes to output enable, slew rate, amplitude, and REFOUT control registers - all while maintaining 1.8V core logic and separate VDDO/VDDA supplies for noise isolation.

Key Specifications

Pinout & Package

Package: 32-lead 5×5mm TQFN (0.5mm pitch), thermally enhanced with exposed pad (GNDA pin 20).

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT8P34S1208NLGI and Si53301-B-GM, the PI6CG18401 uniquely combines on-chip HCSL termination, per-output enable/slew control, and PCIe Gen4-compliant jitter in a 5×5mm package - reducing layout risk and component count without sacrificing configurability or thermal performance.

Availability

PI6CG18401 is available at Aetrix Electronics and suitable for PCIe Gen4 server motherboards, enterprise NVMe SSDs, AI accelerator cards, and industrial embedded computing platforms requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for PI6CG18401 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 timing, power management, and signal integrity solutions for computing, industrial, and communications markets.

The PI6CG18401 belongs to Diodes' PCIe-optimized clock generator product line, designed specifically to replace legacy clock trees in Gen3/Gen4 systems with single-chip, low-power, high-integration alternatives that simplify layout and improve jitter margin.

FAQ

What is the minimum startup time from power-up to stable 100MHz HCSL output?

The PI6CG18401 achieves full output stability within 10ms after power-up and crystal stabilization, with PLL lock time specified at 20ms maximum. The tSTARTUP parameter includes both oscillator start-up and PLL acquisition; actual first-edge delay is ≤1.8ms after PD# de-assertion, per DS39948 Rev 3-2 Section 7.

Can the REFOUT pin be used simultaneously as an SMBus address select pin?

Yes - pin 6 (SADR/REFOUT) functions as either SMBus address selector (when pulled high/low/mid during power-up) or as a 1.8V LVCMOS buffered reference output, but not both concurrently. Configuration is latched at power-up; once set to REFOUT mode, SMBus addressing defaults to fixed 0x68/0x6A based on internal strap state.

How does the on-chip HCSL termination affect PCB layout compared to discrete termination?

On-chip 50Ω termination eliminates eight 33Ω series resistors and eight 50Ω AC-coupling shunt resistors per output pair, reducing netlist complexity, saving ~24mm² board area, and removing stub-induced reflections. Layout requires only direct microstrip routing to the receiver with controlled 100Ω differential impedance - no resistor placement or via transitions near the IC.

Is the PI6CG18401 qualified for automotive applications?

No - the PI6CG18401 is rated for industrial temperature range (–40°C to +85°C) and is not AEC-Q100 qualified. Diodes offers automotive-grade variants (e.g., PI6CG18401Q) with PPAP documentation, IATF 16949 manufacturing, and extended reliability testing; contact Diodes sales for Q-grade part numbers and qualification reports.