NCV8674DS50G ON Semiconductor, NCV8674DS50G Datasheet - Page 9

• Manufacturer Part Number: NCV8674DS50G
• Description: IC REG LDO 5.0V D2PAK-4
• Manufacturer: ON Semiconductor

Specifications of NCV8674DS50G

• Regulator Topology: Positive Fixed
• Voltage - Output: 5V
• Voltage - Input: Up to 45V
• Voltage - Dropout (typical): 0.3V @ 350mA
• Number Of Regulators: 1
• Current - Output: 350mA
• Current - Limit (min): 350mA
• Operating Temperature: -40°C ~ 150°C
• Mounting Type: Surface Mount
• Package / Case: TO-263-2, D⊃2Pak (2 leads + Tab), TO-263AB
• Number Of Outputs: 1
• Polarity: Positive
• Input Voltage Max: 45 V
• Output Voltage: 5 V
• Output Type: Fixed
• Dropout Voltage (max): 0.5 V at 100 mA
• Output Current: 350 mA
• Line Regulation: 25 mV
• Load Regulation: 35 mV
• Voltage Regulation Accuracy: 2 %
• Maximum Operating Temperature: + 150 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Reference Voltage: 1.3 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Circuit Description
output regulator. Careful management of light load
consumption combined with a low leakage process results
in a typical quiescent current of 30 mA. The device has
current capability of 350 mA, with 600 mV of dropout
voltage at full rated load current. The regulation is provided
by a PNP pass transistor controlled by an error amplifier
with a bandgap reference. The regulator is protected by
both current limit and short circuit protection. Thermal
shutdown occurs above 150°C to protect the IC during
overloads and extreme ambient temperatures.
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. Over saturation of the output
power device is prevented, and quiescent current in the
ground pin is minimized. The NCV8674 is equipped with
foldback current protection. This protection is designed to
reduce the current limit during an overcurrent situation.
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. The capacitor value and type should be based on
cost, availability, size and temperature constraints.
Tantalum, aluminum electrolytic, film, or ceramic
capacitors are all acceptable solutions, however, attention
The NCV8674 is a precision trimmed 5.0 V or 12 V fixed
The error amplifier compares the reference voltage to a
The input capacitor C
75
50
25
IN
0
. The output or compensation capacitor, C
0
0
100
100
200
200
IN
300
300
COPPER AREA (mm
in Figure 2 is necessary for
Figure 26.
400
400
out
) and drives the base of
500
500
600
600
2
)
D
D
2
2
PAK 1 oz
PAK 2 oz
700
700
http://onsemi.com
OUT
800
800
900
900
9
must be paid to ESR constraints. The aluminum
electrolytic capacitor is the least expensive solution, but, if
the circuit operates at low temperatures (−25°C to −40°C),
both the value and ESR of the capacitor will vary
considerably. The capacitor manufacturer’s data sheet
usually provides this information. The value for the output
capacitor C
applications; however, it is not necessarily the optimized
solution. Stability is guaranteed at values C
ESR ≤ 7.0 W, within the operating temperature range.
Actual limits are shown in a graph in the Typical
Characteristics section.
Calculating Power Dissipation in a Single Output
Linear Regulator
regulator (Figure 2) is:
Where:
application, and I
consumes at I
permissible value of R
thermal resistance versus copper area graph (Figure 26).
Those designs with cooling area corresponding to R
less than the calculated value in Equation 2 will keep the
die temperature below 150°C. The current flow and
voltages are shown in the Measurement Circuit Diagram.
0.000001
100
The maximum power dissipation for a single output
V
V
I
Once the value of P
The value of R
0.1
OUT(max)
10
IN(max)
OUT(min)
1
Figure 27. NCV8674 @ PCB Cu Area 650 mm
P D(max) + [V IN(max) * V OUT(min) ] @
is the maximum input voltage,
OUT
is the minimum output voltage,
is the maximum output current for the
OUT(max)
0.0001
shown in Figure 2 should work for most
qJA
q
R qJA +
is the quiescent current the regulator
I OUT(max) ) V IN(max) @ I q
can then be compared with those in
.
qJA
PULSE TIME (sec)
PCB Cu thk 1 oz
D(Max)
0.01
can be calculated:
150
D
o
is known, the maximum
C * T A
P D
2
0.1
PAK
1
OUT
Single Pulse
10
≥ 22 mF and
100
(eq. 1)
(eq. 2)
1000
qJA
2
’s