NCV4264-2ST33T3G ON Semiconductor, NCV4264-2ST33T3G Datasheet - Page 9

• Manufacturer Part Number: NCV4264-2ST33T3G
• Description: IC REG LDO 100MA 3.3V SOT-223
• Manufacturer: ON Semiconductor

Specifications of NCV4264-2ST33T3G

• Regulator Topology: Positive Fixed
• Voltage - Output: 3.3V
• Voltage - Input: 4.5 ~ 45 V
• Number Of Regulators: 1
• Current - Output: 100mA
• Current - Limit (min): 150mA
• Operating Temperature: -40°C ~ 150°C
• Mounting Type: Surface Mount
• Package / Case: SOT-223 (3 leads + Tab), SC-73, TO-261
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Dropout (typical): -

Circuit Description
compatible with NCV4264 with a lower quiescent current
consumption. Its output stage supplies 100 mA with
$2.0% output voltage accuracy.
current. It is internally protected against 45 V input
transients, input supply reversal, output overcurrent faults,
and excess die temperature. No external components are
required to enable these features.
Regulator
sample of the output voltage (V
a PNP series pass transistor by a buffer. The reference is a
bandgap design to give it a temperature-stable output.
Saturation control of the PNP is a function of the load
current and input voltage. Oversaturation of the output
power device is prevented, and quiescent current in the
ground pin is minimized.
Regulator Stability Considerations
compensating input line reactance. Possible oscillations
caused by input inductance and input capacitance can be
damped by using a resistor of approximately 1 W in series
with C
helps determine three main characteristics of a linear
regulator: startup delay, load transient response and loop
stability. Tantalum, aluminum electrolytic, film, or
ceramic capacitors are all acceptable solutions, however,
attention must be paid to ESR constraints. The capacitor
manufacturer 's
information. The value for the output capacitor C
shown in Figure 2 should work for most applications;
however, it is not necessarily the optimized solution.
Stability is guaranteed at values of C
ESR v 9 W for the 5.0 V Version, and C
an ESR v 16 W for the 3.3 V Version within the operating
temperature range. Actual limits are shown in a graph in the
Typical Performance Characteristics section.
The NCV4264-2 is functionally and pin for pin
Maximum dropout voltage is 500 mV at 100 mA load
The error amplifier compares the reference voltage to a
The input capacitor C
I2
. The output or compensation capacitor, C
data
sheet
I1
in Figure 2 is necessary for
OUT
usually
) and drives the base of
Q
w 10 mF, with an
Q
provides
w 22 mF with
http://onsemi.com
NCV4264-2
OUT
OUT
this
9
Calculating Power Dissipation in a Single Output
Linear Regulator
regulator (Figure 3) is:
Where:
V
V
application, and I
consumes at I
the maximum permissible value of R
package section of the data sheet. Those packages with
R
keep the die temperature below 150°C. In some cases, none
of the packages will be sufficient to dissipate the heat
generated by the IC, and an external heat sink will be
required. The current flow and voltages are shown in the
Measurement Circuit Diagram.
Heat Sinks
package to improve the flow of heat away from the IC and
into the surrounding air. Each material in the heat flow path
between the IC and the outside environment will have a
thermal resistance. Like series electrical resistances, these
resistances are summed to determine the value of R
Where:
R
R
R
Like R
R
interface between them. These values appear in data sheets
of heat sink manufacturers. Thermal, mounting, and heat
sinking are discussed in the ON Semiconductor application
note AN1040/D, available on the ON Semiconductor
Website.
P D(max) + V IN(max) * V OUT(min) * I Q(max) ) V I(max) * I Q
P qJA +
qJA
R qJA + R qJC ) R qCS ) R qSA
qJC
qCS
qSA
qSA
IN(max)
OUT(min)
The maximum power dissipation for a single output
I
The value of R
A heat sink effectively increases the surface area of the
R
Q(max)
qJA
's less than the calculated value in Equation 2 will
= the junction-to-case thermal resistance,
= the case-to-heat sink thermal resistance, and
are functions of the package type, heat sink and the
= the heat sink-to-ambient thermal resistance.
qJA
appears in the package section of the data sheet.
is the maximum input voltage,
( 150°C * T A )
, it too is a function of package type. R
is the minimum output voltage,
is the maximum output current for the
Q(max)
P D
qJA
Q
. Once the value of P
is the quiescent current the regulator
can then be compared with those in the
qJA
can be calculated:
D(max)
is known,
qCS
(eq. 1)
(eq. 2)
(eq. 3)
qJA
and
: