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Home > Products > Discrete Semiconductor Products > Transistors > Bipolar (BJT) > Single Bipolar Transistors

onsemi MSD1328-RT1G

Name: MSD1328-RT1G
Brand: onsemi
SKU: MSD1328-RT1G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MSD1328-RT1G

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: MSD1328-RT1G.pdf

Description:: TRANS NPN 20V 0.5A SC-59

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Product details

Overview

MSD1328-RT1G from onsemi is an NPN low-voltage output amplifier in SC-59 (SOT-23) package, rated for V_(BR)CEO = 20 V, I_C = 500 mA continuous, and P_D = 200 mW, designed for general-purpose switching and linear amplification in space-constrained consumer and industrial power management circuits.

For engineers reviewing the MSD1328-RT1G datasheet, pinout, applications, or equivalent options, key selection criteria include DC current gain (h_FE = 200–350 at I_C = 500 mA), V_CE(sat) ≤ 0.4 V, V_BE(sat) ≤ 1.2 V, and Pb-free SC-59 packaging compliance.

Technical Context

This discrete NPN transistor operates as a medium-current, low-saturation-voltage switch or Class-A amplifier stage. Its V_(BR)CBO = 25 V and V_(BR)EBO = 12 V define safe bias margins, while thermal limits (T_J = 150 °C, T_stg = −55 to +150 °C) support operation in ambient environments up to 85 °C with derated power dissipation.

The device uses standard silicon bipolar process technology and is characterized at T_A = 25 °C with pulse test conditions (pulse width ≤ 300 µs, duty cycle ≤ 2%). Its h_FE binning (RT1 variant) ensures consistent gain performance across production lots for stable biasing in feedback-controlled circuits.

Key Specifications

Parameter	Value and Actual Design Meaning
V_(BR)CEO	20 V - Maximum collector-emitter voltage before breakdown; sets upper limit for supply rail compatibility in 12 V/15 V systems.
I_C (continuous)	500 mA - Sustained collector current capability; supports driving small relays, LED strings, or logic-level MOSFET gates.
V_CE(sat)	≤ 0.4 V @ I_C = 500 mA, I_B = 20 mA - Low saturation voltage minimizes conduction loss and self-heating in switching applications.
h_FE	200–350 @ V_CE = 2.0 V, I_C = 500 mA - Confirmed DC current gain range enables predictable base drive sizing for reliable turn-on.
P_D	200 mW - Maximum power dissipation at T_A = 25 °C; requires thermal derating above 25 °C ambient per datasheet curve.
T_J	150 °C - Maximum junction temperature; defines absolute thermal safety limit for long-term reliability.

Pinout & Package

MSD1328-RT1G is housed in SC-59 (SOT-23) package, a surface-mount, 3-pin plastic case with standardized footprint and thermal pad design per CASE 318D-04.

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current sink terminal	Reference node for base-emitter junction; connects to ground or low-side return path in common-emitter configurations.
2 (Base)	Control input	Receives forward-bias current to enable conduction; requires series resistor to limit I_B and ensure h_FE-based saturation.
3 (Collector)	Current source terminal	Connects to load and positive supply; carries full I_C during active/saturation; must be routed with adequate copper area for thermal relief.

Key Features

Feature	Design Value
Pb-free construction	Complies with RoHS Directive 2011/65/EU and JEDEC J-STD-020 reflow profile; suitable for lead-free assembly processes.
Low V_CE(sat)	Guaranteed ≤ 0.4 V at rated I_C/I_B, reducing power loss by >30% vs. legacy general-purpose transistors with V_CE(sat) > 0.6 V.
High h_FE binning	RT1 variant guarantees h_FE ≥ 200 and ≤ 350, enabling tighter base drive tolerance and improved circuit predictability.
SC-59 package	Standardized SOT-23 footprint with 1.3 mm × 1.7 mm body size; compatible with automated pick-and-place and AOI inspection systems.

