Datenblatt-pdf.com


LD1117A Schematic ( PDF Datasheet ) - ST Microelectronics

Teilenummer LD1117A
Beschreibung Low drop fixed and adjustable positive voltage regulators
Hersteller ST Microelectronics
Logo ST Microelectronics Logo 




Gesamt 24 Seiten
LD1117A Datasheet, Funktion
LD1117A
Low drop fixed and adjustable positive voltage regulators
Datasheet - production data
SOT-223
Available in ± 2% (at 25 °C) and 4% in full
temperature range
High supply voltage rejection:
– 80 dB typ. (at 25 °C)
Temperature range: 0 °C to 125 °C
TO-220
Description
DPAK
Features
Low dropout voltage:
– 1.15 V typ. @ IOUT = 1 A, 25 °C
Very low quiescent current:
– 5 mA typ. @ 25 °C
Output current up to 1 A
The LD1117A is a low drop voltage regulator able
to provide up to 1 A of output current, available
also in adjustable versions (VREF = 1.25 V). In
fixed versions, the following output voltages are
offered: 1.2 V, 1.8 V, and 3.3 V. The device is
supplied in: SOT-223, DPAK and TO-220. Surface
mounted packages optimize the thermal
characteristics while offering a relevant space
saving advantage. High efficiency is assured by
an NPN pass transistor. Only a very common 10
µF minimum capacitor is needed for stability. Chip
trimming allows the regulator to reach a very tight
output voltage tolerance, within ± 2% at 25 °C.
Fixed output voltage of:
– 1.2 V, 1.8 V, 3.3 V
Adjustable version availability (VREF = 1.25 V)
Internal current and thermal limit
Only 10 µF for stability
Table 1. Device summary
SOT-223
Order codes
DPAK
TO-220
Output voltage
LD1117AS12TR
LD1117AS18TR
LD1117AS33TR
LD1117ASTR
LD1117ADT12TR
LD1117ADT18TR
LD1117ADT33TR
LD1117ADT-TR
LD1117AV33
1.2 V
1.8 V
3.3 V
Adjustable from 1.25 V
July 2013
This is information on a product in full production.
DocID7194 Rev 26
1/24
www.st.com






LD1117A Datasheet, Funktion
Schematic application
4 Schematic application
Figure 3. Application circuit (for fixed output voltages)
A
LD1117A
6/24 DocID7194 Rev 26

6 Page









LD1117A pdf, datenblatt
LD1117A adjustable: application note
7 LD1117A adjustable: application note
LD1117A
The LD1117A adjustable has a thermal stabilized 1.25 ± 0.012 V reference voltage between
the OUT and ADJ pins. IADJ is 60 µA typ. (120 µA max.) and ΔIADJ is 1 µA typ. (5 µA max.).
R1 is normally fixed to 120 Ω. From Figure 6 the following is obtained:
VOUT = VREF + R2 (IADJ + IR1) = VREF + R2 (IADJ +VREF /R1) = VREF (1 + R2 / R1) + R2 x
IADJ.
In normal applications the R2 value is in the range of a few kΩ, so the R2 x IADJ product can
not be considered in the VOUT calculation; the above expression then becomes:
VOUT = VREF (1 + R2 / R1).
In order to have a better load regulation it is important to realize a good Kelvin connection of
R1 and R2 resistors. In particular, the R1 connection must be realized very close to the OUT
and ADJ pins, while the R2 ground connection must be placed as near as possible to the
negative load pin. Ripple rejection can be improved by introducing a 10 µF electrolytic
capacitor placed in parallel to the R2 resistor (see Figure 8).
Figure 8. Adjustable output voltage application
LD1117A
Figure 9. Adjustable output voltage application with improved ripple rejection
LD1117A
12/24
DocID7194 Rev 26

12 Page





SeitenGesamt 24 Seiten
PDF Download[ LD1117A Schematic.PDF ]

Link teilen




Besondere Datenblatt

TeilenummerBeschreibungHersteller
LD1117Adjustable and fixed low drop positive voltage regulatorST Microelectronics
ST Microelectronics
LD1117LOW DROP FIXED AND ADJUSTABLE POSITIVE VOLTAGE REGULATORSUnisonic Technologies
Unisonic Technologies
LD1117A1A Low Dropout Positive Voltage RegulatorTAITRON
TAITRON
LD1117ALow drop fixed and adjustable positive voltage regulatorsST Microelectronics
ST Microelectronics
LD1117ALOW DROP FIXED AND ADJUSTABLE POSITIVE VOLTAGE REGULATORSUnisonic Technologies
Unisonic Technologies

TeilenummerBeschreibungHersteller
CD40175BC

Hex D-Type Flip-Flop / Quad D-Type Flip-Flop.

Fairchild Semiconductor
Fairchild Semiconductor
KTD1146

EPITAXIAL PLANAR NPN TRANSISTOR.

KEC
KEC


www.Datenblatt-PDF.com       |      2020       |      Kontakt     |      Suche