MRFIC2001 Ver la hoja de datos (PDF) - Motorola => Freescale
Número de pieza
componentes Descripción
Fabricante
MRFIC2001 Datasheet PDF : 6 Pages
| |||
TYPICAL CHARACTERISTICS
8.0
7.0
VCC = 3 V
6.0
7.0
5.0
TA = 85°C
VCC = 3 V
4.0
6.0
3.0
4V
5.0
5V
4.0
–180
–120
– 60
0
TA = 25°C
2.0
fRF = 900 MHz
PLO = –7 dBm
1.0
fLO = 1 GHz
0
60
120
180
0
θIM, REFLECTION COEFFICIENT PHASE ANGLE OF
RF PORT IMAGE TERMINATION (°)
– 35°C
25°C
1.0
2.0
3.0
4.0
5.0
ENABLE, ENABLE VOLTAGE (VOLTS)
Figure 11. Noise Figure versus Reflection Coefficient
Phase Angle of RF Port Image Termination
Figure 12. Supply Current versus Enable Voltage
12
TA = 25°C
10
VCC = 5 V
8.0
4V
6.0
3V
4.0
2.0
0
0
1.0
2.0
3.0
4.0
5.0
ENABLE, ENABLE VOLTAGE (VOLTS)
Figure 13. Supply Current versus Enable Voltage
APPLICATIONS INFORMATION
DESIGN PHILOSOPHY
The MRFIC2001 was designed for low cost, small size,
and ease of use. This is accomplished by minimizing the
number of necessary external components.
The most significant external component eliminated
was an image filter between the LNA and mixer. It was
found the ensuing image noise entering the mixer from
the LNA could be minimized by optimizing the LNA input
termination at the image frequency. Also, a double-bal-
anced mixer was used to reject the IF noise from the LNA.
This results in excellent LO and spurious rejection.
To eliminate the need for external baluns or decoupling
elements, the unused LO and RF ports of the mixer are
decoupled internally. Only one of the IF outputs is used,
eliminating the need for an external balun on the IF port
as well. Also, the LNA input is matched to 50 ohms inter-
nally. External matching is required for the LO and IF
ports.
To minimize current drain in various TDD/TDMA sys-
tems, the MRFIC2001 has a TTL/CMOS compatible en-
able pin.
THEORY OF OPERATION
Optimizing the LNA input termination to minimize image
noise is quite simple. The optimum LNA input (RF IN pin) ter-
mination is 1∠30° at the image frequency (regardless of what
the image frequency is). A reflection coefficient magnitude
close to 1 is automatically obtained from a front-end filter,
since the image frequency would be in the stop-band. The 30°
phase angle can be obtained by rotating the phase angle of
the front-end filter with a series 50 ohm transmission line. The
dependance of single-sideband noise figure on the image
phase angle is shown in Figure 11. As the plot indicates, there
is a little over 1.0 dB of variation across all possible phase
angles for a 3.0 V supply. Therefore, setting the phase angle is
not critical. At higher supply voltages setting the phase angle
is more critical (and more rewarding).
MOTOROLA RF DEVICE DATA
MRFIC2001
5
Share Link: 