Decrease Voltage Drop; Power-On Circuit - Quectel UG96 Manual

4.1.2. Decrease Voltage Drop

The power supply range of UG96/UG95 is 3.3V~4.3V and the power supply range of M95 R2.0 is
3.3V~4.6V. Please make sure that the input voltage will never drop below 3.3V and exceed 4.3V, and the
typical power supply is 3.8V. The VBAT to UG96/UG95's VBAT_BB and VBAT_RF pins should be divided
into two separated paths in star structure.
In addition, in order to get a stable power source, it is recommended to use a zener diode with reverse
zener voltage of 5.1V and dissipation power more than 0.5W.
VBAT
+
C1
D1
100uF
5.1V
M95 R2.0 only has two pads for VBAT input, and this is different from UG96/UG95. Therefore, it is not
recommended to mount C1~C4. VBAT_RF pins of UG96/UG95 are compatible with VBAT pins of M95
R2.0.

4.2. Power-on Circuit

UG96/UG95 and M95 R2.0 can be turned on by driving the PWRKEY pin to a low level, though the power
domain of the pin of M95 R2.0 is different from UG96/UG95.
The following circuit is a reference design for turning on the module using PWRKEY.
UG96&UG95&M95 R2.0_Compatible_Design
C5
C3 C4
C2
100nF 33pF 10pF 100uF
Figure 4: Reference Circuit Design of Star Structure
HSPA/UMTS/GSM/GPRS Module Series
UG96&UG95&M95 R2.0 Compatible Design
+
C6 C7 C8
100nF 33pF 10pF
Module
VBAT_RF (UG96/UG95)
VBAT (M95 R2.0)
VBAT_BB (UG96/UG95)
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