tle42994 Infineon Technologies Corporation, tle42994 Datasheet - Page 19

• Manufacturer Part Number: tle42994
• Description: Low Dropout Fixed Voltage Regulator
• Manufacturer: Infineon Technologies Corporation

Reset Reaction Time:
The reset reaction time avoids that short undervoltage spikes trigger an unwanted reset “low” signal. The reset
reaction rime
capacitor
with
•
•
•
Optional Reset Output Pull-Up Resistor
The Reset Output RO is an open collector output with an integrated pull-up resistor. If needed, an external pull-up
resistor to the output Q can be added. In
minimum value for the external resistor
Reset Adjust Function
The undervoltage reset switching threshold can be adjusted according to the application’s needs by connecting
an external voltage divider (
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
with
•
•
•
Data Sheet
t
t
t
V
R
V
Page 22
rr
rr,int
rr,d
RT,new
ADJ1
RADJ,th
: reset reaction time
: reset discharge
: internal reset reaction time
, R
C
: the desired new reset switching threshold
: reset adjust switching threshold given in
ADJ2
V
D
t
rr
RT new
(see typical performance graph for details). Hence, the total reset reaction time becomes:
t
rr
=
,
: resistors of the external voltage divider
considers the internal reaction time
t
rd int
,
=
+
R
----------------------------------------- -
ADJ 1 ,
t
rr d ,
R
ADJ 2 ,
R
+
ADJ1
R
ADJ 2 ,
,
R
ADJ2
×
V
R
) at pin RADJ. For selecting the default threshold connect pin RADJ to
RADJ th
RO,ext
R
Table “Electrical Characteristics Reset Function” on Page 22
,
RO,ext
is given.
:
t
rr,int
Table “Electrical Characteristics Reset Function” on
19
and the discharge time
Block Description and Electrical Characteristics
V
RT,new
is calculated as follows:
t
rr,d
defined by the external delay
Rev. 1.0, 2008-12-04
TLE42994
a