Diodes Incorporated MMBT5551-7-F

Overview

MMBT5551-7-F from Diodes Incorporated is an NPN high-voltage transistor in SOT23 package, rated for V_CEO = 160 V, I_C = 600 mA, and P_D = 300 mW, with h_FE = 80–250 at I_C = 1–50 mA. It serves as a low-power switching and amplification device in voltage-regulated power supplies, signal conditioning stages, and interface logic level translators.

For engineers reviewing the MMBT5551-7-F datasheet, MMBT5551-7-F pinout, MMBT5551-7-F application, or MMBT5551-7-F equivalent, key selection criteria include high-voltage blocking capability (160 V), low V_CE(sat) (≤0.20 V @ 50 mA), thermal performance on FR4 (R_θJA = 417 °C/W), and RoHS-compliant green packaging with SOT23 footprint compatibility.

Technical Context

This discrete NPN bipolar junction transistor operates in active, saturation, and cutoff regions with verified DC current gain (h_FE) spanning 80–250 across collector currents from 1 mA to 50 mA at V_CE = 5 V. Its f_T = 100–300 MHz enables use in RF preamplifier and broadband switching applications up to ~100 MHz.

The device features a robust safe operating area (SOA) validated per JEDEC standards, with pulse power derating down to 0.05 W at T_A = 125 °C and ESD HBM rating of 4 kV. Its SOT23 package supports automated placement and reflow soldering on 2 oz copper FR4 PCBs with minimum pad layout.

Key Specifications

Pinout & Package

MMBT5551-7-F uses the industry-standard SOT23 surface-mount package (3-pin, 2.9 mm × 1.3 mm × 1.0 mm), with matte tin-plated leads compliant with MIL-STD-202 Method 208 solderability requirements.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN high-voltage transistor applications.

Compared with MMBT5551-7-F, MMBT5551LT1G offers identical performance in a different reel configuration, while PN2222A-AP lacks the critical 160 V V_CEO needed for mains-referenced switching-making the former a drop-in alternative and the latter unsuitable for high-voltage applications.

Availability

MMBT5551-7-F is available at Aetrix Electronics and suitable for industrial power supply control, signal level translation, automotive sensor interface, and LED driver applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant green packaging.

Supply support for MMBT5551-7-F 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and distribution operations across Asia, Europe, and North America.

The MMBT5551 belongs to Diodes' general-purpose bipolar transistor product line, engineered for cost-sensitive, high-reliability applications in power conversion, signal conditioning, and interface circuitry where high-voltage tolerance and thermal robustness are essential.

FAQ

What is the maximum continuous collector current for MMBT5551-7-F?

The absolute maximum continuous collector current is 600 mA at T_A = +25°C with proper PCB thermal relief. Derating applies above 25°C: power dissipation drops linearly to zero at +150°C ambient, per the published derating curve (Figure 2). Operation above 600 mA risks thermal runaway or permanent damage.

Is MMBT5551-7-F suitable for automotive applications?

The MMBT5551-7-F is not AEC-Q101 qualified. However, Diodes offers the automotive-grade MMBT5551Q variant, which undergoes extended temperature cycling, HTOL, and ESD testing per AEC-Q101. For non-safety-critical automotive modules operating within −40 to +125°C, qualification validation is required before deployment.

How does the SOT23 package affect thermal performance?

On a standard single-sided FR4 PCB with 2 oz copper and minimum recommended pad layout, the SOT23 package delivers R_θJA = 417 °C/W. This value assumes still-air conditions and steady-state operation; adding thermal vias or copper pour reduces junction-to-ambient resistance by up to 30%, improving reliability in sustained switching duty cycles.

What is the typical base-emitter turn-on voltage?

The typical V_BE(on) is 0.65–0.85 V at I_C = 10 mA and T_A = +25°C, varying with temperature and current. Figure 7 in the datasheet shows V_BE(on) decreases by ~2.2 mV/°C and increases logarithmically with collector current-critical for bias network design in precision amplifier stages.