WPMDM1500602 / 171050601
MagI3C Power Module
VDRM – Variable Step Down Regulator Module
Ratiometric tracking
Ratiometric output tracking indicates that the output voltages of both the master and the slave reach their preset value at the
same time. This means also that the soft-start duration is the same for both modules. The condition to implement a
ratiometric tracking is:
RTKT2 = RFBT1
RTKB2 RFBB1
(15)
The values for the tracking resistive divider should be selected small enough to minimize the effect of the internal 50uA
current source. The curve below shows the ratiometric tracking with RTKT2 = 1kΩ, RTKB2=316Ω (for the feedback resistor
divider the values of the evaluation board are used, see “Bill of Material” on page 48).
5,0
4,0
3,0
2,0
1,0
0,0
0
VIN = 12V, TA = 25 C, CSS1 = 470nF, no load
tSS1 = tSS2
5
10
15
20
25
30
Time [ms]
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© July 2018
Würth Elektronik eiSos GmbH & Co. KG – Data Sheet Rev. 2.0
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