topic Re: ADC input resistance - LPC1114 in LPC Microcontrollers https://community.nxp.com/t5/LPC-Microcontrollers/ADC-input-resistance-LPC1114/m-p/539525#M11877 <HTML><HEAD></HEAD><BODY><STRONG>Content originally posted in LPCWare by sipel_tp on Fri Aug 03 04:17:55 MST 2012</STRONG><BR /><SPAN>Thank you very much</SPAN></BODY></HTML> Wed, 15 Jun 2016 19:41:18 GMT lpcware 2016-06-15T19:41:18Z ADC input resistance - LPC1114 https://community.nxp.com/t5/LPC-Microcontrollers/ADC-input-resistance-LPC1114/m-p/539523#M11875 <HTML><HEAD></HEAD><BODY><STRONG>Content originally posted in LPCWare by sipel_tp on Thu Aug 02 06:26:31 MST 2012</STRONG><BR /><SPAN>I have to measure a battery voltage using LPC1114 ADC. I would like to use a resistor divider to reduce the imput voltage to the ADC pin. The problem I have is I don't know the imput resistance of the pin so I can't design the resistor divider. Can somebody tell me the imput resistance of the LPC1114 ADC pin? Thank you very much. </SPAN><BR /></BODY></HTML> Wed, 15 Jun 2016 19:41:17 GMT https://community.nxp.com/t5/LPC-Microcontrollers/ADC-input-resistance-LPC1114/m-p/539523#M11875 lpcware 2016-06-15T19:41:17Z Re: ADC input resistance - LPC1114 https://community.nxp.com/t5/LPC-Microcontrollers/ADC-input-resistance-LPC1114/m-p/539524#M11876 <HTML><HEAD></HEAD><BODY><STRONG>Content originally posted in LPCWare by jdurand on Thu Aug 02 21:01:02 MST 2012</STRONG><BR /><SPAN>I don't have a data sheet handy but typically the input to a ADC isn't constant. For measuring things like batteries I usually just put a capacitor to ground on the signal so the ADC pulls current out of the capacitor without changing the voltage by enough to care.</SPAN><BR /><BR /><SPAN>On other processors 1M resistors and a 0.1uF capacitor have worked fine.</SPAN></BODY></HTML> Wed, 15 Jun 2016 19:41:18 GMT https://community.nxp.com/t5/LPC-Microcontrollers/ADC-input-resistance-LPC1114/m-p/539524#M11876 lpcware 2016-06-15T19:41:18Z Re: ADC input resistance - LPC1114 https://community.nxp.com/t5/LPC-Microcontrollers/ADC-input-resistance-LPC1114/m-p/539525#M11877 <HTML><HEAD></HEAD><BODY><STRONG>Content originally posted in LPCWare by sipel_tp on Fri Aug 03 04:17:55 MST 2012</STRONG><BR /><SPAN>Thank you very much</SPAN></BODY></HTML> Wed, 15 Jun 2016 19:41:18 GMT https://community.nxp.com/t5/LPC-Microcontrollers/ADC-input-resistance-LPC1114/m-p/539525#M11877 lpcware 2016-06-15T19:41:18Z