Use Instructions

L710HG Hardware Design
20
3.4.2 Power supply requirements
There are four VBAT PIN power for the module, VBAT directly power supply for the module
baseband and PA, and operating rating is 3.4V~4.2V; In the weak network environment, the antenna
will be maximum power emission. Voltage must be stable, because during operation the current drawn
from VCC may vary significantly.
Table 3-7 VBAT power supply interface characteristics
Symbol
Description
Min
Typ
Max
Unit
VBAT
Power supply
voltage
3.4 3.8 4.2
V
IVBAT(peak) Power supply p
current
- - 2000 mA
IVBAT(average,
Power Saving Mode
disabled,
Module regis
tered
with network)
Power supply
average
current
- 14 - mA
IVBAT(power-off)
Power supply
current
in power off
mode
- 17 - uA
IVBAT(power-save
mode)
Power supply
current
in power save
mode(Deep
sleep mode)
- 6 -
uA
3.4.3 Power Supply Design Guide
Make sure that the input voltage at the VBAT pin will never drop below 3.4V even during a transmit
burst when the current consumption rises up to more than 1000 mA. If the power voltage drops below
3.4V, the RF performance of module may be affected. Using large tantalum capacitors (above 300uF)
will be the best way to reduce the voltage drops. If the power current cannot support up to 1000 mA,
users must introduce larger capacitor (typical 1000uF) to storage electric power. For the consideration
of RF performance and system stability, some multi-layer ceramic chip (MLCC) capacitors (0.1/1uF)
need to be used for EMC because of their low ESR in high frequencies. Note that capacitors should be
put beside VBAT pins as close as possible. Also User should keep VBAT net wider than 2 mm to
minimize PCB trace impedance on circuit board. The following figure is the recommended circuit.