DSB45 Development Support Box
Confidential / Released
s
DSB45_HD_V05
Page 27 of 50
01.02.2008
3.1.3
Adjusting the V
BATT+
supply voltage for the GSM module
For test purposes, the V
BATT+
voltage supplied to the GSM module can be adjusted using
slide switches and variable resistors.
The slide switches X613 and X614 serve to set the V
BATT+
voltage range, and the variable
resistors R613 and R614 are used to adjust the supply voltage within the selected range.
Therefore, first set the range (maximum, minimum or nominal supply voltage). Then turn the
screw of the associated resistor R613 or R614 to reduce or increase the desired voltage,
while measuring the module’s input voltage at its test points BATT+ and GND. See [1] for the
position of your module’s test points. As an alternative you can use the test points X153 on
the DSB45. Take into account that voltage drops and ripples may occur. The maximum
voltage is set only via the slide switches, it cannot be adjusted via the resistors.
The position of the switches and the resistors
are illustrated in Figure 3, their settings can be
seen from Figure 11 and Table 14.
The V
BATT+
voltage of your GSM module is
specified in [1].
The default supply voltages provided by the
DSB45 Development Support Box are listed in
Table 13.
Figure 11: Variable resistors R613, R614 and slide
switches X613 and X614
Table 14: Settings for adjusting the supply voltage of GSM module
Voltage
V
adjust
(BATT+)
Slide switch NORM
X614
Slide switch MIN
X613
Variable
resistor
Maximum
values (Volts)
nomV
on
off
R613
1.25 - 4.2
minV
off
on
R614
1.25 - 4.2
maxV
off
off
---
4.45 - 4.55
3.1.3.1
Module specific limits of V
adjust
(BATT+)
AC45:
The minimum supply voltage should be limited to 3.7V. See [3] for details.
MC5x:
These GSM modules are rated for a maximum supply voltage of 4.8V, but, if connected to
DSB45, can be tested only up to the maximum supply voltage of 4.5V.
X614
NORM
X613
MIN
R613
normV
R614
minV
on
on
off
off
