HMMC-5038 Datasheet, PDF (3/5 Pages) Agilent(Hewlett-Packard) – 38 GHz LNA

Applications
The HMMC-5038 low noise
amplifier (LNA) is designed for
use in digital radio communica-
tion systems and point-to-
multipoint links that operate
within the 37 GHz to 40 GHz
frequency band. High gain and
low noise temperature make it
ideally suited as a front-end gain
stage in the receiver. The MMIC
solution is a cost effective
alternative to hybrid assemblies.
Biasing and Operation
The recommended DC bias
condition is with all drains
connected to single 3 volt supply
and all gates connected to an
adjustable negative voltage
supply as shown in Figure 1(a).
The gate voltage is adjusted for a
total drain supply current of
typically 120 mA. Reducing the
current in stages 3 and 4 will
reduce the overall gain. The gain
can be adjusted further by
altering the current through stage
2 with little affect on noise figure.
Optimum noise figure is realized
with V_D1= 3 to 4 volts and I_D1 = 20
to 25 mA.
The second, third, and fourth
stage DC drain bias lines are
connected internally and there-
fore require only a single bond
wire. An additional bond wire is
needed for the first stage DC
drain bias, V_D1.
The third and fourth stage DC
gate bias lines are connected
internally. A total of three DC
gate bond wires are required: One
for V_G1, one for V_G2, and one for
the V_G3-to-V_G4 connection as
shown in Figure 1.
A DC blocking capacitor is
needed in the RF input transmis-
sion line only if there is DC
voltage present. The RF output is
AC-coupled.
Optimum input match is achieved
when an optional capacitive
(~30␣ fF) stub is included on the
input transmission line. This
capacitance compliments the
bond wire inductance to com-
plete the input matching network.
No ground wires are needed
because ground connections are
made with plated through-holes
to the backside of the device.
Assembly Techniques
A conductive epoxy such as
ABLEBOND^® 71-1LM1 or
ABLEBOND^® 84-1LM1 is the
recommended assembly method
provided the Absolute Maximum
Thermal Ratings are not
exceeded. Solder die attach using
a fluxless gold-tin (AuSn) solder
preform may also be used. The
device should be attached to an
electrically conductive surface to
complete the DC and RF ground
paths. The backside metallization
on the device is gold.
It is recommended that the RF
input and RF output connections
be made using either 500 line/inch
(or equivalent) gold wire mesh, or
dual 0.7 mil diameter gold wire.
The RF wires should be kept as
short as possible to minimize
inductance. The bias supply can
be 0.7 mil diameter gold wires.
Thermosonic wedge is the
preferred method for wire
bonding to the gold bond pads.
Mesh wires can be attached using
a 2 mil round tacking tool and a
tool force of approximately
22␣ grams with an ultrasonic
power of roughly 55 dB for a
duration of 76 ± 8 msec. A guided-
wedge at an ultrasonic power
level of 64 dB can be used for the
0.7 mil wire. The recommended
wire bond stage temperature is
150 ± 2°C.
For more detailed information
see HP application note #999
“GaAs MMIC Assembly and
Handling Guidelines.”
GaAs MMICs are ESD sensitive.
Proper precautions should be used
when handling these devices.
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