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LP3878-ADJ: LP3878-ADJ Operating Mode - Do I really need Vin >= Vout + 2V?

Part Number: LP3878-ADJ

Regarding the LP3878-ADJ datasheet section 7.4.1. It states:

7.4.1 Operation With VOUT(TARGET) + 2 V ≤ VIN ≤ 16 V
The device operates if the input voltage is equal to, or exceeds VOUT(TARGET) + 2 V. At input voltages below the
minimum VIN requirement, the device does not operate correctly and output voltage may not reach target value.

So if I want the output Voltage to be +3.3V it sounds like I need an input Voltage of +5.3V or greater.

Is this correct?

  • Hi Tom,

    Yes in order to ensure the output regulation across the operating conditions, we recommend that Vin be 2 V or more above Vout.  The Electrical Characteristics table shows the tested minimum input voltage to maintain output regulation for a Vout of 1 V.  As you can see, depending on the application conditions, you may be able to reduce the headroom (Vin - Vout); however, we recommend a headroom of 2 V.

    Very Respectfully,

    Ryan