RY2121 from RYCHIP, in a SOT-23-5. 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	OUT	power_out	Switched power output. Delivers input voltage to the load through the internal 80mΩ MOSFET when EN is asserted. Discharged through an internal ~150Ω resistance during shutdown.
2	GND	power_in	Device ground reference. Also serves as the case position for θJC thermal measurement per the datasheet note.
3	SET	input	Current-limit programming pin. Connect a resistor RSET from this pin to GND to program the current-limit threshold (e.g. 6.8kΩ ≈ 1.18A typ; range 0.4A to 2A).
4	EN	input	Active-high ON/OFF control. Pull high (VIH ≥ 1.2V) to enable the switch; pull low (VIL ≤ 0.8V) to disable. Do not leave floating. ENB leakage ≤ 1μA at 5.5V.
5	IN	power_in	Power supply input, 2.4V to 5.5V. Source for the switched output through the internal power MOSFET. Monitored by the UVLO circuit (VIN_UVLO ≈ 2.3V with 0.1V hysteresis).

Key specifications

Parameter	Value
Manufacturer	RYCHIP
Package	SOT-23-5
Category	PMIC
Pins	5

Ordering variants

Same part, different packaging or reel option.

RY212170702013

CAD (KiCad official)

Symbol: RY2121
Footprint: Package_TO_SOT_SMD:SOT-23-5
3D model: SOT-23-5 (KiCad packages3D, STEP)

Provenance

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

Datasheet: RYCHIP datasheet (9 pp, sha256 15aeb628abbe0889, 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