give external supply to nrf51

RE: give external supply to nrf51

Sigurd — Tue, 07 Feb 2017 13:29:01 GMT

Hi,

According to the datasheet(page 6) the adjustable version of the LM1117 needs a minimum load current of 1.7mA to maintain regulation. The nRF51 will typically not use this much current, and the adjustable version of LM1117 is therefore not suited for low-power applications.

RE: give external supply to nrf51

nordicbeginner — Mon, 06 Feb 2017 07:20:10 GMT

i am getting 3.3 v. but i am using variable resistor to voltage

RE: give external supply to nrf51

Roger Clark — Fri, 03 Feb 2017 19:46:02 GMT

LM117T is a 3.3V regulator.

If you are getting 3.0v offload, you already have a problem before you attach the nRF51.

RE: give external supply to nrf51

Sigurd — Fri, 03 Feb 2017 15:21:48 GMT

Are you using the same schematics as shown in the datasheet here (page 1)?

RE: give external supply to nrf51

nordicbeginner — Fri, 03 Feb 2017 15:16:52 GMT

supply voltage of LM1117 is 5 v. output is 3 v

RE: give external supply to nrf51

Sigurd — Fri, 03 Feb 2017 15:03:18 GMT

What is the supply voltage to the LM1117? 3.3 V ? or 5 V?

RE: give external supply to nrf51

nordicbeginner — Fri, 03 Feb 2017 13:01:48 GMT

i am getting 3 v when it is not connected to nordic. but when i connect it to nordic it shows me 2.12 v

RE: give external supply to nrf51

Sigurd — Fri, 03 Feb 2017 12:58:03 GMT

You have to use resistors to set the output voltage to the desired value. So you have to use different values on the resistors to get the desired 3.3 V. Please read the datasheet for the regulator.

RE: give external supply to nrf51

nordicbeginner — Fri, 03 Feb 2017 10:41:54 GMT

i am using LM1117 for regulating supply

RE: give external supply to nrf51

Roger Clark — Fri, 03 Feb 2017 10:31:53 GMT

What are you using to supply the power ?

USB is 5V not 3.3V so whatever you are using must be regulating 5V down to 3.3V, or perhaps when you say its a USB supply, you mean something akin to a phone charger ?? but 3.3V ???