W-band Dual Channel Mixer
External components for bias and IF
CHM2378a
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 the best results on noise figure have been obtained on 50Ω. 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 each mixer. One is for the connection of a decoupling capacitor (C1,
C2) and the other one is for the supply voltage connection through an external series
resistance (+V1, +V2). However, if necessary only the “C1, C2” ports can be used.
+V
R_load_IF
C1
V1
1k
IF1
C1
R_bias
V1
1k
C_IF
IF1
RF1
LO
RF2
1k
RF1
LO
RF2
1k
C2
C2
V2
IF2
V2
R_bias
IF2
C_IF
Block diagram of the MMIC
+V
R_load_IF
Recommended IF/DC external
configuration
The recommended values for external components are:
C1,C2
R_bias_t
R_bias_t*C >> 1/F_if
2.5kΩ for 1.5mA current consumption (V = 4.5V, typical LO
power)
From 50 to 200Ω
R_load_if
Notes::
1. R_bias_t = R_bias + 1kΩ when V1 and V2 ports are used.
2. R_bias_t can be adjusted if necessary; this allows optimising the performances when
some parameters are different from recommended (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. DSCHM2378a6354 - 20 Dec 06
5/8
Specifications subject to change without notice
Route Départementale 128, B.P.46 - 91401 ORSAY Cedex - FRANCE
Tel.: +33 (0) 1 69 33 03 08 - Fax: +33 (0) 1 69 33 03 09
UMS [ UNITED MONOLITHIC SEMICONDUCTORS ]
