STP14NF12FP N-Channel MOSFET Equivalent & Substitute Parts

Part Overview

The STP14NF12FP is an N-Channel MOSFET manufactured by STMicroelectronics, rated for 120V drain-to-source voltage with 8.5A continuous drain current at 25°C. This device is part of the STripFET™ II series and features a TO-220FP through-hole package. The component is classified as obsolete, making identification of equivalent and substitute parts essential for ongoing design support, production continuity, and system maintenance. Substitute parts must maintain functional compatibility within the specified electrical and mechanical parameters while accommodating the transition from obsolete to active product status.

Substiute Parts

STP14NF12FP

STMicroelectronicsIn Stock: 688369STP14NF12FP Datasheet

Current PartRFQ

STF20NF20

STMicroelectronicsIn Stock: 15162STF20NF20 Datasheet

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RCX120N25

Rohm SemiconductorIn Stock: 3983RCX120N25 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the STP14NF12FP is determined by the following critical parameters:

Electrical Compatibility Criteria:

• FET Type: N-Channel topology must be maintained
• Technology: MOSFET (Metal Oxide) construction required
• Drain-to-Source Voltage (Vdss): Substitute must equal or exceed 120V
• Continuous Drain Current (Id): Substitute must equal or exceed 8.5A at 25°C
• On-State Resistance (Rds On): Lower or equivalent values ensure thermal performance
• Gate Threshold Voltage (Vgs(th)): Must remain within ±20V gate voltage specification
• Power Dissipation: Substitute must support minimum 25W thermal rating

Mechanical Compatibility Criteria:

• Mounting Type: Through-hole configuration required
• Package Type: TO-220-3 Full Pack or compatible footprint
• Pin Configuration: Standard TO-220 three-pin layout

Compliance & Status Criteria:

• RoHS3 Compliance: Required for regulatory alignment
• Product Status: Active status preferred for long-term availability
• REACH Status: REACH Unaffected classification maintained

Two substitute parts meet these criteria with varying performance enhancements and availability profiles.

Parameter Comparison

Engineering Selection Recommendations

STF20NF20 (STMicroelectronics)

The STF20NF20 is a direct substitute from the same manufacturer with enhanced electrical performance. This device exceeds the STP14NF12FP specifications across all critical parameters: 200V Vdss (versus 120V), 18A continuous drain current (versus 8.5A), and 30W power dissipation (versus 25W). The on-state resistance is reduced to 125 mOhm at 10A, 10V, providing improved thermal efficiency. Gate threshold voltage and maximum gate voltage remain identical at 4V and ±20V respectively. The STF20NF20 maintains the same operating temperature range (-55 to 175°C) and TO-220-3 Full Pack configuration. Product status is Active, ensuring long-term availability and supply chain stability. RoHS3 compliance and REACH Unaffected status align with regulatory requirements. This substitute is suitable for direct replacement in applications where the enhanced voltage and current ratings provide design margin without circuit modification.

RCX120N25 (Rohm Semiconductor)

The RCX120N25 is an alternative substitute from Rohm Semiconductor with the highest voltage rating at 250V Vdss, exceeding the original 120V specification. Continuous drain current is rated at 12A (Ta), surpassing the 8.5A requirement. Power dissipation is specified at 40W (Tc), providing substantial thermal headroom. The device features a higher maximum gate voltage specification of ±30V compared to the original ±20V. The TO-220FM package maintains through-hole mounting compatibility with standard TO-220-3 Full Pack footprint. Product status is Active with RoHS3 compliance and REACH Unaffected classification. Operating temperature maximum is specified at 150°C (TJ), which is lower than the original 175°C specification. This substitute is suitable for applications requiring higher voltage tolerance and thermal performance, with the caveat that the reduced maximum operating temperature must be evaluated against system thermal requirements.

Selection Basis:

Both substitutes maintain N-Channel MOSFET topology, through-hole TO-220 packaging, and regulatory compliance. The STF20NF20 offers manufacturer continuity and balanced performance enhancement. The RCX120N25 provides maximum voltage and current margin with alternative sourcing. Selection between these substitutes depends on supply chain strategy, thermal design requirements, and maximum operating temperature constraints specific to the application.

Frequently Asked Questions (FAQ)

Q: Can the STF20NF20 be used as a direct replacement for the STP14NF12FP without circuit modification?

