OPA551: Do we have example circuit for two OPA551 Parallel design

Hey Yuxi, 

We have this great article here which talks more about parallel design for power amplifiers: Paralleling the OPA593 High-Voltage, High-Current Op Amp for 2 × Output Current 

Let me first start by saying parallel is not immensely challenging, but it does require more care to get working effectively. The linked article can cover in more detail than this E2E response, but one of the most important traits is the balance between amp1 and amp2. We use what is often called a ballast resistor between the amp outputs, and this helps normalize the output referred error to make the separate amplifiers look like one more powerful amp. Note this resistor and internal difference between the separate amplifiers will always have some additional power loss associated with the design. In other words, 2x the power amp does not necessarily mean 2x the output load drive capacity. 

What are the requirements here? 

The OPA55x datasheet also has a small section on parallel design:

I would look to design the circuit like this for the parallel implementation. 

Thanks,

Jacob

Hi Yuxi, 

Both are suitable designs. For more than two amplifiers, I recommend leader follower. For just two parallel amps, either option is fine. 

I personally prefer leader follower as it tends to be more simple to implement.  

Thanks,

Jacob