HMC8410 Datasheet, PDF (13/16 Pages) Analog Devices – Low noise figure: 1.1 dB typical

Data Sheet
APPLICATIONS INFORMATION
Figure 39 shows the basic connections for operating the
HMC8410CHIPS. The data taken herein used wideband bias
tees on the input and output ports to provide both ac coupling and
the necessary supply voltages to the RFIN/VGG1 and RFOUT/VDD
pins. A 5 V dc drain bias is supplied to the amplifier through
the choke inductor connected to the RFOUT/VDD pin, and the
−2 V gate bias voltage is supplied to the RFIN/VGG1 pin through
the choke inductor. The RF signal must be ac-coupled to prevent
disrupting the dc bias applied to RFIN/VGG1 and RFOUT/VDD.
The nonideal characteristics of ac coupling capacitors and
choke inductors (for example, self resonance) can introduce
performance trade-offs that must be considered when using a
single application circuit across a very wide frequency range.
RECOMMENDED BIAS SEQUENCING
The recommended bias sequence during power-up is as follows:
1. Connect to GND.
2. Set RFIN/VGG1 to −2 V.
3. Set RFOUT/VDD to 5 V.
4. Increase RFIN/VGG1 to achieve a typical supply current
(IDQ) = 65 mA.
5. Apply the RF signal.
The recommended bias sequence during power-down is as
follows:
1. Turn off the RF signal.
2. Decrease RFIN/VGG1 to −2 V to achieve a typical IDQ = 0 mA.
3. Decrease RFOUT/VDD to 0 V.
4. Increase RFIN/VGG1 to 0 V.
The bias conditions previously listed (RFOUT/VDD = 5 V and
IDQ = 65 mA) are the recommended operating conditions to
achieve optimum performance. The data used in this data sheet
was taken with the recommended bias conditions. When using
the HMC8410CHIPS with different bias conditions, different
performance than that shown in the Typical Performance
Characteristics section may result.
Figure 29, Figure 30, and Figure 31 show that increasing the
voltage from 3 V to 7 V typically increases P1dB and PSAT at the
expense of power consumption with minor degradation on
noise figure (NF).
HMC8410CHIPS
MOUNTING AND BONDING TECHNIQUES FOR
MILLIMETERWAVE GaAs MMICS
Attach the die directly to the ground plane eutectically or with
conductive epoxy (see the Handling Precautions section).
To bring the radio frequency to and from the chip, implementing
50 Ω transmission lines using a microstrip or coplanar waveguide
on 0.127 mm (5 mil) thick alumina, thin film substrates is recom-
mended (see Figure 37). When using 0.254 mm (10 mil) thick
alumina, it is recommended that the die be raised to ensure that
the die and substrate surfaces are coplanar. Raise the die 0.150 mm
(6 mil) to ensure that the surface of the die is coplanar with the
surface of the substrate. To accomplish this, attach the 0.102 mm
(4 mil) thick die to a 0.150 mm (6 mil) thick, molybdenum (Mo)
heat spreader (moly tab), which can then be attached to the
ground plane (see Figure 37 and Figure 38).
0.102mm (0.004") THICK GaAs MMIC
0.076mm
(0.003")
WIRE BOND
RF GROUND PLANE
0.127mm (0.005") THICK ALUMINA
THIN FILM SUBSTRATE
Figure 37. Die Without the Moly Tab
0.102mm (0.004") THICK GaAs MMIC
0.076mm
(0.003")
WIRE BOND
RF GROUND PLANE
0.150mm (0.005") THICK
MOLY TAB
0.254mm (0.010") THICK ALUMINA
THIN FILM SUBSTRATE
Figure 38. Die With the Moly Tab
Place microstrip substrates as close to the die as possible to
minimize bond wire length. Typical die to substrate spacing is
0.076 mm to 0.152 mm (3 mil to 6 mil).
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