I'm designing a power supply for data acquisition device which needs clean 5V. I decided to use ADP1613 and ADM7150 ICs to get 6.2V from SEPIC DC/DC converter and 5V from LDO. Power requirement is 5V@200mA and less then 1mV ripple. I want to ask if it is possible to review my design? I've attached layout screenshot. It is a 4 layer PCB where:
top - signal layer inner1 - PGND isolated from rest of the PCB (green lines) inner2 - signal and GND bottom - GND and signal - feedback DC/DC signals
Is it possible to verify grounding for this design ? Any suggestion is welcomed?
So what is your input voltage range?
It is a 5V (4.8-5.2V).
So why not use a boost?
So to answer your first post. It appears you have L5 connected incorrectly. Did you use the ADP161x- SEPIC design tool?
you can do the design, it will give you a BOM. see the schematic in the tool.
SEPIC seems to generate less noise this is the main reason why it was selected. Schematics is based on PRD1146 reference design. I will check inductor. Acctualy I use ADP161x Coupled SEPIC-Ćuk which supports output filter calculation for positive rail. Main components like inductor and output filter is taken from BOM generated with ADP161x Coupled SEPIC-Ćuk tool, the negative power supply is ignored. Can I use results from this tool this way ?
Regarding L5 inductor there is a difference in PRD1146 reference design connection and schematics generated by ADP161x- SEPIC design tool - this is due to different part part used or there is a other reason for different inductor connection ?