TPS737-Q1: When can tps737-q1 output 1A?

Elec Cheng

Part Number: TPS737-Q1

Hi Expert,

As you know, TPS737-q1 can output 1A. But the use case could be very limited. As an example, I want 5Vto3.3V @1A. The power dissipated on TPS737-q1 is about 1.7W. The junction temp could be 88℃. If we think ambient temp is 85℃, it exceeds the range. I just don't know exactly under what situation it can be used since I think 1.7V voltage drop is small enough. Thanks!

BR,

Elec Cheng

over 2 years ago

0 Srikanth Lolla Venkata over 2 years ago

TI__Genius 12040 points

Hello Elec,

The minimum dropout required for 1A load current is 500mV. If using Vout = 3.3V, then VIN can be as low as 3.8V (and upto 4V) to support 1A of load current. In such a case the power dissipation would be small enough to ensure that the junction temperature does not exceed 125ºC. Thanks!

Regards,

Srikanth

0 Elec Cheng over 2 years ago in reply to Srikanth Lolla Venkata

TI__Expert 7055 points

Hi Srikanth,

Thanks for your answer. According to your answer, it seems that 1A LDO is naturally so limited for many occasions because the allowed voltage drop is too small. I even doubt whether it really has the chance to use in real circuit for full 1A output. If you have seen this kind of case, please share with me. I'm really curious. Thanks a lot!

BR,

Elec Cheng

0 Srikanth Lolla Venkata over 2 years ago in reply to Elec Cheng

TI__Genius 12040 points

Hi Elec,

Please note that the θ_JA provided in the datasheet is under the assumption that the part is housed on a JEDEC standard High-K board. Significant improvements can be made to lower the θ_JA by following some good layout practices listed in the following app note: https://www.ti.com/lit/an/slvae85/slvae85.pdf. The θ_JA can be reduced by as much as 50%, which would increase the allowable input voltage to as high as 4.8V while supporting 1A of load current and 3.3V of Vout.

Regards,

Srikanth

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TPS737-Q1: When can tps737-q1 output 1A?