PROCESSOR-SDK-AM69A: AM69A LP-HCSL REF CLK

ASIM BOZDAG

Part Number: PROCESSOR-SDK-AM69A
Other Parts Discussed in Thread: AM69A, CDCE6214

I am going to to use PCIe GEN3 in AM69A. In the design I will use a clock generator and a clock multiplier for ref clocks.

But at this point I have a question.

The clock generator will generate ref clks with 1.8V output voltage . However clock multiplier output voltages are 3.3v and AM69A serdes voltages are 1.8V also.

In this diagram can I directly connect ref clks to each other. Or do I have to use ac coupling caps ?

Could you please give information?

5 months ago

0 Robert Eschler 5 months ago

TI__Mastermind 43600 points

I'm not familiar with the Renesas device and its clock output specifications. The SERDES input clock requirements are defined in the data manual section 6.6.10 (SERDES 2L PHY/4L PHY Electrical Requirements)

https://www.ti.com/lit/gpn/am69

0 ASIM BOZDAG 5 months ago in reply to Robert Eschler

Prodigy 30 points

Dear Robert

Let me remove renesas device and connect directly CDCE6214 outputs directly to AM69A serdes ref clks in.

But I will connect cdce6214 output clks voltages (VDDO_12 and VDDO_34) to 3.3V instead of 1.8V.

Since AM69A serdes voltages are 1.8V , Does this circuit work? Does LP-HCSL outputs capable of working either 1.8v or 3.3V?

Thank you

0 Robert Eschler 5 months ago in reply to ASIM BOZDAG

TI__Mastermind 43600 points

The datasheet for seems to indicate can support LP-HCSL outputs with any of the power supply configurations. To verify, you need to create a new E2E ticket with specific CDC6214 questions, so that it can get routed to correct group/person.

Clock & timing

Clock & timing forum

PROCESSOR-SDK-AM69A: AM69A LP-HCSL REF CLK