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The ON Semiconductor MMBT2222A is a SOT-23 packaged NPN transistor designed as a space-saving, surface-mount counterpart to the classic 2N2222A. It combines a 40 V collector-emitter rating, up to ~600 mA collector current, low saturation voltage and a high transition frequency (~300 MHz). This article will discuss the device’s key specifications and features, pinout and CAD models, common equivalents and more.
The ON Semiconductor MMBT2222A is a compact, general-purpose NPN transistor in an SOT-23 package, designed for reliable switching and small-signal amplification. With a collector-emitter voltage rating of around 40 V and the ability to handle up to 600 mA, it offers solid performance for everyday electronic applications. Its small SMD footprint makes it ideal for compact or high-density PCB layouts where space is limited.
Engineers commonly use the MMBT2222A for tasks such as driving LEDs, interfacing logic signals, amplifying small signals, or switching low-to-moderate power loads. Its high gain-bandwidth capability supports moderate-speed circuits, while its wide operating temperature range ensures stable operation in various environments. As an SMD counterpart to the classic 2N2222A through-hole transistor, it is a trusted, versatile choice for modern designs.
If you are interested in purchasing the MMBT2222A, feel free to contact us for pricing and availability.
| Pin Number | Pin Name | Description |
| 1 | Base (B) | Controls transistor switching; receives input signal. |
| 2 | Emitter (E) | Current flows out through this pin; usually connected to ground. |
| 3 | Collector (C) | Main current path; connected to the load. |
| Parameter | MMBT2222A (SMD) | 2N2222A (TH) | BC549 | BC639 | 2N2369 | 2N3906 (PNP) |
| Type | NPN | NPN | NPN | NPN | NPN | PNP |
| Package | SOT-23 | TO-92 / TO-18 | TO-92 | TO-92 | TO-18 / TO-92 | TO-92 |
| VCEO Max | 40 V | 40 V | 30 V | 80 V | 40 V | –40 V |
| IC Max | 600 mA | 800 mA | 100 mA | 1 A | 200 mA | 200 mA |
| Power Dissipation | ~300 mW | ~500 mW | ~500 mW | ~1 W | ~350 mW | ~625 mW |
| Transition Frequency (fT) | ~300 MHz | ~300 MHz | ~100 MHz | ~50–100 MHz | ~500 MHz | ~250 MHz |
| Notes | SMD version of 2N2222A | Very close match | Low-noise amplifier | Higher voltage/current | High-speed switch | Complementary PNP |
| Category | Specification |
| Transistor Type | NPN |
| Mounting Type | Surface Mount (SMD) |
| Package / Case | SOT-23 / TO-236-3 / SC-59 |
| Number of Pins | 3 |
| Polarity | NPN |
| Element Configuration | Single |
| hFE (Min) | 100 |
| Gain Bandwidth Product (fT) | 300 MHz |
| Collector-Emitter Voltage (VCEO) | 40 V |
| Collector-Base Voltage (VCBO) | 75 V |
| Emitter-Base Voltage (VEBO) | 6 V |
| Max Collector Current (IC) | 600 mA |
| Current Rating (General) | 500 mA |
| Collector-Emitter Saturation Voltage (VCE(sat)) | < 300 mV @ 150 mA |
| Collector-Emitter Breakdown Voltage | 40 V |
| Collector Cutoff Current (ICBO) | 10 nA |
| Power Dissipation (PD) | 300–350 mW |
| Frequency (Max) | 300 MHz |
| Operating Temperature Range | −55°C to +150°C (TJ) |
| Moisture Sensitivity Level (MSL) | 1 (Unlimited) |
| Termination | SMD / SMT |
| Packaging Option | Tape & Reel |
| Base Part Number | MMBT2222 |
| Published | 2016 |
| RoHS Status | RoHS Compliant |
| Lead-Free | Yes |
| Halogen-Free | Yes |
| Dimensions (Approx.) | 3.05 mm (L) × 1.4 mm (W) × 1.0 mm (H) |
-Epitaxial Planar Die Construction for enhanced reliability and consistent performance.
-Low Saturation Voltage, typically VCE(sat) < 300 mV at 150 mA, improving efficiency in switching applications.
-Complementary PNP Pair Available: MMBT2907A for push-pull or signal pairing circuits.
-Ideal for Low-Power Amplification and Switching, supporting general-purpose designs in compact electronics.
-High Transition Frequency (fT ≈ 250–300 MHz) enabling moderate-speed signal processing.
-Fast Switching Capability, suitable for digital interfaces, drivers, and logic-level control.
-SOT-23 Surface-Mount Package, saving PCB space and enabling automated manufacturing.
-Fully Lead-Free and RoHS Compliant, meeting environmental and safety standards.
-Halogen-Free and Antimony-Free “Green” Device options available for eco-friendly designs.
-Wide Operating Temperature Range, supporting reliable performance in harsh environments.
In the first circuit, the MMBT2222A operates as the lower NPN transistor in a simple complementary pair with the PNP MMBT2907. Here, the MMBT2222A handles the ground-side switching, pulling current through the PNP device when activated. As Q2 (MMBT2222A) turns on, it sinks current from Q1 (MMBT2907), allowing the PNP transistor to conduct and deliver the input voltage to the output node. This configuration demonstrates how the MMBT2222A can control higher-side current indirectly through a complementary transistor, enabling efficient switching with minimal component count.
In the second circuit, the MMBT2222A plays a more integrated role in a precision control system. Multiple MMBT2222A transistors work alongside the PNP MMBT2907 and a MOSFET to regulate output voltage. One MMBT2222A device handles signal amplification, while another provides switching control for the MOSFET gate. Together, they ensure stable voltage regulation by responding quickly to changes in the control voltage. This showcases the MMBT2222A’s versatility in both low-level signal processing and higher-current switching paths within more advanced analog circuits.
-General-purpose switching for low to medium currents
-Driving LEDs, relays, small motors, and solenoids
-Signal amplification in low-power audio and RF circuits
-Logic-level interfacing and digital signal control
-Push-pull or complementary transistor stages (paired with MMBT2907A)
-High-speed switching circuits due to its fast transition frequency
-Voltage regulation and reference circuits
-Transistor-based level shifters and buffer stages
-Sensor signal conditioning and small-signal processing
-Use in compact or portable devices requiring SOT-23 SMD packaging
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