Low Noise Amplifiers with Double Loop Feedback
- PDF / 537,686 Bytes
- 18 Pages / 439.37 x 666.142 pts Page_size
- 89 Downloads / 204 Views
Low Noise Amplifiers with Double Loop Feedback Miguel A. Martins · Koen van Hartingsveldt · Jorge R. Fernandes · Manuel M. Silva · Chris J.M. Verhoeven
Received: 16 August 2011 / Revised: 10 September 2012 / Published online: 25 September 2012 © Springer Science+Business Media New York 2012
Abstract In this paper we describe the design of a low noise amplifier (LNA) using two feedback loops, one with a transformer, and the other with a resistor. We determine first the double loop feedback (DLF) topologies that are suitable for LNA design. One of these is analyzed in detail, first assuming an ideal amplifying block, and then with a nonideal block (to determine the gain required for the amplifying block to be considered as ideal). Simulation results show that it is possible to obtain wideband DLF LNAs with very low noise figure. Keywords Double loop feedback · Low noise amplifier · Wideband low noise amplifier (LNA)
M.A. Martins () · J.R. Fernandes · M.M. Silva INESC-ID/Instituto Superior Técnico/TU Lisbon, Portugal, Rua Alves Redol 9, 1000-029 Lisbon, Portugal e-mail: [email protected] url: www.inesc-id.pt J.R. Fernandes e-mail: [email protected] M.M. Silva e-mail: [email protected] K. van Hartingsveldt Catena Microelectronics bv, Elektronicaweg 40, 2628 XG Delft, The Netherlands e-mail: [email protected] url: www.catena.nl C.J.M. Verhoeven Technical University of Delft, Mekelweg 4, 2628 CD Delft, The Netherlands e-mail: [email protected] url: www.tudelft.nl
542
Circuits Syst Signal Process (2013) 32:541–558
1 Introduction Wideband low noise amplifiers (LNAs) are required for many applications, such as ultra-wideband (UWB) systems and software-defined radio [1, 12]. A wideband LNA must have high gain, low noise figure and good input impedance matching. In addition, the LNA should be linear and consume low power. Some techniques used to design wideband LNAs are resistive impedance matching, common-gate (base) topology [8], and use of an LC-ladder matching network [7]. Connecting a resistance in parallel with the high input impedance of an amplifier, equal to the output resistance of the preceding stage, implies a 3 dB increase of the noise figure. The common-gate (base) [8] is an alternative approach; however, it also increases the noise figure significantly. The use of an LC-ladder matching network to increase the bandwidth of a narrow-band LNA [7] requires several inductors, which increases the area. A better technique than the above procedures to increase an amplifier’s bandwidth, is to use negative feedback [2, 16]. This has additional advantages: improved noise performance, gain insensitivity against parameter variations, precise control of input and output impedances, and reduced nonlinear distortion [18]. With single-loop feedback, the amplifying block usually has a finite gain, meaning that the LNA performance is sensitive to the amplifying block parameter variations. In this paper we investigate double loop feedback (DLF) LNAs [15], in which the amplifying
Data Loading...
