VIPER38LD from STMicroelectronics, in a SOIC-16. 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	GND	power_in	Device ground and source of the power MOSFET.
2	GND	power_in	Device ground and source of the power MOSFET.
3	N.C.	unconnected	Not connected.
4	N.A.	unconnected	Not available for user; mechanically connected to the controller die pad and highly recommended to be connected to GND (pins 1-2) to improve noise immunity.
5	VDD	power_in	Supply voltage of the control section that also provides the charging current of the external capacitor during startup.
6	CONT	input	Control pin used for current limit setpoint reduction via an external resistor to ground and for output voltage monitoring, where a voltage above VOVP shuts the IC down.
7	FB	input	Control input for duty cycle control; a voltage below VFBbm activates burst-mode operation and a level close to VFBlin means the cycle-by-cycle overcurrent setpoint is being approached.
8	EPT	passive	Allows connection of an external capacitor for extra power management; if the function is not used, the pin must be connected to GND.
9	N.C.	unconnected	Not connected.
10	N.C.	unconnected	Not connected.
11	N.C.	unconnected	Not connected.
12	N.C.	unconnected	Not connected.
13	DRAIN	passive	High-voltage drain pin rated to 800 V drain-to-source; the built-in high-voltage startup bias current is drawn from this pin and it is connected to the metal frame for heat dissipation.
14	DRAIN	passive	High-voltage drain pin rated to 800 V drain-to-source; the built-in high-voltage startup bias current is drawn from this pin and it is connected to the metal frame for heat dissipation.
15	DRAIN	passive	High-voltage drain pin rated to 800 V drain-to-source; the built-in high-voltage startup bias current is drawn from this pin and it is connected to the metal frame for heat dissipation.
16	DRAIN	passive	High-voltage drain pin rated to 800 V drain-to-source; the built-in high-voltage startup bias current is drawn from this pin and it is connected to the metal frame for heat dissipation.

Key specifications

Parameter	Value
Manufacturer	STMicroelectronics
Package	SOIC-16
Category	Power Management (PMIC)
Pins	16

