My radio device requires the following Vin Specifications
Vin range 3v2 to 4v5 nominal 3v6 Current 2amps peak Ripple less than 250mV up to 10KHz, Ripple less than 40mV from 10kHz to 100kHz and Ripple less than 5mW greater than 100KHz
From the outside world I would like to supply my radio devices with a voltage range 9 - 36V
What can you suggest for regulator options?
Should a use a two step approach.... a pre-regulator to drop the voltage down to 9-12V then a very low ripple DC-D regulator.
Should I add DC capacitive filtering to achieve the ver low ripple requirements
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You need to bring the ground end of C2 and D1 together directly Move the parts around until they almost touch
The next priority is to get C3 to ground near the same point.
If this is a multilayer PCB, a GND1 can be an internal layer that on other parts of the PCB is a trace layer. The whole idea here is to keep the ripple currents local to the circuit.
If this is a stand alone item, the GND2, input and output should all be in one small area. Don't put them on opposite ends of the PCB as would seem intuitive.
The connection between C1 and C4 should be also as short as you can make it.
L1 and L3 are basically large RF beads. They need to be lossy.
All the capacitors are actually collections of capacitors as needed to get the ESR and ESL numbers low enough.
So, use a prebuilt DC/DC converter with regulation. For 24V input and 3.3V output, these are easily available prebuilt and off-the- shelf. (input "24V" can mean a range of 9V to 36V...).
It's not usually worthwhile designing your own power converters; the Murata/Power-One/Vicor/Ericsson... designs pretty much cover this territory.
You need to bring the ground end of C2 and D1 together directly Move the parts around until they almost touch
The next priority is to get C3 to ground near the same point.
If this is a multilayer PCB, a GND1 can be an internal layer that on other parts of the PCB is a trace layer. The whole idea here is to keep the ripple currents local to the circuit.
If this is a stand alone item, the GND2, input and output should all be in one small area. Don't put them on opposite ends of the PCB as would seem intuitive.
The connection between C1 and C4 should be also as short as you can make it.
L1 and L3 are basically large RF beads. They need to be lossy.
All the capacitors are actually collections of capacitors as needed to get the ESR and ESL numbers low enough.
Many of the other makers provide the information you need to work out the ripple. You need to do some looking at those data sheets and math on what you find.
If you do a design, you will likely find that the ripple is determined by the capacitors.
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I have also consulted from time to time on the side. On some of those I have been asked not to talk about the where.
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