PLL Tuned UHF Transmitter for Data Transfer Applications, Rev. 1.7
Freescale Semiconductor2
1 Transmitter Functional Description . . . . . . . . . . . . . . . . . . . . . .4
2 Phase Locked Loop and Local Oscillator . . . . . . . . . . . . . . . . .4
3 Radio Frequency (RF) Output Stage . . . . . . . . . . . . . . . . . . . .4
4 Modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
5 Microcontroller Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
6 State Machine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
7 Power Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
8 Data Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
9 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
10 RF Output Spectrum. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
11 Output Power Measurement. . . . . . . . . . . . . . . . . . . . . . . . . .14
12 Complete Application Schematic and
PCB for OOK Modulation . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
13 Complete Application Schematic and
PCB for FSK Modulation. . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
14 Recommendations for FSK Modulation . . . . . . . . . . . . . . . . .19
15 Case Outline Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
List of Figures
Figure 1.Simplified Block Diagram . . . . . . . . . . . . . . . . . . . . . . . 3
Figure 2.Crystal Pulling Configurations. . . . . . . . . . . . . . . . . . . . 5
Figure 3.State machine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 4.Signals Waveform and Timing Definition . . . . . . . . . . . 7
Figure 5.RF Spectrum at 434 MHz Frequency Band
Displayed with a 5 MHz Span . . . . . . . . . . . . . . . . . . . 11
Figure 6.RF Spectrum at 434 MHz Frequency Band
Displayed with a 50 MHz Span . . . . . . . . . . . . . . . . . . 11
Figure 7.RF Spectrum at 434 MHz Frequency Band
Displayed with a 1.5 GHz Span . . . . . . . . . . . . . . . . . 12
Figure 8.RF Spectrum at 434 MHz Band
for a 70 kHz FSK Deviation at 4.8 kbit/s . . . . . . . . . . . 12
Figure 9.Output Power Measurement Configurations . . . . . . . . 13
Figure 10.Output Model and Matching Network
for 434 MHz Band . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 11.Output Power at 434 MHz Band vs Rext Value . . . . . 14
Figure 12.Application Schematic for OOK Modulation,
434 MHz Frequency Band. . . . . . . . . . . . . . . . . . . . . . 15
Figure 13.Two-Button Keyfob Board Layout. . . . . . . . . . . . . . . . 16
Figure 14.Application Schematic for FSK Modulation,
Serial Configuration, 434 MHz Frequency Band . . . . . 17
Figure 15.Application PCB Layout for FSK Modulation,
Serial Configuration, 434 MHz Frequency Band . . . . . 18
Figure 16.Crystal Load Capacitance Contributors Schematic . . 19
Figure 17.Case Outline Dimensions . . . . . . . . . . . . . . . . . . . . . 20
List of Tables
Table 1. Pin Function Description . . . . . . . . . . . . . . . . . . . . . . . . 3
Table 2. Absolute Maximum Ratings. . . . . . . . . . . . . . . . . . . . . . 3
Table 3. Band Selection and Associated Divider Ratios . . . . . . . 4
Table 4. DATACLK Frequency vs Crystal Oscillator Frequency. . 5
Table 5. Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . 8
Table 6. External Components Description for OOK. . . . . . . . . 15
Table 7. Typical Crystal Characteristics (SMD Package) . . . . . 16
Table 8. External Components Description for FSK . . . . . . . . . 17
Table 9. Crystal Pulling Capacitor Values vs
Carrier Frequency Total Deviation -1- . . . . . . . . . . . . . 18
Table 10.Crystal Pulling Capacitor Values vs
Carrier Frequency Total Deviation -2- . . . . . . . . . . . . . 18
Table 11.Pads and Tracks Parasitic Values . . . . . . . . . . . . . . . . 19
