TDA5250D2 Datasheet, PDF (34/97 Pages) Infineon Technologies AG – ASK/FSK 868MHz Wireless Transceiver

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TDA 5250 D2
preliminary
Functional Description
3.4.18 Sequence Timer
The sequence timer has to control all the enable signals of the analog
components inside the chip. The time base is the 32 kHz RC oscillator.
After the first POWER ON or RESET a 1 MHz clock is available at the clock
output pin. This clock output can be used by an external µP to set the system
into the desired state and outputs valid data after 500 µs (see Figure 3-15 and
Figure 3-16, t_CLKSU)
There are two possibilities to start the device after a reset or first power on:
- PWDDD pin is LOW: Normal operation timing is performed after t_SYSSU (see
Figure 3-15).
- PWDDD pin is HIGH (device in power down mode): A clock is offered at the
clock output pin until the device is activated (PWDDD pin is pulled to LOW).
After the first activation the time t_SYSSU is required until normal operation
timing is performed (see Figure 3-16 ).
This could be used to extend the clock generation without device program-
ming or activation.
Note: It is required to activate the device for the duration of t_SYSSU after first
power on or a reset. Only if this is done the normal operation timing is
performed.
With default settings the clock generating units are disabled during PD,
therefore no clock is available at the clock output pin. It is possible to offer a
clock signal at the clock output pin every time (also during PD) if the CLK_EN
Bit in the CONFIG register is set to HIGH.
RESET
or 1^st POWER ON
PWDDD = low
STATUS
XTAL EN
DC OFFSET COMPENSATION
PEAK DETECTOR EN
DATADETECTION EN
POWER AMP EN
t_CLKSU
0.5ms
TX activ or RX activ
PD
CLOCK FOR EXTERNAL µP
if RX
if RX
if RX
t_TXSU
1.1ms
t_SYSSU
8ms
if TX
t_CLKSU
0.5ms
t_RXSU
2.2ms
t_{D D SU}
2.6ms
TX activ
PD
t_TXSU
1.1ms
t_CLKSU
0.5ms
Figure 3-15 1^st start or reset in active mode
RX activ
TX activ
RX activ
t_RXSU
2.2ms
t_TXSU
1.1ms
t_DDSU
2.6ms
t_{R XS U}
2.2ms
t_{D D S U}
2.6ms
Sequenzer_Timing_pupstart.wmf
Note: The time values are typical values
Wireless Components
3 - 24
Specification, July 2002