LT1521CS8#PBF from Analog Devices, in a SO-8. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	OUT	power_out	Regulated output supplying the load, requiring a minimum 1.5µF output capacitor to prevent oscillation.
2	ADJ	input	Error-amplifier input on the adjustable LT1521 with 3.75V reference, 50nA bias current into the pin, internally clamped to 6V and -0.6V, giving a 3.75V to 20V output range (pin 2 is SENSE on the fixed -3/-3.3/-5 versions).
3	GND	power_in	Ground pin, one of pins 3, 6 and 7 that are ground on the S8 package.
4	NC	unconnected	No internal connection.
5	SHDN	input	Active-low shutdown input, pulled low to turn the output off, internally clamped to 7V and -0.6V, may be left open for output on (on above 2.80V max, off below 0.25V min threshold, pull-up current limited to 5mA).
6	GND	power_in	Ground pin, one of pins 3, 6 and 7 that are ground on the S8 package.
7	GND	power_in	Ground pin, one of pins 3, 6 and 7 that are ground on the S8 package.
8	IN	power_in	Power input, withstands reverse voltage of 20V with no reverse current flow, and should be bypassed with 1µF to 10µF if far from the main input filter capacitor.

Key specifications

Parameter	Value
Manufacturer	Analog Devices
Package	SO-8
Category	Power Management ICs
Pins	8

Electrical characteristics

Limits as printed in the datasheet (page.json metadata.characteristics carries them as data).

Parameter	Symbol	Min	Typ	Max	Unit	Conditions	Page
Regulated Output Voltage (Adjust pin tied to output)	VOUT	3.695	3.75	3.805	V	VIN = 4.3V, IOUT = 1mA, TJ = 25°C	3
Regulated Output Voltage (Adjust pin tied to output)	VOUT	3.64	3.75	3.86	V	4.8V < VIN < 20V, 1mA < IOUT < 300mA, over temperature	3
Line Regulation			1.5	20	mV	ΔVIN = 4.3 to 20V, IOUT = 1mA	3
Load Regulation (TJ ≤ 25°C)			-20	-30	mV	ΔILOAD = 1mA to 300mA, TJ ≤ 25°C	3
Load Regulation (TJ > 25°C)			-20	-55	mV	ΔILOAD = 1mA to 300mA, TJ > 25°C	3
Dropout Voltage			130	170	mV	ILOAD = 1mA, TJ = 25°C	3
Dropout Voltage				250	mV	ILOAD = 1mA, over temperature	3
Dropout Voltage			290	350	mV	ILOAD = 50mA, TJ = 25°C	3
Dropout Voltage				450	mV	ILOAD = 50mA, over temperature	3
Dropout Voltage			350	420	mV	ILOAD = 100mA, TJ = 25°C	3
Dropout Voltage				550	mV	ILOAD = 100mA, over temperature	3
Dropout Voltage			400	470	mV	ILOAD = 150mA, TJ = 25°C	3
Dropout Voltage				600	mV	ILOAD = 150mA, over temperature	3
Dropout Voltage			500	600	mV	ILOAD = 300mA, TJ = 25°C	3
Dropout Voltage				750	mV	ILOAD = 300mA, over temperature	3
Ground Pin Current			12	25	µA	ILOAD = 0mA	3
Ground Pin Current			65	100	µA	ILOAD = 1mA	3
Ground Pin Current			300	450	µA	ILOAD = 10mA	3
Ground Pin Current			0.8	1.5	mA	ILOAD = 50mA	3
Ground Pin Current			1.4	2.5	mA	ILOAD = 100mA	3
Ground Pin Current			2.2	4	mA	ILOAD = 150mA	3
Ground Pin Current			6.5	12	mA	ILOAD = 300mA	3
Adjust Pin Bias Current			50	100	nA	TJ = 25°C	3
Shutdown Threshold (Off to On)			1.2	2.8	V	VOUT = Off to On	3
Shutdown Threshold (On to Off)		0.25		0.75	V	VOUT = On to Off	3
Shutdown Pin Current			2	5	µA	VSHDN = 0V	3
Quiescent Current in Shutdown			6	12	µA	VIN = VOUT (NOMINAL) + 1V, VSHDN = 0V	3
Ripple Rejection		50	58		dB	VIN, VOUT = 1V(Avg), VRIPPLE = 0.5VP-P, fRIPPLE = 120Hz, ILOAD = 150mA	3
Current Limit			400	800	mA	VIN, VOUT = 7V, TJ = 25°C	3
Current Limit		320	400		mA	VIN = VOUT (NOMINAL) + 1.5V, ΔVOUT =, 0.1V	3
Input Reverse Leakage Current				1	mA	VIN =, 20V, VOUT = 0V	4
Reverse Output Current			5	10	µA	VOUT = 3.8V, VIN < 3.75V, TJ = 25°C	4
Input Voltage		-20		20	V		2
Output Pin Reverse Current				10	mA		2
Adjust Pin Current				10	mA		2
Shutdown Pin Input Voltage		-0.6		6.5	V		2
Shutdown Pin Input Current				5	mA		2
Storage Temperature Range		-65		150	°C		2
Operating Junction Temperature Range (Commercial)		0		125	°C	Commercial	2
Lead Temperature (Soldering, 10 sec)				300	°C		2
Maximum Junction Temperature	TJMAX			125	°C	S8 package	2
Thermal Resistance Junction-to-Ambient	θJA		70		°C/W	S8 package	2
Thermal Resistance Junction-to-Ambient			60		°C/W	S8, topside 2500mm2, backside 2500mm2, board 2500mm2	10
Thermal Resistance Junction-to-Ambient			68		°C/W	S8, topside 225mm2, backside 2500mm2, board 2500mm2	10
Thermal Resistance Junction-to-Ambient			74		°C/W	S8, topside 100mm2, backside 2500mm2, board 2500mm2	10

Materials and finish

As the datasheet states them (page.json metadata.appearance; the 3D model's colours follow it).

Part	Material	Colour / plating	Datasheet says	Page
contacts	copper		3/32" FR-4 board with one ounce copper. All NC leads were	10

CAD (KiCad official)

Symbol: LT1521CS8#PBF
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SO-8 (KiCad packages3D, STEP)
3D model files: lt1521cs8-pbf-etched.step / lt1521cs8-pbf-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lt1521cs8-pbf.step / lt1521cs8-pbf.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

Datasheet: Analog Devices datasheet (16 pp, sha256 a580c39ec72785d9, retrieved 2026-10-31, tier: manufacturer)
Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-sonnet-5-5 (text), consensus claude-sonnet-5-5 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
CAD: KiCad official libraries (CC-BY-SA 4.0).

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LT1521CS8#PBF

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