This Product Selection Guide contains information to help select products in the PTC Resettable Fuses category on DigiKey.com
PTC Resettable Fuses are designed to stop current flow when it exceeds a certain limit (overcurrent protection). The Fuses work by increasing its resistance as its temperature rises due to the current increase. The trip current ranges from 14 mA to 50 A with the Time to trip ranging from 8 ms to 90 s. PTC = Positive Temperature Coefficient.
SelectionCharacteristics
Type: Indicates the core technology used by the fuse, defining its behavior.
Voltage - Max: The maximum DC voltage to which a device should be subjected; by extension, the maximum permissible supply voltage in a circuit protected by a device.
Current - Hold (Ih) (Max): Characterizes the maximum current flow through a device that will not cause the device to trip, under manufacturer-defined test conditions. Observed values will vary strongly with application conditions.
Current - Trip (It): Current flow that will cause the device to “trip” under manufacturer’s specified test conditions. Strongly dependent on ambient temperature.
Current - Max: The maximum current to which a device should be subjected under normal, continuous operating conditions.
Time to Trip: Time required for a device to enter a high-resistance state when subject to a manufacturer-defined current flow.
Resistance - Initial (Ri) (Min): The minimum resistance of the device in a resting state, before current is applied to it.
Resistance - Post Trip (R1) (Max): The maximum resistance value of the device after a manufacturer-specified duration following the device tripping. Essentially its ‘resetted’ resistance.
Resistance - 25°C (Typ): Nominal device resistance at the indicated device temperature; subject to manufacturing variation within the listed resistance tolerance value for a device.
Operating Temperature: Recommended operating temperature, typically given in a range or as a maximum. Exceeding these temperatures may affect performance or damage the device and other system components.
Ratings: Minimum performance standards of the device, which are typically set by a third party.
Mounting Type: Indicates how the device is attached.
Package / Case: Indicates the type of protective case used on an electronic component to allow easy handling, installation, and protection. This selection was determined to be the closest industry standard applicable to the supplier’s device packaging. Typically it is best to check the actual dimensions from the datasheet rather than depend on this terminology when designing your circuit.
Size / Dimension: The physical dimensions of the device. Typically given as Length by Width, in Inches (Millimeters).
Height - Seated (Max): Indicates how far the device will extend above the surface to which it has been attached.
Thickness (Max): Primarily applicable to surface-mounted devices; indicates maximum device dimension in a direction perpendicular to a device’s mounting plane.
Lead Spacing: The distance between the device’s leads, given in Inches (Millimeters)
ProductExamples
| MFR PART # | PTS120660V010 |
|---|---|
| DIGIKEY PART # | 283-3133-2-ND - Tape & Reel (TR) |
| MANUFACTURER | Eaton - Electronics Division |
| DESCRIPTION | Polymeric PTC Resettable Fuse 60V 100 mA Ih Surface Mount 1206 (3216 Metric), Concave |
| DATASHEET | Click Here |
| MFR PART # | RXEF050-2 |
|---|---|
| DIGIKEY PART # | RXEF050-2HFTR-ND - Tape & Reel (TR) |
| MANUFACTURER | Littelfuse Inc. |
| DESCRIPTION | Polymeric PTC Resettable Fuse 72V 500 mA Ih Through Hole Radial, Disc |
| DATASHEET | Click Here |
| MFR PART # | MF-GSMF300/36X-2 |
|---|---|
| DIGIKEY PART # | MF-GSMF300/36X-2TR-ND - Tape & Reel (TR) |
| MANUFACTURER | Bourns Inc. |
| DESCRIPTION | Polymeric PTC Resettable Fuse 36V 3 A Ih Surface Mount Nonstandard SMD |
| DATASHEET | Click Here |
| MFR PART # | MF-S200 |
|---|---|
| DIGIKEY PART # | MF-S200-ND |
| MANUFACTURER | Bourns Inc. |
| DESCRIPTION | Polymeric PTC Resettable Fuse 30V 2 A Ih User Defined Strap |
| DATASHEET | Click Here |
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MediaLinks
Articles
Circuit Protection Requires Careful Consideration
TechForum
What is a PTC Resettable Fuse?
Choosing the Correct PTC Resettable Fuse
What is a PPTC Fuse?