Ischia, giugno 2006Riunione Annuale GE 2006 High-dynamic-range VGA with temperature compensation and linear-in-dB gain control Francesco Carrara and Giuseppe Palmisano Radio Frequency Advanced Design Center (RF-ADC) Università di Catania Facoltà di Ingegneria DIEES Catania - ITALY STMicroelectronics Catania site Sistemi Elettronici Integrati – B17

Ischia, giugno 2006Riunione Annuale GE 2006 INTRODUCTION Requirements for WCDMA TX VGAs Wide dynamic range (as high as 74 dB for Class 3 user equipment) Temperature compensation for accurate control over such a wide dynamic range Decibel-linear gain characteristic to minimize the resolution of the DAC driving the control terminal High linearity to comply with ACLR specification TX VGAs are crucial in optimizing the channel capacity of code-division systems like WCDMA Main requirements are:

Ischia, giugno 2006Riunione Annuale GE 2006 CIRCUIT DESIGN VGA schematic Linear-in-dB gain control though exponential variation of the tail current Temperature compensation (PTAT control current I CTRL ) Parasitic path compensation (dummies Q9-Q10) for extended dynamic range 46-GHz-f T 0.8-μm silicon bipolar process by STMicroelectronics

Ischia, giugno 2006Riunione Annuale GE 2006 EXPERIMENTAL RESULTS Gain control characteristic V CC = 3 V, f = 400 MHz, P in = -10 dBm T = 30 °C

Ischia, giugno 2006Riunione Annuale GE 2006 EXPERIMENTAL RESULTS Performance summary

Ischia, giugno 2006Riunione Annuale GE 2006 TO PROBE FURTHER Related publications F. Carrara and G. Palmisano, High-dynamic-range VGA with temperature compensation and linear-in-dB gain control, IEEE J. Solid-State Circuits, vol. 40, pp , Oct F. Carrara, C. Santagati, and G. Palmisano, High-dynamic-range VGA with temperature compensation and linear-in-dB gain control, in Proc. IEEE Bipolar/BiCMOS Circuits and Technology Meeting (BCTM 2004), Montréal, Canada, Sept. 2004, pp C. D. Presti, F. Carrara, and G. Palmisano, Variable-gain up- conversion mixer with current reuse for 5-GHz W-LAN applications, in Proc. European Conf. on Circuit Theory and Design (ECCTD 2005), Cork, Ireland, Aug. 2005, vol. 1, pp