Datasheet

TLE4263-2ES
Application Information
Data Sheet 18 Rev. 1.0, 2008-04-21
with
•
C
D
: capacitance of the delay capacitor to be chosen
•
t
rd,new
: desired power-on reset delay time
•
t
rd
: power-on reset delay time specified in this datasheet
For a precise calculation also take the delay capacitor’s tolerance into consideration.
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:
(1)
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 “Reset Function” on Page 13
V
RT new,
R
ADJ 1,
R+
ADJ 2,
R
ADJ 2,
------------------------------------------
V
RADJ th,
×=