UM9995
ULTRA LOW MAGNETIC MRI SWITCHING
DIODES
DESCRIPTION
KEY FEATURES
The UM9995 was developed for switching applications in MRI systems
that require an ultra low magnetic image. The UM9995 is also excellent
for shunt mount applications with good switch performance from VHF
and higher. The selection of the proper materials for the package insures
the minimum magnetic image required for MRI applications. The
performance is achieved using discrete low inductance PIN diodes
assembled with special hardware to permit good electrical and
mechanical properties The Microsemi UM9995 PIN diode is constructed
using a fused-in-glass process, which results in a highly reliable, hermetic
package. The process utilizes symmetrical, full faced metallurgical bonds
to both surfaces of the silicon chip. This construction greatly minimizes
the normal parasite inductance and capacitance found in conventional
glass or ceramic packaged diodes, which employ straps, springs, or
washers.
Ultra low magnetic
construction
Low inductance
package
High power handling
capability
Low bias current
requirement
Excellent distortion
properties
Passivated chip
Metallurgical bond
Non-cavity design
Thermally matching
configuration
Available in surface or
shunt mount packages
WWW .
Microsemi
.C
OM
This is an actual
Magnetic Image
of the
standard UM9601 and
the specially constructed
UM9995
PIN diode (in
a 3T MRI system).
UM9995
UM9995
Fig. 1 Image of the UM9995 compared to standard Switch diode
Copyright
2004
Rev. 0, 2004-10-15
Microsemi
Page 1
UM9995
ULTRA LOW MAGNETIC MRI SWITCHING
DIODES
ELECTRICAL PARAMETERS
@ 25°C (unless otherwise specified)
Parameter
Symbol
Conditions
Min
Typ.
Max
Units
WWW .
Microsemi
.C
OM
Series Resistance
Total Capacitance
Parallel Resistance
Forward Voltage
(Note 1)
Carrier Lifetime
I-Region Width
Rs
Ct
Rp
V
f
I = 100 mA
F = 100 MHz
V = 100V
F = 1MHz
V = 100 V
F = 100 MHz
I
F
= 100 mA ,
If = 10 mA
-
-
100
-
2.0
80
0.4
-
-
0.85
0.6
1.2
-
-
Ω
pF
kΩ
V
µs
µm
τ
W
Note: 1 Short duration test pulse used to minimize self – heating effect.
ELECTRICAL PARAMETERS @25ºC
(unless
otherwise specified)
Ρo
Flange at 25ºC
Free Air
Peak Power (1 µs @ 25ºC)
Storage Temperature
Operating Temperature
7.5 W
θt
20ºC/W
1.5 W
-
10 kW
-65 to +150ºC
-65 to +150ºC
UM9995
UM9995
Copyright
2004
Rev. 0, 2004-10-15
Microsemi
Page 2
UM9995
ULTRA LOW MAGNETIC MRI SWITCHING
DIODES
STYLE “G
”
WWW .
Microsemi
.C
OM
STYLE “SM”
UM9995
UM9995
PRODUCT PRELIMINARY DATA – Information contained in this document is pre-production
data, and is proprietary to Microsemi Corp. It may not be modified in any way without the express
written consent of Microsemi Corp. Product referred to herein is not guaranteed to achieve
preliminary or production status and product specifications, configurations, and availability may
change at any time.
Copyright
2004
Rev. 0, 2004-10-15
Microsemi
Page 3
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