TDA5100A Datasheet, PDF (23/29 Pages) Infineon Technologies AG – ASK Transmitter 434 MHz

TDA 5100 A
preliminary
Applications
2. Design hints on the buffered clock output (CLKOUT)
The CLKOUT pin is an open collector output. An external pull up resistor (RL)
should be connected between this pin and the positive supply voltage. The
value of RL is depending on the clock frequency and the load capacitance CLD
(PCB board plus input capacitance of the microcontroller). RL can be calculated
to:
RL =
1
fCLKOUT *8*CLD
Table 4-2
CL[pF]
5
10
20
fCLKOUT=3.39 MHz
RL[kOhm]
6.8
3.3
1.8
Remark: To achieve a low current consumption and a low
spurious radiation, the largest possible RL should be chosen.
Wireless Components
4-6
Specification, March 2001