I've tried to figure out which exactly Parts i need, so i created a list: 1x Component: U1 , Type: DC-DC Step-up , Description: LTC3525ESC6-3.3#TRMPBF , Value: LTC3525-3.3 , Package: SC-70 , Manufacturer: LINEAR , Manufacturer part: LTC3525ESC6-3.3 (price: $4.16) 1x Component: L1 , Type: Inductor , Description: I DC = 400mA min , Value: 10uH , Package: 1210 , Manufacturer: Murata , Manufacturer part: LQH32CN100K33L (price: $0,25) 1x Component: C1 , Type: Capacitor , Description: X7R 10V 10% , Value: 1uF , Package: 0603 , Manufacturer: TDK , Manufacturer part: C1608X7R1A105K080AC (price: $0,088) or: 1x Component: C1 , Type: Capacitor , Description: X7R 16V 10% , Value: 1uF , Package: 0603 , Manufacturer: TAIYO YUDEN , Manufacturer part: EMK107B7105KA-T (price: $0,16) or: 1x Component: C1 , Type: Capacitor , Description: X5R 16V 10% , Value: 1uF , Package: 0603 , Manufacturer: TDK , Manufacturer part: C1608X5R1C105K080AA (price: $0,012) or: 1x Component: C1 , Type: Capacitor , Description: X5R 6.3V 10% , Value: 1uF , Package: 0603 , Manufacturer: KEMET , Manufacturer part: C0603C105K9PACTU (price: $0,01) 1x Component: C2 , Type: Capacitor , Description: X5R 10V 20% , Value: 10uF , Package: 0603 , Manufacturer: TAIYO YUDEN , Manufacturer part: LMK107BJ106MALTD (price: $0,504) or: 1x Component: C2 , Type: Capacitor , Description: X5R 6.3V 10% , Value: 10uF , Package: 0603 , Manufacturer: TDK , Manufacturer part: C1608X5R0J106K080AB (price: $0,088) I would prefere for both Capacitor's á the last ones: 1x Component: C1 , Type: Capacitor , Description: X5R 6.3V 10% , Value: 1uF , Package: 0603 , Manufacturer: KEMET , Manufacturer part: C0603C105K9PACTU (price: $0,01) 1x Component: C2 , Type: Capacitor , Description: X5R 6.3V 10% , Value: 10uF , Package: 0603 , Manufacturer: TDK , Manufacturer part: C1608X5R0J106K080AB (price: $0,088) The Reason is: the max voltage of the LTC3525 is 6V and thermal running temperature is min: -40°C and max: +85°C Capacitor -> X5R or X7R types, not Y5V. E.g.: C1: http://de.mouser.com/ProductDetail/TDK/C1608X7R1A105K080AC/?qs=sGAEpiMZZMs0AnBnWHyRQEWjzA2rN6H9FHl8tRG0a%252bQ%3d C2: http://de.mouser.com/Search/ProductDetail.aspx?qs=PzICbMaShUde1djJr8Be9g== Alternative C2 Package: 0805 Package 0603 is in inch.. Metrisch would be: 1608 X5R = -55°C , +85°C , +/- 15% X7R = -55°C , +125°C , +/- 15% http://de.wikipedia.org/wiki/Kerko#Klasse-2-Keramikkondensatoren Part search pages: http://de.mouser.com/Passive-Components/Capacitors/Ceramic-Capacitors/MLCCs-Multilayer-Ceramic-Capacitors/Multilayer-Ceramic-Capacitors-MLCC-SMD-SMT/_/N-bkrdv/ http://www.newark.com/ceramic-multilayer-mlcc-capacitors-smd http://www.jameco.com/1/3/10uf-smd-capacitor http://at.farnell.com/jsp/search/browse.jsp?N=2001+215745&Ntk=gensearch&Ntt=CAPACITOR+CERAMIC+10uF+0603&Ntx=mode+matchallpartial http://octopart.com LTC3525ESC6-3.3: Betriebstemperatur, min.: -40°C max.: +85°C Versorgungsspannung, max.: 6V Versorgungsspannung, min.: 1V BAT state: http://jeelabs.org/2013/05/15/what-if-we-want-to-know-the-battery-state/