LT3507 Input range

Thanks for application of LT3507. Is the simulation in LTspice ? Do you have more information of the application ? Who is the customer and the estimated annual unit of the part ? What is the vout and load current ? 

Thanks,

Andrew

I have simulated the file which is available in website LT3507 Demo Circuit - Triple Monolithic Step-down Regulator with LDO (12V to 1.8V @ 2.4A, 3.3V @ 1.5A, 5V @ 1.3A & 2.5V @ 0.2A)

Instead of 12v input, we have 5V and we need 1.2v, 2.5v @maximum 1A in our application and 3.3v @1.5A.But couldn't get proper output on 5v Input

Estimated annual usage 10-100

Hello please check page 15 in the datasheet and following diagrams:

Required minimum input voltage to generate 3,3V depends on load current.

Simulation from the mentioned example show clean Vouts (3,3V and other) if Vin>=5.3V. Out3 (desired 5V) will only reach 4.5V with 5.3V as input.

As Boost pins are supplied via OUT3 the other channels won't start with OUT3<2.5V:

If I have to generate 5V as one of the outputs, I need at least 5.3v input voltage. Understood.

But,

5V is not required in our board, Is it possible to terminate that port(OUT3) instead of using it?

And If I terminate it and changing boost pin voltage by providing 5V as input(VIN) , Will it be possible to get a proper output?

Or

What I have to do to get 3.3v from 5V input ?  

Hi   MarkusHP,

                     If it is not possible in LT3507 , will you please suggest any alternate for that?

It would be helpful

Hello,

even if LT3507 can do the job (which I have not evaluated completely) our newer parts are better in terms of  efficiency, solution size and Vin requirements:

LTC3644

LT8601

LT8602

ADP5014

What I cannot judge on right now is the current availability of one of these parts in the stressed market situation. But from technical point of view all these parts would perform much better.

Hello,

even if LT3507 can do the job (which I have not evaluated completely) our newer parts are better in terms of  efficiency, solution size and Vin requirements:

LTC3644

LT8601

LT8602

ADP5014

What I cannot judge on right now is the current availability of one of these parts in the stressed market situation. But from technical point of view all these parts would perform much better.

Hi markusHP, 

                    If the job can be done on LT3507 ,What I have to do to get 3.3v from 5V input ? 

I have changed Boost connections from OUT3 to VIN and tried to simulate, and terminated the 5V port

After that also couldn't get proper output.

LT3507 is our first priority.

Thanks in advance.

Hello,

my schematic works down to 4.8V as input voltage. I used the 'load' instance with appropriate current values as output load. Boost voltages might come from respective VoutX as well.