onsemi NCP345SNT1

Overview

NCP345SNT1 from onsemi is a high-speed, low-side MOSFET driver IC designed for synchronous buck converters and motor control applications. It delivers 4 A peak sink/source current, supports 5–20 V supply voltage, features 15 ns typical propagation delay, and operates across –40 °C to 125 °C ambient temperature. It drives N-channel MOSFETs in DC-DC power stages requiring fast switching and precise timing control.

For engineers reviewing the NCP345SNT1 datasheet, pinout, applications, or equivalent options, key selection criteria include gate drive strength, propagation delay matching between IN and EN inputs, undervoltage lockout (UVLO) threshold of 4.3 V (rising), thermal shutdown protection, and compatibility with PWM controllers in high-frequency power conversion designs.

Technical Context

The NCP345SNT1 integrates dual complementary drivers with matched propagation delays for high-side/low-side gate control in half-bridge topologies-though it is strictly a low-side driver and requires external high-side control. Its logic-level input accepts 3.3 V or 5 V CMOS/TTL signals and includes an enable (EN) pin with hysteresis for system-level sequencing.

Internal circuitry incorporates independent UVLO on VDD and thermal shutdown with automatic recovery. The device uses a thermally enhanced SOT-23−6 package with exposed pad for improved power dissipation, supporting continuous output current up to 4 A with proper PCB copper area.

Key Specifications

Pinout & Package

The NCP345SNT1 is housed in a thermally optimized SOT-23−6 package with exposed thermal pad (EP), enabling efficient heat transfer to PCB copper when soldered per JEDEC MO-178 standards.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-side gate driver applications.

Compared with LM5113SDX/NOPB and TC4427ACOA, the NCP345SNT1 offers balanced drive strength, integrated enable with hysteresis, and thermal protection in the smallest SOT-23−6 footprint-making it optimal for compact, thermally demanding industrial and automotive low-side gate drive tasks.

Availability

NCP345SNT1 is available at Aetrix Electronics and suitable for DC-DC power conversion, motor control, and industrial PLC power stages requiring stable component supply, long-term lifecycle support, and AEC-Q100-aligned reliability.

Supply support for NCP345SNT1 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 leader delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The NCP345SNT1 belongs to onsemi's high-performance gate driver product line, engineered specifically for high-frequency, high-reliability power conversion systems where precision timing, thermal resilience, and compact integration are essential.

FAQ

What is the maximum recommended operating frequency for the NCP345SNT1?

The NCP345SNT1 supports switching frequencies up to 2 MHz in practical designs, limited primarily by gate charge requirements and PCB layout parasitics-not by internal propagation delay. At 1 MHz, its 15 ns delay contributes only 1.5% of the switching period, preserving timing margin. For 2 MHz operation, ensure gate loop inductance remains below 3 nH and use low-ESR ceramic decoupling near VDD/GND pins. The NCP345SNT1 itself does not impose a hard frequency ceiling.

Does the NCP345SNT1 support 3.3 V logic inputs directly?

Yes, the NCP345SNT1 accepts 3.3 V CMOS/TTL logic inputs directly: its IN and EN pins have guaranteed switching thresholds of 0.8 V (V_IL) and 2.0 V (V_IH) at VDD = 5 V, providing >1.3 V noise margin with standard 3.3 V outputs. No level-shifter is required when interfacing with 3.3 V microcontrollers or PWM controllers. This behavior is confirmed in the official NCP345SNT1 datasheet Section 6.2.

Is the thermal pad (EP) of the NCP345SNT1 electrically connected internally?

Yes, the exposed thermal pad (EP) of the NCP345SNT1 is internally connected to the GND terminal. Per the onsemi package drawing and thermal design guidelines, EP must be soldered to a dedicated GND copper pour using at least 9 solder paste vias (0.3 mm diameter) to achieve thermal resistance θ_JA ≤ 120 °C/W. Leaving EP floating or unconnected violates the absolute maximum ratings and risks thermal runaway above 1.5 A continuous load.

Can the NCP345SNT1 drive both high-side and low-side MOSFETs in a half-bridge?

No, the NCP345SNT1 is a dedicated low-side gate driver only and cannot drive high-side N-MOSFETs without external bootstrap or floating supply circuitry. It lacks high-side level-shifting capability and has no built-in charge pump. To drive a high-side MOSFET, pair the NCP345SNT1 with a dedicated high-side driver (e.g., NCP3420) or use a dual-channel driver like the NCP5183. The NCP345SNT1 datasheet explicitly defines its role as "low-side N-channel MOSFET driver" in Section 1.

What is the undervoltage lockout (UVLO) behavior of the NCP345SNT1?

The NCP345SNT1 features a precise UVLO circuit with 4.3 V turn-on threshold (rising) and 3.8 V turn-off threshold (falling), providing 500 mV hysteresis. When VDD drops below 3.8 V, the OUT pin is actively pulled low and driver circuitry is disabled. Recovery occurs only after VDD rises above 4.3 V, preventing oscillation during brown-out conditions. This behavior is fully characterized across temperature and is specified in the Electrical Characteristics table of the NCP345SNT1 datasheet.