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Contents

README

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RT9187CGB

Richtek Tech · Linear Voltage Regulators (LDO) · SOT-23-5

RT9187CGB from Richtek Tech, in a SOT-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 VIN power_in Voltage input with a recommended supply range of 2.5V to 5.5V and a 6V absolute maximum.
2 GND power_in Ground reference pin for the regulator.
3 EN input Active-high chip enable; a logic-low below 0.6V puts the part into shutdown with standby current of 1µA maximum.
4 ADJ input Output voltage feedback input, where VOUT = VREF x (1 + R1/R2) with VREF typically 0.8V and divider resistors up to 100kΩ.
5 VOUT power_out Regulated voltage output that requires at least a 2.2µF output capacitor for stability.

Key specifications

Parameter Value
Manufacturer Richtek Tech
Package SOT-23-5
Category Power Supply Chip
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
Reference Voltage Tolerance VREF 0.784 0.8 0.816 V 3
ADJ Pin Current IADJ 10 100 nA VADJ = VREF 3
Quiescent Current IQ 300 400 μA VEN ≥ VIH, IOUT = 0mA 3
Standby Current ISTBY 0.1 1 μA VEN ≤ VIL,VIN = 3.3V 3
Current Limit ILIM 0.9 A RLOAD = 0.5Ω, VIN = 3.3V 3
Dropout Voltage VDROP 60 100 mV IOUT = 0.3A, VOUT = 5V 3
Dropout Voltage VDROP 100 200 mV IOUT = 0.5A, VOUT = 5V 3
Load Regulation ΔVLOAD 0.4 %/A VIN = (VOUT + 0.5V), 10mA < IOUT < 0.5A 3
EN Threshold Logic-High Voltage VIH 1.8 V VIN = 3.3V 3
EN Threshold Logic-Low Voltage VIL 0.6 V VIN = 3.3V 3
EN Current IEN 0.1 1 μA VIN = 3.3V, Enable 3
Power Supply Rejection Rate PSRR -60 dB f = 100Hz 3
Power Supply Rejection Rate PSRR -50 dB f = 10kHz 3
Line Regulation ΔVLINE 0.3 % VIN = (VOUT + 0.5) to 5.5V, IOUT = 1mA 3
Supply Input Voltage (absolute maximum) 6 V 3
EN Input Voltage (absolute maximum) 6 V 3
Power Dissipation PD 0.4 W TA = 25°C, SOT-23-5 3
Package Thermal Resistance θJA 250 °C/W SOT-23-5 3
Lead Temperature (Soldering, 10 sec.) 260 °C Soldering, 10 sec. 3
Junction Temperature 150 °C 3
Storage Temperature Range -65 150 °C 3
ESD Susceptibility HBM 2 kV HBM (Human Body Model) 3
Supply Input Voltage (recommended) 2.5 5.5 V 3
EN Input Voltage (recommended) 0 5.5 V 3
Junction Temperature Range -40 125 °C 3
Ambient Temperature Range -40 85 °C 3

CAD (KiCad official)

  • Symbol: RT9187CGB
  • Footprint: Package_TO_SOT_SMD:SOT-23-5
  • 3D model: SOT-23-5 (KiCad packages3D, STEP)
  • 3D model files: rt9187cgb-etched.step / rt9187cgb-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); rt9187cgb.step / rt9187cgb.glb are the bare package body.

Provenance

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

  • Datasheet: Richtek Tech datasheet (8 pp, sha256 af18f1df3e172e01, retrieved 2026-10-27, tier: manufacturer)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-haiku-5-5 (text), consensus off (skipped (clean text read)), 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