UM9401B MICROSEMI, UM9401B Datasheet - Page 7

• Manufacturer Part Number: UM9401B
• Manufacturer: MICROSEMI
• Type: Switchr

Specifications of UM9401B

• Configuration: Single
• Mounting: Through Hole
• Pin Count: 2
• Lead Free Status / RoHS Status: Supplier Unconfirmed

diode antenna switch can handle depends on the
diode resistance, R
SWR, σ, and the nominal impedance, Z
expression is as follows:
which gives both the maximum and typical diode
resistance, R
maximum power dissipation rating of the PIN diode
depends both on the length of the diode leads and the
temperature of the contacts to which the leads are
connected. A graph defining the maximum power
dissipation at various combinations of overall lead
length (L) and lead temperature (T
data section. From these curves and the above
equation, the power handling capability of the PIN
diode may be computed for a specific application.
maximum transmitter power that an antenna
switch using UM9401s and UM9415s can safely
handle for various forward currents and lead
temperatures. These curves are based on a typical
design condition of a ½ in. total overall lead length,
50 Ω line impedance, and a totally mismatched
antenna (σ = ∞). For the case of a perfectly matched
antenna, the maximum transmitter power can be
increased by a factor of 4.
Design Information
switch using PIN diodes consists of a diode placed in
series with the transmitter and a shunt diode placed a
quarter wavelength from the antenna in the direction
of the receiver as shown. For low frequency
operation, the quarter wave line may be simulated by
lumped elements. Typical performance of antenna
switches using PIN diodes forward biased at 100 mA
is less than 0.2 dB insertion loss and 30 dB isolation
during transmit; at zero bias the receive insertion loss
The maximum CW transmitter power, P
Characteristic curves are shown in the data section
Curves are also presented which show the
A circuit configuration for a two-way radio antenna
Copyright  2005
Rev. 0, 2005-09-15
S
as a function of forward current. The
S
, power dissipation, P
L
) is given in the
O
. The
T(max)
D
, antennae
, a PIN
Microsemi
is less than 0.3 dB. This performance is achievable
across a ±20 % bandwidth at center frequencies
ranging from 10 to 500 MHz.
UM9401 / UM9402 / UM9415
COMMERCIAL TWO-WAY RADIO
TRANSMITTER
TRANSMITTER
DC SUPPLY
DC SUPPLY
ANTENNA SWITCH DIODES
L = Z
C = 1/2 πf
D1
D1
C
O
/ 2 πf
ANTENNA
ANTENNA
O
L
Z
L
O
/4
C
O
(H)
(F)
D2
D2
RECEIVER
RECEIVER
Page 7