TPS65381-Q1: Please help recommend a suitable LDO to replace TPS65381

user5707026 said:

1.  The actual measurement of this power supply. High current will cause TPS65381 breakdown of TPS65381 and damage the chip.
Second, we want to reduce costs;

• Can you go into more detail about the test your performed that damaged the TPS65381-Q1 PMIC?
• How much current was being delivered out of the PMIC?
• What type of damage occurred and how did you identify the device is damaged?
• Can you provide oscilloscope captures of the tests you performed?

The experts on this device will reply to your question and propose some solutions, but I expect they will ask similar questions before they can propose a solution to your problem.

Hello,

I want to make sure I understood your request. You want to replace the PMIC TPS65381 by simple LDOs and you need 2 rails 5V or 3.3V and 1.2V. What is the current consumption on each rail?

There is an option single device (TPS65320-Q1 or TPS65321-Q1) with 2 rails configurable BUCK + LDO. The quiescent current is very low i.e 100uA. Please check the specification and let me know if it fits your solution.

Regards

Dears

Yes, you want to replace the PMIC TPS65381 by simple LDOs and you need 2 rails 5V or 3.3V and 1.2V. Three-output LDOs with car-grade requirements are required. The maximum input is 13V, and the output requires 5V / 1A, 3.3V / 500ma, 1.2V / 500ma, of which 1.2 and 3.3V are given to the periphery of the microcontroller and the core, to ensure that the core current is not less than 500ma.

Thanks a lot.

Elsa Duan

Hello Elsa,

LDO directly supplied from battery and 500mA, will cause huge power losses. The 3.3V LDO power losses is (13V - 3.3V)x0.5A = 4.85W. For this power you need a 5V step down BUCK and 2 LDOs supplied from the 5V. TPS65320 integrated LDO is only 280mA.

Replacing the PMIC TPS65381 by discrete solution may become more expensive and larger board space. The minimum discrete solution is:

- BUCK with input voltage Vbat = 13V and output voltage 5V. Should support at least 1.5A load

- LDO with input voltage 5V (BUCK output) and output voltage 3.3V. Power losses 0.85W

- LDO with input voltage 5V (BUCK output) and output voltage 1.2V. Power losses 1.9W

Regards, Mahmoud