A low-voltage programmable-gain CMOS amplifier with very-low temperature-drift

• Autor(a) principal: De Lima, J. A. [UNESP]
• Data de Publicação: 2001
• Outros Autores: Dualibe, C. [UNESP]
• Tipo de documento: Artigo de conferência
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1109/ISCAS.2001.921934; http://hdl.handle.net/11449/66425
• topic: Aspect ratio; Bandwidth; CMOS integrated circuits; Computer simulation; Electric potential; Gain control; Complementary metal oxide semiconductor (CMOS) amplifiers; Low-voltage low-power circuits (LVLP) circuits; Amplifiers (electronic)

A new topology for a LVLP variable-gain CMOS amplifier is presented. Input- and load-stage are built around triode-transconductors so that voltage-gain is fully defined by a linear relationship involving only device-geometries and biases. Excellent gain-accuracy, temperature-insensitivity; and wide range of programmability, are thus achieved. Moreover, adaptative biasing improves the common-mode voltage stability upon gain-adjusting. As an example, a 0-40dB programmablegain audio-amplifier is designed. Its performance is supported by a range of simulations. For VDD=1.8V and 20dB-nominal gain, one has Av=19.97dB, f3db=770KHz and quiescent dissipation of 378μW. Over temperatures from -25°C to 125°C, the 0. ldB-bandwidth is 52KHz. Dynamic-range is optimized to 57.2dB and 42.6dB for gains of 20dB and 40dB, respectively. THD figures correspond to -60.6dB@Vout= 1Vpp and -79.7dB@Vout= 0.5 Vpp. A nearly constant bandwidth for different gains is also attained.