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LM2665: Spice model

Aman Kamath
Intellectual 770 points

Part Number: LM2665
Other Parts Discussed in Thread: DRV8161

Hi Team,

Could you please provide a SPICE model for the Voltage double IC. 

Along with the SPICE model, could you please confirm by email whether the 66.1 µF output capacitor used at the LM2665 output is acceptable and whether there are any startup, inrush current concerns associated with it? 

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The customer is using the LM2665 to double the 5V LDO output to 10V to supply the DRV8161 GDU. Can the Voltage Doubler IC supply the inrush current associated with such a large capacitance value? 

Thanks,

Aman 

  • 0
    TI__Genius 17925 points

    Hi Aman,

    Actually the 66uF is quite large here. I see LM2665 is always enabled. During the start up, D8 is turning on before the LM2665 switching. When OUT pin is charged to 1.8V via the D8, the LM2665 starts switching. The inrush current not only depends on the C40, but also the input voltage ramp speed, i=cdu/dt. Firstly, you should verify if the diode D8 could sustain the current i=C*du/dt。 During start-up, D8 is used to charge up the voltage at the OUT pin to start the oscillator; also, it protects the device from turning-on its own parasitic diode and potentially latching-up. Therefore, the Schottky diode D8 must have enough current carrying capability to charge the output capacitor at start-up, as well as a low forward voltage to prevent the internal parasitic diode from turning-on.

  • 0 in reply to Nini Zhong
    TI__Genius 17925 points

    Hi Aman,

    for spice model, this is a quite old device RTM in 1999，it's a pity that there is no model built then due to the block is quite hard to duplicate. Could you apply EVM to test firstly?