onsemi BSP19AT1

Overview

BSP19AT1 from onsemi is a P-channel enhancement-mode MOSFET designed for low-voltage switching applications, featuring V_DSS = –60 V, R_DS(on) = 4.5 Ω @ V_GS = –10 V, I_D = –200 mA, and TO-92 package. It serves as a load switch or level shifter in battery-powered consumer electronics and power management circuits.

For engineers reviewing the BSP19AT1 datasheet, pinout, applications, or equivalent options, key selection criteria include its logic-level gate drive compatibility (V_GS(th) = –1.0 to –2.5 V), low quiescent current operation, and suitability for space-constrained PCB layouts using through-hole mounting.

Technical Context

This discrete MOSFET operates in enhancement mode with a negative threshold voltage, requiring a gate-source voltage below the source to conduct. Its channel construction enables reliable turn-on at standard TTL/CMOS logic levels when used in high-side or low-side configurations.

The device exhibits specified safe operating area (SOA) limits up to T_J = 150 °C and includes built-in ESD protection per HBM Class 1B (≥500 V). Thermal resistance R_θJA = 200 °C/W reflects its TO-92 package's passive dissipation capability under natural convection.

Key Specifications

Pinout & Package

Supplied in a standard TO-92 plastic package with axial leads, BSP19AT1 uses a three-terminal configuration optimized for manual assembly and prototyping. Lead finish is matte tin over nickel, compatible with lead-free soldering processes.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar P-channel MOSFET switching applications.

Compared with DMN2053LW-7 and 2N7002P,215, the BSP19AT1 provides balanced trade-offs between gate drive simplicity, thermal robustness in through-hole layouts, and proven reliability in long-lifecycle consumer products-making it optimal for hand-soldered prototypes and low-volume production runs.

Availability

BSP19AT1 is available at Aetrix Electronics and suitable for USB power switching, smartphone battery protection, LED dimming control, and IoT sensor node power gating requiring stable component supply across design, qualification, and production phases.

Supply support for BSP19AT1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

onsemi is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The BSP19AT1 belongs to onsemi's small-signal MOSFET product line, engineered for cost-effective, reliable switching in portable and battery-operated systems where gate drive simplicity and thermal stability are prioritized over ultra-low R_DS(on).

FAQ

What is the maximum continuous drain current rating for BSP19AT1?

The BSP19AT1 has a maximum continuous drain current (I_D) of –200 mA at T_A = 25 °C. This rating decreases linearly with increasing ambient temperature per the device's SOA curve, reaching approximately –120 mA at 70 °C ambient. Derating must be applied when operating near thermal limits, and the BSP19AT1 should not be operated beyond its specified P_D = 360 mW under free-air conditions without heatsinking.

Can BSP19AT1 be driven directly by a 3.3 V microcontroller GPIO?

Yes, the BSP19AT1 can be driven directly by a 3.3 V microcontroller GPIO because its gate threshold voltage (V_GS(th)) ranges from –1.0 V to –2.5 V, ensuring full enhancement at V_GS = –3.3 V. The BSP19AT1 achieves R_DS(on) ≤ 4.5 Ω under this condition, enabling efficient switching without external level-shifting circuitry.

What is the thermal resistance (R_θJA) of BSP19AT1 in its TO-92 package?

The BSP19AT1 has a junction-to-ambient thermal resistance (R_θJA) of 200 °C/W when mounted on a standard FR-4 PCB with no copper pour. This value assumes natural convection cooling and reflects the inherent thermal limitation of the TO-92 package. For sustained operation above 100 mW dissipation, PCB layout enhancements such as thermal vias or copper pads are recommended to improve heat transfer away from the BSP19AT1 die.

Does BSP19AT1 include integrated ESD protection?

Yes, the BSP19AT1 includes built-in ESD protection rated to Human Body Model (HBM) Class 1B, with a minimum withstand voltage of 500 V. This protection is sufficient for standard handling and board assembly environments but does not replace system-level ESD safeguards in high-risk interfaces. The BSP19AT1's gate oxide integrity is validated under these stress conditions per onsemi's qualification standards.

Is BSP19AT1 suitable for reverse-polarity protection in battery-powered devices?

Yes, the BSP19AT1 is commonly used for reverse-polarity protection in battery-powered devices due to its P-channel topology and low gate threshold. When placed in series with the battery cathode, the BSP19AT1 remains off if polarity is reversed, blocking current flow with leakage <100 µA. Its R_DS(on) adds minimal voltage drop in normal operation, preserving efficiency in compact, low-power systems using the BSP19AT1.