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LM27342MYEVAL: About supporting to adjustable output

Part Number: LM27342MYEVAL
Other Parts Discussed in Thread: LM27342

Hello,


Regarding to LM27342MY(LM27342 EVM), my customer is asking some question.

Due to adjustable output, they replaced to variable resistor at FB resistor(R1,R2).

But when the setting(sweep) range of variable resistor is wide, the device is broken (burned).

(Maybe over current or over voltage.)

(Question)

(1) Can this device support to adjustable output?

If so, how solution is possible? Replacing to variable resistor, is there any problem or concern?

(2) Could you please give us comment or opinion about cause of broken (burned) device at this time?

(I think that it might cause by overshoot (1or2-order delay)of feedback control.)

 

Regards,

Tao2199


  • Hello ,

    Here are answers to your questions :
    1 ) Can this device support to adjustable output?
    If so, how solution is possible? Replacing to variable resistor, is there any problem or concern?
    Ambreesh: You should be able to change output given the customer has verified the loop comp over Input and output voltage range .

    (2) Could you please give us comment or opinion about cause of broken (burned) device at this time?
    (I think that it might cause by overshoot (1or2-order delay)of feedback control.)
    Ambreesh : Is the switching stable over different output voltage options ? How is the switch node looks like ? Please use small GND loop probes and inspect input voltage , switch node and inductor current waveform .


    ---Ambreesh