Datasheet

Data Sheet ADP195
Rev. C | Page 11 of 12
TIMING
Turn-on delay is defined as the delta between the time that V
EN
reaches >1.2 V until V
OUT
rises to ~10% of its final value. The
ADP195 includes circuitry to have typical 5 μs turn-on delay at
3.6 V V
IN
to limit the V
IN
inrush current. As shown in Figure 26,
the turn-on delay is dependent on the input voltage.
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 5 10 15 20 25 30 35 40
TIME (µs)
VOL
T
AGE (V)
V
EN
V
IN
= 1.2V
V
IN
= 1.8V
V
IN
= 2.5V
V
IN
= 3.6V
08679-021
Figure 26. Typical Turn-On Delay Time with Varying Input Voltage
The rise time is defined as the delta between the time from
10% to 90% of V
OUT
reaching its final value. It is dependent on
the RC time constant where C = load capacitance (C
LOAD
) and
R = RDS
ON
||R
LOAD
. Because RDS
ON
is usually smaller than R
LOAD
,
an adequate approximation for RC is RDS
ON
× C
LOAD
. An input
or load capacitor is not needed for the ADP195; however, capacitors
can be used to suppress noise on the board. If significant load
capacitance is connected, inrush current is a concern.
CH1 2V CH2 1V M4µs A CH1 2.32V
2
3
1
T 10%
V
EN
B
W
CH3 200mA Ω B
W
V
OUT
LOAD CURRENT
08679-022
B
W
Figure 27. Typical Rise Time and Inrush Current,
C
LOAD
= 1 μF, V
IN
= 1.8 V, No Load
CH1 2V CH2 1V M4µs A CH1 2.32V
2
3
1
T 10%
V
EN
B
W
CH3 200mA Ω B
W
V
OUT
LOAD CURRENT
08679-023
Figure 28. Typical Rise Time and Inrush Current,
C
LOAD
= 1 μF, V
IN
= 1.8 V, Load = 200 mA
The turn-off time is defined as the delta between the time from
90% to 10% of V
OUT
reaching its final value. It is also dependent on
the RC time constant.
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0 20406080100
TIME (µs)
VOLTAGE (V)
V
EN
V
OUT
AT 200mA
V
OUT
AT 100mA
08679-024
Figure 29. Typical Turn-Off Time