ncv4949a ON Semiconductor, ncv4949a Datasheet - Page 7

• Manufacturer Part Number: ncv4949a
• Description: Ncv4949a 100 Ma, 5.0 V, Low Dropout Voltage Regulator With Reset And Sense
• Manufacturer: ON Semiconductor

voltage regulator. Several outstanding features and auxiliary
functions are implemented to meet the requirements of
supplying
applications. It is also suitable in other applications where
the included functions are required. The modular approach
of this device allows the use of other features and functions
independently when required.
Voltage Regulator
PNP transistor as a regulating element. With this structure,
very low dropout voltage at currents up to 100 mA is
obtained. The dropout operation of the standby regulator is
maintained down to 3.0 V input supply voltage. The output
voltage is regulated up to a transient input supply voltage of
35 V.
function of the input supply voltage is shown in Figure 16.
is less than 200 mA.
region and to improve the transient response in this region,
the dropout voltage is controlled. The quiescent current as
a function of the supply input voltage is shown in Figure 17.
Short Circuit Protection:
of short circuit, the output current is foldback current limited
as described in Figure 15.
The NCV4949A is a monolithic integrated low dropout
The voltage regulator uses an isolated collector vertical
A typical curve showing the standby output voltage as a
The current consumption of the device (quiescent current)
To reduce the quiescent current peak in the undervoltage
The maximum output current is internally limited. In case
6.00
5.00
4.00
3.00
2.00
1.00
0.00
0
Figure 15. Foldback Characteristic of V
microprocessor
50
100
150
I
out
(mA)
systems
200
250
in
OPERATING DESCRIPTION
automotive
300
out
http://onsemi.com
350
7
Preregulator
the internal supply voltage to 6.0 V. This internal voltage is
present at Pin 3 (V
output because the output capability is very small ( 100
mA).
supply voltages less than 8.0 V. In this case a capacitor (100
nF - - 1.0 mF) must be connected between Pin 3 and GND. If
this feature is not used Pin 3 must be left open.
5.0 V
V
out
To improve transient immunity a preregulator stabilizes
This output may be used to improve transient behavior for
Figure 17. Quiescent Current versus Supply Voltage
3.0
2.5
2.0
1.5
1.0
0.5
0 V
Figure 16. Output Voltage versus Supply Voltage
0
0
2.0 V
T
J
= 25C
5.0
Z
). This voltage should not be used as an
5.0 V
V
10
CC
, SUPPLY VOLTAGE (V)
15
R
V
R
L
CC
V
L
= 100 Ω
out
= 5.0 k
20
25
35 V
30