AR 1000S1G6C, Operating And Service Manual

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Model 1000S1G6C
50 Rev A
3.2.3 A3, A5-A8 and A13-A28 Quad Amp, High Power
The power module operates on a dual supply of VGG = -8V and VDD = +24V, with a VDD draw of 11.5 amps
and VGG draw below 0.1 amps. Power-on sequence is to apply VGG first, and then VDD, reversing this
sequency for power-off. Active closed-loop bias circuits provide for the safe operation of the amplifier into a
wide range of load VSWR, at all prescribed drive levels and frequencies. Proprietary coupling circuitry
provides superior module input and output matching and isolation, to yield best gain and power flatness across
the band, under all operating conditions. The module provides approximately 10 dB small-signal gain and 10
dB input and output return loss, with 75 watts average power at 3 dB compression, over the 1000–6000 MHz
band.
Two fault circuit outputs are provided to indicate (1) RF FET drain current faults, indiscriminately an over- or
under-current of either RF FET assembly, and (2) a thermal fault. A FET drain current fault may result from
operating the amplifier beyond the prescribed load, drive, or modulation conditions, or as the result of
compromised module components. If certain conditions generate a predictable fault, those operating conditions
should be reviewed to verify they do not violate the safe operating parameters of the amplifier, such as a high
peak power which may violate maximum allowable input power in any signal with high peak-to-average ratio.
It is normal that faults occurring under high drive or load VSWR conditions may not be repeated in the absence
of those conditions, and it is also possible that incorrect configuration or tuning of the gain structure within an
amplifier may generate faults in a properly operating module, by forcing it behind safe operating limits. The
Thermal Fault circuit is operable on VGG supply only and will serve to provide a fault before the application
of VDD is module temperature is below 0°C, or if module temperature exceeds safe operating limits for long-
term reliability. Both fault circuits are “open drain” designs, which pull an external supply (+3.3V with 1 k-
ohm series resistance) low, to generate a fault signal.”
3.2.4 A4, A9-A12 Four-Way Splitter
The Four-Way splitter splits the input signal into four equal-amplitude, equal-phase signals. The amplitude of
each signal is 6– 6.5dB below the input signal when both outputs are terminated into 50Ω loads.
3.2.5 A29, A30 8-Way Combiner
A29 and A30 are Eight-Way Combiners with impedance-matching. When the outputs of the two sets of eight
final amplifiers are fed to the two eight-way combiners, the combined output will be approximately 9.0 dB
above the output of a single final amplifier.
3.2.6 A31 Two-Way Combiner
A31 is a Two-Way Combiner with impedance-matching. When the outputs of the two eight-way combiners f
are fed to the two-way combiner, the combined output will be approximately 3.0 dB above the output of a single
final amplifier.
3.2.7 A32 Dual Directional Coupler
The 60 dB Dual Directional Coupler is connected to the output of the 16-way combiner. The coupler monitors
the forward and reflected power. A separate set of isolated coupler ports provide the forward and reverse sample
ports.