Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

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

onsemi MSD1328-ST1

Name: MSD1328-ST1
Brand: onsemi
SKU: MSD1328-ST1
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: MSD1328-ST1

Manufacturer:: onsemi

Category:: Single Bipolar Transistors

Package:: -

Datasheet:: MSD1328-ST1.pdf

Description:: TRANS NPN GP BIPO 20V SC-59

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:519,000

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

MSD1328-ST1 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 h_FE = 350–500 at I_C = 500 mA / V_CE = 2.0 V. It serves as a general-purpose switching or linear amplification device in power management and interface circuits.

For engineers reviewing the MSD1328-ST1 datasheet, pinout, applications, or equivalent options, key selection criteria include its guaranteed DC current gain range, low V_CE(sat) ≤ 0.4 V at 500 mA, SC-59 thermal performance (P_D = 200 mW), and Pb-free compliance per ordering variant MSD1328-ST1G.

Technical Context

This discrete NPN transistor operates in standard forward-active and saturation modes. Its design supports medium-current switching with validated V_BE(sat) ≤ 1.2 V at I_B = 50 mA and I_C = 500 mA, and exhibits tight h_FE binning (350–500) distinguishing it from the MSD1328-RT1 variant (200–300).

Thermal limits are defined by T_J = 150°C maximum junction temperature and T_stg = −55 to +150°C storage range. The SC-59 package provides surface-mount compatibility with standardized footprint per CASE 318D−04, enabling automated assembly in space-constrained PCB layouts.

Key Specifications

Parameter	Value and Actual Design Meaning
V_(BR)CEO	20 V - Maximum collector-emitter voltage before breakdown under open-base condition; defines safe operating voltage ceiling in switching applications.
I_C (continuous)	500 mA - Continuous collector current rating; sets upper limit for steady-state load drive capability without derating.
h_FE	350–500 - DC current gain range at V_CE = 2.0 V, I_C = 500 mA; enables predictable base drive sizing for saturation control.
V_CE(sat)	≤ 0.4 V - Collector-emitter saturation voltage at I_C = 500 mA, I_B = 20 mA; directly determines conduction loss in switch-mode operation.
P_D	200 mW - Maximum power dissipation at T_A = 25°C; constrains thermal design margin in ambient-limited environments.
T_J max	150°C - Absolute maximum junction temperature; informs thermal interface requirements and reliability derating curves.

Pinout & Package

MSD1328-ST1 uses the SC-59 (SOT-23) surface-mount package (CASE 318D), with standardized 3-pin layout and JEDEC-compliant footprint dimensions (L = 1.25–1.65 mm, W = 2.70–3.10 mm, H = 0.95–1.00 mm).

Pin/Terminal	Circuit Role	Design Meaning
1 (Emitter)	Current exit path for majority carriers	Connected to ground or low-side return; polarity-sensitive for correct biasing and current flow direction.
2 (Base)	Control terminal for minority carrier injection	Receives drive current to modulate collector current; requires series resistor for stable biasing in switching use.
3 (Collector)	Current entry path for majority carriers	Connected to load or supply rail; carries full switched current and must route accordingly for thermal and EMI control.

Key Features

Feature	Design Value
Guaranteed h_FE binning	350–500 at I_C = 500 mA - Enables consistent base drive calculation across production lots without gain-margin overdesign.
Low V_CE(sat)	≤ 0.4 V - Reduces conduction losses below 200 mW at rated current, supporting higher efficiency in battery-powered switches.
SC-59 package	Standardized SOT-23 footprint - Ensures compatibility with high-volume pick-and-place equipment and reflow profiles per J-STD-020.
Pb-free variants available	MSD1328-ST1G marked - Meets RoHS Directive 2011/65/EU and JEDEC JS709C solderability requirements.

Applications

LED Driver Circuit	DC-DC Converter Switch
Use Scenario: Driving high-brightness LEDs in automotive interior lighting with PWM dimming. IC Role / Device Role / Timing Role: NPN switch controlling LED current path between supply and ground. Use Value: Low V_CE(sat) minimizes voltage drop across the transistor, preserving forward voltage headroom for the LED string.	Use Scenario: Low-side synchronous rectifier or main switch in 5 V input buck converters. IC Role / Device Role / Timing Role: Medium-current power switch toggling inductor current path during switching cycles. Use Value: Guaranteed h_FE range allows precise base drive design to ensure full saturation at 500 mA without excessive base current waste.
Load Switch Interface	Industrial Sensor Signal Conditioning
Use Scenario: Enabling/disabling 12 V solenoid loads via microcontroller GPIO. IC Role / Device Role / Timing Role: General-purpose digital load switch interfacing logic-level control to higher-power actuator. Use Value: V_(BR)CEO = 20 V provides 8 V margin above 12 V rail, accommodating transient spikes without breakdown.	Use Scenario: Amplifying low-level analog signals from RTD or thermistor bridges. IC Role / Device Role / Timing Role: Linear-mode NPN amplifier in emitter-follower or common-emitter configuration. Use Value: Tight h_FE binning reduces gain variation across units, improving calibration stability in precision analog front-ends.

LED Driver Circuit

DC-DC Converter Switch

Use Scenario: Driving high-brightness LEDs in automotive interior lighting with PWM dimming.

IC Role / Device Role / Timing Role: NPN switch controlling LED current path between supply and ground.

Use Value: Low V_CE(sat) minimizes voltage drop across the transistor, preserving forward voltage headroom for the LED string.

Use Scenario: Low-side synchronous rectifier or main switch in 5 V input buck converters.

IC Role / Device Role / Timing Role: Medium-current power switch toggling inductor current path during switching cycles.

