zldo1117 Diodes, Inc., zldo1117 Datasheet - Page 8

• Manufacturer Part Number: zldo1117
• Description: 1a Low Dropout Positive Regulator 1.2v, 1.5v, 1.8v, 2.5v, 3.3v, 5.0v And Adjustable Outputs
• Manufacturer: Diodes, Inc.

Typical application circuits
Figure 1 Basic adjustable regulator with 5V output
Figure 2 Adjustable regulator with I
Because I
A. Output capacitor selection is critical for regulator stability. Larger C
B. C
C. C
D. An external diode is recommended to protect the regulator if the input instantaneously is shorted to GND.
E. This device is designed to be stable with tantalum and MLCC capacitors with an ESR less than 0.47Ω.
Issue 1
(see Note C)
V
V
improving transient response and loop stability.
used.
OUT
OUT
Vin
ADJ
in
is recommended if ZLDO1117 is not located near the power supply filter.
10 F
can be used to improve ripple rejection. If C
=
=
ADJ
. 1
. 1
25
typically is 55μA, its effect is negligible in most applications.
25
•
•
⎧
⎨
⎩
⎧
⎨
⎩
1
1
+
+
R
330
110
R
IN
2
1
I
1N4002 (See Note D)
⎫
⎬
⎭
ADJ
ZLDO1117
+
+
55
I
ADJ
ADJ
•
10
•
C
(see Note B)
R
−
OUT
ADJ
2
6
ADJ
•
330
errors
⎫
⎬
⎭
V
=
REF
. 5
www.diodes.com
02
V
ADJ
~ 0.4%
8 of 12
R1
is used, a C
R2
Using
then the output voltage becomes:
100 F
(see Note A)
Vout
V
V
out
OUT
OUT
out
that is larger in value than C
values benefit the regulator by
=
=
. 1
. 1
25
25
•
•
⎧
⎨
⎩
⎧
⎨
⎩
1
1
+
+
R
330
110
R
2
1
⎫
⎬
⎭
⎫
⎬
⎭
©
=
Diodes Incorporated
5
0 .
V
ADJ
ZLDO1117
June 2009
must be