Thanks Dan. This serious EE stuff is, shall we say, challenging to me. The only components I have that I think might have noise sensitivity are an Atmel ATmega 328P and an XBee radio. The ATmega has its AREF tied to ground via 0.01 uF cap. I don't use the ADC, so its pins are tied to Vcc...
Thanks so much for the explanations. The message I take from this is that I can tie PS, GND, and PGND together near the chip and connect all other components to this single ground bus. Please correct me if I'm wrong or oversimplifying.
-Russ
Hi all,
I'm designing V2 of a PCB that uses a TI TPS6102x boost converter (http://www.ti.com/lit/ds/symlink/tps61020.pdf). I don't understand the schematic concerning the logic ground and power ground. All the caps and R2 are tied to PGND while PS and GND are tied to power ground. What's the...
Bingo! The backwards cap was the problem! Only two components to position correctly and I screwed up one of them. What a n00b! :-} Thanks so much for all the help and great advice.
LightYear, thanks especially for the advice on the tantalum cap. 70 mOhm ESR caps are 1/3 the price!
-Russ
According to Wikipedia, "Most tantalum capacitors are polarized devices. When subjected to the wrong polarity, the capacitor depolarizes and the dielectric oxide layer breaks down, causing it to fail." So it seems that I should assume my capacitor is toast. Now this particular one costs $3.50...
IRstuff, what aspect of the ground traces are you concerned about? As soon as I get this power supply working correctly, I'll be designing V2 of this board, so any suggestions are greatly appreciated.
Dan, what would you tighten for production layout? Would you move the capacitors even...
LiteYear, thanks for your response. I'm using an external variable power supply that I've ranged between 2 and 5V; I get the same result across the range. I have not applied any load other than the Extech voltmeter. Might that be a problem?
I can certainly post my schematic if my previous...
Comcokid, thanks so much for your response. This component is on a PCB I designed based on TI's requirements as I understood them, keeping everything as close as I could. I've attached a photo. C1 (C2 on my PCB) is a 10 uF ceramic. C2 (C4 on my PCB) is a 2.2 uF ceramic. C3 is a Kemet 100 uF...
I measure less than 10 mA, but I don't have the feedback pin wired at all. I got the impression from TI's doc that that was only used with the adjustable voltage components (61020, 61028, and 61029). Figures 28 and 29 show FB unwired. Did I misunderstand?
-Russ
Hi all,
I'm an experienced software engineer designing my first commercial hardware device (we're a startup with no money to hire a real EE). It's a battery-powered sensor using the TI TPS61025 synchronous boost converter to provide a fixed 3.3V output. I designed and built it according to...
