Application Circuit - Holtek HT66F03T3 Quick Start Manual

Application Circuit

The circuit in the frame is the harmonic inhibiting enhancement circuit which can be
ignored if not necessary.
Note: The value in the parentheses is for 433MHz. For example, 433.92MHz the Crystal
Y1 should be 13.56MHz.
Adjust Output Power with External Resistors
R1 in the application circuit is used to adjust the RF output power. In this example, the R1
resistor values for the 50 demo board and corresponding typical values of conducted
RF output levels are listed in the table below. R1 in the HT46/48R01T3 demo board uses
a dipole antenna which can be adjusted to an appropriate radiation to meet the
specifications of the design.
Output Power
HT66F03T3/68F03T3 MCU with 315MHz/433MHz ASK Transmitter
R1()
(dBm)
10 0
3 390
0 560
Typical I
433MHz
7.8
5.0
4.0
2
of PA (mA)
D
315MHz
8.8
5.0
4.0