Device Overview
BSS138 is an onsemi 50 V N-channel enhancement-mode MOSFET in SOT-23. It is intended for low-voltage, low-current switching, small-signal load control and gate-drive applications where compact size matters more than very low conduction resistance.
Key Selection Information
| Parameter | Verified Information |
|---|---|
| Manufacturer | onsemi |
| Exact MPN | BSS138 |
| Drain-source voltage | 50 V absolute maximum |
| Continuous drain current | 0.22 A absolute-maximum rating at TA = 25 °C under the datasheet thermal note |
| RDS(on), VGS = 10 V | 3.5 Ω maximum at ID = 0.22 A |
| RDS(on), VGS = 4.5 V | 6.0 Ω maximum at ID = 0.22 A |
| Gate threshold voltage | 0.8 V minimum / 1.3 V typical / 1.5 V maximum at VDS = VGS, ID = 1 mA |
| Total gate charge | 1.7 nC typical / 2.4 nC maximum at VDS = 25 V, ID = 0.22 A, VGS = 10 V |
| Input / output / reverse capacitance | 27 pF / 13 pF / 6 pF typical at VDS = 25 V, VGS = 0 V, 1 MHz |
| Package | SOT-23-3 |
Engineering Selection Notes
The 3.5 Ω and 6.0 Ω values are both maximum RDS(on) specifications but at different gate voltages. A 3.3 V GPIO drive is below both guaranteed on-resistance test voltages, so the device should not be evaluated as if either guaranteed resistance automatically applies at 3.3 V.
Gate threshold is measured at only 1 mA and indicates the onset of conduction, not full enhancement. It is therefore unsuitable as a gate-drive target for estimating low-loss load current.
The 0.22 A continuous-current value is an absolute-maximum rating tied to thermal assumptions. Real continuous load current must be derated for ambient temperature, board thermal resistance and conduction/switching losses.
Official Engineering Resources
Quality & Verification Support
Third-party inspection or testing can be arranged according to customer requirements. Testing fees are borne by the buyer. Additional verification requirements can be discussed before shipment.
Request a Quote
For BSS138 sourcing, provide the required quantity, destination, target Date Code if applicable, and any inspection or testing requirements.
