Part Number:LM2700MT-ADJEV
I attempted to modify this Eval board for a 12V input and 17V output based on the Webbench Design Report. I did the following:
Added Cc2, 220pF Cap, using PN GRM31A5C2J221JW01D
Replaced Cc with 2.2nF Cap, using PN GRM3195C1H222JA01D
Replace Rc with 162K Res, using PN CRCW1206162KFKEA
Replace R1 with 1.05K Res, using CRCW12061K05FKEA
Replace R2 with 13K Res, using CRCW120613K0FKEA
When I connected to a power supply, set to 12VDC, 1A limit, the supply output dropped to ~1.6VDC.
I'm running at 600Khz. Its not clear, absent actually in the users manual, but I've had the SD jumpers in both On and Off, although I assume from the schematic that floating is fine?
Why would my input be practically shorted when I apply power? I can't see why there would be a problem w/ changing the above values on the eval board based on the Webbench report. I didn't change was Cout, I left it as 22uF, and Cin as a single 4.7uF, but this shouldn't cause what I'm seeing should it?
Please point me at what I may be doing wrong here.