a first resistor string comprising a first plurality of resistors coupled in series, wherein the first plurality of resistors comprise first resistors and second resistors connected at a first node;

a first transistor and a second transistor coupled in parallel between a first end of the first resistor string and a reference voltage node, wherein a second end of the first resistor string is coupled to a supply voltage node;

a second resistor string comprising a second plurality of resistors coupled in series, wherein the second plurality of resistors comprise third resistors and fourth resistors connected at a second node;

a third transistor coupled between a first end of the second resistor string and the reference voltage node, wherein a second end of the second resistor string is coupled to the supply voltage node;

a plurality of switches coupled in parallel, wherein each switch of the plurality of switches is coupled between a third node and a respective node in the second resistor string; and

an amplifier, wherein a first input terminal of the amplifier is coupled to the first node, and a second input terminal of the amplifier is coupled to the third node.