UMTS/HSPA+ Module Series
UG89 Hardware Design
UG89_Hardware_Design 25 / 73
The following figure shows a reference design for a +5V input power source. The typical output of the
power supply is about 3.8V and the maximum load current is 3.0A.
DC_IN
MIC29302WU
IN
OUT
E
N
G
N
D
A
D
J
2
4
1
3
5
VBAT
100nF
470uF
100nF
100K
47K
470uF
470R
51K
1%
1%
4.7K
47K
VBAT_EN
Figure 5: Reference Circuit of Power Supply
3.6. Power-on/off/Reset Scenarios
3.6.1. Turn on the Module Using the PWRKEY
The following table shows the pin definition of PWRKEY.
Table 8: Pin Description of PWRKEY
When UG89 is in power-down mode, it can be turned on to normal mode by driving the PWRKEY pin to a
low level for at least 500ms. It is recommended to use an open drain/collector driver to control the PWRKEY.
A simple reference circuit is illustrated in the following figure.
Pin Name Pin No.
I/O
Description
Comment
PWRKEY
79
DI
Turn on/off the module VBAT power domain