Other Parts Discussed in Thread: LMR50410
Hi Team,
The Tj formula of LMR50410 is currently being calculated, at 85℃
1. Please help confirm the setting of the subscript red box!
2.Does Trise & Tfall refer to Table 7.6 of the datasheet? THX
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Hi Team,
The Tj formula of LMR50410 is currently being calculated, at 85℃
1. Please help confirm the setting of the subscript red box!
2.Does Trise & Tfall refer to Table 7.6 of the datasheet? THX
HI
below is the raising and falling time for your refer, tested at 600mA. The Theta JA at PCB board will be smaller than JEDEC value, it is around 80deg C/W . we don't know the Qg value, cause the fet is small, the drive loss will not dominated the power loss, so you value should be fine.
Thanks
Vin |
SW Raising time |
SW Falling time |
12 |
5ns |
2ns |
24 |
5ns |
2ns |
36 |
5ns |
3ns |
Hi Danel,
Thank you!
More question,
What is the Ton_min & Ton _max in the figure below refers to?
It seems to be switch on-time too,THX
Hi
LMR50410 have frequency folderback feature, which means when you have like 33V to 3.3V with 2.1Mhz, the on time based on 2.1Mhz will be less than 60ns, then the device will keep working at its min on time and adjust the frequency to make the duty cycle stable. same as min off time, when Vin and Vo is very close, the device will extend the on time and fixed the off time at 110ns(typical) until its ton reach 7.5us, so that the max duty can reach around 98%-99%, but at this time, the frequency will become around 133Khz.