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The LM1117 is a series of low dropout voltage regulators with a dropout of 1.2V at 800mA of load current. It 
has the same pin-out as National Semiconductor’s industry standard LM317. The LM1117 is available in an 
adjustable version, which can set the output voltage from 1.25V to 13.8V with only two external resistors. In 

addition, it is also available in five fixed voltages, 1.8V, 2.5V, 2.85V, 3.3V, and 5V. The LM1117 offers 

current limiting and thermal shutdown. Its circuit includes a zener trimmed band-gap

reference to as-sure output voltage accuracy to within ±1%. The LM1117 series is available in SOT- 223, 
TO-220, and TO-252 D-PAK packages. A minimum of 10μF tantalum capacitor is required at the output to 

improve the transient response and stability.



Available in 1.8V, 2.5V, 2.85V, 3.3V, 5V, and Adjustable Versions



Space Saving SOT-223 Package



Current Limiting and Thermal Protection



Output Current 800mA



Line Regulation 0.2% (Max)



Load Regulation 0.4% (Max)



Temperature Range



LM1117 0°C to 125°C



LM1117I -40°C to 125°C



2.85V Model for SCSI-2 Active Termination



Post Regulator for Switching DC/DC Converter



High Efficiency Linear Regulators 15



32” TFT TV Service Manual 10/01/2005



Battery Charger



Battery Powered Instrumentation

16.1

16.3

16.2

16.4

16.5

The MP2012 is a fully integrated, internally compensated 1.2MHz fixed frequency PWM step-down 

converter. It is ideal for powering portable equipment that runs from a single cell Lithium-Ion (Li+) Battery, 
with an input range from 2.7V to 6V. The MP2012 can provide up to 1.5A of load current with output voltage 

as low as 0.8V. It can also operate at 100% duty cycle for low dropout applications. With peak current mode 

control and internal compensation, the MP2012 is stable with ceramic capacitors and small inductors. Fault 
condition protection includes cycle-by-cycle current limiting and thermal shutdown.



2.7-6V Input Operation Range



Output Adjustable from 0.8V to VIN



1μA Max Shutdown Current.



Up to 95% Efficiency



100% Duty Cycle for Low Dropout



Applications



1.2MHz Fixed Switching Frequency



Stable with Low ESR Output Ceramic



Capacitors



Thermal Shutdown



Cycle-by-Cycle Over Current Protection



Short Circuit Protection



Available in 6-pin 3x3mm QFN

1

FB

Feedback input. An external resistor divider from the output 
to GND, tapped to the FB pin sets the output voltage.

2

GND, Exposed 

Pad

Ground pin. Connect exposed pad to ground plane for 

proper thermal performance.

3

SW

Switch node to the inductor.

4

PVIN

Input supply pin for power FET.

5

VIN

Input Supply pin for controller. Put small decoupling 

ceramic near this pin.

6

EN

Enable input, “High” enables MP2012. EN is pulled to GND 
with 1Meg internal resistor.

17.1

17.2

17.3

The RT8283A is a high-efficiency, monolithic synchronous step-down DC/DC converter that can deliver up 

to 3A output current from a 4.5V to 23V input supply. The RT8283A's current mode architecture and 
external compensation allow the transient response to be optimized over a wide range of loads and output 

capacitors. Cycle-by-cycle current limit provides protection against shorted outputs and soft-start eliminates 

input current surge during start-up. The RT8283A also provides output under voltage protection and thermal 
shutdown  protection.  The  low  current  (<3μA)  shutdown  mode  provides  output  disconnect,  enabling  easy 

power management in battery powered systems. The RT8283A is available in a SOP-8 package.



±1.5% High Accuracy Feedback Voltage



Integrated N-MOSFET Switches



Current Mode Control



Fixed Frequency Operation : 340kHz



Output Adjustable from 0.8V to 20V



Up to 95% Efficiency



Thermal Shutdown Protection

18.1

18.2

BOOT

Bootstrap for high-side gate driver. Connect a 0.1

μF or 

greater ceramic capacitor from BOOT to SW pins.

VIN

Input Supply 4.5V to 23V. Must bypass with a suitably 
large ceramic capacitor.

SW

Phase Node--Connect to external L-C filter..

GND

Ground. 

FB

Feedback Input pin is connected to the converter output. 
It is used to set the output of the converter to regulate to 

the desired value via an internal res divider. For an 

adjustable output, an external res divider is connected to 

this pin.

COMP

Compensation Node. COMP is used to compensate the 
regulation Control loop. Connect a series RC network 

from COMP to GND. In some cases, an additional 

capacitor from COMP to GND is required.

EN

Enable Input Pin. Logic high enables the converter; a 

logic low forces the RT8253A into shutdown mode. 

Attach this pin to VIN with a 100kΩ pull up resistor for 

automatic startup. 

SS

Soft-Start Control Input. SS controls the soft-start period. 
Connect a capacitor from SS to GND to set the soft-start 
period. A 0.1

μF capacitor sets the soft-start period to 

13.5ms.

18.3