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TPS563208: Enable threshold

Martin Vit
Prodigy 95 points
Part Number: TPS563208

Hello TI,

 Voltage_Regulators_TI.pdf

 

We are using voltage regulators TPS563208, which should have enable threshold above 1,6 V according to datasheet.

But in reality voltage regulators are switched on above 4,9V at enable input. That is complication for us, because we designed schematic for 3,3V enable signal. See attached schematic.

Could You please explain me what is wrong?

 

Many thanks

Martin Vit 

 

Martin Vít

HW Development Engineer

Legal Entity Pilsen

Kontron

Teslova 1 | 301 00 Plzeň | Czech Republic

P: +420 378775459

martin.vit@kontron.com

 

Best Regards

  • 0
    TI__Genius 10070 points
    Hi,

    From the schematic, R26=100Kohm, R17=38.3Kohm, when Vin reaches to 5.7V, Vout starts to increase.
    If you use external signal to enable the device, the Ven should be higher than 1.6V. And as you know, 1.6V is the min value, so the Ven may be a little higher than 1.6V.

    Shawn
  • 0 in reply to Shawn Nie
    Prodigy 95 points
    No, the behaviour is diferent. I connected to the circuit 2 power supplies. One 12V and second directly to enable pin (pin 2 of J5). (grounds are connected together) And regulators are starting, when at enable pin is 4,9V. Resistor divider R26 / R17 should have at R17 3,3V when Vin is 12V. In this case regulators doesn't work.
  • 0
    Prodigy 95 points
    Hi all, I found the issue. I found a bug in PCB which leads to additional impedance on PCB via from 4-10KOhm which is the cause of lower voltage on EN pin -> not an IC issue.