HMMC-1002 Datasheet, PDF (3/8 Pages) Agilent(Hewlett-Packard) – DC- 50 GHz Variable Attenuator

Applications
The HMMC-1002 is designed to be
used as a gain control block
in an AGC assembly. Because of
its wide dynamic range and
return loss performance, the
HMMC-1002 may also be used as
a broadband pulse modulator or
single-pole single-throw, non-
reflective switch.
Operation
The attenuation of the
HMMC-1002 is adjusted by
applying negative voltages to V1
and V2. V1 controls the drain-to-
source resistances of the series
FETs while V2 controls the drain-
to-source resistances of the shunt
FETs. For any HMMC-1002 the
values of V1 may be adjusted so
that the device attenuation versus
voltage is monotonic for both V1
and V2; however, this will slightly
degrade the input and output
return loss.
The attenuation of the
HMMC-1002 may also be con-
trolled using only a single input
voltage by utilizing the on-chip
DC reference circuit and the
driver circuit shown in Figure 4.
This circuit optimizes VSWR for
any attenuation setting. Because
of process variations, the values
of V_REF, R_REF, and R_L are different
for each wafer if optimum
performance is required. Typical
values for these elements are
given. The ratio of the resistors
R1 and R2 determines the sensi-
tivity of the attenuation versus
voltage performance of the
attenuator. For more information
on the performance of the
HMMC-1002 and the driver
circuits previously mentioned see
MWTC’s Application Note #37,
“HMMC-1002 Attenuator: Attenua-
tion Control.” For more
S-parameter information, see
MWTC’s Application Note #44,
“HMMC-1002 Attenuator:
S-Parameters.”
Assembly Techniques
Solder die attach using a AuSn
solder preform is the recom-
mended assembly method;
however, an epoxy die attach
method using ABLEBOND^®
71-1LM1 or ABLEBOND^® 36-2
may also be employed. Gold
thermosonic wedge bonding with
0.7 mil wire is the recommended
method for bonding to the device.
Tool force should be
22␣ grams␣ ± ␣ 1␣ gram,stagetempera-
ture is 150␣ ± ␣ 2 °C, and ultrasonic
power and duration of 64 ± 1␣ dB
and 76 ± 8␣ msec, respectively.
The top and bottom metallization
is gold.
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.
RF_IN
RF_OUT
DC Reference Circuit
DC_IN
V₁
Figure 1. HMMC-1002 Schematic.
DC_OUT
V₂
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