CHA2098RBF
Ref. : DSCHA2098RBF2057 -26-Feb.-02
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Specifications subject to change without notice
1."
United Monolithic Semiconductors S.A.S.
Route Dpartementale 128 - B.P.46 - 91401 Orsay Cedex France
Tel. : +33 (0)1 69 33 03 08 - Fax : +33 (0)1 69 33 03 09
20-33GHz High Gain Buffer Amplifier
GaAs Monolithic Microwave IC in SMD leadless package
Description
The monolithic microwave IC (MMIC) in the
package is a high gain broadband three-
stage monolithic buffer amplifier. It is
designed for a wide range of applications,
from military to commercial communication
systems. The circuit is manufactured with a
PM-HEMT process, 0.25m gate length, via
holes through the substrate, air bridges and
electron beam gate lithography.
It is supplied in a new SMD leadless chip
carrier.
Main Features
Broadband performance: 20-40GHz
Small signal gain 18dB (typical)
SMD leadless package
Pout-1dB : +15dBm (typical).
Dimensions: 5.08 x 5.08 x 0.97 mm
3
SMD Package Dimensions
"Please note that PIN 1 is located in the lower left corner of the package (front-side view) for all SMD-type packages from United Monolithic Semiconductors. It is indicated
by a triangle on the package lid. Starting with PIN 1 the other pads are numbered counter-clockwise (front-side view). ATTENTION: The dot on the backside of the
package (i.e. side with metallic pads) is just for fabrication purposes and does NOT indicate the location of PIN
CHA2098RBF
20-33GHz High Gain Buffer Amplifier
Ref. : DSCHA2098RBF2057 -26-Feb.-02
2/6
Specifications subject to change without notice
"
Route Dpartementale 128 , B.P.46 - 91401 ORSAY Cedex - FRANCE
Tel.: +33 (0)1 69 33 03 08 - Fax : +33 (0)1 69 33 03 09
Schematic
Typical Bias Conditions
for an ambient Temperature of +25C
Symbol
Pin No.
Parameter
Values
Unit
Vd
6
Drain bias voltage
3.5
V
Vg1
1
Gate bias voltage (1st stage)
-0.1
V
Vg2, Vg3
2
Gate bias voltage (2nd and 3rd stage)
-0.1
V
Id
6
Drain current
150
mA
All other pins are not used for this device.
Absolute Maximum Ratings
Tamb. = 25C (1)
Symbol
Parameter
Values
Unit
Vd
Drain bias voltage
4.0
V
Id
Drain bias current
200
mA
Vg
Gate bias voltage
-2.0 to +0.4
V
Ta
Operating temperature range (2)
-40 to +85
C
Tstg
Storage temperature range
-55 to +155
C
(1) Operation of this device above anyone of these parameters may cause permanent damage.
(2) Upper temperature limit strongly dependent on motherboard design; ratings given for
ideal thermal coupling
20-33GHz High Gain Buffer Amplifier
CHA2098RBF
Ref. : DSCHA2098RBF2057 -26-Feb.-02
3/6
Specifications subject to change without notice
Route Dpartementale 128 , B.P.46 - 91401 ORSAY Cedex - FRANCE
Tel.: +33 (0)1 69 33 03 08 - Fax : +33 (0)1 69 33 03 09
Typical results on PCB (recommended motherboard layout)
Vd=3.5V, Id adjusted at 150mA
Gain & Return Loss
-20
-15
-10
-5
0
5
10
15
20
25
20
22
24
26
28
30
32
34
36
38
40
Frequency ( GHz )
Input Return Loss (dB)
Linear Gain (dB)
Output Return Loss (dB)
CHA2098RBF
20-33GHz High Gain Buffer Amplifier
Ref. : DSCHA2098RBF2057 -26-Feb.-02
4/6
Specifications subject to change without notice
"
Route Dpartementale 128 , B.P.46 - 91401 ORSAY Cedex - FRANCE
Tel.: +33 (0)1 69 33 03 08 - Fax : +33 (0)1 69 33 03 09
Footprint
20-33GHz High Gain Buffer Amplifier
CHA2098RBF
Ref. : DSCHA2098RBF2057 -26-Feb.-02
5/6
Specifications subject to change without notice
Route Dpartementale 128 , B.P.46 - 91401 ORSAY Cedex - FRANCE
Tel.: +33 (0)1 69 33 03 08 - Fax : +33 (0)1 69 33 03 09
Application note
The design of the motherboard has a strong impact on the over all performance
since the transition from the motherboard to the package is comparably large. In
case of the SMD type packages of United Monolithic Semiconductors the
motherboard should be designed according to the information given in the following
to achieve good performance. Other configurations are also possible but can lead to
different results. If you need advise please contact United Monolithic Semiconductors
for further information.
SMD type packages of UMS should allow design and fabrication of micro- and mm-
wave modules at low cost. Therefore, a suitable motherboard environment has been
chosen. All tests and verifications have been performed on Rogers RO4003. This
material exhibits a permittivity of 3.38 and has been used with a thickness of 200m
[8 mils] and a 1/2oz or less copper cladding. The corresponding 50 Ohm
transmission line has a strip width of about 460m [approx. 18 mils].
The contact areas on the motherboard for the package connections should be
designed according to the footprint given above. The proper via structure under the
ground pad is very important in order to achieve a good RF and lifetime
performance. All tests have been done by using a grid of plenty plated through vias
with a diameter of less than 200m [8 mils] and a spacing of less than 400m [16
mils] from the centres of two adjacent vias. The via grid should cover the whole
space under the ground pad and the vias closest to the RF ports should be located
near the edge of the pad to allow a good RF ground connection. Since the vias are
important for heat transfer, a proper via filling should be guaranteed during the
mounting procedure to get a low thermal resistance between package and heat sink.
For power devices the use of heat slugs in the motherboard instead of a via grid is
recommended.
For the mounting process the SMD type package can be handled as a standard
surface mount component. The use of either solder or conductive epoxy is possible.
The solder thickness after reflow should be typical 50m [2 mils] and the lateral
alignment between the package and the motherboard should be within 50m [2
mils]. Caution should be taken to obtain a good and reliable contact over the whole
pad areas. Voids or other improper connections, in particular, between the ground
pads of motherboard and package will lead to a deterioration of the RF performance
and the heat dissipation. The latter effect can reduce drastically reliability and lifetime
of the product.
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