TDA5252G2 INFINEON [Infineon Technologies AG], TDA5252G2 Datasheet - Page 59

• Manufacturer Part Number: TDA5252G2
• Description: ASK/FSK 915MHz Wireless Transceiver
• Manufacturer: INFINEON [Infineon Technologies AG]

3.5
The I/Q Limiters are DC coupled multistage amplifiers with offset-compensating feedback circuit
and an overall gain of approximately 80dB each in the frequency range of 100Hz up to 350kHz.
Receive Signal Strength Indicator (RSSI) generators are included in both limiters which produce DC
voltages that are directly proportional to the input signal level in the respective channels. The
resulting I- and Q-channel RSSI-signals are summed to the nominal RSSI signal.
Figure 3-19
The DC offset compensation needs 2.2ms after Power On or Tx/Rx switch. This time is hard wired
and independent from external capacitors C C on pins 31 to 38. The maximum value for this
capacitors is 47nF.
RSSI accuracy settling time = 2.2ms + 5*RC=2.2ms+5*37k*2.2nF=2.6ms
R - internal resistor; C - external capacitor at Pin 29
Table 3-11
Data Sheet
[nF]
220
100
Cc
47
22
10
Q- Filter
I- Filter
C
Limiter and RSSI
c
Limiter Bandwidth
Limiter and Pinning
f g
f g
38
37
C
lower limit
c
f3dB
1000
[Hz]
100
220
470
2200
36
35
C
c
34
Limiter
Limiter
Q
I
33
59
C
IQ Filter
c
upper
f3dB
limit
- ll -
- ll -
- ll -
- ll -
32
31
Quadr.
Quadr.
Corr.
Corr.
C
RSSI
setup time not guaranteed
setup time not guaranteed
SUM
29
Eval Board
Comment
RSSI
TDA5252 G2
Version 1.1
Application
37k
2007-02-26
limiter input.wmf