DP83869HM: drive led with 1.8V vddio

Zeev Gerber

Part Number: DP83869HM
Other Parts Discussed in Thread: SN74LVC1G06, SN74LVC3G06, SN74LVC3G07, SN74LVC1G07, SN74LVC2G06, SN74LVC2G07

Hi,

I work with vddio of 1.8V.

pls. advise who to drive the phy leds because direct drive is not working when you have 1.8V.

regards

zeev gerber

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 323390 points

Add a buffer between the pin and the LED. SN74LVC1G07/SN74LVC2G07/SN74LVC3G07 are active low; inverters like the SN74LVC1G06/SN74LVC2G06/SN74LVC3G06 have active-high inputs. The open-drain outputs allow connecting the anode to a higher supply like 3.3 V or 5 V. (Also, the high-impedance inputs of the buffers make it easier to add pull-up/-down resistors for the straps.)

0 Zeev Gerber over 4 years ago in reply to Clemens Ladisch

Intellectual 500 points

Hi,

what is the default for led polarity?

In DS wrote "Default depends on strap".

the strap in my design is resistor to ground.

is it active high or active low?

regards

zeev gerber

0 Gokul Koraganji over 4 years ago in reply to Zeev Gerber

TI__Mastermind 19250 points

Hi Zeev,

The LED polarity will be active high when the strap resistor is placed to ground.

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Regards,
Gokul.

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DP83869HM: drive led with 1.8V vddio