IAM-91563-TR1 Avago Technologies US Inc., IAM-91563-TR1 Datasheet - Page 9

• Manufacturer Part Number: IAM-91563-TR1
• Description: IC,Downconverter,GAAS,TSSOP,6PIN,PLASTIC
• Manufacturer: Avago Technologies US Inc.

Specifications of IAM-91563-TR1

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Impedance matching can be accomplished with lumped
element components, transmission lines, or a combi-
nation of both. The use of surface mount inductors and
capacitors is convenient for lower frequencies to mini-
mize printed circuit board space. The use of high
impedance transmission lines works well for higher
frequencies where lumped element inductors may have
excessive parasitics and/or self-resonances.
If other types of matching networks are used, it should
be noted that while the RF input terminal of the IAM-
91563 is at ground potential, it should not be used as a
current sink. If the input is connected directly to a
preceding stage that has a voltage present, a DC block-
ing capacitor should be used.
IF port
The IAM-91563 can be used for downconvesion to
intermediate frequencies in the 50 to 700 MHz range.
Similar to the RF port, the reflection coefficient at the
IF is fairly high and Equation 1 can be used to predict
a mismatch gain of up to 2.2 dB by impedance match-
ing. A well matched IF port will also provide the
optimum output power and LO-to-IF isolation. Reflec-
tion coefficients for the IF port are shown in the
Typical Reflection Coefficients Table.
The IF port impedance matching network should be of
the low pass filter type to reflect RF and LO power back
into the mixer while allowing the IF to pass through.
The shunt C, series L type of network in Figure 24 is a
very practical choice that will meet the low pass filter
requirement while matching any IF impedances over
the 50 - 700 MHz range to 50 ohms.
Figure 24. IF Output LPF Matching.
The DC bias is also applied to the mixer through the IF
port. Figure 25 shows how an inductor (RFC) is used to
isolate the IF from the DC supply. The bias line is
bypassed to ground with a capacitor to keep RF off of
the DC supply lines and to prevent dips or peaks in the
response of the mixer.
RF
LO
IF
Output
IF
Figure 25. Bias Connection.
LO Port
The LO input port is internally matched to 50 Ω within
a 2.2:1 VSWR over the entire operating frequency range.
Additional matching will normally not be needed. How-
ever, if desired, a small series inductor can be used to
provide some improvement in the LO match and thus
reduce the LO drive level requirement by up to 0.7 dB.
Reflection coefficients for the LO port are shown in the
table of Typical Reflection Coefficients.
Source Bypass Pin
The Source Bypass pin should be RF bypassed to
ground at both the RF and LO frequencies as well as the
IF. Many capacitors with values large enough to ad-
equately bypass lower intermediate frequencies con-
tain parasitics that may have resonances in the RF
band. It is often practical to use two capacitors in
parallel for this purpose instead of one. A small value,
high quality capacitor is used to bypass the RF/LO
frequencies and a large value capacitor for the IF.
When biased in the high linearity mode, a resistor is
added from the Source Bypass pin to ground.
High Linearity Mode
The IAM-91563 has a feature that allows the user to
place an external resistor from the Source Bypass pin
to ground and increase the device current from a
nominal 9 mA to as high as 20 mA. The additional
current increases mixer linearity (IP
power(P
rent is shown in Figures 26 and 27.
1dB
RF
). Mixer performance at higher device cur-
LO
IF
9
Capacitor
Bypass
RFC
3
) and output
Output
IF
V
d