Hi guys,
I'd like to build an isolated power supply for a USB DAC (follow signature for more). After getting some hints from 1Audio and searching on line I've come up with a couple alternatives. Any experience out there in using these?
LT3439 needs a center-tapped primary. It uses bipolars with slew rate control. External clock input might be good to sync it with the sample rate of the DAC. However, it is quite expensive, and I plan to build more than one.
http://cds.linear.com/docs/en/datasheet/3439fs.pdf
MAX256 is an H-bridge controller with optional external clock. It does not need a center-tapped primary and costs at least 30 % less than the LT.
MAX256 3W Primary-Side Transformer H-Bridge Driver for Isolated Supplies - Overview
The datasheet refers to their MAX3535E for inductor selection, see page 21 of
http://datasheets.maximintegrated.com/en/ds/MAX3535E-MXL1535E.pdf
Magnetics from Coilcraft are easy to get our hands on in low quantities.
MAX13253 is spanking new and not yet priced. It uses a center-tapped primary like the LT and allows for internal spread-spectrum oscillator or external clock:
http://datasheets.maximintegrated.com/en/ds/MAX13253.pdf
MAX258 has internal clock and center-tapped primary at a much lower price:
MAX258 500mA Push-Pull Transformer Driver for Isolated Power Supplies - Overview
The general idea is to take 5V from VBUS and generate something like 10VDC from a rectified secondary. Or something similar which can power a nice shunt regulator for the DAC.
Cheers,
Børge
I'd like to build an isolated power supply for a USB DAC (follow signature for more). After getting some hints from 1Audio and searching on line I've come up with a couple alternatives. Any experience out there in using these?
LT3439 needs a center-tapped primary. It uses bipolars with slew rate control. External clock input might be good to sync it with the sample rate of the DAC. However, it is quite expensive, and I plan to build more than one.
http://cds.linear.com/docs/en/datasheet/3439fs.pdf
MAX256 is an H-bridge controller with optional external clock. It does not need a center-tapped primary and costs at least 30 % less than the LT.
MAX256 3W Primary-Side Transformer H-Bridge Driver for Isolated Supplies - Overview
The datasheet refers to their MAX3535E for inductor selection, see page 21 of
http://datasheets.maximintegrated.com/en/ds/MAX3535E-MXL1535E.pdf
Magnetics from Coilcraft are easy to get our hands on in low quantities.
MAX13253 is spanking new and not yet priced. It uses a center-tapped primary like the LT and allows for internal spread-spectrum oscillator or external clock:
http://datasheets.maximintegrated.com/en/ds/MAX13253.pdf
MAX258 has internal clock and center-tapped primary at a much lower price:
MAX258 500mA Push-Pull Transformer Driver for Isolated Power Supplies - Overview
The general idea is to take 5V from VBUS and generate something like 10VDC from a rectified secondary. Or something similar which can power a nice shunt regulator for the DAC.
Cheers,
Børge