Mobile Tech Co. Ltd 64MXFWBF110A Manuale Utente
11
Table
Table
Table
Table3:
3:
3:
3: Power
Power
Power
Power supply
supply
supply
supply pins
pins
pins
pins on
on
on
on the
the
the
the half-circle
half-circle
half-circle
half-circle connector
connector
connector
connector
Num
Name
Function
I/O
Min
(V)
(V)
Type
(V)
(V)
Max
(V)
(V)
Note
1,2
VBAT
Power
Supply
Supply
Input
3.3
4.2
4.6
Please make sure
t h a t t h e i n p u t
voltage will never
drops below 3.3V
even in a transmit
burst during which
t h e
t h a t t h e i n p u t
voltage will never
drops below 3.3V
even in a transmit
burst during which
t h e
c u r r e n t
consumption may
r i s e u p t o 2 A .
r i s e u p t o 2 A .
3,65,67
GND
GND
GND
Minimizing
Minimizing
Minimizing
Minimizing power
power
power
power losses
losses
losses
losses
Please pay special attention to the supply power when you are designing your applications.
Please make sure that the input voltage will never drops below 3.3V even in a transmit
burst during which the current consumption may rise up to 2A. If the power voltage drops
below 3.3V, the module may be switched off. You should also take the resistance of the
power supply lines on the host board or of battery pack into account.
Please make sure that the input voltage will never drops below 3.3V even in a transmit
burst during which the current consumption may rise up to 2A. If the power voltage drops
below 3.3V, the module may be switched off. You should also take the resistance of the
power supply lines on the host board or of battery pack into account.
3.5.
3.5.
3.5.
3.5. Power
Power
Power
Power up
up
up
up and
and
and
and power
power
power
power down
down
down
down scenarios
scenarios
scenarios
scenarios
3.5.1.
3.5.1.
3.5.1.
3.5.1.
Turn
Turn
Turn
Turn on
on
on
on MD251
MD251
MD251
MD251
MD251 can be turned on by following two ways:
�
�
Via PWRKEY pin: You can turn on the MD251 to normal operating mode by driving
the PWRKEY to a low level voltage for 1500ms;
the PWRKEY to a low level voltage for 1500ms;
�
Via RTC interrupt: starts ALARM modes;
�
For some application system, we can connect the “PWRKEY” to “GND” so that the
module will be turn on as soon as the 3.8V power supply to the module. But, if
“PWRKEY” linked to “GND”, other keypad pin could not work. Here is a circuit to
make the module power on automatically. If the module power on, the GPIO which is
PD will output high level, on consequence, the “PWR_KEY” will be high level so that
other keypad pin could work.
module will be turn on as soon as the 3.8V power supply to the module. But, if
“PWRKEY” linked to “GND”, other keypad pin could not work. Here is a circuit to
make the module power on automatically. If the module power on, the GPIO which is
PD will output high level, on consequence, the “PWR_KEY” will be high level so that
other keypad pin could work.