Circuit and method of canceling leakage current in an analog array

An analog circuit, comprising:

• an amplifier having first and second inputs and an output, said first input being coupled for receiving a first input signal, said output providing an output signal;
• circuit means coupled between a terminal at which a second input signal is applied and said second input of said amplifier for providing a programmable impedance, said circuit means including a plurality of switches to control said programmable impedance;
• and
• a compensation circuit coupled to said first input of said amplifier for providing a compensation current that matches leakage current from said circuit means into said second input of said amplifier and prevents drift in said output signal of said amplifier.

A method of compensating for leakage current in an analog circuit, comprising the steps of:

• providing a differential amplifier having first and second inputs;
• providing a parasitic leakage current into said first input of said differential amplifier;
• and
• injecting a compensation current into said second input of said differential amplifier that matches said parasitic leakage current and cancels effects of said parasitic leakage current by creating a common mode signal that is rejected by said differential amplifier.