Use Value: Guaranteed h_FE range allows precise base drive design to ensure full saturation at 500 mA without excessive base current waste.

Load Switch Interface

Industrial Sensor Signal Conditioning

Use Scenario: Enabling/disabling 12 V solenoid loads via microcontroller GPIO.

IC Role / Device Role / Timing Role: General-purpose digital load switch interfacing logic-level control to higher-power actuator.

Use Value: V_(BR)CEO = 20 V provides 8 V margin above 12 V rail, accommodating transient spikes without breakdown.

Use Scenario: Amplifying low-level analog signals from RTD or thermistor bridges.

IC Role / Device Role / Timing Role: Linear-mode NPN amplifier in emitter-follower or common-emitter configuration.

Use Value: Tight h_FE binning reduces gain variation across units, improving calibration stability in precision analog front-ends.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MMBT4401LT1G	h_FE = 100–300 (lower gain range); V_(BR)CEO = 40 V (higher voltage rating)	Better suited for 24 V systems; less suitable where high gain at 500 mA is required	Select when higher V_CEO margin is prioritized over gain consistency at medium current.
PN2222A	TO-92 through-hole package; h_FE = 100–300; P_D = 625 mW (higher power)	Not surface-mount compatible; requires manual or wave-solder assembly	Choose only for prototyping or legacy through-hole designs where SC-59 footprint is unavailable.

Compared with MMBT4401LT1G and PN2222A, the MSD1328-ST1 offers superior h_FE consistency at 500 mA and optimized SC-59 thermal resistance for compact automated assemblies, though with lower voltage rating than MMBT4401LT1G and no through-hole option like PN2222A.

Availability

MSD1328-ST1 is available at Aetrix Electronics and suitable for LED driver circuits, DC-DC converter switches, and industrial sensor signal conditioning requiring stable component supply and RoHS-compliant sourcing.

Supply support for MSD1328-ST1 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 IoT applications.

The MSD1328-ST1 belongs to onsemi's general-purpose bipolar transistor product line, engineered for reliable medium-current switching and amplification in cost-sensitive, high-volume surface-mount applications.

FAQ

What is the guaranteed h_FE range for MSD1328-ST1?

The MSD1328-ST1 has a guaranteed DC current gain (h_FE) range of 350 to 500 when measured at V_CE = 2.0 V and I_C = 500 mA. This binning distinguishes it from the MSD1328-RT1 variant and ensures predictable base drive requirements in production designs using the MSD1328-ST1.

Is MSD1328-ST1 available in a Pb-free version?

Yes, the Pb-free version is designated MSD1328-ST1G and shares identical electrical specifications and SC-59 packaging with the standard MSD1328-ST1. Both variants are supplied in 3000-piece tape-and-reel format and comply with RoHS Directive 2011/65/EU.

What is the pin configuration of MSD1328-ST1?

The MSD1328-ST1 uses the SC-59 (SOT-23) package with pin 1 = Emitter, pin 2 = Base, and pin 3 = Collector - confirmed by the official marking diagram and case outline CASE 318D−04. This configuration is fixed and not interchangeable with alternate SOT-23 transistor pinouts.

What is the maximum continuous collector current for MSD1328-ST1?

The maximum continuous collector current for MSD1328-ST1 is 500 mA at T_A = 25°C. Derating is required above 25°C ambient per the thermal characteristics table, with junction temperature limited to 150°C. Peak current capability is 1000 mA for pulsed operation.

How does MSD1328-ST1 differ from MSD1328-RT1?

The MSD1328-ST1 and MSD1328-RT1 share identical package, voltage ratings, and thermal specs, but differ in h_FE binning: MSD1328-ST1 is specified for 350–500, while MSD1328-RT1 is 200–300. This makes the MSD1328-ST1 preferable where higher and more consistent current gain at 500 mA is required in the final circuit design.

MSD1328-ST1 Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: -

Packaging:: Bulk

Product Status:: Obsolete

Transistor Type:: -

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

Voltage - Collector Emitter Breakdown (Max):: -

Vce Saturation (Max) @ Ib, Ic:: -

Current - Collector Cutoff (Max):: -

DC Current Gain (hFE) (Min) @ Ic, Vce:: -

Power - Max:: -

Frequency - Transition:: -

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: -

Supplier Device Package:: -

MSD1328-ST1 FAQ

1.How can I place an order for MSD1328-ST1 through Aetrix?

Please submit a Request for Quotation (RFQ) for MSD1328-ST1 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-ST1 reliable?

The price and inventory of MSD1328-ST1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MSD1328-ST1 is usually 5 days.

3.What payment methods are accepted for MSD1328-ST1?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MSD1328-ST1 transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MSD1328-ST1?

MSD1328-ST1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MSD1328-ST1 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-ST1?

For technical support, including MSD1328-ST1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MSD1328-ST1 requirements.

6.How does Aetrix verify that MSD1328-ST1 is sourced from the original manufacturer or authorized distributors?

All MSD1328-ST1 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-ST1 meets industry standards.

7.What is the process for return or replacement of MSD1328-ST1?

All MSD1328-ST1 units undergo pre-shipment inspection (PSI). If there is an issue with MSD1328-ST1, 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-ST1 part is unused and in its original packaging.

Return procedure for MSD1328-ST1:

1.Submit a request within 90 days.

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

Tech Hub

2026-09-09 Counterfeit Electronic Components: How to Detect, Authenticate, and Test Suspect Parts

Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …

2026-09-08 Obsolete Electronic Components: How to Source and Evaluate Replacements

A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.

2026-09-07 TTL vs CMOS Logic Levels: 74HC and 74HCT Compatibility Explained

TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.

2026-09-04 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-02 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…