RF430FRL152H: Access to 0,9V VREF to generate my bias voltage

Hello 

We are designing a low cost medical patch 

we are targeting to use the RF430FRL152, we need to have a 1/3 of ADC range voltage to bias our sensor

ca we have access to the 0,9V VREF voltage inorder to use it ?

we use the LPV542 and we still have a free chanel, in this case via a Mohms voltage divider buffered into the LPV we can have our external ref 

looking forward for your support 

best regards

Ziad