Other Parts Discussed in Thread: TPS7A49, , TPS7A39
I am using the TPS7A49 and TPS7A30. Input voltages are +/- 15 VDC respectively, and output voltages are +/- 10 VDC respectively. Output current draw is very low-- about 12 mA. Here is a snippet from my schematic showing their connections. As far as I can tell, they are connected by the book. The pins labeled as pins 9 refer to the power pad. Input and output filter capacitors are X7R and are placed close to the parts. These parts are hand soldered to several first-article PCBs for testing. As such the power pad is not soldered. However, power dissipation is so low that the ICs don't get even the slightest bit warm. My problem is that both ICs will sometimes, but not always, show some wandering in their output voltages. Specifically the output voltages will drift around by 1 to 3 mV in a frequency band of about 0.1 Hz to a bit below 1 Hz. This wandering can easily be seen on a scope. Other than that, the outputs look quiet with no visible oscillation. This wandering is a critical fault in my application and we are desperate for a fix. I have noticed that these parts are hard to get. Do you think it's possible we have received bootleg parts? Has TI seen that problem with these ICs? Your earliest response would be hugely appreciated. Thanks in advance for any light you can shed on this situation.