onsemi MMBT5551LT1H

Overview

MMBT5551LT1H from onsemi is an NPN silicon high-voltage general-purpose transistor in SOT-23 package, rated for 160 V_CEO, 180 V_CBO, and 600 mA continuous collector current, with minimum DC current gain (h_FE) of 80 at I_C = 1.0 mA and V_CE = 5 V - used in high-voltage switching and amplifier stages in industrial power supplies and interface circuits.

For engineers reviewing the MMBT5551LT1H datasheet, pinout, applications, or equivalent options, key selection criteria include verified V_CEO/V_CBO ratings, h_FE consistency across temperature, SOT-23 thermal derating behavior, and AEC-Q101 qualification status for automotive-grade reliability validation.

Technical Context

This device operates as a discrete NPN bipolar junction transistor optimized for high-voltage linear amplification and fast-switching applications up to 120 V collector supply. Its base-emitter saturation voltage remains ≤1.2 V at I_C = 50 mA and I_B = 5 mA, while collector-emitter saturation voltage stays ≤0.25 V under identical conditions.

Thermal performance is defined for two board types: 225 mW dissipation on FR-5 (R_JA = 556 °C/W) and 300 mW on alumina substrate (R_JA = 417 °C/W), with junction temperature range spanning −55°C to +150°C and ESD robustness >8 kV (HBM).

Key Specifications

Pinout & Package

SOT-23 (TO-236) surface-mount package per Case 318, Style 6; 3-pin plastic package with gull-wing leads, 1.9 mm pitch, and 2.9 mm × 1.3 mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MMBT5551LT1H, MMBT5551LT1G offers identical performance with standard RoHS compliance, while BC847B,215 trades 160 V capability for higher gain in low-voltage logic interfaces - making MMBT5551LT1H irreplaceable in 100+ V applications requiring automotive-grade reliability.

Availability

MMBT5551LT1H is available at Aetrix Electronics and suitable for industrial power supply feedback, automotive LED driver switching, high-voltage signal amplification, and interface level shifting requiring stable component supply and long-term lifecycle support.

Supply support for MMBT5551LT1H 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 (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power and signal management solutions, with leadership in automotive, industrial, cloud computing, and IoT markets.

The MMBT5551LT1H belongs to onsemi's high-voltage bipolar transistor family designed specifically for ruggedized switching and amplification in automotive and industrial power systems where reliability under voltage stress is critical.

FAQ

What is the maximum collector-emitter voltage rating for MMBT5551LT1H?

The MMBT5551LT1H has a guaranteed minimum collector-emitter breakdown voltage V(BR)_CEO of 160 Vdc at I_C = 1.0 mA and I_B = 0. This rating is validated per JEDEC JESD22-A114 test conditions and defines the absolute maximum DC voltage the device can block in common-emitter configuration without avalanche conduction.

Is MMBT5551LT1H qualified for automotive applications?

Yes, MMBT5551LT1H is AEC-Q101 qualified and PPAP capable, with S-prefix variants (e.g., SMMBT5551LT1G) explicitly designated for automotive use. The MMBT5551LT1H itself shares the same die, wafer fab process, and qualification testing as its S-prefixed counterparts, meeting stress-test requirements for temperature cycling, humidity, and mechanical shock.

What is the DC current gain (h_FE) range for MMBT5551LT1H at 10 mA collector current?

At I_C = 10 mA and V_CE = 5 V, the MMBT5551LT1H exhibits a minimum h_FE of 80 and a typical value of 150–200, with upper limit unspecified. This gain range ensures predictable current amplification in bias networks and low-frequency amplifier stages across commercial temperature range.

Can MMBT5551LT1H replace MMBT5550LT1H in existing designs?

MMBT5551LT1H can replace MMBT5550LT1H where higher voltage blocking is needed: it offers 160 V_CEO versus 140 V_CEO and 180 V_CBO versus 160 V_CBO, with identical pinout, package, and thermal characteristics. No PCB changes are required, but verify that circuit timing and gain margins remain acceptable given the slightly higher h_FE floor.

What is the thermal resistance (R_JA) of MMBT5551LT1H on standard FR-5 PCB?

The MMBT5551LT1H has a thermal resistance R_JA of 556 °C/W when mounted on a standard FR-5 board (1.0 × 0.75 × 0.062 in.) at T_A = 25°C. This value assumes no added copper pour; adding 1-inch² of 2-oz copper on layer 1 reduces R_JA by ~30%, improving power handling up to ~300 mW continuous.