TDA5220XT Infineon Technologies, TDA5220XT Datasheet - Page 29

• Manufacturer Part Number: TDA5220XT
• Manufacturer: Infineon Technologies

Specifications of TDA5220XT

• Operating Temperature (min): -40C
• Operating Temperature (max): 125C
• Operating Temperature Classification: Automotive
• Product Depth (mm): 4.4mm
• Product Length (mm): 9.7mm
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / Rohs Status: Compliant

In order to reduce the turn-on time in the presence of large values of C a precharge
circuit was included in the TDA5220 as shown in the following figure.
Figure 12
This circuit charges the capacitor C13 with an inrush current I
duration of T
at the input of the data filter. This voltage is limited to 2.5V. As soon as these voltages
are equal or the duration T
as the sum of R4 and R5 is sufficiently large and thus can be neglected. T
calculated according to the following formula:
Preliminary Specification
2
is the time constant of the charging process of C18 which can be calculated as
20k
24
2
Principle of the precharge circuit
until the voltage U
U2
+3.1V
R4
R4+R5=600k
Uc>Us
C18
23
U
threshold
-
OTA
R5
2
Uc<Us
T
is exceeded the precharge circuit is disabled.
0 / 240uA
2
+2.4V
U2<2.4V : I=240uA
U2>2.4V : I=0
c
appearing on the capacitor is equal to the voltage U
2
I
load
ln
2






1
-
+
20
20
29
2
1
k
3
Uc
4 .
V
C13
V
R1






C
19
2
Us
2
Data Filter
1
6 .
load
of typically 220µA for a
ASK/FSK Switch
V 1.1, 2004-10-20
Applications
2
can then be
TDA 5220
s