TLE42794 Datasheet, PDF (18/28 Pages) Infineon Technologies AG – Low Dropout Fixed Voltage Regulator

TLE42794
Block Description and Electrical Characteristics
Reset Output Pull-Up Resistor R_RO:
The Reset Output RO is an open collector output requiring an external pull-up resistor. In Table “Electrical
Characteristics Reset Function” on Page 20 a minimum value for the external resistor R_RO is given. Keep in
mind to stay within the values specified for the Reset Output RO in Table 4.1 “Absolute Maximum Ratings” on
Page 8
Reset Adjust Function
The undervoltage reset switching threshold can be adjusted according to the application’s needs by connecting
an external voltage divider (R_ADJ1, R_ADJ2) at pin RADJ. For selecting the default threshold connect pin RADJ to
GND.
When dimensioning the voltage divider, take into consideration that there will be an additional current constantly
flowing through the resistors.
With a voltage divider connected, the reset switching threshold V_RT,new is calculated as follows:
V_{RT, new}
=
R-----_{A---D----J--,--1----}+_{-----R----A----D----J--,--2-}
R_{ADJ, 2}
×
V _{R A D J,}
th
with
• V_RT,new: the desired new reset switching threshold
• R_ADJ1, R_ADJ2: resistors of the external voltage divider
• V_RADJ,th: reset adjust switching threshold given in Table “Electrical Characteristics Reset Function” on
Page 20
Supply _I
Co n tr o l
In t.
Supply
V_RADJ,th
OR
I_D,ch
I_D,dch
V_DST
GND
BlockDiagram_ResetAdjust.vsd
Figure 6 Block Diagram Reset Function
D
C_D
Q
C_Q
R_RO
RO
I _RO
R_ADJ,1
VDD
Re se t
M ic ro-
Cont rolle r
RADJ
I _RADJ
R_ADJ,2
GND
Data Sheet
18
Rev. 1.1, 2008-10-09