Datasheet

PM6641 Device description
Doc ID 13510 Rev 3 27/47
7.5 Output voltage divider
PM6641 switching regulators are adjustable voltage converters.
If the feedback pin (VFB_1S8, VFB_1S5, VFB_1S05 respectively belonging to
VDDQ (1.8 V), 1.5 V, 1.05 V rail) is directly tied to the rail output capacitor the internal divider
with pre-fixed output voltage value is activated and the nominal output voltages are
selected.
If the feedback pin is connected to the output voltage divider central tap (as depicted in
Figure 30)
Figure 30. SW regulator with external divider
the PM6641 switching regulator automatically recognizes the external divider and the output
voltage is regulated to the following value:
Equation 5
Vout_1Sxx
VFB_1Sxx
R
1
R
2
V8.01
R
R
Sxx1_Vout
2
1
⋅
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
+=