TDK5110XT Infineon Technologies, TDK5110XT Datasheet - Page 30

• Manufacturer Part Number: TDK5110XT
• Manufacturer: Infineon Technologies

Specifications of TDK5110XT

• Operating Temperature (min): -40C
• Operating Temperature (max): 125C
• Operating Temperature Classification: Automotive
• Product Depth (mm): 4.4mm
• Operating Supply Voltage (min): 2.1V
• Operating Supply Voltage (typ): 2.5/3.3V
• Lead Free Status / Rohs Status: Compliant

Wireless Components
4.7 Application Hints on the Power-Amplifier
The power amplifier operates in a high efficient class C mode. This mode is
characterized by a pulsed operation of the power amplifier transistor at a current
flow angle of
passes the fundamental frequency component of the pulse spectrum of the
collector current to the load. The load and its resonance transformation to the
collector of the power amplifier can be generalized by the equivalent circuit of
Figure 4-8. The tank circuit L//C//RL in parallel to the output impedance of the
transistor should be in resonance at the operating frequency of the transmitter.
Figure 4-8
The optimum load at the collector of the power amplifier for “critical” operation
under idealized conditions at resonance is:
A typical value of R
“Critical” operation is characterized by the RF peak voltage swing at the
collector of the PA transistor to just reach the supply voltage V
The high degree of efficiency under “critical” operating conditions can be
explained by the low power losses at the transistor. During the conducting
phase of the transistor, its collector voltage is very small. This way the power
loss of the transistor, equal to i
small current flow angles of
In practice the RF-saturation voltage of the PA transistor and other parasitics
reduce the “critical” R
R
LC
R
LC
V
2
P
S
2
O
2
3
Equivalent power amplifier tank circuit
. 0
2
01
<<
LC
450
. A frequency selective network at the amplifier output
LC
for an RF output power of P
4 - 10
.
L
<<
C
*u
C
CE
, is minimized. This is particularly true for
R
V
L
S
o
= 10 mW is:
Specification, October 2002
S
.
Applications
TDK 5110
Equivalent_power_wmf.