AMMC-3040 Datasheet, PDF (6/6 Pages) Agilent(Hewlett-Packard) – 18-36 GHz Double-Balanced Mixer with Integrated LO Amplifier/Multiplier

Biasing for Sub-Harmonic Mixing
The LO amplifier in the AMMC-3040 can also be used
as a frequency doubler. Optimum conversion efficiency
as a doubler is obtained with an input power level of
3 to 8 dBm.
Frequency multiplication is achieved by reducing the
bias on the first stage FET to efficiently generate har-
monics. The remaining three stages are then used to
provide amplification.
While many bias methods could be used to generate
and amplify the desired harmonics within the AMMC-
3040’s LO amplifier, the following information is sug-
gested as a starting point for subharmonic mixing
applications.
Frequency doubling is accomplished by biasing the
first stage FET at pinch-off by setting V_g1 = V_p ≈ –1.1
volts. The remaining three stages are biased for normal
amplification, e.g., V_gg is adjusted such that I_d2 + I_d3 + I_d4 ≈
250 mA. The drain voltage, Vdd, for all four stages should
be 3.5 to 4.5 volts. The assembly diagram shown in
Figure 16(b) can be used as a guideline.
In all cases, Cb ≥ 100 pF to assure stability.
IF Output Port
The IF output port is located near the middle of the die,
allowing this connection to be made from either side
of the chip for maximum layout flexibility.
The LO and RF signals are reflectively terminating at
the IF port by connecting a 20-mil (500 µm) long bond
wire from the IF output pad on the MMIC to a shunt
0.6 pF chip capacitor mounted off- chip as indicated
in Figure 16.
Assembly Techniques
The backside of the AMMC-3040 chip is RF ground. For
microstripline applications, the chip should be attached
directly to the ground plane (e.g., circuit carrier or heat-
sink) using electrically conductive epoxy . ^[1,2]
For best performance, the topside of the MMIC should
be brought up to the same height as the circuit sur-
rounding it. This can be accomplished by mounting a
gold plated metal shim (same length and width as the
MMIC) under the chip, which is of the correct thickness
to make the chip and adjacent circuit coplanar.
The amount of epoxy used for chip and or shim at-
tachment should be just enough to provide a thin fillet
around the bottom perimeter of the chip or shim. The
ground plane should be free of any residue that may
jeopardize electrical or mechanical attachment.
For use on coplanar circuits, the chip can be mounted
directly on the topside ground plane of the circuit as
long as care is taken to ensure adequate heat sinking.
Multiple vias underneath the chip will significantly
improve heat conduction.
The location of the RF, LO, and IF bond pads is shown
in Figure 15. Note that all RF input and output ports are
in a Ground-Signal-Ground configuration. The IF port is
located near the middle of the die, which allows for
maximum layout flexibility since the IF connection can
be made from either side of the chip.
RF connections should be kept as short as reasonable
to minimize performance degradation due to series
inductance. A single bond wire is sufficient for all signal
connections. However, double-bonding with 0.7 mil
gold wire or the use of gold mesh is recommended for
best performance, especially near the high end of the
frequency range.
Thermosonic wedge bonding is the preferred method
for wire attachment to the bond pads. Gold mesh can
be attached using a 2 mil round tracking tool and a
tool force of approximately 22 grams with an ultrasonic
power of roughly 55 dB for a duration of 76 ± 8 mS.
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.
Caution should be taken to not exceed the Absolute
Maximum Ratings for assembly temperature and time.
The chip is 100 µm thick and should be handled with
care. This MMIC has exposed air bridges on the top
surface and should be handled by the edges or with
a custom collet (do not pick up die with vacuum on
die center.)
This MMIC is also static sensitive and ESD handling
precautions should be taken.
Notes:
1. Ablebond 84-1 LM1 silver epoxy is recommended.
2. Eutectic attach is not recommended and may jeopardize reliability
of the device.
Ordering Information:
AMMC-3040-W10 = 10 devices per tray
AMMC-3040-W50 = 50 devices per tray
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Data subject to change. Copyright © 2005-2008 Avago Technologies Limited. All rights reserved. Obsoletes 5989-3932EN
AV02-1040EN - June 24, 2008