I am powering a TPS40400 unit with a test circuit and not getting any pulses out. I have ADDR0 and ADDR1 pins terminated with resistors to ground. I have the CTRL pin pulled high (3.3V), and the other circuits connected. I get the BP6 and BP3 voltages (6.5V, 3.3V approx), and I tried connecting a buck stage to it, as well as driving the COMP pin externally with a voltage. There are no pulses produced. The High side drive output is at 0.5V or so. The Low side drive is 0V. The track pin is tied to 3.3V so from the block diagram I should have only the SS and REF internally enabling the amplifiers. I cannot figure out why there is no output.
I also have an EVM for the 40400 with me and that clearly works fine. Is there any thing I am doing wrong here? As long as the above conditions are satisfied, the pulses should come out at least when I drive the COMP pin.
How do I know if something in the chip is damaged?
Ram
