UM9601_06 Datasheet, PDF (12/16 Pages) Microsemi Corporation – FOR MICROSTRIP 900 MHz ANTENNNA SWITCHES

UM9601 – UM9608
FOR MICROSTRIP 900 MHz ANTENNNA SWITCHES
C OS O S
AND MICROWAVE APPLICATIONS
The CW power handling capacity is determined by the
allowable power dissipation of the series mounted UM9401.
Using a gap in the line of 0.190” (4.82mm) and lead soldered
attached spacing of 0.250” (6.35mm) the power rating of the
UM9401 is 6 watts at a 25 ^oC ambient. This was determined by
performing a thermal resistance measurement on the circuit
mount UM9401. The relationship that derives the maximum
transmitter power, P_T is:
P_T
=
P_DISS
Rs
Zo

σ+
2σ
1


2
where σ = maximum antenna SWR
Using resistance values for UM9401 and UM9601 the
maximum transmitter power curve is given and shows that this
circuit is able to handle 100 watts of transmitter power at 100
mA forward bias and totally mismatched antenna at an ambient
temperature of 60 ^oC. For a perfectly match antenna the power
handling increases to 400 watts under the same bias and
ambient conditions.
Distortion is an important consideration in the selection of a
PIN diode antenna switch design. The UM9401 and UM9601
PIN diodes are designed for low distortion applications. The
level of distortion produced by this 900 MHz antenna switch
when operated in the transmit state (forward bias of 100 mA) is
expected to be at least 90 dB below the carrier for a 50 watt
transmitter level. In the receiver
state (zero bias) the intermodulation distortion
caused by two in-band signals at 0 dBm are estimated to be at
least 100 dB below this level
MAX. TRANSMITTER POWER vs FORWAD CURRENT FOR
UM9601/UM9401 900 MHz MICROSTRIP ANTENNA SWITCH
103
TYPICAL
Zo = 50 Ohms
102
SWR = INFINITE
200mA
100 mA
101
50 mA
20 mA
10 mA
100
0
25
50
75
100
125
150
175
AMBIENT TEMPERATURE
Copyright  2005
Rev. 0, 2006-01-17
Microsemi
Page 12