ECO8005

APPLICATION NOTE A wide-band class-A linear power amplifier (174 − 230 MHz) with 2 transistors BLV33F ECO8005 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 2 transistors BLV33F 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 ECO8005 1998 Mar 23 2 Philips Semiconductors A wide-band class-A linear power amplifier (174 − 230 MHz) with 2 transistors BLV33F 1 ABSTRACT Application Note ECO8005 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 BLV33F, 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 −52 and −53 dB. At this power level the cross-modulation varied from 15 to 18%. The power gain is between 13.3 and 13.6 dB. For natural convection cooling the heatsink temperature is 40 °C above ambient temperature. 2 INTRODUCTION For application in T.V. transposers and transmitters for Band III a wideband linear power amplifier has been designed with 2 transistors BLV33F, coupled by means of 3 dB −90° hybrids. Each transistor is adjus...