Datasheet

( ) ( )
( ) ( ) ( )
( ) ( )
0 d 0
0 0 0
d 0 d
Vi(t) sin t t t
4 1 1
LO(t) sin t sin 3 t sin 5 t ...
3 5
2
Vo(t) cos t cos 2 t t ...
= w + w + j + w
é ù
= w + w + w
ê ú
p
ë û
é ù
= w + f - w - w + f
ë û
p
f
Vi(t) Vo(t)
LO(t)
500Ω
500Ω
500Ω
500Ω
500Ω
500Ω
I/V Sum
Amp
Cext
Cext
Rint/Rext
Rint/Rext
CW_OUTM
CW_OUTP
Mixer Clock 1
Mixer Clock 2
Mixer Clock 8
LNA1
IN1
INM1
LNA2
IN2
INM2
LNA8
IN8
INM8
ACT1
ACT2
ACT8
CW I or Q CHANNEL
Structure
INPUT1
INPUT2
INPUT8
CW_AMPINP
CW_AMPINM
10Ω
10Ω
AFE5808A
www.ti.com SLOS729B –OCTOBER 2011–REVISED APRIL 2012
Note: the 10Ω resistors at CW_AMPINM/P are due to internal IC routing and can create slight attenuation.
Figure 70. A Complete In-phase or Quadrature Phase Channel
The CW mixer in the AFE5808A is passive and switch based; passive mixer adds less noise than active mixers.
It achieves good performance at low power. The below illustration and equations describe the principles of mixer
operation, where Vi(t), Vo(t) and LO(t) are input, output and local oscillator (LO) signals for a mixer respectively.
The LO(t) is square-wave based and includes odd harmonic components as the below equation expresses:
Figure 71. Block Diagram of Mixer Operation
(2)
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