Title :
An integrated programmable low-noise charge pump
Author :
Hakkinen, Jukka ; Rahkonen, Timo ; Kostamovaara, J.
Author_Institution :
Dept. of Electr. Eng. & Infotech., Oulu Univ.
Abstract :
This paper presents the design and implementation of an integrated programmable low-noise charge pump based on the op-amp current mirror. The presented 4-bit structure, designed for the output circuitry of a phase-frequency detector, provides output currents ranging from 0 to 7.5 mA with a 500 μA resolution. The device also has an output impedance of over 10 MΩ for output voltages ranging from 0.7 to 4.3 V. The current imbalance between the source and sink currents is less than 3%, and the output current noise spectral density is 18.7 pA/√Hz for an output current of 500 μA. Feedback-which keeps the voltage over the charge pump constant during switching-is employed to reduce switching transients. The structure operates from a 5.0 V supply and is processed in a 0.8 μm BiCMOS process
Keywords :
BiCMOS integrated circuits; current mirrors; operational amplifiers; phase detectors; programmable circuits; transients; 0 to 7.5 mA; 0.7 to 4.3 V; 0.8 micron; 4 bit; 500 muA; BiCMOS process; noise spectral density; op-amp current mirror; output currents; output impedance; output voltages; phase-frequency detector; programmable low-noise charge pump; switching transients; Charge pumps; Circuits; Mirrors; Operational amplifiers; Output feedback; Phase detection; Phase frequency detector; Signal to noise ratio; Synthesizers; Voltage;
Conference_Titel :
Electronics, Circuits and Systems, 1999. Proceedings of ICECS '99. The 6th IEEE International Conference on
Conference_Location :
Pafos
Print_ISBN :
0-7803-5682-9
DOI :
10.1109/ICECS.1999.812254
