NCV8184 ON Semiconductor, NCV8184 Datasheet - Page 7

• Manufacturer Part Number: NCV8184
• Description: Micropower 70ma Low Dropout Tracking Regulator/line Driver
• Manufacturer: ON Semiconductor

External Capacitors
stability. Without it, the regulator output will oscillate.
Actual size and type may vary depending upon the
application load and temperature range. Capacitor effective
series resistance (ESR) is also a factor in the IC stability.
Worst-case is determined at the minimum ambient
temperature and maximum load expected.
desired value above the minimum. One possible purpose of
this would be to maintain the output voltage during brief
conditions of negative input transients that might be
characteristic of a particular system.
temperatures expected in the system. To maintain regulator
stability down to -40°C, a capacitor rated at that temperature
must be used.
REGULATOR®s is available in the SMART REGULATOR
application note, “Compensation for Linear Regulators,”
document number SR003AN/D, available through our
website at http://www.onsemi.com.
Calculating Power Dissipation in a Single Output
Linear Regulator
regulator (Figure 23) is:
where:
permissible value of R
The output capacitor for the NCV8184 is required for
The output capacitor can be increased in size to any
The capacitor must also be rated at all ambient
More information on capacitor selection for SMART
The maximum power dissipation for a single output
V
V
I
application,and
I
I
Once the value of PD(max) is known, the maximum
OUT(max)
Q
OUT(max)
IN(max)
OUT(min)
PD(max) + { V IN (max) * V OUT (min) } I OUT (max)
is the quiescent current the regulator consumes at
is the maximum input voltage,
.
) V IN (max)I Q
is the minimum output voltage,
is the maximum output current, for the
R qJA + 150°C * T A
qJA
can be calculated:
P D
http://onsemi.com
(eq. 2)
(eq. 1)
NCV8184
7
Package Thermal Data Section of the data sheet. Those
packages with R
equation 2 will keep the die temperature below 150°C.
dissipate the heat generated by the IC, and an external heat
sink will be required.
Heatsinks
package to improve the flow of heat away from the IC and
into the surrounding air.
outside environment will have a thermal resistance. Like
series electrical resistances, these resistances are summed to
determine the value of R
where:
R
functions of the package type, heatsink and the interface
between them. These values appear in heat sink data sheets
of heatsink manufacturers.
V
qJA
The value of R
In some cases, none of the packages will be sufficient to
IN
A heatsink effectively increases the surface area of the
Each material in the heat flow path between the IC and the
R
R
R
R
qJC
qCS
qSA
qJC
, it is a function of package type. R
Figure 23. Single Output Regulator with Key
= the junction-to-case thermal resistance,
appears in the package section of the data sheet. Like
= the case-to-heatsink thermal resistance, and
= the heatsink-to-ambient thermal resistance.
I
IN
Performance Parameters Labeled
R qJA + R qJC ) R qCS ) R qSA
qJA
qJA
can then be compared with those in the
's less than the calculated value in
Control
Features
REGULATOR
qJA:
SMART
I
Q
®
qCS
I
and R
OUT
qSA
(eq. 3)
V
OUT
are