Hi,
I am planing to use the 9BV0641 PCI clock fanout to fan out a PCIe 3.0 clock to a packet switch and two PCie 1.0 outputs. I have questions about configuration and start up routine. I can't use the SMBus during start up, other than debugging, I was wondering if this is possible? I read that you can configure the IC through the pins but was not able to understand which pins I should used and how should I set them up. Can you help in this regards? Any documents or reference designs are welcomed.
Best regards,
Besnik
Unfortuneatly, no as this device can not be configured without the use of the sending command sequences via the SMBus / I2C.
I am surprised by the answer. The datasheet says "Pin/software selectable PLL bandwidth and PLL Bypass; minimize phase jitter for each application • Outputs blocked until PLL is locked; clean system start-up. Configuration can be accomplished with strapping pins; SMBus interface not required for device control". I am tying all the enables high and bypassing the PLL. Can you eloborate on your answer and the differences with the datasheet?
Yes, but it uses default settings that may not match your desired configuration.
What are the default setting?
Let me check further into that and get back to you.
Internal request to Engineering ( TECHSUPP-7972 )
Also are there any other parts that I can use that do not require I2C for configuration? Or have internal memory.
Comments from Engineering:
This device has no OTP, everything that can be set is defined in metal. The pin functions are also defined. Note that if all the OE# pins are tied high, the outputs are disabled. If the desire is for all the outputs to be enabled, then the OE# pins need to be tied low. Also, bypass mode is the correct operating mode. The SMBus would only be needed/wanted for any debug purposes. I don’t think that will be needed since the part is operating as a fanout buffer.
Make sure that there are no 50ohm pull downs on the outputs, they are not needed with LP-HCSL output types.
There is another buffer about to be released that has OTP, but what exact configuration changes would interest the customer. Such configuration could only be offered for high volumes since the part is only factory programmable.