A Low Noise High Intercept Point Amplifier for 1930-1990 MHz using the ATF-33143 PHEMT - App Note

The Avago Technologies ATF-33143 is one of a family of high dynamic range, low noise PHEMT devices designed for use in low cost commercial applications in the VHF through 6 GHz frequency range. The ATF-33143 is the device with the largest gate periphery (1600 micron gate width) with 2 GHz performance tested and guaranteed at a Vce of 4 V and Id of 80 mA. The ATF-33143 is housed in a 4-lead SC-70 (SOT-343) surface mount plastic package. In this application note, the ATF-33143 is described in a high dynamic range low noise amplifier designed specifically for the 1930 to 1990 MHz PCS base station market. When biased at a Vds of 4 volts and an Ids of 80 mA, the ATF-33143 amplifier has a minimum of 13 dB gain, a 0.7 dB noise figure and an output intercept point of +32.5 dBm. The amplifier has an input return loss of 8 to 9 dB and an output return loss of greater than 20 dB. The design techniques presented in this application note can be applied to LNAs at other frequencies in the 1500 MHz through 2500 MHz frequency range. The amplifier is etched on 0.031 inch thickness FR-4 printed circuit board material for low manufacturing costs. The amplifier makes use of low cost miniature multilayer chip inductors for small size.