TDA5251 Infineon Technologies, TDA5251 Datasheet - Page 67

• Manufacturer Part Number: TDA5251
• Description: TXRX FSK/ASK SGL LP TSSOP-38
• Manufacturer: Infineon Technologies
• Type: Transceiverr

Specifications of TDA5251

• Package / Case: 38-TSSOP
• Frequency: 315MHz
• Data Rate - Maximum: 64kbps
• Modulation Or Protocol: ASK, FSK
• Applications: RKE, Remote Control Systems
• Power - Output: 13dBm
• Sensitivity: -109dBm
• Voltage - Supply: 2.1 V ~ 5.5 V
• Current - Receiving: 9.3mA
• Current - Transmitting: 14mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Operating Frequency: 0.35 MHz
• Operating Supply Voltage: 2.5 V, 3.3 V, 5 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Product Depth (mm): 4.4mm
• Product Length (mm): 9.7mm
• Operating Supply Voltage (min): 2.1V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Compliant
• Other names: SP000014554; TDA5251; TDA5251INTR; TDA5251XT

3.7.1
The high time of data is used to measure the frequency of the data signal. For Manchester coding
either the data frequency or half of the data frequency have to be detected corresponding to one
high time or twice the high time of data signal.
A time period of 3*2*T is necessary to decide about valid or invalid data.
Figure 3-31
Example to calculate the thresholds for a given data rate:
- Data signal manchester coded
- Data Rate: 2kbit//s
- f
Then the period equals to
respectively the high time is 0,25ms.
We set the thresholds to +-10% and get: T1= 0,225ms and T2= 0,275ms
The thresholds TH1 and TH2 are calculated with following formulas
Data Sheet
clk
= 13,125 MHz
Frequency Window for Data Rate Detection
Window Counter timing
possible
possible
GATE 1
GATE 2
DATA
TH2
TH1
2
⋅
T
0
0
=
T2
T1
=
T
=
T2
2kbit/s
T1
⋅
0
0
1
⋅
f
f
2*T2
2*T1
clk
4
clk
2*T
4
67
=
1
1
0,5ms
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[3 – 38]
0
[3 – 36]
t
t
t
window_count_timing.wmf
TDA5251 F1
Version 1.1
Application
2007-02-26