tda5251f1 Infineon Technologies Corporation, tda5251f1 Datasheet - Page 64

• Manufacturer Part Number: tda5251f1
• Description: Ask/fsk 315mhz Wireless Transceiver
• Manufacturer: Infineon Technologies Corporation

Confidential
Component calculation: (rule of thumb)
3.6.3
The TDA5251 data output can be digital (pin 28) or in analog form by using the peak detector output
and changing some settings.
To get an analog data output the slicer must be set to lowpass mode (Reg. 0, D15 = LP = 0) and
the peak detector capacitor at pin 12 or 13 has to be changed to a resistor of about 47kOhm.
Figure 3-26
3.6.4
For a safe and fast threshold value generation the peak detector is turned on by the sequencer
circuit (see Section 2.4.18) only after the entire receiving path is active.
In the off state the output of the positive peak detector is tied down to GND and the output of the
negative peak detector is pulled up to VCC.
Preliminary Specification
C
C
P
n
³
³
2
100
100
2
*
*
T
T
k
k
L
L
Peak Detector - Analog output signal
Peak Detector – Power Down Mode
W
W
1
2
Peak Detector as analog Buffer (v=1)
T
L1
T
L2
– longest period of no signal change (LOW signal)
Data
Filter
– longest period of no signal change (HIGH signal)
Signal
100k
Slicer Threshold
Detector
Detector
R
+ Peak
- Peak
+
-
DataSlicer
64
Contr.
Logic
100k
100k
Vcc
DATA
PDP
PDN
28
13
SLC
14
12
47k
C
SLC
TDA5251 F1
Version 1.0
Application
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2003-02-18
PkD_analog.wmf