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RT9742EGJ5

Richtek Tech · Power Distribution Switches · TSOT-23-5

RT9742EGJ5 from Richtek Tech, in a TSOT-23-5. 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 VOUT power_out Switch output voltage, the source of the internal N-MOSFET, which supplies the load.
2 GND power_in Ground.
3 FLG output Active-low N-channel open-drain fault flag output that asserts after about 10 ms of over-current or over-temperature, and needs an external pull-up resistor (10k to 100k).
4 EN/EN input Chip enable input (active high or active low depending on version), with VIH 1.5V min and VIL 0.75V max, 0V to 6V range; do not float it.
5 VIN power_in Power input voltage and drain of the internal MOSFET, with a 2.7V to 6V operating range and 7V absolute maximum; bypass with a 10µF capacitor to GND.

Key specifications

Parameter Value
Manufacturer Richtek Tech
Package TSOT-23-5
Category Power Management (PMIC)
Pins 5

Electrical characteristics

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

Parameter Symbol Min Typ Max Unit Conditions Page
Supply Input Voltage, VIN VIN 2.7 6 V 5
EN Voltage EN 0 6 V 5
Junction Temperature Range TJ -40 125 °C 5
Ambient Temperature Range TA -40 85 °C 5
Supply Input Voltage, VIN VIN 7 V 5
EN Voltage EN -0.3 7 V 5
FLAG Voltage FLG 7 V 5
Power Dissipation, PD (TSOT-23-5) PD 0.49 W TA = 25°C 5
Junction Temperature TJ 150 °C 5
Storage Temperature Range TSTG -65 150 °C 5
Lead Temperature (Soldering) 260 °C Soldering, 10 sec. 5
ESD Susceptibility HBM 2 kV Human Body Model 5
Package Thermal Resistance, θJA (TSOT-23-5) θJA 203 °C/W JEDEC 51-7 four-layer board, TA = 25°C 5
Input Quiescent Current IQ 30 40 μA Switch on, VOUT = open 5
Input Shutdown Current ISHDN 0.1 1 μA VIN = 5V, no load on OUT, device OFF, VEN = 0V or VEN = 5V 5
Switch On Resistance (RT9742XXJ5/V, this variant) RDS(ON) 70 mΩ 5
Over Current Trip Threshold (RT9742E group) ITRIP 1.55 2.1 2.25 A VIN = 5V, 100A/s 5
Current Limit (RT9742E group) ILIM 1.5 1.65 1.8 A VOUT = 1V 6
EN/EN Threshold Logic_High Voltage VIH 1.5 V VIN = 2.7V to 6V 6
EN/EN Threshold Logic_Low Voltage VIL 0.75 V VIN = 2.7V to 6V 6
EN/EN Input Current IEN 0.5 0.5 μA VEN = 0V, VEN = 5V 6
Output Leakage Current ILEAKAGE 0.5 1 μA VEN = 0V, RLOAD = 0 6
Reverse Leakage Current IREV 1 μA VOUT = 5V, VIN = 0V 6
Reverse Voltage Trip Point VREV 200 mV VOUT vs VIN (comparison symbol lost in extraction) 6
Output Turn-On Rise Time tON_RISE 1.5 ms 10% to 90% of VOUT rising 6
Turn-On Time tON 2.1 ms From enable to 90% of VOUT 6
FLG Output Resistance RFLG 10 Ω ISINK = 1mA 6
FLG Off Current IFLG_OFF 0.01 1 μA VFLG = 5V 6
FLG Delay Time tD 10 ms From fault condition to FLG assertion 6
Shutdown Auto-Discharge Resistance RDischarge 100 Ω VEN = 0V, VEN = 5V 6
Under-Voltage Lockout VUVLO 2.4 V VIN rising 6
Under-Voltage Hysteresis VUVLO 0.1 V VIN decreasing 6
Thermal Shutdown Protection TSD 140 °C Note 6 (guaranteed by design) 6
Thermal Shutdown Hysteresis TSD 20 °C Note 6 (guaranteed by design) 6

CAD (KiCad official)

  • Symbol: RT9742EGJ5
  • Footprint: Package_TO_SOT_SMD:TSOT-23-5
  • 3D model: TSOT-23-5 (KiCad packages3D, STEP)
  • 3D model files: rt9742egj5-etched.step / rt9742egj5-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); rt9742egj5.step / rt9742egj5.glb are the bare package body.

Provenance

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

  • Datasheet: Richtek Tech datasheet (19 pp, sha256 4512463eff0aa45d, retrieved 2026-10-19, 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