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TPS82150: Leakage Current int the EN pin

Eli az
Intellectual 730 points
Part Number: TPS82150

Hello,

We are using a buck converter part number TPS82150SILT.

the nominal voltage input of the converter in the design is 16V, output voltage is 4V and the nominal current drawn from the converter is about 20mA. During testing, he input current of the converter rose to about 16mA. After further  investigating the failure, it looks like there is an impedance of about 1.3KOhm instead of the nominal high impedance into that pin during normal operation.

We should note that in our design, the buck is powered by soft starting switch of about 0.73v/mSec, however in our design the VIN and EN pins are connected by a 1KOhm  resistor and there is an additional 100nF capacitor between EN and GND. The SS capacitor in our design is 22nF. 

we`d like t knw the following:

1. Is that a known failure f the part? If so, can you please elaborate on the use?

2. Is using an C filter in EN pin a design mistake?

3. s there any impact on the further operation of the device? Is there any data regarding life span of devices with this kind of leakage issue?

  • 0
    TI__Mastermind 47580 points

    Hi Eli,

    1. No, there is no any known failure for this part.

    2. No, that is incorrect. You should remove that 100nF cap from EN pin. Because that 1k+100nF cap may cause the EN voltage higher than VIN+0.3V during power off. EN pin absolute max voltage rating is Vin+0.3V as below. The device may damage if this spec was violated.

    3.  Please double check the soldering to see if any cold solder, solder bridge or flux contamination. Deep clean clean the TPS82150 area before power up the device. If still not working after cleaning, please replace a good device to see if that leakage is gone.

    Hope this helps,

    Thanks,

    Nancy