LT3905EUD#TRPBF from Analog Devices, in a QFN-16-EP(3x3). 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	ILIM	output	Open-drain overload indicator that pulls low when ILIM_MON reaches the 1.348V threshold and releases when ILIM_MON drops by 50mV; max recommended sink current is 2mA, leave open if unused.
2	LOS_MON	output	Loss-of-signal monitor that sources 10% of the APD current, is the positive input of the LOS comparator, is clamped to 2.25V, and needs a resistor to GND (tie to GND if unused).
3	ILIM_MON	output	APD overload monitor that sources 5% of the APD current, is clamped to 2.25V, needs a resistor to GND to set gain, with a 1.248V regulation setpoint and 1.348V current-limit threshold; must not float (tie to GND if unused).
4	MON	output	Current monitor output that sources 20% of the APD current, clamped to 2.25V, with a resistor to GND setting the monitor gain.
5	APD	output	APD cathode connection; the maximum current of this pin is 7mA (typ).
6	MONIN	power_in	Power supply for the APD and all current monitors, connected to VOUT through an external lowpass filter for lowest noise (65V absolute maximum).
7	SW	passive	Switch pin, drain of the internal power FET and anode of the internal Schottky, connected to the switching side of the inductor with minimal trace length (65V absolute maximum).
8	VOUT	power_out	Boost converter output, cathode of the internal power Schottky, with an output smoothing capacitor to GND (65V absolute maximum).
9	GND	power_in	Ground, tied to the exposed pad.
10	VIN	power_in	Input supply pin for 2.7V to 12V operation, bypassed with a capacitor to GND as close to the IC as possible.
11	EN/UVLO	input	Master enable and VIN undervoltage lockout with 1.2V threshold, 25mV internal hysteresis and 3µA hysteresis current; shutdown current is <1µA when low, or drive with a digital signal above 1.5V.
12	CTRL	input	External reference input to the FB error amp when below 1.248V; tie to VIN if unused.
13	LOS	output	Open-drain loss-of-signal indicator that goes high when LOS_MON is below LOS_ADJ; max recommended sink current is 2mA, leave open if unused.
14	LOS_ADJ	input	External reference input for the loss-of-signal comparator with 20mV internal hysteresis; tie to VIN for a fixed 1.248V threshold or if unused.
15	FB	input	Feedback pin connected to a resistor divider between VOUT and GND with a 1.248V internal reference; pull above 1.8V to disable the step-up converter.
16	fSEL	input	Frequency selector: tie to VIN for 2MHz operation or to GND for 1MHz operation.
17	GND	power_in	Exposed pad, ground, must be soldered to a large PCB copper area for proper functionality and heat sinking.

Key specifications

Parameter	Value
Manufacturer	Analog Devices
Package	QFN-16-EP(3x3)
Category	Power Management ICs
Pins	17

