Dear All,
On our board we are using TPS40304 device to generate 0.8V output supply. The input supply is 5V to the device and when the device is powered ON, the device is failing and following are our observations:
1. The device is moving to its minimum duty cycle operation mode. The PWM Output at the Gate drive is 100ns. Instead it should have been 256ns. (0.8V/5V * 1.66us)
2. Second observation is that the Output generated is 0.006V instead of 0.8V, but at the FB (Feedback) pin we can measure constant of 0.6V supply. This is simply confusing since the output is 0V, we are suspecting that there could be a short internal to the IC....
3. The impedance between the FB and COMP pin is found to be around 411 Ohms. But for other TPS40304 device present on board it is in the order of MOhms.
4. This case has been observed in two out of two boards as soon as the power supply is turned ON.
5. Other supply generated from TPS40304 is 1.5V constant output from 12V input supply is being generated properly.
Could you please help us in this regard. Kindly consider this request as urgent and please provide your valuable inputs.
Regards,
Khader Shareef
