PLL Tuned UHF Transmitter for Data Transfer Applications, Rev. 1.7
RF Output Spectrum
Freescale Semiconductor10
10 RF Output Spectrum
The following figures represent spectrums of the transmitter carrier, measured in conduction mode. Three different spans have
been used. The 5 MHz span spectrum (Figure 5) shows phase noise response close to the RF carrier and the noise suppression
within the PLL-loop bandwidth. The 50 MHz span spectrum (Figure 6) shows phase noise and reference spurious. Finally, the
1.5 GHz span spectrum (Figure 7) shows the second and third harmonics of carrier. All spectrums are measured in OOK
modulation at DATA=1.
Figure 8 shows the spectrum in case of FSK modulation with 45 kHz deviation at 4 kbit/s data rate.
2.41
Data to RF delay difference between
falling and rising edges,
t
delay_difference
MODE = 0, see note 3.5 5.25 7.5 µs
2.42
MODE = 1, see note –200 — 200 ns
Note: This parameter is depending on crystal characteristics, load capacitor values (see Tabl e 4) and PCB track capacitance.
Note: Delay difference definition
3
Microcontroller Interfaces
3.1
Input low voltage Pins: BAND, MODE, ENABLE, and DATA 0 — 0.3 x
V
CC
V
3.2
Input high voltage 0.7 x
V
CC
—V
CC
V
3.3
Input hysteresis voltage — — 120 mV
3.4
Input current Pins: BAND, MODE,DATA = 1 — — 100 nA
3.5
ENABLE pulldown resistor — 180 — kΩ
3.6
DATACLK output low voltage C
load
= 2 pF 0 — 0.25 x
V
CC
V
3.7
DATACLK output high voltage 0.75 x
V
CC
—V
CC
V
3.8
DATACLK rising time C
load
= 2 pF, measured from 20% to 80% of the
voltage swing
— 250 500 ns
3.9
DATACLK falling time — 150 400 ns
3.10
DATACLK settling time,
t
DATACLK_settling
45% < duty cycle f
DATACLK
< 55% — 800 2000 µs
Table 5. Electrical Characteristics (continued)
Parameter Test Conditions, Comments
Limits
Unit
Min. Typ. Max.
Input data
Demodulated data
t
delay_rise
t
delay_fall
From 50% of data edge to corresponding
t
delay_difference
=t
delay_fall
–t
delay_rise
demodulated signal envelope edge:
