TPS71710 over output

my design is

:input 3.3V,

:EN connect to VIN through 10kohm resistor,

:input and out capacitor is 1uF,NR capacitor is 10nF

with no load output is 2.2V

Has this been damaged? or other reasons?

Trevor：

Hi Jinying,

First, Please double check that the IC you used is TPS71710, NOT TPS71721;

Second, Please double check the input voltage is not exceed 7.0V. May be the IC was damaged by the too high input voltage.

Third, Please double check the Ground pad is grounding.

jin jinying：

回复 Trevor:

Thanks first!

I have checked the IC code is BMU, and it is TPS71710

and the input voltage is 3.3V, please show the power on waveform

the Ground is grounding

Johnsin Tao：

回复 jin jinying:

You  should  make sure the output current is less than 200mA(The best is 150mA) too any time , a big inrush(more the 200mA) may damage the chip.

Or else:

Please apple the free sample in the TI Website:

www.ti.com.cn/…/buy.tsp

The apply way:

www.ti.com.cn/…/gencontent.tsp

It is seen that the chip is tinpot.  

jin jinying：

回复 Johnsin Tao:

thanks!

Test is with no load

I have buy 2 groups of IC

the new case: when connected EN through 10kohm to Vin, it can't work, ann the Ven = 0.6V

then i connected EN directed to Vin, it can work,but Vout = 1.1V, Vin changes to 2.2V??

this IC is damaged when powerUP?

My input power is Angient DC analyzer

Johnsin Tao：

回复 jin jinying:

The chip is bad, The MAX  EN current is  1uA, So the MAX voltage drop in 10kohm is  10k* 1uA=10mV, not 3.3-0.3=2.7V,

It is obvious that the EN is abnormal.   the EN current  become to  (3.3-0.6)/10k=270uA.

The EN High level is 1.25 > 0.6V,  So disable the LDO.

When connec Vin to EN, the abnormal  EN  pull down the Vin.

The powering on will not damage the chip, because is only  3.3V,  You may check the ESD.

But  I  conviction  you  buy  some fakes ,Please apple the free sample in the TI Website.