.:madworm:.'s photos with the keyword: step-down

KIS-3R33S

KIS-3R33S

.:madworm:.
31 May 2012 116
Testing...
Higher output voltage mod #2

Higher output voltage mod #2

.:madworm:.
31 May 2012 124
Removed the two 51k upper resistors of the feedback voltage divider. Now it can be tuned with an external 200k trimmer pot wired as a simple voltage divider between the output and GND. The wiper goes to the adjust pin (blue).
KIS-3R33S

KIS-3R33S

.:madworm:.
31 May 2012 123
Be careful when removing the legs.
KIS-3R33S output ripple voltage

KIS-3R33S output ripple voltage

.:madworm:.
01 Jun 2012 193
230mA output current Once I have a working dummy load, I can test if these modules really withstand the advertised 3A continuous and 4A peak current.
KIS-3R33S

KIS-3R33S

.:madworm:.
31 May 2012 123
Got rid of most of the silicone rubber.
KIS-3R33S

KIS-3R33S

.:madworm:.
31 May 2012 143
Popped the cap
Finished KIS-3R33S board

Finished KIS-3R33S board

.:madworm:.
31 May 2012 139
Current consumption in power-down mode is about 60µA.
Higher output voltage mod #1

Higher output voltage mod #1

.:madworm:.
31 May 2012 141
I removed an optional Zener diode on the output side and replaced it with a 10µF ceramic capacitor. This seems to be enough to get it stable, at least at light loads. If this is still the case at 3A is a different matter.
KIS-3R33S

KIS-3R33S

.:madworm:.
31 May 2012 152
Modified to output 4.5V instead of the standard 3.3V. The most useful "manual" for this device is currently this one. Maybe I will add a blog post about it, which may be around for longer.
KIS-3R33S inductor voltage drop

KIS-3R33S inductor voltage drop

.:madworm:.
01 Jun 2012 205
CH1: inductor input, CH2: inductor output, MATH: CH1-CH2 Note that the "math scale" does NOT compensate for probe attenuation.
KIS-3R33S

KIS-3R33S

.:madworm:.
31 May 2012 106
Silly-cone thermal compound. Not terribly hard to remove, but it is annoying.
KIS-3R33S

KIS-3R33S

.:madworm:.
31 May 2012 118
All legs gone
KIS-3R33S output ripple voltage

KIS-3R33S output ripple voltage

.:madworm:.
01 Jun 2012 202
230mA output current. Very far from the rated 3A. I think I need to get or build some sort of dummy load to test this thing further. Big fat transistor, big fat heatsink, current sense resistor + opamp as constant current source. Mabe some 4mm banana binding posts to use my DMM as current meter.
KIS-3R33S

KIS-3R33S

.:madworm:.
31 May 2012 130
Missing legs
KIS-3R33S

KIS-3R33S

.:madworm:.
31 May 2012 100
These step-down modules are currently available on ebay for about 40¢ per piece (pack of 20). Input voltage 5V-23V output a bit lower. 3A continuous current, 4A peak. They DO require an additional output capacitor to run stably.
22 items in total