SI4438 Datasheet, PDF (27/44 Pages) Silicon Laboratories – Low active power consumption

Si4438
Number
0x2200
0x2201
0x2202
0x2203
Command
PA_MODE
PA_PWR_LVL
PA_BIAS_CLKDUTY
PA_TC
Summary
Sets PA type.
Adjust TX power in fine steps.
Adjust TX power in coarse steps
and optimizes for different
match configurations.
Changes the ramp up/down time
of the PA.
5.4.1. Si4438: +20 dBm PA
The +20 dBm configuration utilizes a class-E matching configuration. Typical performance for output power steps,
voltage, and temperature are shown in Figures 7–9. The output power is changed in 128 steps through
PA_PWR_LVL API. For detailed matching values, BOM, and performance at other frequencies, refer to the PA
Matching application note.
TX Power vs. PA_PWR_LVL
25
20
15
10
5
0
-5
-10
-15
-20
-25
-30
-35
0
10 20 30 40 50 60 70 80 90 100 110 120
PA_PWR_LVL
Figure 7. +20 dBm TX Power vs. PA_PWR_LVL
TX Power vs. VDD
22
20
18
16
14
12
10
1.8 2 2.2 2.4 2.6 2.8 3 3.2 3.4 3.6
Supply Voltage (VDD)
Figure 8. +20 dBm TX Power vs. VDD
Rev 1.0
27