Applications

LED Driver Circuit	Microcontroller GPIO Expander
Use Scenario: Driving 20–50 mA white LEDs from 3.3 V or 5 V microcontroller outputs. IC Role / Device Role / Timing Role: NPN switch controlling LED anode current path; emitter grounded, collector tied to LED cathode. Use Value: V_CE(sat) ≤ 0.4 V ensures >90% efficiency at 50 mA, minimizing heat rise in compact LED modules.	Use Scenario: Amplifying weak sensor signals or buffering digital outputs in battery-powered IoT nodes. IC Role / Device Role / Timing Role: Common-emitter amplifier stage providing current gain for analog signal conditioning or level-shifting. Use Value: h_FE ≥ 200 enables single-transistor gain stages without external bias networks, reducing BOM count.
DC Motor Control (Small)	Power Supply Enable Switch
Use Scenario: PWM-driven control of 12 V, <100 mA cooling fans or vibration motors in portable devices. IC Role / Device Role / Timing Role: Low-side switch in H-bridge half-bridge or single-MOSFET gate driver interface. Use Value: I_C(P) = 1000 mA peak supports motor startup surge currents without secondary protection.	Use Scenario: Enabling/disabling auxiliary rails (e.g., 3.3 V LDO output) under MCU control in multi-rail power systems. IC Role / Device Role / Timing Role: High-side or low-side enable switch placed between regulator output and load. Use Value: V_(BR)CEO = 20 V provides 5 V margin over 15 V max input, ensuring robustness against transient overvoltage events.

LED Driver Circuit

Microcontroller GPIO Expander

Use Scenario: Driving 20–50 mA white LEDs from 3.3 V or 5 V microcontroller outputs.

IC Role / Device Role / Timing Role: NPN switch controlling LED anode current path; emitter grounded, collector tied to LED cathode.

Use Value: V_CE(sat) ≤ 0.4 V ensures >90% efficiency at 50 mA, minimizing heat rise in compact LED modules.

Use Scenario: Amplifying weak sensor signals or buffering digital outputs in battery-powered IoT nodes.

IC Role / Device Role / Timing Role: Common-emitter amplifier stage providing current gain for analog signal conditioning or level-shifting.

Use Value: h_FE ≥ 200 enables single-transistor gain stages without external bias networks, reducing BOM count.

DC Motor Control (Small)

Power Supply Enable Switch

Use Scenario: PWM-driven control of 12 V, <100 mA cooling fans or vibration motors in portable devices.

IC Role / Device Role / Timing Role: Low-side switch in H-bridge half-bridge or single-MOSFET gate driver interface.

Use Value: I_C(P) = 1000 mA peak supports motor startup surge currents without secondary protection.

Use Scenario: Enabling/disabling auxiliary rails (e.g., 3.3 V LDO output) under MCU control in multi-rail power systems.

IC Role / Device Role / Timing Role: High-side or low-side enable switch placed between regulator output and load.

Use Value: V_(BR)CEO = 20 V provides 5 V margin over 15 V max input, ensuring robustness against transient overvoltage events.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT3904LT1G	Lower I_C = 200 mA, higher V_CE(sat) = 0.3 V (typ.) but only rated to 100 mA; h_FE = 100–300.	Suitable for ≤100 mA loads; not recommended for 500 mA continuous operation.	Select when cost sensitivity outweighs current headroom needs and thermal budget allows lower I_C.
PN2222A-AP	TO-92 package, higher P_D = 625 mW, but larger footprint and no Pb-free option; V_(BR)CEO = 40 V.	Preferred for through-hole prototyping or high-temperature environments where SC-59 thermal limits are exceeded.	Choose for manual assembly or thermal-limited designs requiring >200 mW dissipation at elevated ambient.

Compared with MMBT3904LT1G and PN2222A-AP, MSD1328-RT1G delivers optimal balance of 500 mA current capability, low 0.4 V saturation voltage, and compact Pb-free SC-59 packaging-making it ideal for volume-manufactured, space-constrained, medium-current switching applications.

Availability

MSD1328-RT1G is available at Aetrix Electronics and suitable for LED driver circuits, microcontroller GPIO expansion, small DC motor control, and power supply enable switching requiring stable component supply and RoHS-compliant sourcing.

