LD1117XX12C STMicroelectronics, LD1117XX12C Datasheet - Page 24

• Manufacturer Part Number: LD1117XX12C
• Description: Fixed low drop positive voltage regulator
• Manufacturer: STMicroelectronics

Specifications of LD1117XX12C

• Fixed Output Voltage Of: 1.2 V, 1.8 V, 2.5 V, 3.3 V, 5.0 V
• Supply Voltage Rejection: 75 dB (typ.)

LD1117 adjustable: application note
7
Figure 11. Adjustable output voltage application
Figure 12. Adjustable output voltage application with improved ripple rejection
24/41
LD1117 adjustable: application note
The LD1117 adjustable has a thermal stabilized 1.25 ± 0.012 V reference voltage between
the OUT and ADJ pins. I
R
V
In normal application R
be considered in the V
V
In order to have the better load regulation it is important to realize a good Kelvin connection
of R
ADJ pin, while R
Load pin. Ripple rejection can be improved by introducing a 10 µF electrolytic capacitor
placed in parallel to the R
OUT
OUT
1
is normally fixed to 120 Ω. From
1
and R
= V
= V
REF
REF
2
+ R
resistors. In particular R
(1 + R
2
2
ground connection must be placed as near as possible to the negative
(I
2
ADJ
/ R
OUT
2
+I
1
ADJ
value is in the range of few kΩ, so the R
).
2
R1
calculation; then the above expression becomes:
resistor (see
) = V
is 60 µA typ. (120 µA max.) and ΔI
Doc ID 2572 Rev 31
REF
Figure 10
+ R
1
connection must be realized very close to OUT and
Figure 11
2
(I
ADJ
we obtain:
+V
).
REF
/R
1
) = V
ADJ
REF
2
x I
is 1 µA typ. (5 µA max.).
(1 + R
ADJ
product could not
2
/ R
1
) + R
LD1117xx
2
x I
ADJ
.