A fully differential Complementary Metal-Oxide Semiconductor (CMOS) Variable
Gain Amplifier (VGA) consisting of complementary differential pairs with source
degeneration, a current gain stage with programmable current mirror, and resistor loads is
designed for high frequency and low power communication applications, such as an Ultra
Wideband (UWB) receiver system. The gain can be programmed from 0dB to 42dB in 2dB
increments with -3dB bandwidth greater than 425MHz for the entire range of gain. The 3rd-order
intercept point (IIP3) is above -13.6dBm for 1Vpp differential input and output
voltages. These low distortion broadband features benefit from the large linear range of the
differential pair with source degeneration and the low impedance internal nodes in the
current gain stages. In addition, common-mode feedback is not required because of these
low impedance nodes. Due to the power efficient complementary differential pairs in the
input stage, power consumption is minimized (9.5mW) for all gain steps. The gain control
scheme includes fine tuning (2dB/step) by changing the bias voltage of the proposed
programmable current mirror, and coarse tuning (14dB/step) by switching on/off the source degeneration resistors in the differential pairs. A capacitive frequency compensation
scheme is used to further extend the VGA bandwidth.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/5843 |
| Date | 17 September 2007 |
| Creators | Chen, Lin |
| Contributors | Silva-Martinez, Jose |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | 1713243 bytes, electronic, application/pdf, born digital |
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