onsemi NST846MTWFTBG

Overview

NST846MTWFTBG from onsemi is an NPN general-purpose transistor rated for 65 V_CEO, 100 mA continuous collector current, and optimized for low-power surface-mount amplifier applications in space-constrained automotive and industrial PCBs. It features a DFN1010-3 (XDFNW3) wettable-flank package qualified to AEC-Q101 and supports reliable optical inspection.

For engineers reviewing the NST846MTWFTBG datasheet, pinout, applications, or equivalent options, key selection criteria include its 220–450 h_FE range at 10 mA, 100 MHz f_T, 0.25 V V_CE(sat) at I_C/I_B = 10 mA/0.5 mA, and thermal resistance of 220 °C/W under standard JEDEC conditions.

Technical Context

The NST846MTWFTBG operates as a silicon NPN bipolar junction transistor with DC current gain specified from 220 (min at I_C = 10 mA) to 450 (max), supporting linear amplification and switching functions. Its 100 MHz transition frequency and low 1.0–3.0 pF output capacitance enable stable performance in RF-coupled preamplifier stages up to VHF bands.

Thermal design is constrained by a 570 mW power dissipation limit at T_A = 25°C and a junction temperature range of −65°C to +150°C. The XDFNW3 package's wettable flanks ensure solder joint integrity verification via automated optical inspection-critical for automotive-grade manufacturing traceability.

Key Specifications

Pinout & Package

Package: XDFNW3 (Case 521AC), ultra-compact 1.00 mm × 1.00 mm × 0.38 mm DFN with wettable flanks, Pb-free and RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN general-purpose transistor applications.

Compared with MMBT8050DWLT1G and BC846BWT1G, the NST846MTWFTBG uniquely balances AEC-Q101 compliance, wettable-flank AOI readiness, and 100 MHz f_T in a 1.0 mm² footprint-making it optimal for miniaturized, high-reliability signal amplification where thermal and inspection constraints dominate.

Availability

NST846MTWFTBG is available at Aetrix Electronics and suitable for automotive cabin sensors, industrial IoT signal conditioning, and consumer audio preamp stages requiring stable component supply, long-term lifecycle support, and AEC-Q101-compliant sourcing.

Supply support for NST846MTWFTBG 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 NST846MTWFTBG belongs to onsemi's NSV-prefix automotive-qualified general-purpose transistor family, engineered specifically for space-constrained, high-reliability amplifier and switching functions in harsh-environment electronics.

FAQ

What is the maximum operating junction temperature for the NST846MTWFTBG?

The NST846MTWFTBG has a specified junction temperature range of −65°C to +150°C. This wide range supports operation in under-hood automotive environments and industrial enclosures without forced cooling. Derating is required above 25°C ambient per the R_JA = 220 °C/W thermal resistance; at 85°C ambient, maximum allowable power dissipation drops to approximately 260 mW to maintain T_J ≤ 150°C. The NST846MTWFTBG's thermal design relies on proper PCB copper area under the exposed pad.

Is the NST846MTWFTBG pin-compatible with the BC846BWT1G?

Yes, the NST846MTWFTBG and BC846BWT1G share identical XDFNW3 (Case 521AC) packaging, pin assignment (1=Base, 2=Emitter, 3=Collector), and footprint dimensions (1.00 mm × 1.00 mm). Both are AEC-Q101 qualified and support wettable-flank AOI. However, the NST846MTWFTBG specifies a higher V_(BR)EBO (6.0 V vs. 5.0 V) and slightly broader V_BE(on) range, making it preferable in designs requiring enhanced ESD robustness at the base terminal.

Does the NST846MTWFTBG require special PCB layout considerations?

Yes-the NST846MTWFTBG's XDFNW3 package includes an exposed thermal pad (pin 2, Emitter) that must be soldered to a minimum 100 mm² copper area on the PCB for thermal performance and mechanical reliability. Use thermal vias under the pad (≥4× 0.3 mm diameter) connected to inner ground planes. Maintain ≥0.2 mm solder mask clearance around all three terminals to ensure AOI visibility of wettable flanks. Avoid routing high-speed traces directly beneath the device to prevent coupling into the low-impedance emitter node.

What is the typical noise figure of the NST846MTWFTBG and at what conditions is it measured?

The NST846MTWFTBG has a typical noise figure of 1.0 dB, measured at I_C = 0.2 mA, V_CE = 5.0 V, source resistance R_S = 2.0 kΩ, frequency f = 1.0 kHz, and bandwidth BW = 200 Hz. This low noise performance makes the NST846MTWFTBG well-suited for microphone preamplifiers and other low-level analog signal chains where signal integrity is critical. Noise figure degrades at higher collector currents due to increased shot noise, so bias optimization is essential for noise-sensitive applications.

Can the NST846MTWFTBG be used in switching applications, and what is its typical turn-on delay?

Yes, the NST846MTWFTBG supports switching applications with typical V_CE(sat) = 0.25 V at I_C/I_B = 10 mA/0.5 mA and f_T = 100 MHz. While no explicit turn-on delay (t_on) is published, its small geometry and low C_obo (1.0–3.0 pF) imply sub-10 ns switching transitions under light capacitive loads. For precise timing-critical switching, external base resistors should be minimized and drive current maximized to reduce storage time; the NST846MTWFTBG is not optimized for high-speed digital logic but performs reliably in <1 MHz enable/disable control paths.