CHM2179B Datasheet, PDF (6/9 Pages) United Monolithic Semiconductors – W-band Mixer

CHM2179b
W-band Mixer
Typical Bias and IF Configuration
Several external configurations are possible for bias and IF. The objective is to give
flexibility for the integration.
As this component is mainly dedicated to low IF use, there are several possibilities for
interfacing with low noise IF amplifier. The optimum IF load for conversion loss is 200Ω,
however depending on the IF amplifier noise characteristic this load can be modified in order to
optimise the noise figure. A series capacitor, between IF output and the load is recommended.
Due to high sensitivity to electrical discharges an integrated resistance is used and two ports
are available for biasing. One is for the connection of a decoupling capacitor (C_ext) and the
other one is for the supply voltage connection through an external series resistance (+V port).
However, in order to keep the compatibility with the CHM2179, only the “C_ext” port can be
used.
C_bias
C_ext
LO
+V
R_bias1
+V
1k
+V
R_load_IF
C_IF
IF
C_bias
R_bias2
C_ext
+V
1k
RF
LO
R_load_IF
C_IF
IF
RF
Recommended external bias and
IFconfiguration
Other possible configuration
(Compatible with the previous version)
The recommended values for external components are:
C_bias
R_bias1
R_bias2
R_load_IF
R_bias*C >> 1/F_IF
2.9kΩ for 1mA current consumption (V = 4.5V, typical LO
power)
R_bias2 = R_bias1 + 1kΩ
From 50 to 200Ω
Notes::
1. R_bias = R_bias1 + 1kΩ when “+V” port is used, otherwize R_bias = R_bias2
2. R_bias can be adjusted if necessary; This allows to optimise the performances when some
parameters are different from recommended ones (Supply voltage, LO power …). However
maximum ratings for the current have to be taken into account.
3. A series capacitor at IF outputs is recommended for DC decoupling.
Ref. : DSCHM2179b6013 - 13 Jan 06
6/9
Specifications subject to change without notice
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