LM74610-Q1: LM74610 Minimum capacitor and minimum Body diode ON time.

Soichi Nishimura

Expert 4565 points

Part Number: LM74610-Q1

Hello team,

Our customer wants to confirm the minimum Body diode ON time of LM74610Q1.

The minimum recommend capacitance is 220nF that is described in page 14 of the datasheet.

So, the minimum body diode ON time is (220nFx1.15V)/46uA=5.5ms

Is this correct?

If the customer use the capacitance less than 220nF, What happen in this case?

For example, customer use 1nF capacitor, what issue do we think to happen?

Regards,

Nishimura

over 7 years ago

0 Brian Daugherty over 7 years ago

TI__Expert 5940 points

Hi Sochi,

I will dig into this early next week.

Brian

0 Soichi Nishimura over 7 years ago in reply to Brian Daugherty

TI__Expert 4565 points

Hello team,

I am waiting almost 1 month from your reply. Can you support this device?

Regards,

Nishimura

0 Brian Daugherty over 7 years ago in reply to Soichi Nishimura

TI__Expert 5940 points

Nishimura,

Yes, you have the correct equation (#4, pg 11). 1.15v comes from the typical values of Vcap upper and Vcap lower thresholds of 6.3v and 5.15v so there will be some tolernace around that (along with the 46uA tolernace). Recommendation is to stay withing the DS values for Vcap of 220nF to 4.7uF. Obviously, going lower than 220nF will reduce the on time and off time but I don't know where the duty cycle and perhaps on time limits will be adversely affected to cause bad behavior by the circuit.

Brian

Power management

Power management forum

LM74610-Q1: LM74610 Minimum capacitor and minimum Body diode ON time.