Supply support for MSD1328-RT1G 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 delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and edge applications.

The MSD1328-RT1G belongs to onsemi's general-purpose bipolar transistor product line, engineered for reliable, cost-effective switching and amplification in high-volume consumer and industrial electronics.

FAQ

What is the maximum continuous collector current rating for MSD1328-RT1G?

The MSD1328-RT1G is rated for 500 mA continuous collector current (I_C) at T_A = 25 °C. This rating decreases with rising ambient temperature due to thermal derating; at 85 °C ambient, the usable I_C drops to approximately 350 mA based on its 200 mW power dissipation limit and thermal resistance characteristics. Always verify actual operating temperature in the final PCB layout.

Does MSD1328-RT1G support Pb-free reflow soldering?

Yes, MSD1328-RT1G is a Pb-free device compliant with RoHS Directive 2011/65/EU and qualified for standard lead-free reflow profiles per JEDEC J-STD-020. Its SC-59 package is rated for peak reflow temperatures up to 260 °C, making it compatible with automated SMT assembly lines using SAC305 or similar alloys.

What is the guaranteed h_FE range for MSD1328-RT1G at typical operating conditions?

The MSD1328-RT1G RT1 variant guarantees h_FE between 200 and 350 when measured at V_CE = 2.0 V and I_C = 500 mA. This binning ensures predictable base drive requirements and stable DC biasing in amplifier or saturated-switch designs without needing gain compensation circuitry.

Can MSD1328-RT1G replace older PN2222-type transistors in existing designs?

MSD1328-RT1G can serve as a functional upgrade in many PN2222-based circuits, offering higher I_C (500 mA vs. 600 mA max for PN2222 but with better thermal packaging), lower V_CE(sat), and Pb-free compliance. However, its SC-59 footprint differs from TO-92, so PCB redesign is required. Electrical behavior is similar but not drop-in due to package and thermal profile differences.

What is the emitter-base breakdown voltage (V_(BR)EBO) specification for MSD1328-RT1G?

The emitter-base breakdown voltage for MSD1328-RT1G is specified as 12 V minimum, tested with I_E = 10 µA (not 10 A as misprinted in some tables). This rating defines the maximum reverse bias that can be applied across the base-emitter junction without risk of avalanche conduction or permanent degradation during normal operation or ESD events.

MSD1328-RT1G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Transistor Type:: NPN

Current - Collector (Ic) (Max):: 500 mA

Voltage - Collector Emitter Breakdown (Max):: 20 V

Vce Saturation (Max) @ Ib, Ic:: 400mV @ 20mA, 500mA

Current - Collector Cutoff (Max):: 100nA (ICBO)

DC Current Gain (hFE) (Min) @ Ic, Vce:: 200 @ 500mA, 2V

Power - Max:: 200 mW

Frequency - Transition:: -

Operating Temperature:: 150°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SC-59

MSD1328-RT1G FAQ

1.How can I place an order for MSD1328-RT1G through Aetrix?

Please submit a Request for Quotation (RFQ) for MSD1328-RT1G on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MSD1328-RT1G reliable?

The price and inventory of MSD1328-RT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MSD1328-RT1G is usually 5 days.

3.What payment methods are accepted for MSD1328-RT1G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MSD1328-RT1G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MSD1328-RT1G?

MSD1328-RT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MSD1328-RT1G order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MSD1328-RT1G?

For technical support, including MSD1328-RT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MSD1328-RT1G requirements.

6.How does Aetrix verify that MSD1328-RT1G is sourced from the original manufacturer or authorized distributors?

All MSD1328-RT1G products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MSD1328-RT1G meets industry standards.

7.What is the process for return or replacement of MSD1328-RT1G?

All MSD1328-RT1G units undergo pre-shipment inspection (PSI). If there is an issue with MSD1328-RT1G, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MSD1328-RT1G part is unused and in its original packaging.

Return procedure for MSD1328-RT1G:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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