Infineon Technologies MMBT3904LT1HTSA1

Overview

MMBT3904LT1HTSA1 from ON Semiconductor is an NPN silicon switching transistor in SOT-23 package, rated for 40 V V_CEO, 200 mA I_C, and 330 mW P_tot at T_S ≤ 71°C. It delivers high DC current gain (h_FE = 100 min at I_C = 10 mA), low V_CE(sat) (0.2 V typ at I_C/I_B = 10 mA/1 mA), and 300 MHz f_T, enabling use in low-voltage digital logic interface and signal switching circuits.

For engineers reviewing the MMBT3904LT1HTSA1 datasheet, MMBT3904LT1HTSA1 pinout, MMBT3904LT1HTSA1 application, or MMBT3904LT1HTSA1 equivalent, key selection criteria include verified V_CE(sat) performance at 10–100 mA drive levels, thermal resistance (R_thJS ≤ 240 K/W), RoHS-compliant SOT-23 footprint compatibility, and AEC-Q101 qualification for automotive-grade reliability.

Technical Context

This discrete NPN transistor operates as a saturated switch or small-signal amplifier with defined breakdown limits: V_(BR)CEO = 40 V, V_(BR)CBO = 60 V, and V_(BR)EBO = 6 V. Its h_FE varies from 40 (min at I_C = 100 µA) to 300 (max at I_C = 100 µA), supporting stable biasing across wide collector current ranges.

Dynamic behavior includes t_d/t_r/t_f ≤ 35 ns / 35 ns / 50 ns under standardized 3 V switching conditions, and C_cb = 3.5 pF max at V_CB = 5 V - critical for high-speed digital gate driving and pulse shaping in microcontroller I/O expansion.

Key Specifications

Pinout & Package

MMBT3904LT1HTSA1 uses the industry-standard SOT-23 surface-mount package (3-pin, 1.3 mm × 2.9 mm footprint), optimized for automated placement and reflow soldering in space-constrained PCBs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN switching transistor applications.

Compared with BC847BW and PN2222A-AP, MMBT3904LT1HTSA1 offers optimal balance of SMT manufacturability, AEC-Q101 qualification, and predictable V_CE(sat) at 10–50 mA - making it preferred for volume automotive and industrial control designs requiring consistent switching behavior.

Availability

MMBT3904LT1HTSA1 is available at Aetrix Electronics and suitable for microcontroller I/O expansion, LED driver interface, and relay coil driver applications requiring stable component supply, automotive-grade reliability, and SOT-23 footprint compatibility.

Supply support for MMBT3904LT1HTSA1 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

ON Semiconductor is a global semiconductor supplier focused on energy-efficient electronics, delivering power management, analog, sensor, and discrete solutions for automotive, industrial, and cloud infrastructure markets.

MMBT3904LT1HTSA1 belongs to ON Semiconductor's general-purpose bipolar transistor product line, engineered for cost-sensitive, high-reliability switching applications where predictable saturation characteristics and AEC-Q101 validation are mandatory.

FAQ

Is MMBT3904LT1HTSA1 pin-compatible with standard SOT-23 NPN transistors like 2N3904?

Yes - MMBT3904LT1HTSA1 follows JEDEC-standard SOT-23 pinout (Emitter-Base-Collector on pins 1-2-3), matching 2N3904, BC847B, and other industry-standard SOT-23 NPN transistors. No PCB redesign is needed when substituting within same voltage/current class.

What is the maximum allowable junction temperature during continuous operation?

The absolute maximum junction temperature (T_j) is 150°C. At ambient temperatures up to 85°C and with proper PCB copper area (≥100 mm² thermal pad), the device sustains 200 mA I_C continuously while staying within thermal limits per its R_thJS ≤ 240 K/W specification.

Does this part support PWM switching at frequencies above 100 kHz?

Yes - with f_T = 300 MHz and t_f ≤ 50 ns, MMBT3904LT1HTSA1 reliably switches at 100–500 kHz in low-duty-cycle PWM applications. Performance remains stable up to 10% duty cycle; for >50% duty, derate I_C to maintain thermal safety.

How does AEC-Q101 qualification impact its use in non-automotive designs?

AEC-Q101 qualification confirms robustness against temperature cycling, humidity, and mechanical stress - directly improving field reliability in industrial controls, medical devices, and outdoor equipment. It does not restrict usage; rather, it provides verified margin beyond standard commercial-grade testing.