Electrical characteristics

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

Parameter	Symbol	Min	Typ	Max	Unit	Conditions	Page
Drain-to-source (ground) voltage	VDRAIN			800	V		7
Pulse drain current	IDRAIN			3	A	limited by TJ = 150 °C	7
Control input pin voltage	VCONT	-0.3		6	V		7
Feedback voltage	VFB	-0.3		5.5	V		7
EPT input pin voltage	VEPT	-0.3		5	V		7
Supply voltage	VDD	-0.3			V	IDD = 25 mA; self limited	7
Input current	IDD			25	mA		7
Power dissipation	PTOT			1.5	W	TA < 60 °C	7
Operating junction temperature range	TJ	-40		150	°C		7
Storage temperature	TSTG	-55		150	°C		7
Thermal resistance junction pin (SO16N)	RthJP			35	°C/W	dissipated power = 1 W	7
Thermal resistance junction-to-ambient (SO16N)	RthJA			110	°C/W	dissipated power = 1 W	7
Thermal resistance junction-to-ambient, 100 mm2 Cu (SO16N)	RthJA			80	°C/W	dissipated power = 1 W; standard single side FR4 board with 100 mm2 Cu (35 µm)	7
Breakdown voltage	VBVDSS	800			V	IDRAIN = 1 mA, VFB = GND, TJ = 25 °C	8
OFF-state drain current	IOFF			60	µA	VDRAIN = max rating, VFB = GND, TJ = 25°C	8
Drain-source on-state resistance	RDS(on)			4.5	Ω	IDRAIN = 0.4 A, VFB = 3 V, VEPT = GND, TJ = 25 °C	8
Drain-source on-state resistance	RDS(on)			9	Ω	IDRAIN = 0.4 A, VFB = 3 V, VEPT = GND, TJ = 125 °C	8
Drain-source start voltage	VDRAIN_START	60	80	100	V		8
Startup charging current	IDDch1	-2	-3	-4	mA	VDRAIN = 120 V, VEPT = GND, VFB = GND, VDD = 4 V	8
Restart charging current (after fault)	IDDch2	-0.4	-0.6	-0.8	mA	VDRAIN = 120 V, VEPT = GND, VFB = GND, VDD = 4 V	8
VDD operating voltage range	VDD	8.5		23.5	V	After turn-on	8
VDD clamp voltage	VDDclamp	23.5			V	IDD = 20 mA	8
VDD startup threshold	VDDon	13	14	15	V	VDRAIN = 120 V, VEPT = GND, VFB = GND	8
VDD undervoltage shutdown threshold	VDDoff	7.5	8	8.5	V		8
VDD restart voltage threshold	VDD(RESTART)	4	4.5	5	V	VDRAIN = 120 V, VEPT = GND, VFB = GND	8
Operating supply current, not switching	IDD0			0.7	mA	VFB = GND, FOSC = 0 kHz, VEPT = GND, VDD = 10 V	8
Operating supply current, switching	IDD1			2.5	mA	VDRAIN = 120 V, FOSC = 60 kHz	8
Operating supply current, with protection tripping	IDD_FAULT			400	uA	VDD = 10 V	8
Operating supply current with VDD < VDD_OFF	IDD_OFF			270	uA	VDD = 7 V	8
Overload shutdown threshold	VFBolp	4.5	4.8	5.2	V		9
Overload detection threshold	VFBlin	3.2	3.5	3.7	V		9
Burst mode threshold	VFBbm	0.54	0.6	0.66	V	Voltage falling	9
Feedback sourced current	IFB1	-150	-200	-280	uA	VFB = 0.3 V	9
Dynamic resistance	RFB(DYN)	14		21	kΩ	VFB < 3.3 V	9
Delta VFB / Delta ID	HFB	0.5		2	V/A		9
Low-level clamp voltage	VCONT_l	0.4	0.5	0.6	V	ICONT = -100 µA	9
High-level clamp voltage	VCONT_h	5	5.5	6	V	ICONT = 1 mA	9
Max drain current limitation	IDlim	1.07	1.15	1.23	A	VFB = 4 V, ICONT = -10 µA, TJ = 25 °C	9
Soft-start time	tSS	7.6	8.5	9.4	ms		9
Minimum turn-on time	tON_MIN	220	400	480	ns		9
Peak drain current during burst mode	ID_BM	115	190	265	mA	VFB = 0.6 V	9
Oscillator frequency (L type)	FOSC	54	60	66	kHz	VFB = 1 V	9
Modulation depth (L type)	FD	-4		4	kHz		9
Modulation frequency	FM	830	920	1010	Hz		9
Maximum duty cycle	DMAX	70		80	%		9
Second overcurrent threshold	IDMAX		1.7		A		9
Overvoltage protection threshold	VOVP	2.7	3	3.3	V		9
Overvoltage protection strobe time	tSTROBE	1.5	2	2.5	µs		9
EPT shutdown threshold	VEPT(STOP)	3.6	4	4.4	V	ICONT < -10 µA	10
EPT restart threshold	VEPT(RESTART)	0.4	0.6	0.8	V		10
Sink/source current	IEPT	4	5	6	µA		10
Thermal shutdown temperature	TSD	150		160	°C		10
Thermal shutdown hysteresis	THYST		30		°C		10
Propagation delay	td		20		ns		9
Leading edge blanking	tLEB		380		ns		9
Effective (energy related) output capacitance	COSS		17		pF	VDRAIN = 0 to 640 V, TJ = 25°C	8

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		Note: The copper area for heat dissipation has to be designed under the DRAIN pins.	6

CAD (KiCad official)

Symbol: VIPER38LD
Footprint: Package_SO:SOIC-16_3.9x9.9mm_P1.27mm
3D model: SOIC-16 (KiCad packages3D, STEP)
3D model files: viper38ld-etched.step / viper38ld-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); viper38ld.step / viper38ld.glb are the bare package body.

Provenance

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

Datasheet: STMicroelectronics datasheet (31 pp, sha256 bbbaecc97a22b630, retrieved 2026-11-05, tier: manufacturer)
Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-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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