opa541s

[odysseybmx414]

does anybody know how to connect 8 opa541's wihtout any other ics or transistors? or maybe 4

[kafka]

????

[Alcaid]

Do you mean in a bridge-parallell setup?

[Evan Shultz]

You can parallel them by tying their corresponding pins together. This will allow you to run lower impedance loads. Make sure you add a small value, high watt resistor to each OP541 output when they're in parallel to force current sharing between devices.

To bridge them and get more voltage output [more power at fixed impedance] you will need an in-phase and an inverted input signal. This requires either an inverting op amp or a balanced driver such as the Burr Brown DRV134. Check the National Overture series IC datasheets for more detail on the differences between parallel and bridging.

[odysseybmx414]

thanx evan im going to check on texas instruments website for a part like that and i will hget a couple samples thank you for your help

[odysseybmx414]

would you mind posting a schematic of a paralleled amp wth the drv134?

[Alcaid]

Originally posted by odysseybmx414
would you mind posting a schematic of a paralleled amp wth the drv134?

If you parallell you don't need the drv134, it's only needed when bridging.

[odysseybmx414]

for a bridged-parallel setup, is the schematic the same as in national's app note for bridging and parallel? just u use for U5 the DRV134? and the rest opa541's? and this should give me somewhere around 400 watts into 8 ohms? i am planning on building a stereo amp with this setup for each channel (four opa's per channel)

[Evan Shultz]

Which National app note are you looking at? I can't tell what U5 is. The LM4780 is a good place to look because it has both parallel and bridge circuits on pages 5 and 6. If you copy the idea of those circuits you will have it.

Make sure you do not exceed the power output and rail voltages when operating into lower impedances. There should be a graph in the OPA541 datasheet which will allow you to find these parameters into various load impedances.

The DRV134 produces an in-phase and inverted version of the input signal. Those 2 DRV134 outputs are the inputs to 2 separate amplifiers for bridge operation. The in-phase and inverted signals can also be produced by a dual opamp with one op amp set as a buffer and the other as an inverter. The DRV134 simply has extremely precise gain and requires no external parts which is why it is likely a better and easier choice than the op amp scenario.

I think 400W into 8ohm is a little optimistic, but it might be possible. Good luck.

[odysseybmx414]

im talking about nationals app note #1192