TDK5110FHTMA1 Infineon, TDK5110FHTMA1 Datasheet - Page 31

• Manufacturer Part Number: TDK5110FHTMA1
• Description: Transmitter Ask/Fsk Sgl Tssop10
• Manufacturer: Infineon

Wireless Components
The output power P
characterised by R
The power efficiency (and the bandwidth) increase when operating at a slightly
higher R
The collector efficiency E is defined as
The diagram of Figure 4-9 was measured directly at the PA-output at V
Losses in the matching circuitry decrease the output power by about 1.5 dB. As
can be seen from the diagram, 250
at 3 V. For an approximation of R
two formulas can be used:
and
Figure 4-9
The DC collector current I
vary with the load resistor R
amplifiers. The collector current will show a characteristic dip at the resonance
frequency for this type of “overcritical” operation. The depth of this dip will
increase with higher values of R
E
P
R
V
OUT
OPT
P
S
O
I
L
C
, as shown in Figure 4-9.
~
~
R
18
16
14
12
10
V
8
6
4
2
0
Output power P
OPT
0
S
L
> R
100
o
4 - 11
LC
is reduced by operating in an “overcritical” mode
c
.
o
of the power amplifier and the RF output power P
L
(mW) and collector efficiency E vs. load resistor R
. This is typical for overcritical operation of class C
200
RL [Ohm]
L
.
OPT
300
and P
is the optimum impedance for operation
OUT
400
at other supply voltages those
500
Specification, October 2002
Pout [mW]
10*Ec
Applications
TDK 5110
Power_E_vs_RL.wmf
S
= 3 V.
L
.
o