A typical RF transmitter requires maximum start up time. The transient energy during the startup can be higher than the energy required by the electronics during the actual transmission. In order to reduce start up energy consumption, reduce the power dissipation in transmitter. This power dissipation in transmitter is reduced by lowering the phase noise of VCO.In this paper comparison is made between different architectures of CMOS LC tank VCO such as differentional cross coupled, complementary cross coupled ,cross coupled with pseudo resistance and Quadrature VCO with reconfigurable LC tank which are used to design high performance LC tank VCO for low power RF transmitter .From the comparison table 1,we note that complementary cross coupled LC VCO provides best tuning range i.e.21% and cross coupled with pseudo resistance LC VCO provides lowest phase i.e.-125.5 dBc/Hz among the other VCOs, it also has minimum power consumption, highest tuning range and best FOM i.e.-190.84.

1. Hyun Seok Choi, Quang Diep Bui, and Chul Soon Park, “A low-power CMOS VCO for 2.4GHz WLAN,” IEEE Compound Semiconductor Integrated Circuit (CSIC) Symposium, pp. 1–4, Oct. 2007.
2. Hyun Seok Choi, Quang Diep Bui, and Chul Soon Park, “A low-power CMOS VCO for 2.4GHz WLAN,” IEEE Compound Semiconductor Integrated Circuit (CSIC) Symposium, pp. 1–4, Oct. 2007.
3. Yuemei Li Zheying Li Bo Li Chunlei Wang,” 2.4GHz VCO Design and Tail Current Analysis”,7th International conference on ASIC 2007
4. Mohammad Niaboli-Guilani” A Low Power Low Phase CMOS Voltage Controlled Oscillator” 17th IEEE International Conference on Electronics, Circuits, and Systems (ICECS), 2010.
5. Cheol-Hoe Kim, Soo-Hwan Shin, and Hyung-Jou Yoo” A Low Phase Noise and Low Power Series Coupled Quadrature VCO Using Reconfigurable LC Tank” Radio and Wireless Symposium, vol.on page 395, 2008 IEEE.
6. Design of Analog CMOS Integrated Circuits”by Behzad Razavi.
7. Andrew Y.Wang,”Energy Efficient Modulation and MAC for Asymmetric RF Microsensor Systems”, ISLPED?01 August6-7, 2001.
8. Y. H. Chee,” A 46% Efficient 0.8dBm Transmitter for Wireless Sensor Networks”, IEEE 2006 Symposium on VLSI Circuits Digest of Technical Papers.
9. K.bult, ABurstein,”Low Power Systems for Wireless Microsensors”, ISLPED 1996 Monterey CA USA.
10. Bo Zhao,” An Ultra-Low-Supply Dual-Band VCO for wireless Sensor Networks,” International Conference on Communication, Circuits and Systems, 2009, on pages 797-801.
11. Hannes Reinisch “An Electro-Magnetic Energy Harvesting SystemWith 190 nW Idle Mode Power Consumption for a BAW Based Wireless Sensor Node”, IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 46, NO. 7, JULY 2011.
12. Benton H. Calhoun,” Design Considerations for Ultra-Low Energy Wireless Microsensor Nodes”, IEEE TRANSACTIONS ON COMPUTER, VOL. 54, NO. 6, JUNE 2005.

Voltage-controlled oscillator (VCO) CMOS low power low phase noise FOM