Dear Sir,
Please suggest me a LDO with active low enable pin.
Vout=1.2
Iout=3A
Regards
Amit
The power supply selection tools will provide you with a list of LDOs that meet your power requirements. You can then review the ICs in more detail to find one with an active low enable. I don't think one exists. One option is to invert your enable signal with a simple inverter IC, or by using a MOSFET.
This is also a good question that you can work with your local distributor to answer.
The closest part that meets your needs would be the TPS75701/TPS75801. However, the lowest output voltage these can provide is 1.22V not 1.20V. So if you used our selection tool and entered 1.20V as the your desired output votlage, these IC's would not show up. Also, their minimum input voltage is 2.8V so at full output current, this regulator would need an external heat sink and/or additional airflow to dissipate (2.8V-1.22V)*3A = 4.7W.
If you have a 3.3V or 5V rail available to provide VBIAS, then I recommend either the TPS74401 or TPS74901. You can provide the VIN power rail for either of these with a 1.5V or 1.8V rail and reduce the required power dissipation. Both of these parts can be configured to provide 1.20V using external feedback resistors however, you will need an external, low-cost FET to invert your enable signal.