AT86RF211SAHW Atmel, AT86RF211SAHW Datasheet - Page 24

• Manufacturer Part Number: AT86RF211SAHW
• Manufacturer: Atmel

Specifications of AT86RF211SAHW

• Lead Free Status / Rohs Status: Compliant

4.3.1
24
0894C–WIRE–11/08
Power Amplification
The Power Amplifier has been built to deliver more than 14 dBm (25 mW in the three most common fre-
quency bands). This power level is intended to be measured on the aerial port with a correct output
matching network. Note that correct calculation of the matching network guarantees optimal power
efficiency.
Figure 4-21. Output of the Power Amplifier
The PA must be correctly matched to deliver the best output power and current consumption.
22 on page 24
Figure 4-22. Output Matching of the Power Amplifier
Note:
This network has the benefit of filtering the output signal’s harmonic levels; hence it can be designed to
meet a particular regulation.
It is mandatory to implement low impedance grounding techniques. Excessive inductor values to ground
can not only limit the PA output voltage swing, but can also trigger RF instability. Board design is vital to
avoid parasitic loss when a high output power is needed (a direct short connection to a single low imped-
ance ground plane).
An Automatic Level Control (ACL) loop is integrated to minimize the PA’s sensitivity to temperature, pro-
cess and power supply variations. For instance, at 85°C, the output power is approximately 2 dB less
than at 25°C. At -40°C, the output power is higher than at 25°C. The ALC is controlled by a generated
current as shown in
Vcc
The filter is designed to meet relevant regulations. Refer to the Application Note “AT86RF211S Transceiver
for ISM Radio Applications - RF BOM versus Application Requirements” reference 5305, for details.
PA Output
gives an example of the typical recommended output network in the 868 MHz band.
Power Supply
Filtering
RF
Figure 4-23 on page
1.5 nH
A
50Ω
Supply Inductor:
18 nH at 433 MHz
12 nH at 868 MHz
10 nH at 915 MHz
25.
C0
L1
~ 50Ω Matched Filtering
C1
L2
C2
e2v semiconductors SAS 2008
AT86RF211S
C3
Aerial
Figure 4-