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TPS7A39: 21.7~22.3V to 14.5~15.5V, -7.3~-6.7V to -13.5~-12.5V

Jeff YANG
Genius 5435 points
Part Number: TPS7A39

Hi,

As title, I would like to know TPS7A39 suitable for this application?

1. Vin 21.7~22.3V to Vout 14.5~15.5V

2. Vin -7.3~-6.7V to Vout  -13.5~-12.5V

Thanks!

Jeff

  • 0
    TI__Expert 6570 points

    edit to clarify thermal values & negative LDO capability

    Hi Jeff,

    TPS7A39 is suitable for this application. Voltages are within range and device thermals can support this.

    Power Dissipation: 

    Junction Temperature:

    1. PD = (21.7 - 14.5) * 0.15 = 1.08W or PD = (22.3 - 15.5) * 0.15 = 1.02W

    125°C = TA + 44.4 * 1.08 or 125°C = TA + 44.4 * 1.02

    This is not possible unless the voltage drop is decreased so that the device temperature is within operating range. 

    2. A negative LDO cannot regulate from a greater negative value to a lesser negative value, ie -7.3 to -13.5. The inverse, however is possible and the LDO could regulate from -13.5 to -7.3.

    I hope this is helpful,

    Erin