Alan Li

Alan Li is a senior applications engineer with Analog Devices Inc., Norwood, Mass. He has a BSEE from Florida International University.

Author Articles

Digital Volume Control Eliminates Zipper Noise

By Alan Li, April 27, 2006

In low-end audio systems, digital potentiometers can be used as audio attenuators or amplifiers (Fig. 1). Unfortunately, a large change in volume at an arbitrary time can cause an abrupt discontinuity in the audio signal. The result is audible clicking, o
Precision Programmable Current Sources Use Digital Pots

By Peter Khairolomour, April 28, 2005

The circuit that's shown in Figure 1 implements a programmable 0- to 20-mA precision current source. The REF192 low-headroom 2.5-V voltage reference (U1) can source up to 30 mA. An AD5280 digital potentiometer (U2) controls the voltage-divider ratio of
Precision Programmable Current Sources Use Digital Pots

By Alan Li, March 31, 2005

The circuit shown in Figure 1 implements a programmable 0- to 20-mA precision current source. The REF192 low-headroom 2.5-V voltage reference (U1) can source up to 30 mA. An AD5280 digital potentiometer (U2) cont