NCP694 ONSEMI [ON Semiconductor], NCP694 Datasheet - Page 6

• Manufacturer Part Number: NCP694
• Description: 1A CMOS Low-Dropout Voltage Regulator
• Manufacturer: ONSEMI [ON Semiconductor]

shown in Figure 5, Typical Application Schematic.
Input Decoupling (C1)
recommended and should be connected as close as possible
to the pins of NCP694 device. Higher values and lower ESR
will improve the overall line transient response.
Output Decoupling (C2)
augmented to fulfill stringent load transient requirements.
The regulator accepts ceramic chip capacitors as well as
tantalum devices. If a tantalum capacitor is used, and its ESR
is large, the loop oscillation may result. Because of this,
select C2 carefully considering its frequency characteristics.
Larger values improve noise rejection and load regulation
transient response.
Enable Operation
limits of threshold are covered in the electrical specification
section of this data sheet. If the enable is not used then the
pin should be connected to V
(NCP694DxxxxT1G) have additional circuitry in order to
reach the turn−off speed faster than normal type. When the
mode is into standby with CE signal, auto discharge
transistor turns on.
Hints
If their impedance is high, noise pickup or unstable
operation may result.
A typical application circuit for the NCP694 series is
A 4.7 mF capacitor either ceramic or tantalum is
The minimum decoupling value is 4.7 mF and can be
The enable pin CE will turn on or off the regulator. These
Please be sure the V
Figure 3. Output Voltage Setting
GND
Radj
in
Vout
ADJ
and GND lines are sufficiently wide.
in
Iadj
. The D version devices
R1
R2
Vref = 1 V
I1
I2
APPLICATIONS INFORMATION
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6
1.8
1.6
1.4
1.2
1.0
0.8
as close as possible to the circuit, and make leads as short as
possible.
Thermal
necessary to provide some thermal relief. The maximum
power dissipation supported by the device is dependent
upon board design and layout. Mounting pad configuration
on the PCB, the board material, and also the ambient
temperature effect the rate of temperature rise for the part.
This is stating that when the NCP694 has good thermal
conductivity through the PCB, the junction temperature will
be relatively low with high power dissipation applications.
Output Voltage Setting of Adjustable Version.
output voltage as shows Figure 3. Output Voltage Setting.
The equation for the output voltage is mentioned in equation
below.
given by ADJ pin consumption. The typical resistance R
is showed in Figure 4. ADJ Pin Resistance
−50
V
Set external components, especially the output capacitor,
As power across the NCP694 increases, it might become
An external two resistors are required for setting desired
For better accuracy, choosing R2 << R
Figure 4. ADJ Pin Resistance vs. Temperature
out
+ V
+ V
+ V
+ 1.0 @ 1 ) R1 R
+ V
−25
ref
ref
ref
ref
) R1 @ I
) R1 @ V
@ 1 ) R1 R
) R1 @ I1
T
J
, TEMPERATURE (°C)
0
adj
ref
) I2
25
R
adj
adj
adj
) R1 R2
) R1 R2
) R1 @ V
50
adj
ref
reduces the error
75
R2
100
(eq. 1)
adj