SMY51 MOSFET — Specifications & Equivalents
About the SMY51
The SMY51 is a P-channel MOSFET with a drain–source voltage (VDS) rating of 31 V, a continuous drain current (ID) of 0.02 A and an on-resistance (RDS(on)) of 150 Ω. It can dissipate up to 0.24 W. It is supplied in the DIL6 package.
At a glance
- Type: P-channel MOSFET
- Max drain–source voltage (VDS): 31 V
- Max continuous drain current (ID): 0.02 A
- On-resistance (RDS(on)): 150 Ω
- Power dissipation (PD): 0.24 W
- Package: DIL6
Typical applications
With its 31 V drain–source rating the SMY51 sits in the low-voltage class of switching MOSFETs, typically found in 12 V and 24 V automotive and industrial rails, synchronous buck converters, load switching and reverse-polarity protection and H-bridges for small motors.
At 0.02 A it is aimed at small-signal and light-load switching rather than power conversion.
On-resistance of 150 Ω is relatively high, so this part is better suited to low duty-cycle or low-current switching than to continuous high-current conduction.
Gate drive and switching notes
Keep gate–source voltage within the ±31 V maximum; exceeding it punctures the gate oxide and destroys the device permanently.
Choosing a replacement for the SMY51
A drop-in substitute for the SMY51 must be the same P-channel type and offer a drain–source rating of at least 31 V, a continuous drain current rating of at least 0.02 A and an on-resistance no higher than 150 Ω if efficiency and heat matter.
Mechanically, check the replacement against the DIL6 footprint and confirm the pin order — parts sharing a package outline do not always share a pinout.
Where the application switches inductive loads or runs near the voltage limit, keep extra headroom rather than choosing a part that only just meets the original numbers.
Frequently asked questions
What is the SMY51?
The SMY51 is a P-channel MOSFET (metal-oxide-semiconductor field-effect transistor). It is rated for 31 V drain-source and 0.02 A continuous drain current.
What is the maximum voltage of the SMY51?
The SMY51 has a maximum drain-source voltage (Vds) of 31 V. Treat this as an absolute maximum and design with margin, especially when switching inductive loads.
How much current can the SMY51 handle?
It is rated for 0.02 A of continuous drain current, with power dissipation limited to 0.24 W. Real-world capability depends on your heatsinking and ambient temperature.
What is the on-resistance of the SMY51?
On-resistance (Rds(on)) is 150 Ω. Multiply by the square of your load current to estimate conduction loss.
What package does the SMY51 come in?
It is listed in DIL6. Verify the pinout of the specific variant, as one outline can carry different pin assignments.
What can I use to replace the SMY51?
No verified equivalents are listed yet. Choose a part of the same polarity that meets or exceeds every rating above and shares a compatible package and pinout.
Key Specifications
| Type | MOSFET |
|---|---|
| Channel Type | P -Channel |
| Drain-Source Voltage (Vds) | 31 V |
| Gate-Source Voltage (Vgs) | 31 V |
| Drain Current (Id) | 0.02 A |
| Drain-Source On-Resistance (Rds) | 150 |
| Package | DIL6 |
| Power Dissipation (Pd) | 0.24 W |
Equivalent & Replacement Parts
No verified equivalents are listed for SMY51 yet.