A: The STF20NF20 is electrically compatible as a direct replacement. Both devices share identical gate threshold voltage (4V @ 250µA), maximum gate voltage (±20V), and operating temperature range (-55 to 175°C). The STF20NF20 provides enhanced specifications: higher Vdss (200V vs. 120V), higher continuous drain current (18A vs. 8.5A), and improved on-state resistance (125 mOhm vs. 180 mOhm). These enhancements do not require circuit modification and provide design margin. The TO-220-3 Full Pack configuration ensures mechanical compatibility with existing PCB layouts and thermal management solutions.

Q: What are the key differences between the STF20NF20 and RCX120N25 substitutes?

A: The STF20NF20 (STMicroelectronics) and RCX120N25 (Rohm Semiconductor) differ in voltage rating, current rating, and thermal specifications. The STF20NF20 is rated for 200V Vdss and 18A continuous drain current with 30W power dissipation. The RCX120N25 is rated for 250V Vdss and 12A continuous drain current with 40W power dissipation (Tc). The RCX120N25 features a higher maximum gate voltage (±30V vs. ±20V) but a lower maximum operating temperature (150°C vs. 175°C). Both maintain through-hole TO-220 packaging and RoHS3 compliance. Selection depends on whether higher voltage tolerance (RCX120N25) or higher current capacity (STF20NF20) is prioritized for the application.

Q: Why is the STP14NF12FP classified as obsolete, and what does this mean for component sourcing?

A: The STP14NF12FP is classified as obsolete by STMicroelectronics, indicating that the manufacturer has discontinued active production and support. Obsolete status typically results from product line consolidation, technology advancement, or market transition. Existing inventory may be available through authorized distributors, but long-term supply cannot be guaranteed. The identification of active substitute parts (STF20NF20 and RCX120N25) ensures design continuity and production support for new builds and maintenance applications. Both substitutes are classified as Active, providing reliable long-term availability.

Q: Are the TO-220FP and TO-220FM packages mechanically interchangeable?

A: The TO-220FP (STP14NF12FP and STF20NF20) and TO-220FM (RCX120N25) packages are both three-pin through-hole configurations within the TO-220 family and share the same standard pin spacing and footprint. Both are classified as TO-220-3 Full Pack in this reference. Mechanical interchangeability is confirmed for PCB mounting and thermal management applications. Thermal interface materials and heatsink mounting solutions designed for TO-220 packages are compatible with both variants.

Q: What compliance certifications are maintained across all three devices?

A: All three devices (STP14NF12FP, STF20NF20, and RCX120N25) maintain RoHS3 compliance and REACH Unaffected status. RoHS3 compliance confirms the absence of restricted hazardous substances in accordance with EU Directive 2011/65/EU. REACH Unaffected status indicates that the devices are not subject to REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) regulatory requirements. Both certifications ensure compatibility with environmental and regulatory standards across global markets. ECCN classification (EAR99) and HTSUS code (8541.29.0095) are consistent across all devices, supporting customs and export compliance documentation.

Q: How do gate charge and input capacitance differences affect circuit design when substituting the STP14NF12FP?

A: Gate charge (Qg) and input capacitance (Ciss) are provided for the STP14NF12FP (21 nC @ 10V, 460 pF @ 25V) and STF20NF20 (39 nC @ 10V, 940 pF @ 25V). The STF20NF20 exhibits higher gate charge and input capacitance due to its higher current rating and enhanced performance characteristics. These parameters affect gate drive circuit design, switching speed, and power dissipation in the gate driver. Higher gate charge requires increased gate drive current or extended switching time. Higher input capacitance increases capacitive loading on the gate driver. For the RCX120N25, these parameters are not specified in the provided data. Circuit designers must evaluate whether existing gate drive circuits can accommodate the STF20NF20's increased gate charge and capacitance, or whether gate driver modifications are necessary to maintain switching performance and efficiency.

Q: What is the significance of the different temperature measurement points (Tc vs. Ta) in the power dissipation specifications?

A: Power dissipation is specified at different measurement points across the devices. The STP14NF12FP and STF20NF20 specify power dissipation at Tc (case temperature): 25W and 30W respectively. The RCX120N25 specifies power dissipation at both Ta (ambient temperature) of 2.23W and Tc (case temperature) of 40W. Tc measurement reflects the thermal performance when the device is mounted on a heatsink, representing realistic operating conditions in thermal management applications. Ta measurement reflects power dissipation in free air without active cooling. The RCX120N25's 40W Tc rating provides substantial thermal margin compared to the original 25W specification. Designers must ensure that thermal management solutions (heatsinks, thermal interface materials) are adequate for the selected substitute's power dissipation characteristics.