SN65LVDS386EVM: P1 and P3 Header pinouts

Steve Widener

Part Number: SN65LVDS386EVM

It is not clear on the EVM how the P1 and P3 headers are pinned out - Please provide guidance so that we can identify each pin on the Headers and associate that to the EVM schematic

over 8 years ago

0 Ikechukwu Anyiam over 8 years ago

TI__Mastermind 35130 points

Hi Steve,

From the schematic, BOM, and picture of the EVM from this document: http://www.ti.com/lit/ug/sllu013/sllu013.pdf

I believe P3 is pinned out like so:

And P1/P2 are pinned out like so:

Regards,

I.K.

0 Go Bravos over 8 years ago in reply to Ikechukwu Anyiam

TI__Expert 6090 points

Hi I.K.,

The user’s guide (SLLU013) indicates that resistors may need to be changed if looking at the LVTTL output with a scope with a 50-ohm input impedance.

From page 2-5:

Is the LVTTL output not at 50 ohm impedance?

0 Ikechukwu Anyiam over 8 years ago in reply to Go Bravos

TI__Mastermind 35130 points

Hi Bravos,

The LVTTL outputs are not 50 ohms. Please see the equivalent input/output schematic diagrams on page 18 of the datasheet:
www.ti.com/.../sn65lvds386.pdf

Regards,
I.K.

0 Steve Widener over 8 years ago in reply to Ikechukwu Anyiam

TI__Genius 11010 points

The datasheet output charateristic graphs (Figures 5 and 6) show a V-I curve that indicate an equivalent output impedance (from the slope of the curves) that is greater than the 5 ohms shown in the equivalent circuit. The impedance looks like ~ 33 - 50 ohms just by using the slope (depending on the output current). Please confirm.

0 Steve Widener over 8 years ago in reply to Ikechukwu Anyiam

TI__Genius 11010 points

Figures 5 & 6 of the datasheet show Vo characteristics from 0mA to > 60mA sourcing or sinking. However, the ABS max for Iout is shown a 12mA. Is it acceptable to load more than 12mA? If so why do Figures 5 and 6 suggest that it is ok to load beyond 12mA?

0 HA over 8 years ago in reply to Steve Widener

TI__Intellectual 1810 points

Hi Bravos,

Yes, the V-I curves indicate output impedance higher than 5 ohm shown on the simplified schematic drawing shown on Figure 13 of the datasheet (www.ti.com/.../sn65lvds386.pdf). It's between 25 and 35 ohms for output current of between -12 and 12mA supported by the device.

Best regards,
Hassan.

0 HA over 8 years ago in reply to Steve Widener

TI__Intellectual 1810 points

Hi Bravos,

Output currents higher than 12mA are not guaranteed and the device maybe damaged. Moreover, the output voltage VOH decreases and VOL increases when the output current is increased. You may violate VIH(min) or VIL (max) values of receiving devices with higher output currents.

Best regards,
Hassan.

Interface

Interface forum

SN65LVDS386EVM: P1 and P3 Header pinouts