tle4678 Infineon Technologies Corporation, tle4678 Datasheet - Page 15

• Manufacturer Part Number: tle4678
• Description: Low Drop Out Linear Voltage Regulator 5 V Fixed Output Voltage
• Manufacturer: Infineon Technologies Corporation

7
7.1
The reset function provides several features:
Output Undervoltage Reset:
An output undervoltage condition is indicated by setting the Reset Output “RO” to “low”. This signal might be used
to reset a microcontroller during low supply voltage.
Power-On Reset Delay Time
The power-on reset delay time
time period from exceeding the upper reset switching threshold
reset output “RO” from “low” to “high”. The power-on reset delay time
capacitor
V
In case a power-on reset delay time
capacitor’s value can be derived from the specified value given in
with
•
•
•
The formula is valid for
Undervoltage Reset Delay Time
Unlike the power-on reset delay time, the undervoltage reset delay time
event where the delay capacitor
starts. Therefore, the undervoltage reset delay time
from
A delay capacitor
similar as above:
with
•
•
•
The formula is valid for
Datasheet
D
= 0 V.
t
t
C
t
t
C
d,PWR-ON
d,PWR-ON,100nF
d
d,100nF
D
V
: Desired undervoltage reset delay time
D
: Delay capacitor required.
: Delay capacitor required
C
C
D
D
D
=
C
: Power-on reset delay time specified in
V
= 100nF
= 100nF
D
: Desired power-on reset delay time
DST,lo
Reset Function
Description Reset Function
connected to pin “D” which is charged up by the delay capacitor charge current
: Power-on reset delay time specified in
and the external delay capacitor
C
D
for a different undervoltage reset delay time as specified in
t
t
C
C
d,PWR-ON
d
D
D
/
t
d,100nF
10nF. For precise timing calculations consider also the delay capacitor’s tolerance.
10nF. For precise timing calculations consider also the delay capacitor’s tolerance.
t
C
d,PWR-ON
/
D
t
d,PWR-ON,100nF
is assumed to be discharged to
t
d,PWR-ON
allows a microcontroller and oscillator to start up. This delay time is the
different from the value for
C
Item 7.2.14
t
D
d
.
is defined by the delay capacitor charge current
15
Item 7.2.15
V
RT,hi
Item
V
D
=
until the reset is released by switching the
7.2.15:
V
t
d,PWR-ON
t
d
DST,lo
considers a short output undervoltage
C
only before the charging sequence
D
is defined by an external delay
= 100nF is required, the delay
Item 7.2.14
Rev. 1.0, 2008-07-31
can be calculated
I
D,ch
Reset Function
starting from
I
TLE4678
D,ch
starting
(1)
(2)