User's Manual

Smart Machine Smart Decision

SIM5360A_User_Manual_V1.03 2014-07-03

(ESR=0.7Ω) and C

=1µF(Please refer to Figure 8—Application circuit).

Figure 7: VBAT voltage drop during burst emission (GSM/GPRS)

3.1.1 Power Supply Pin

Two VBAT pins are dedicated to connect the supply voltage.

Table 4: Pin description

Pin type Pin name Min Typ Max Unit

POWER VBAT 3.4 3.8 4.2 V

Note:

1. When the module is power off, users must pay attention to the issue about current leakage. Refer to

Chapter 3.10.2.

3.1.2 Design Guide

Make sure that the input voltage at the VBAT pin will never drop below 3.3V even during a transmit burst

when the current consumption rises up to more than 2A. If the power voltage drops below 3.3V, the

module may be shut down automatically. Using large tantalum capacitors (above 100uF) will be the best

way to reduce the voltage drops. If the power current cannot support up to 2A, users must introduce larger

capacitor (typical 1000uF) to storage electric power, especially GPRS multiple time slots emission.

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 minimize the PCB trace

impedance from the power supply to the VBAT pins through widening the trace to 80 mil or more on the

board. The following figure is the recommended circuit.

In addition, in order to get a stable power source, it is suggested to use a zener diode of which reverse

zener voltage is 5.1V and dissipation power is more than 500mW.