User's Manual

POWER AMPLIFIER HEATSINK ASSEMBLY
TSM21Q-365 Rev 0 July 17, 2009 PA Assembly 29
6 LOW POWER SWEEP AMPLIFIERS
Note: Low power sweep of PA modules should not be required under normal circumstances – even when
replacing FET devices. There are no tuning adjustments on these modules.
1. Ensure that terminations are in place in the test setup. All modules require 50 Ω source and load
impedances to prevent damage and for consistent results during testing.
2. Connect the module to a sweep system, typically as shown in Figure 1. The sweep generator should be
adjusted to give a linear sweep from 160 to 240 MHz so that all of High Band or Band III is swept, with a
small amount of out-of-band signal on both ends.
3. Connect the lab power supply +50 V to the positive supply bus bar, and the negative to the chassis of the
amplifier. The current should be limited to 7 or 8 A for this test. Caution: observe polarity!
4. With the power supply switched on, the current drawn should be not more than the bias current for all the
devices together - about 4 amperes (8 x 0.5 A) for the PA module.
The swept in-band frequency response, for High Band modules, should be essentially flat within ±1 dB as shown
in Figure 1, with gain approximately 15 to 16dB.
Figure 19 Module Sweep Setup