STM901-30 ST Microelectronics, Inc., STM901-30 Datasheet - Page 7

• Manufacturer Part Number: STM901-30
• Description: RF Power Module Linear Base Station Applications . Linear Power Amplifier
• Manufacturer: ST Microelectronics, Inc.

APPLICATIONS RECOMMENDATIONS
OPERATION LIMITS
The STM901-31 power module should never be op-
erated under any condition which exceeds the Ab-
solute Maximum Ratings presented on this data
sheet. Nor should the module be operated continu-
ously at any of the specified maximum ratings. If
the module is to be operated under any condition
such that it may be subjected to one or more of the
maximum rating conditions, care must be taken to
monitor other parameters which may be affected.
DECOUPLING
Failure to properly decouple any of the voltage sup-
ply pins will result in oscillations at certain operating
frequencies. Therefore, it is recommended that
these pins be bypassed as indicated in the Module
DC and Test Fixture Configuration drawing of this
data sheet.
MODULE MOUNTING
To insure adequate thermal transfer from the mod-
ule to the heatsink, it is recommended that a satis-
factory thermal compound such as Dow Corning
340, Wakefield 120-2 or equivalent be applied be-
tween the module flange and the heatsink.
The heatsink mounting surface under the module
should be flat to within +/- 0.05 mm (+/- 0.002
inch). The module should be mounted to the
heatsink using 3 mm (or 4-40) or equivalent screws
torqued to 5-6 kg-cm (4-6 in-lb).
The module leads are attached to the equipment
PC board using 180°C solder applied to the leads
with a properly grounded soldering iron tip, not to
exceed 195 C, applied a minimum of 2 mm (0.080
inch) from the body of the module for a duration not
to exceed 15 seconds per lead. It is imperative that
no other portion of the module, other than the
leads, be subjected to temperatures in excess of
100 C (maximum storage temperature), for any pe-
riod of time, as the plastic moulded cover, internal
components and sealing adhesives may be ad-
versely affected by such conditions.
Due to the construction techniques and the materi-
als used within the module, reflow soldering of the
flange heatsink or the leads, is not recommended.
THERMAL CONSIDERATIONS
It will be necessary to provide a suitable heatsink in
order to maintain the module flange temperature at
or below the maximum case operating temperature.
In a case where the module output power will be
limited to +44.7 dBm (30W PEP) and designing for
the worst case double-tone efficiency of 25%, the
power dissipated by the module will be 48 watts.
The heatsink must be designed such that the ther-
mal rise will be less than the difference between
the maximum ambient temperature at which the
module will operate and the maximum operating
case temperature of the module while dissipating
48 watts.
At T
I
+44.7dBm PEP, maximum junction temperatures for
the individual transistors should be below the fol-
lowing values:
Q3
case
0.05A, I
Q1 = 115°C
Q2 = 130°C
Q3 = 125°C
Q4 = 145°C
+85°C, V
Q4
0.2A, Z
26v, I
L
Q1
50 ohms and P
0.1A, I
Q2
0.18A,
OUT
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