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LM63460-Q1: LM63460AASQRYFRQ1

Roy Chan
Expert 4020 points
Part Number: LM63460-Q1

Hi Application team:

   My customer has design in LM63460AASQRYFRQ1 from 24V to 12V . 

but customer is tested Input current consumption is around 2mA(Vin=12.3V) to 6mA(Vin=24V) without load current (Iout=0A) in PFM mode cannot meet the design spec . I have two questions , could you please help give comments?

(1) Base on the spec Quiescent current (7uA / 10ruA typ with Vout=3.3V/5V)   , if we need meet ~uA spec , May I know the only way is need change FB pull high resistor RFBT to 1Mohm and fine tune the FB pull down resistor to reduce input current consumption?  

(2)  If design spec Vout=12V from Vin=16V to 36V with no load (Iout=0A). Will the input quiescent current same as the spec definition as above question 1 ?   

Schematic as below attachment 

(1) Vin min =  16V

 (2) Vin typ = 24V 

 (3) Vin max= 36V.

 (4) Vout =12V with +/-5% tolerance.

 (5) Iout= 0A test input quiescent current 

 (6) SW freq ~ 2.07MHz  (Auto mode)

  • 0
    TI__Mastermind 35210 points

    Hello Roy,

    A current in the mA does not seem reasonable for an auto mode device. I expect it to be << 50uA.

    Having a larger FB resistance will improve iQ, but, there is something else going on here.

    Can they confirm that they are measuring current only into our device and that the load is disconnected?

    Also, can they provide the SW waveform in sleep state to confirm the device has reduced its frequency in PFM?

    For the Vin range specified, the device should be operating in PFM, so, the quiescent current should be about the same across it.