NCP1086 ON, NCP1086 Datasheet - Page 5

• Manufacturer Part Number: NCP1086
• Description: 1.5 A Adjustable and 3.3 V Fixed Output Linear Regulator
• Manufacturer: ON

adjustable and 3.3 V output voltages at currents up to 1.5 A.
The regulator is protected against overcurrent conditions
and includes thermal shutdown.
transistor and requires an output capacitor for stability. A
detailed procedure for selecting this capacitor is included in
the Stability Considerations section.
Adjustable Operation
of 1.25 V to 5.5 V. An external resistor divider sets the
output voltage as shown in Figure 15. The regulator
maintains a fixed 1.25 V (typical) reference between the
output pin and the adjust pin.
current to flow to ground. This current creates a voltage
across R2 that adds to the 1.25 V across R1 and sets the
The NCP1086 voltage regulator series provides
The NCP1086 series has a composite PNP−NPN output
The adjustable output device has an output voltage range
A resistor divider network R1 and R2 causes a fixed
0.100
0.075
0.050
0.025
85
75
65
55
45
35
25
15
10
Figure 11. Ripple Rejection vs. Frequency
Figure 13. Load Regulation vs. Output Current
0
1
0
T
I
(V
V
C
OUT
CASE
RIPPLE
Adj
IN
− V
= 0.1 mF
= 6A
10
= 25 C
OUT
= 1.6V
2
(Adjustable Output)
= 3V)
(Adjustable Output)
PP
10
Frequency (Hz)
Output Current (A)
3
T
CASE
1.0
10
= 25 C
4
T
CASE
APPLICATIONS INFORMATION
10
= 125 C
5
T
CASE
http://onsemi.com
= 0 C
10
NCP1086
6
2.0
5
overall output voltage. The adjust pin current (typically
50 mA) also flows through R2 and adds a small error that
should be taken into account if precise adjustment of V
is necessary.
pin current.
2.0 mA. R1 and R2 should be the same type, e.g. metal film
for best tracking over temperature. While not required, a
bypass capacitor from the adjust pin to ground will improve
ripple rejection and transient response. A 0.1 mF tantalum
capacitor is recommended for “first cut” design. Type and
value may be varied to obtain optimum performance vs
price.
0.65
0.60
0.55
0.50
0.45
0.40
The output voltage is set according to the formula:
The term I
R1 is chosen so that the minimum load current is at least
85
75
65
55
45
35
25
15
1.0
10
Figure 14. Minimum Load Current vs V
1
V OUT + V REF
T
I
(V
V
OUT
CASE
RIPPLE
Figure 12. Ripple Rejection vs. Frequency
IN
Adj
2.0
− V
= 6A
10
= 25 C
OUT
= 1.6V
2
R2 represents the error added by the adjust
= 3V)
(Adjustable Output)
3.0
(3.3 V Fixed Output)
PP
T
Frequency (Hz)
V
10
T
CASE
CASE
IN
C
3
R1 ) R2
− V
IN
4.0
= C
= 0 C
R1
= 25 C
OUT
OUt
10
(V)
= 22 mF Tantalum
4
) I Adj
5.0
T
CASE
10
6.0
5
IN
= 125 C
R2
− V
OUT
OUT
10
7.0
6