User's Manual

A8000 User Guide
Confidential
A8000_User_Guide_V1.0 Page 7 of 22 2009/05/13
GPRS DATA
GPRS data transfer in progress. Power consumption depends on network settings (e.g.
power control level), uplink/downlink data rates and GPRS configuration (e.g. used
multi-slot settings).
SWITCH OFF Normal shutdown by using the SWITCH_ON. In this case only the power supply for the
RTC is remained. Software is not active. So the application interfaces cannot work.
Operating voltage (connected to VBAT) remains applied.
2.1 Power Supply
The power supply of the GSM engine has to be a single voltage source in the range of 3.5V～4.2V.
It must be able to withstand a sufficient current in a transmission burst which typically rises to 2A
instantly. Additionally, the power supply must be able to account for increased current consumption
if the module is exposed to inappropriate conditions, for example antenna mismatch.
2.1.1 Power Supply Pads on A8000
2 VBAT pads of A8000 connector are dedicated to connect the supply voltage, and 10 GND pads
are recommended for grounding. VDD_LRTC used to back up RTC and VDD_LIO is a 2.85V LDO
output for user application, max current 15mA, SWITCH_ON has the ON/OFF key function and
RESET_N can reset system with logic low level. Table2-1 lists the power supplies of A8000.
Table2-1: Power supplies of A8000
Signal Name PIN No. I/O Description Notes
VBAT 61,62 I
Positive operating voltage
3.3 V-4.2 V, I
typ
≤ 2 A during
transmit burst, the minimum
operating voltage must never fall
below 3.3 V.
CDT 64 I
Charger detect(only for A8000
recommended charging
scheme, see Figure2-4)
-
CS 65 O
Charging switch(only for
A8000 recommended charging
scheme, see Figure2-4)
-
VDD_LRTC 43 I/O
Can be used to back up
the RTC when VBAT is not
applied.
1.8-2.0V, 4mA
VDD_LIO 18 O
A8000 LDO output, can used
to drive led.
Output voltage 2.85V, and the max
output drive current not exceed 15mA
SWITCH_ON 44 I
ON/OFF key to turn on/off
A8000.
Pull the pin up to the VDD_LRTC to
turn on/off A8000.