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TLV760: TLV760

Ernie Falcone
Prodigy 10 points
Part Number: TLV760
Other Parts Discussed in Thread: LM317

Can you stacking regulators to increase voltage (2 12V to create a 12V and 24V output for example) or can you raise the output level of the 12v using external resistors and which configuration is most stable. The current availability and lead times on parts if forcing me to consider solutions that I would not have done in the past. The 12 V SOT-23 TLV760 is available for now. Thanks Ernie

  • 0
    TI__Genius 12040 points

    Hello Ernie,

                      TLV760 is not an adjustable output LDO, so external resistors will not help increase the output voltage. There are a few points to consider if you wish to stack LDO's. If I understood your idea correctly, you have a primary LDO whose output you wish to connect to the ground of a secondary LDO whose output will then be 24V with respect to the ground of the primary LDO. Below are some issues to consider:

    (1) Please ensure that the input voltage to both LDO's is bought up at the same time (preferably connected together). If the primary LDO is powered on first, GND of the secondary LDO would already be high and there would be a VIN-GND Abs Max rating violation on the secondary LDO and this could damage it.

    (2) The secondary LDO will have some current flowing out of the GND pin (ground current). LDO's can only source current, they cannot sink current safely. Hence to ensure that the primary LDO does not sink the GND current of the secondary LDO, an external resistor will always have to be connected to the output of the primary LDO to provide a path for the GND current.

    (3) To ensure stability, the input and output caps of the secondary LDO will have to be connected to the GND of the secondary LDO.

    (4) Any line or load variation on the primary LDO will result in variation of GND voltage of the secondary LDO and degrade its performance. 

    Please verify if the setup meets your spec requirements before scaling. In my opinion, a simpler solution would be look for an LDO that can directly support 24V output. LM317 device, for example, is in stock and available for purchase in TI store. Thanks!

    Regards,

    Srikanth