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HUAWEI MU509-65 HSDPA LGA Module
Hardware Guide
Figure 3-13 Driving circuit
For resistance of R placed on user board, choose the value such that it satisfies the
following equation:
I
*R+V
F
V
: Forward voltage
F
I
: Forward current
F
Take an LED as an example, Figure 3-14 shows its I
the desired current through the LED I
according to I
(3.8-1.5)/0.003 = 767 Ω.
The brightness of the LED depends on the current value, and for most of the indicator
lights the current from 2 mA to 5 mA is already enough.
Issue 01 (2016-04-08)
Module
(DCE)
LED_MODE
LED_STATUS
= VBAT
F
- V
curves, and the corresponding value for resistance of R is
F
F
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
Description of the Application Interfaces
R
V
I
F
F
R
V
I
F
F
- V
curves. If VBAT is 3.8 V and
F
F
is 3 mA, then the voltage of the LED V
F
VBAT
is 1.5 V
F
31
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