TDA5220XT Infineon Technologies, TDA5220XT Datasheet - Page 19

• 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

3
3.1
Figure 3
The LNA automatic gain control circuitry consists of an operational transimpedance
amplifier that is used to compare the received signal strength signal (RSSI) generated
by the Limiter with an externally provided threshold voltage U
following figure the threshold voltage can have any value between approximately 0.8 and
2.8V to provide a switching point within the receive signal dynamic range.
This voltage U
generated by attaching a voltage divider between the 3VOUT pin
(Pin 24) which provides a temperature stable 3V output generated from the internal
bandgap voltage and the THRES pin. If the RSSI level generated by the Limiter is higher
than U
TAGC pin (Pin 4). Otherwise, the OTA generates a negative current. These currents do
not have the same values in order to achieve a fast-attack and slow-release action of the
Preliminary Specification
thres
, the OTA generates a positive current I
Applications
Application Circuit
LNA Automatic Gain Control Circuity
thres
R S S I > U
R S S I < U
is applied to the THRES pin (Pin 23) The threshold voltage can be
3 V O U T
t h re s h o ld
t h r e s h o ld
2 4
: I
: I
lo a d
lo a d
2 0 k
= 4 . 2 µ A
= - 1 .5 µ A
T A G C
+ 3 . 1 V
C 5
R 4
U
4
I
C
lo a d
T H R E S
19
U
U
U
U
c
c
c m a x
c m in
: < 2 . 6 V : G a in h ig h
: > 2 . 6 V : G a in lo w
C 1 8
2 3
= V
= 1 . 6 7 V
O T A
C C
U
load
t h r e s h o ld
- 0 . 7 V
G a in c o n t r o l
R 5
. This yields a voltage rise on the
v o lt a g e
V C C
R S S I ( 0 . 8 - 2 . 8 V )
L N A
thres
. As shown in the
V 1.1, 2004-10-20
Applications
TDA 5220