UCD9090: PMBus DATA/CLK Trise requirment

Cosmin P

Part Number: UCD9090

Hello,

The UCD9090 datasheet states that it is compliant with PMBus 1.1 specification.
Extract from the standard:

Extract from the datasheet:

Actually the 120ns is required for 1MHz PMBus clock - is this a typo or a real requirment?

Is the 120ns requirment in still place if the bus is used at 100kHz?
Is there a recommenced pull-up resistor to achieve 120ns TR for 400kHz?

Thank you

0 Cosmin P over 6 years ago

actually pictures did not 'stick'...

PMBus 1.1 has for TRmax 300ns
Datasheet has for TRmax 120ns

0 yihe over 6 years ago in reply to Cosmin P

yes ,it is a typo in the datasheet, it should be 300ns which follows 400KHz spec.

we are working on the DS to fix this.

regards

Yihe

0 Cosmin P over 6 years ago in reply to yihe

Thank you.

If the UCD is used at 100kHz, the TR requirment stays at 300ns or can it be relaxed to 1000ns as per SMBus 2.0 spec?

We are measuring 700ns in sthe system with 1k pull-up resistors to 3.3V

What is the UCD9090 pull down current capability?

0 yihe over 6 years ago in reply to Cosmin P

yes, ucd follows 100ks spec.
the IO driving capability is +/- 6mA
regards
Yihe

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