I am looking for a step-up regulator design from +5V to approx. 42V with an Iout Max of 700mA - 1A. The most important additional factor is the approx. MAX size of the final design. I have a very limited amount of PCB real estate. I probably have no more than 20mm x 20mm but probably even less than this. If I can't find something within this area I might need to go to a lower output voltage (maybe even drop to half of the Voltage output !). What would be good also if this regulator had the option for a negative output as well. Can you help me with this ?
I would consider LT3757A:
The inductor would be on one side of the PCB and the controller, the MOSFET, and the sensing resistor would be on the other side.
Thank you for getting back to me.
The LT3757 appears to be way over kill !
I need 2 output supplies between 0.75A - 1A. I could be I could go a little lower than this but not much. I think I am going to have a total Max of 400 mm squared (when using both sides of the PCB). My Max input voltage is +5V. I am looking at +/-12V or if I can find something +/-24 V would be better. I doubt +42V & -24V outputs are not going to be even an option for the area I have (even though this would give me the most flexibility in my design !). I have been sorting through some options offered by Linear and the best thing I have found so far is the the LT8582 1.5MHz, 5V to ±12V Boost and Inverting Converter (found in the Typical Applications). I did a basic calculation of PCB area just used by the components and I think the area comes out to approx 240 mm squared.
Do you know of any better than this ?
The average input current can be calculated as, assuming 100% efficiency:
Output_Power / Input_voltage = 42V x 1A / 5V = 8.4A
The existing monolithic boost parts won't be able to handle such high current. It has to be a controller like the LT3757A.
Thank you for your quick reply !
How does what you answer address my notes about the LT8582 1.5MHz, 5V to ±12V (0.6A max for each output) Boost and Inverting Converter ?
The LT8582 may also work. The inverting output utilizes two-inductor topology so you need bigger space.
If current can be little lower, please consider ADP5071, LT3471.
This is an article about bipolar power solutions :https://www.analog.com/en/technical-articles/bipolar-power-Solutions-for-precision-test-and-measurement-systems.html