ECO7904

APPLICATION NOTE A wide-band class-A linear power amplifier (174 − 230 MHz) with two transistors BLV33 ECO7904 w w w t a .D S a e h U 4 t e .c m o w w w .D a S a t e e h U 4 t m o .c Philips Semiconductors A wide-band class-A linear power amplifier (174 − 230 MHz) with two transistors BLV33 CONTENTS 1 2 3 4 5 6 7 8 ABSTRACT INTRODUCTION DESIGN OF THE AMPLIFIER ADJUSTMENTS OF THE AMPLIFIER ASSEMBLING OF THE AMPLIFIER AND MECHANICAL DATA MEASURED RESULTS CONCLUSION REFERENCES Application Note ECO7904 1998 Mar 23 2 Philips Semiconductors A wide-band class-A linear power amplifier (174 − 230 MHz) with two transistors BLV33 1 ABSTRACT Application Note ECO7904 For application in driver or final stages of TV-transposers in band III (174 − 230 MHz) a linear wideband power amplifier has been designed with 2 transistors BLV33, coupled by means of 3 dB −90° hybrids. Each transistor is adjusted in class-A at VCE = 25 V and IC = 3.25 A. A demonstration model showed a peak sync output power of 40 W at a 3-tone I.M. distortion between −56 and −58 dB. At this power level the cross-modulation varied from 6 to 7.5%. The power gain is between 8.35 and 8.6 dB. 2 INTRODUCTION For application in T.V. transposers and transmitters for band III a wideband linear power amplifier has been designed with 2 transistors BLV33, coupled by means of 3 dB −90° hybrids. Each transistor is adjusted in class-A at VCE = 25 V and IC = 3.25 A. 3 DESIGN OF THE AMPLIFIER For class-A operati...