Datasheet
ADP194 Data Sheet
Rev. A | Page 10 of 12
TIMING
Turn-on delay is defined as the delta between the time that EN
reaches >1.1 V until VOUT rises to ~10% of its final value. The
ADP194 includes circuitry to set the typical 1.5 s turn-on delay
at 3.6 V V
IN
to limit the V
IN
inrush current. As shown in Figure 20,
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
0 2040608010
TIME (µs)
VOL
0
T
AGE (V)
V
EN
V
IN
= 1.5V
V
IN
= 1.8V
V
IN
= 2.5V
V
IN
= 3.6V
08629-020
Figure 20. Typical Turn-On Delay Time with Varying Input Voltage
The rise time of VOUT is defined as the time delta between the
10% and 90% points of VOUT as it transitions to its final value.
It is dependent on the RC time constant where C = load capacit-
ance (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
. The ADP194 does not need any input or load capacitor,
but capacitors can be used to suppress noise on the board. If
significant load capacitance is connected, inrush current may
be a concern.
089629-021
CH1 500mV
B
W
CH3 1.00V
B
W
A CH3 400mV
2
1
3
CH2 200mA Ω
B
W
M20.0µs
T 10.00%
V
EN
V
OUT
LOAD CURRENT
Figure 21. Typical Rise Time and Inrush Current with V
IN
= 1.8 V, C
LOAD
= 1 F
089629-022
CH1 1.00V
B
W
CH3 1.00V
B
W
CH2 200mA Ω
B
W
M4.00µs A CH3 400mV
2
1
3
T 10.00%
V
OUT
V
EN
LOAD CURRENT
Figure 22. Typical Rise Time and Inrush Current with V
IN
= 3.6 V, C
LOAD
= 1 µF
The fall time or turn-off time of VOUT is defined as the time
delta between the 90% and 10% points of VOUT as it transi-
tions to its final value. The turn-off time is also dependent on
the RC time constant.
089629-023
CH1 500mV
B
W
CH3 1.00V
B
W
CH2 200mA Ω
B
W
M2.00µs A CH3 400mV
2
1
3
T 10.00%
V
OUT
V
EN
LOAD CURRENT
Figure 23. Typical Turn-Off Time, V
IN
= 1.8 V, R
LOAD
= 3.6 Ω
089629-024
CH1 1.00V
B
W
CH3 1.00V
B
W
CH2 200mA Ω
B
W
M2.00µs A CH3 400mV
2
1
3
T 10.00%
V
OUT
V
EN
LOAD CURRENT
Figure 24. Typical Turn-Off Time, V
IN
= 3.6 V, R
LOAD
= 7.5 Ω