ncv8504pwadjr2 ON Semiconductor, ncv8504pwadjr2 Datasheet - Page 10

• Manufacturer Part Number: ncv8504pwadjr2
• Description: 2.5v, 3.3v, 5.0v, Adjustable/400ma Ldo W/ Reset, Delay, Adjustable Reset, Early Warning
• Manufacturer: ON Semiconductor

of the circuit depicted in Figure 15. As the input voltage falls
(V
voltage on the FLAG output to go low.
V
Voltage, Delay Switching Threshold, and the Delay Charge
Current. The delay follows the equation:
Example:
three main characteristics of a linear regulator: start-up
delay, load transient response and loop stability.
availability, size and temperature constraints. A tantalum or
aluminum electrolytic capacitor is best, since a film or
ceramic capacitor with almost zero ESR can cause
instability. 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
manufacturers data sheet usually provides this information.
should work for most applications, however it is not
necessarily the optimized solution.
FLAG
MON
Flag Monitor
Ref. Voltage
MON
t DELAY +
Figure 17 shows the FLAG Monitor waveforms as a result
The delay time is controlled by the Reset Delay Low
Using C
Assume reset Delay Low Voltage = 0.
Use the typical value for V
Use the typical value for Delay Charge Current = 4.2 μA.
The output or compensation capacitor helps determine
The capacitor value and type should be based on cost,
The value for the output capacitor C
MON
Figure 17. FLAG Monitor Circuit Waveform
), the Monitor threshold is crossed. This causes the
5.0 V options).
t DELAY +
DELAY
STABILITY CONSIDERATIONS
[ C DELAY (V dt * Reset Delay Low Voltage) ]
SETTING THE DELAY TIME
= 33 nF.
FLAG MONITOR
[ 33 nF(1.8 * 0) ]
Delay Charge Current
4.2 mA
dt
= 1.8 V (2.5 V, 3.3 V, and
OUT
+ 14 ms
shown in Figure 18
APPLICATION NOTES
NCV8504 Series
http://onsemi.com
10
*C
regulator (Figure 19) is:
P D(max) + [V IN(max) * V OUT(min) ] I OUT(max)
where:
permissible value of R
package section of the data sheet. Those packages with
R
the die temperature below 150°C.
dissipate the heat generated by the IC, and an external
heatsink will be required.
V
**C
IN
qJA
0.1 μF
IN
The maximum power dissipation for a single output
V
V
I
application, and
I
I
Once the value of P
The value of R
In some cases, none of the packages will be sufficient to
C
OUT(max)
Q
OUT(max)
OUT
Figure 18. Test and Application Circuit Showing
IN(max)
OUT(min)
IN
required if regulator is located far from the power supply filter
CALCULATING POWER DISSIPATION IN A
's less than the calculated value in equation 2 will keep
is the quiescent current the regulator consumes at
V
Figure 19. Single Output Regulator with Key
*
SINGLE OUTPUT LINEAR REGULATOR
IN
required for stability. Capacitor must operate at minimum
Performance Parameters Labeled
is the maximum input voltage,
.
) V IN(max) I Q
is the minimum output voltage,
is the maximum output current for the
I
IN
qJA
Output Compensation
R qJA + 150°C *
NCV8504
temperature expected
can then be compared with those in the
qJA
REGULATOR®
RESET
D(max)
}
can be calculated:
V
SMART
Control
Features
OUT
P D
is known, the maximum
I
Q
T A
R
RST
I
OUT
33 μF
C
OUT
V
OUT
**
(1)
(2)