TMI33431E from TMI, in a ESOP-8. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	BS	passive	High-side gate driver bootstrap pin. Provides supply to the high-side LDMOS gate driver; charged to VSW+5V when the low-side switch is on. Connect a 100nF ceramic capacitor between BS and SW.
2	IN	power_in	Power input pin. Recommended operating range 4.5V to 30V; absolute maximum 36V. Bypass with local ceramic decoupling to GND.
3	EN	input	Enable input with an internal 5V Zener clamp. Drive to logic high (rising threshold ~1.15V) to enable the converter; drive low to enter micro-power shutdown. Must not be left floating; if pulled up to VIN via a resistor, keep EN sink current below 1mA.
4	SS	passive	Soft-start and tracking pin. An external capacitor to GND, charged by an internal 2.6µA current source, sets the internal 0.8V reference rise time (tSS = CSS·VREF/ISS). The SS pin voltage overrides the internal reference during startup.
5	FB	input	Feedback pin for the error amplifier. Connect to the mid-point of an external R1/R2 divider from VOUT to GND; the loop regulates FB to the internal 0.8V reference (VFBTH typ 800mV, ±2%). FB pin bias current is ±50nA max.
6	COMP	output	External loop compensation node; error-amplifier output. Connect an R-C network to GND to set the control-loop bandwidth and phase margin for peak current-mode operation.
7	GND	power_in	Ground reference and return for the controller. Tie to the exposed thermal pad and the system power ground plane.
8	SW	power_out	Switch node; common source of the internal high-side and low-side power MOSFETs. Connect to the external power inductor. Absolute-max range −0.3V to 36V (−5V to 38V for <10ns transients).
EP	EP	power_in	Exposed thermal pad, internally connected to Power GND. Solder to a large PCB ground copper area for thermal dissipation and low-impedance power return.

Key specifications

Parameter	Value
Manufacturer	TMI
Package	ESOP-8
Category	PMIC
Pins	9

Ordering variants

Same part, different packaging or reel option.

TMI33431E

CAD (KiCad official)

Symbol: TMI33431E
Footprint: Package_SO:SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.29x3mm
3D model: ESOP-8 (KiCad packages3D, STEP)

Provenance

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

Datasheet: TMI datasheet (15 pp, sha256 a7aa4912dfad3f7f, retrieved 2026-08-17, tier: lcsc)
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF