Hello, I need to bias an amplifier with 10V and 350mA.
I used opamp U4 in non inverting mode to take 5V and convert it into 10V .
I used the opamp to buffer this amplifier from other stages so the current will be purely for this device.
because I need 350mA and10V then the load is effectively its 28Ohm.
350mA*28Ohm=10V.
But when I connect the non inverting buffer(gain 2) to the load, I get far from the intended results.
Where did I go wrong implementing the biasing of this amplifier.
https://www.analog.com/media/en/technical-documentation/data-sheets/hmc907apm5e.pdf

 

You went wrong by trying to apply Ohm’s Law when it does not apply.

Ohm’s Law is
I = V / R

Two corollaries of Ohm’s Law are
V = I x R
R = V / I

The amplifier specs are 10 V @ 350 mA.
Ohm’s Law is not to be applied here.
The specs mean to say, with a power supply of 10 V, a typical current consumption is about 350 mA. Don’t take this too literally. It might take 100 mA.

It means that a 10 V supply capable of supplying 500 mA would be suitable.

 

Hello,I have 10V power supply and I need to supply 5V amplifiers and 10V amplifiers using it. I want to create an issolated current supply for my 10V amplifier in the photo. Its 10V and 350mA the load is 10/0.35=28 is there a "buffer regulator" component you could reccomend me to make this issolated current biasing supply?
Thanks.
https://www.analog.com/media/en/technical-documentation/data-sheets/hmc907apm5e.pdf

 

I already told you. You need a 10 V power supply that can provide at least 500 mA.

More importantly, note that the amplifier will have to dissipate 4 W.

 

Hello Mrchips,My solution is to use the same regulator with different resistor configuration.
I split the voltage drop between several regulators.
My biggest dillema is with the power issue
one regulator is 12V to 10V it supplies 350mA to an amplifier, so the regulator has 0.7W threw it.
Other regulator is (7.2-5V)*0.6A=1.2W

I am using DDPAK-5 package, given the photo from the data sheet , how can I know the proper conditions for this regulator not to burn?
Full Ltspice is attached.
Thanks.

 

For the third time I am telling you to ignore the 350 mA.
Just use a 1 A @ 10 V followed by 5 V linear regulators.

Use appropriately sized heat sinks.

 

hi yef,
Use the Power plot option in LTSpice.
E

 

hi yef,
This plot shows a1 second period for power.
E