STMicroelectronics STS9NH3LL

Overview

STS9NH3LL from STMicroelectronics is an N-channel 30 V, 9 A Power MOSFET in SO-8 package, featuring 0.022 Ω R_DS(on) at V_GS = 10 V, 7.0 nC total gate charge, and optimized R_DS(on) × Q_g trade-off at 4.5 V for high-efficiency buck regulator high/low-side switching.

For engineers reviewing the STS9NH3LL datasheet, STS9NH3LL pinout, STS9NH3LL application, or STS9NH3LL equivalent, key selection criteria include conduction loss (R_DS(on) = 0.022 Ω @ 10 V), switching loss (Q_g = 7.0 nC), thermal resistance (R_thj-amb = 50 °C/W on 1 in² FR-4), avalanche energy rating (E_AS = 100 mJ), and SO-8 package compatibility with standard PCB layout practices.

Technical Context

This STripFET™ III device uses a single-feature-size strip-based process to minimize both conduction and switching losses simultaneously. Its low 0.020 Ω R_DS(on) at V_GS = 4.5 V and 7.0 nC Q_g enable efficient operation in fast-switching DC-DC converters.

The MOSFET supports unclamped inductive switching with 100 mJ single-pulse avalanche energy and exhibits 15 ns reverse recovery time (t_rr) with 5.7 nC Q_rr under 9 A, 100 A/µs di/dt conditions - critical for synchronous rectification and hard-switched topologies.

Key Specifications

Pinout & Package

STS9NH3LL is housed in a standard SO-8 surface-mount package (JEDEC MS-012AC) with exposed drain pad for enhanced thermal performance. Pin 1–4 are source terminals (internally paralleled), Pin 5–8 are drain terminals (internally paralleled), and Gate is on Pin 3 per internal schematic (Figure 1).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel Power MOSFET applications.

Compared with IRF7470PBF and Si7852DP-T1-GE3, STS9NH3LL delivers superior high-frequency efficiency due to its 7.0 nC Q_g and 0.020 Ω R_DS(on) @ 4.5 V - making it optimal for motherboard VRMs and telecom intermediate bus converters where 500 kHz–1 MHz operation dominates.

Availability

STS9NH3LL is available at Aetrix Electronics and suitable for server VRM power stages, desktop motherboard buck converters, and industrial PLC I/O modules requiring stable component supply and legacy design continuity.

Supply support for STS9NH3LL 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs, discrete devices, and MEMS sensors for automotive, industrial, and consumer markets.

STS9NH3LL belongs to ST's STripFET™ III Power MOSFET product line, engineered specifically for high-efficiency, high-frequency DC-DC conversion in computing and communications infrastructure where minimizing both conduction and switching losses is essential.

FAQ

Is STS9NH3LL still in active production?

No - STS9NH3LL is marked as Obsolete by STMicroelectronics per its official documentation. However, Aetrix Electronics maintains verified legacy inventory with full traceability and extended lifecycle support for ongoing production programs requiring this specific SO-8 MOSFET's electrical and thermal characteristics.

What is the maximum safe operating temperature for STS9NH3LL?

The absolute maximum junction temperature (T_J) is 150 °C. With R_thj-amb = 50 °C/W on a 1 in² FR-4 board, sustained 9 A operation requires case temperature ≤75 °C to maintain 75 °C thermal margin - achievable via copper pour and moderate airflow in typical motherboard layouts.

Can STS9NH3LL be used in synchronous rectification configurations?

Yes - its 15 ns reverse recovery time (t_rr) and 5.7 nC reverse recovery charge (Q_rr) at 9 A, 100 A/µs di/dt make it suitable for synchronous rectification in buck and flyback topologies, provided gate timing avoids shoot-through and body diode conduction is minimized through precise dead-time control.

Does STS9NH3LL require a gate resistor for stability?

Yes - test data specifies R_G = 4.7 Ω for switching time measurements. A 2.2–10 Ω gate resistor is recommended to dampen ringing, control dV/dt, and prevent spurious turn-on from Miller coupling - especially critical in high-side configurations with fast-rising V_DS transitions.