Electrical characteristics

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

Parameter	Symbol	Min	Typ	Max	Unit	Conditions	Page
Operating Voltage Range	VIN	2.7		12	V		3
Feedback Voltage	VFB	1.238	1.248	1.258	V	VCTRL = 1.5V	3
Feedback Voltage (full temp range)	VFB	1.223		1.273	V	VCTRL = 1.5V, full operating temperature range	3
Feedback Line Regulation			0.005	0.025	%/V	2.7V ≤ VIN ≤ 12V	3
FB Pin Bias Current			15	75	nA		3
FB Standby Threshold		1.65	1.8	1.95	V	VFB Rising	3
CTRL to FB Offset		-13	0	13	mV	VCTRL = 0.5V	3
CTRL Input Bias Current			15	75	nA	Current Out of Pin, VCTRL = 0.5V	3
MON Pin Voltage Clamp		2.35		2.5	V	IAPD = 300µA, RMON = Open	3
LOS_MON Pin Voltage Clamp		2.35		2.5	V	IAPD = 300µA, RLOS_MON = Open	3
LOS_MON Pin Bias Current			10	50	nA	Current Out of Pin, IAPD = 0A, VLOS_MON = 1V	3
ILIM_MON Pin Bias Current			35	175	nA	Current Out of Pin, IAPD = 0A, VILIM_MON = 1V	3
APD Monitor (MON) Current Gain		0.185	0.2	0.215		300nA ≤ IAPD ≤ 3µA, 12V ≤ MONIN ≤ 65V	3
APD Monitor (MON) Current Gain		0.196	0.2	0.204		3µA ≤ IAPD ≤ 3mA, 12V ≤ MONIN ≤ 65V	3
LOS_MON Current Gain		0.092	0.1	0.108		3µA ≤ IAPD ≤ 30µA, 12V ≤ MONIN ≤ 65V	3
LOS_MON Current Gain		0.096	0.1	0.104		30µA ≤ IAPD ≤ 3mA, 12V ≤ MONIN ≤ 65V	3
ILIM_MON Current Gain		0.045	0.05	0.055		30µA ≤ IAPD ≤ 300µA, 12V ≤ MONIN ≤ 65V	3
ILIM_MON Current Gain		0.048	0.05	0.052		300µA ≤ IAPD ≤ 3mA, 12V ≤ MONIN ≤ 65V	3
APD Monitor Voltage Drop		3.7	3.95	4.2	V	MONIN, APD at IAPD = 3mA, MONIN = 65V	3
Switching Frequency		0.9	1	1.1	MHz	fSEL = 0V	3
Switching Frequency		1.8	2	2.2	MHz	fSEL = 2V	3
Maximum Duty Cycle		90	95		%	fSEL = 0V	3
Maximum Duty Cycle		80	90		%	fSEL = 2V	3
Switch Current Limit		350	400	450	mA		3
Switch Leakage Current			0.1	3	µA	SW = 65V	3
Schottky Reverse Leakage				3	µA	VOUT, SW = 65V	3
Loss of Signal Comparator Internal Threshold		1.185	1.248	1.31	V	LOS_ADJ = 1.5V, LOS_MON Falling	3
Loss of Signal Comparator External Threshold		0.95		1.05	V	LOS_ADJ = 1.0V, LOS_MON Falling	3
ILIM_MON Voltage Regulation Threshold	VIFB	1.223	1.248	1.273	V	VFB = 0.5V	4
ILIM_MON Voltage Regulation Threshold (full temp)	VIFB	1.211		1.285	V	VFB = 0.5V, full operating temperature range	4
ILIM_MON APD Current Limit Threshold	VILIM	1.323	1.348	1.373	V		4
ILIM_MON APD Current Limit Threshold (full temp)	VILIM	1.311		1.385	V	full operating temperature range	4
ILIM_MON APD Current Limit Line Regulation				10	µA/V	VAPD = 0V, ∆IAPD/∆VMONIN, 5V < VMONIN < 65V	4
ILIM_MON Indicator Threshold		-30	-10	-2	mV	VILIM_MON Rising; printed as VILIM, 30 /, 10 /, 2 mV	4
EN/UVLO Threshold		1.128	1.2	1.272	V	VENUVLO Falling	4
EN/UVLO Threshold (full temp)		1.104	1.2	1.296	V	VENUVLO Falling, full operating temperature range	4
fSEL Voltage Threshold		0.7	0.9	1.1	V	fSEL Rising	4
LOS Output Low Voltage				0.3	V	ILOS = 2mA	4
ILIM Output Low Voltage				0.3	V	IILIM = 2mA	4
LOS Off-State Leakage				1	µA	VIN = VLOS = 12V	4
ILIM Off-State Leakage				1	µA	VILIM = 12V	4
Supply Current, Shutdown			0.1	1	µA	VENUVLO = 0V, Device in Shutdown	3
Supply Current, Before Trip Point			6	10	µA	VENUVLO = 1.1V, Before Trip Point	3
Supply Current, Switcher Standby			250	350	µA	VENUVLO = 1.3V, VFB = 2V, Switcher Standby	3
Supply Current, Not Switching			650	750	µA	VENUVLO = 1.3V, VFB = 1.5V, Not Switching	3
Switch On-Resistance			0.75		Ω	ISW = 150mA	3
Schottky Forward Voltage			780		mV	ISCHOTTKY = 150mA	3
Loss of Signal Comparator Hysteresis			20		mV	LOS_MON Rising	3
EN/UVLO Hysteresis Current			3		µA	VENUVLO = 1.1V, Device in Shutdown	4
Absolute Max VIN, FB, EN/UVLO, CTRL, fSEL, LOS_ADJ, LOS, ILIM				12	V		2
Absolute Max VOUT, SW, MONIN, APD				65	V		2
Absolute Max MON, LOS_MON, ILIM_MON				2.5	V		2
Operating Ambient Temperature Range		-40		125	°C	Note 2	2
Operating Junction Temperature Range		-40		125	°C	Note 2	2
Storage Temperature Range		-65		125	°C		2
Thermal Resistance Junction-Ambient	θJA		68		°C/W	UD package	2
Thermal Resistance Junction-Case	θJC		7.5		°C/W	UD package	2

CAD (KiCad official)

Symbol: LT3905EUD#TRPBF
Footprint: Package_DFN_QFN:QFN-16-1EP_3x3mm_P0.5mm_EP1.7x1.7mm
3D model: QFN-16-EP(3x3) (KiCad packages3D, STEP)
3D model files: lt3905eud-trpbf-etched.step / lt3905eud-trpbf-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); lt3905eud-trpbf.step / lt3905eud-trpbf.glb are the bare package body.

Provenance

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

Datasheet: Analog Devices datasheet (18 pp, sha256 17d3a9e9e9c939b5, retrieved 2026-10-30, 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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LT3905EUD#TRPBF

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3D Model

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