AMS1117 low-dropout regulator pinout

The original 800 mA AMS1117 is available in fixed and resistor-adjustable versions. Its metal tab carries the regulated output.

SOT-223 fixed 4 contacts

TO-252 fixed 4 contacts

SOT-223 adjustable 4 contacts

TO-252 adjustable

4 contacts Current package

Advanced Monolithic Systems · Three lead positions and a connected metal tab.

TO-252 adjustable pinout

TO-252 adjustable

View from the marked face, with the tab above the body and leads 1–3 below from left to right. Scroll the map to reach all contacts.

Selected pin details

1 · ADJ

Input · Control

Feedback node. The regulator holds the output about 1.25 V above this node.

Advanced Monolithic Systems AMS1117, 800 mA datasheet, p. 1

Electrical limits · Link to this pin

All 4 pins

Pin	Signal	Direction	Function
1	ADJ Input	Input	Feedback node. The regulator holds the output about 1.25 V above this node.
2	VOUT Output	Output	Regulated output. Fit the output capacitor close to the device.
3	VIN Supply	Supply	Unregulated positive supply. Allow voltage headroom for dropout and keep the return path short.
TAB	VOUT Output	Output	Metal tab connected to VOUT internally. Include its net when laying out the footprint.

Signal assignments

Adjustable regulator

Set the output with R1 between VOUT and ADJ and R2 between ADJ and ground. R1 also provides the minimum load current.

Electrical limits

Parameter	Limit	Conditions and source
Rated output current800 mA	800 mA	Derate for the package, PCB and ambient temperature. Advanced Monolithic Systems AMS1117, 800 mA datasheet, Electrical Characteristics
Dropout at 800 mA1.3 V maximum	1.3 V maximum	Dropout is defined at a 1% change in output voltage. Advanced Monolithic Systems AMS1117, 800 mA datasheet, Electrical Characteristics
Stability capacitor22 µF solid tantalum	22 µF solid tantalum	Recommended for all conditions covered in Application Hints. Check capacitor polarity and voltage rating. Advanced Monolithic Systems AMS1117, 800 mA datasheet, Application Hints

Models and documents

The reference follows the Advanced Monolithic Systems 800 mA datasheet. Pin 1 is ground on the fixed version and the feedback input on the adjustable version.

AMS1117CD: Adjustable TO-252. Set VOUT with the feedback divider.

Advanced Monolithic Systems AMS1117, 800 mA datasheet· Archived copy of the Advanced Monolithic Systems document. See pin connections, electrical characteristics and Application Hints.
Source register· Document revisions, applicable order codes, consulted sections and available file checksums.