IR21531SPBF from Infineon Technologies, in a SOIC-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	VCC	power_in	Logic and internal gate drive supply voltage, 10V min to VCLAMP (15.6V nominal internal zener clamp) recommended; do not drive from a low-impedance DC source above VCLAMP.
2	RT	passive	Oscillator timing resistor input; recommended minimum RT is 10 kOhm.
3	CT	passive	Oscillator timing capacitor input; recommended minimum CT is 330 pF and pulling it below the 2.1V typ shutdown threshold disables both outputs.
4	COM	power_in	IC power and signal ground reference for all voltages.
5	LO	output	Low side gate driver output, in phase with RT, swinging -0.3V to VCC + 0.3V.
6	VS	power_in	High voltage floating supply return, steady state -3V to 600V and should not fly more than 5V below ground.
7	HO	output	High side gate driver output, swinging VS - 0.3V to VB + 0.3V.
8	VB	power_in	High side gate driver floating supply, VCC - 0.7V to VCLAMP recommended, 625V absolute maximum.

Key specifications

Parameter	Value
Manufacturer	Infineon Technologies
Package	SOIC-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
Rising VCC undervoltage lockout threshold	VCCUV+	8.1	9	9.9	V		4
Falling VCC undervoltage lockout threshold	VCCUV-	7.2	8	8.8	V		4
VCC undervoltage lockout hysteresis	VCCUVH	0.5	1	1.5	V		4
Micropower startup VCC supply current	IQCCUV		75	150	µA	VCC ≤ VCCUV-	4
Quiescent VCC supply current	IQCC		500	950	µA		4
VCC zener clamp voltage	VCLAMP	14.4	15.6	16.8	V	ICC = 5mA	4
Oscillator frequency	fosc	19.4	20	20.6	kHz	RT = 36.9kΩ	4
Oscillator frequency	fosc	94	100	106	kHz	RT = 7.43kΩ	4
RT pin duty cycle	d	48	50	52	%	fo < 100kHz	4
CT pin current	ICT		0.001	1	uA		4
UV-mode CT pin pulldown current	ICTUV	0.3	0.7	1.2	mA	VCC = 7V	4
Upper CT ramp voltage threshold	VCT+		8		V		4
Lower CT ramp voltage threshold	VCT-		4		V		4
CT voltage shutdown threshold	VCTSD	1.8	2.1	2.4	V		4
High-level RT output voltage, VCC - VRT	VRT+		10	50	mV	IRT = 100µA	4
High-level RT output voltage, VCC - VRT	VRT+		100	300	mV	IRT = 1mA	4
Low-level RT output voltage	VRT-		10	50	mV	IRT = 100µA	4
Low-level RT output voltage	VRT-		100	300	mV	IRT = 1mA	4
UV-mode RT output voltage	VRTUV		0	100	mV	VCC ≤ VCCUV-	4
SD-Mode RT output voltage, VCC - VRT	VRTSD		10	50	mV	IRT = 100µA, VCT = 0V	4
SD-Mode RT output voltage, VCC - VRT	VRTSD		10	300	mV	IRT = 1mA, VCT = 0V	4
Micropower startup VBS supply current	IQBSUV		0	10	µA	VCC ≤ VCCUV-	4
Quiescent VBS supply current	IQBS		30	50	µA		4
Minimum required VBS voltage for proper functionality from RT to HO	VBSMIN		4	5	V	VCC=VCCUV+ + 0.1V	4
Offset supply leakage current	ILK			50	µA	VB = VS = 600V	4
High level output voltage, VBIAS - VO	VOH		0	100	mV	IO = OA	5
Low-level output voltage, VO	VOL		0	100	mV	IO = OA	5
UV-mode output voltage, VO	VOL_UV		0	100	mV	IO = OA, VCC ≤ VCCUV-	5
Output rise time	tr		80	150	nsec		5
Output fall time	tf		45	100	nsec		5
Shutdown propogation delay	tsd		660		nsec		5
Output deadtime (HO or LO)	td	0.35	0.6	0.85	µsec		5
Steady state high side floating supply offset voltage	VS	-3		600	V	note 2	2
Supply voltage	VCC	10			V	maximum is VCLAMP	2
Supply current	ICC			5	mA	note 3	2
Junction temperature	TJ	-40		125	°C		2
Timing resistor value	RT	10			kΩ		3
CT pin capacitor value	CT	330			pF		3
High side floating supply voltage	VB	-0.3		625	V		2
Supply current	ICC			25	mA	note 1	2
RT pin current	IRT	-5		5	mA		2
Allowable offset voltage slew rate	dVs/dt	-50		50	V/ns		2
Maximum power dissipation (8 Lead SOIC)	PD			0.625	W	@ TA ≤ +25°C	2
Thermal resistance, junction to ambient (8 Lead SOIC)	RthJA			200	°C/W		2
Junction temperature	TJ	-55		150	°C		2
Storage temperature	TS	-55		150	°C		2
Lead temperature (soldering, 10 seconds)	TL			300	°C		2

CAD (KiCad official)

Symbol: IR21531SPBF
Footprint: Package_SO:SOIC-8_3.9x4.9mm_P1.27mm
3D model: SOIC-8 (KiCad packages3D, STEP)
3D model files: ir21531spbf-etched.step / ir21531spbf-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); ir21531spbf.step / ir21531spbf.glb are the bare package body.

Provenance

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

Datasheet: Infineon Technologies datasheet (9 pp, sha256 aa2e6f4ba065c24d, retrieved 2026-10-31, tier: lcsc)
Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-sonnet-5-5 (text+vision), consensus claude-opus-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).

Datasheet PDF

IR21531SPBF

Verified IR21531SPBF

Verification log 1 record

3D Model

Symbol & Footprint

Schematic Symbol

PCB Footprint

Datasheet

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