SN65EPT21: CML to TTL/CMOS translation

Juergen Schneider

Part Number: SN65EPT21

Hi,

I planned to apply the circuit SN65EPT21 ( supported by +3.3V) to translate a differential CML- Signal ( CML- Driver is supported by +2.5V) to a single- ended TTL/ CMOS- Signal. What kind of termination is there required ( D+ & D- Inputs of SN65EPT21) ?

1.) 100 ohm on D+ & D- ?
2.) or 2x 50 ohm from D+ & D- to GND ?
3.) or 2x 50 ohm from D+ & D- to +2.5V ?

Thanks in advance for your help,
Juergen

over 7 years ago

0 Lee Sledjeski over 7 years ago

TI__Mastermind 43795 points

Hi Jurgen,

I am assuming the CML driver is already terminated to 2.5V, so either #1 or #3 would work. The differential input common mode for theSN65EPT21 is 1.2-3.3V. Either type of termination will fall within the inputs normal range of operation.

Regards,

Lee

0 Juergen Schneider over 7 years ago in reply to Lee Sledjeski

Prodigy 20 points

Hi Lee,

Thanks for the fast response. Yes, the CML driver ist terminated to 2.5V. I checked #1 with Texas TINA and all voltages are in normal range.

Regards,

Juergen

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SN65EPT21: CML to TTL/CMOS translation