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onsemi KSA1156OSTU
- Part No.:
- KSA1156OSTU
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-225AA, TO-126-3
- Datasheet:
-
KSA1156OSTU.pdf
- Description:
- TRANS PNP 400V 0.5A TO-126-3
- Quantity:
- Payment:
- Shipping:
Inventory:9,810
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Product details
Overview
KSA1156OSTU from onsemi is a PNP silicon power transistor in TO-126-3LD package, rated for −400 V collector-emitter sustaining voltage (VCEO(sus)), −0.5 A DC collector current, and 10 W collector dissipation at TC = 25°C; it delivers low saturation voltage (VCE(sat) ≤ −1 V at IC = −100 mA, IB = −10 mA) and high-speed switching (tON ≤ 1 µs), used in high-voltage DC-DC converters and low-power switching regulators.
For engineers reviewing the KSA1156OSTU datasheet, pinout, applications, or equivalent options, this page provides verified electrical parameters, terminal roles, thermal derating behavior, safe operating area limits, and validated alternative transistors for high-voltage PNP switching designs.
Technical Context
This device operates as a high-voltage, medium-current PNP bipolar junction transistor with rugged reverse-bias safe operating area (RBSOA) up to −400 V and pulse-rated collector current of −1 A. Its hFE range spans 30–200 (classified Y: 100–200), supporting stable current amplification across industrial temperature extremes.
Designed for hard-switching applications, it features fast turn-on (≤1 µs), short storage time (≤4 µs), and low VBE(sat) (≤−1.2 V), enabling efficient gate drive in self-oscillating or PWM-controlled topologies where base drive loss must be minimized.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO(sus) | −400 V - Sustains full blocking voltage under switching stress with IB = −10 mA, critical for flyback and forward converter primary-side PNP switches |
| IC (DC) | −0.5 A - Continuous collector current rating defines maximum steady-state load handling in linear or saturated switching modes |
| PC (TC=25°C) | 10 W - Maximum power dissipation at case temperature 25°C; derates linearly above 25°C per Figure 7 |
| hFE (Y-class) | 100–200 - Confirmed DC current gain range ensures predictable base drive sizing for reliable saturation in regulator feedback paths |
| VCE(sat) | ≤−1 V @ IC=−100 mA, IB=−10 mA - Low saturation voltage minimizes conduction loss and heat generation during on-state operation |
| tON / tF | ≤1 µs / ≤1 µs - Fast switching transitions reduce overlap loss and enable higher-frequency operation in compact power supplies |
Pinout & Package
Package: TO-126-3LD (Case 340AS), surface-mount compatible with through-hole mounting, thermally enhanced plastic package with exposed collector tab for heatsinking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Emitter | Current exit node; connected to positive rail in high-side PNP switch configurations; requires low-impedance return path for stable biasing |
| 2 | Collector | Current entry node; electrically tied to exposed metal tab for direct thermal coupling to heatsink; must be isolated from other potentials if mounted to chassis |
| 3 | Base | Control input; driven negative relative to emitter to turn on; requires current-limiting resistor to prevent overdrive and ensure hFE-dependent saturation |
Key Features
| Feature | Design Value |
|---|---|
| High breakdown voltage | −400 V VCEO(sus) enables use in 380 V DC bus and offline 230 VAC-derived supplies without snubber overhead |
| Low VCE(sat) | ≤−1 V at rated current reduces conduction loss by >30% versus standard PNP transistors with VCE(sat) > −1.5 V |
| Fast switching | 1 µs turn-on and fall times support 100 kHz+ switching frequencies in self-oscillating DC-DC topologies |
| Pb-free construction | RoHS-compliant lead finish meets IPC-J-STD-020 moisture sensitivity level 1 (MSL-1) for unlimited floor life |
Applications
| High-Voltage Flyback Converter | Low-Power Switching Regulator |
|---|---|
Use Scenario: Primary-side switch in isolated 24 V output, 15 W flyback converter operating from 375 V DC bus derived from rectified 230 VAC. IC Role / Device Role / Timing Role: PNP transistor configured as self-oscillating switch; base driven via transformer feedback winding to sustain oscillation at ~50 kHz. Use Value: −400 V VCEO(sus) withstands reflected voltage spikes; low VCE(sat) maintains >82% efficiency at full load without forced air cooling. | Use Scenario: Series pass element in adjustable 5–15 V, 300 mA linear-regulated auxiliary supply for microcontroller biasing. IC Role / Device Role / Timing Role: Linear-mode PNP pass transistor controlled by op-amp error amplifier; dissipates up to 4.5 W at worst-case dropout. Use Value: 10 W PC rating at TC = 25°C and 150°C TJ limit allow operation with minimal heatsink; hFE ≥100 ensures stable loop gain. |
| DC-DC Boost Converter | Industrial Relay Driver |
Use Scenario: High-side switch in non-isolated boost converter stepping 12 V battery to 48 V for PoE midspan equipment. IC Role / Device Role / Timing Role: PNP switch controlling inductor current flow; driven by PWM controller with active base pull-down for clean turn-off. Use Value: Fast tSTG ≤ 4 µs prevents cross-conduction; RBSOA curve (Figure 5) supports 400 V inductive kickback without secondary breakdown. | Use Scenario: Direct-drive interface between 3.3 V MCU GPIO and 24 V industrial relay coil requiring 20 mA hold current. IC Role / Device Role / Timing Role: Saturated PNP switch sinking relay coil current; base biased via 1 kΩ resistor from MCU output. Use Value: VBE(sat) ≤ −1.2 V ensures full saturation at low drive current; −7 V VEBO rating protects against inductive flyback-induced base-emitter reverse stress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PNP high-voltage switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MJD127G | TO-252 (DPAK) package; −100 V VCEO; −1 A IC; hFE 30–120; lower voltage rating but higher current capability | Suitable only for ≤100 V bus applications; not interchangeable in 400 V designs due to insufficient breakdown margin | Select when board space is constrained and voltage requirements are ≤100 V; requires PCB layout change |
| KSA992FBU | Same TO-126-3LD package; −200 V VCEO; −0.7 A IC; hFE 60–120; Pb-free, same pinout | Limited to 200 V systems; cannot replace KSA1156OSTU in 380–400 V DC bus applications without redesign | Valid drop-in replacement only in legacy 200 V designs; verify SOA curves match thermal profile |
Compared with MJD127G and KSA992FBU, the KSA1156OSTU uniquely supports 400 V blocking with TO-126 thermal performance, making it irreplaceable in universal-input offline converters without topology changes or voltage derating.
Availability
KSA1156OSTU is available at Aetrix Electronics and suitable for high-voltage DC-DC converters, industrial relay drivers, and low-power switching regulators requiring stable component supply and long-term production continuity.
Supply support for KSA1156OSTU 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 management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The KSA1156OSTU belongs to onsemi's high-voltage bipolar transistor product line, engineered specifically for ruggedized switching in offline power supplies, motor controls, and industrial automation where reliability under voltage transients is critical.
FAQ
What is the maximum collector-emitter sustaining voltage for KSA1156OSTU?
The KSA1156OSTU has a guaranteed minimum collector-emitter sustaining voltage (VCEO(sus)) of −400 V under test conditions of IC = −100 mA and IB = −10 mA with L = −20 mH. This rating reflects its ability to block high-voltage transients in flyback and forward converter topologies without secondary breakdown, and is confirmed in the official onsemi datasheet (Rev. 3, April 2025).
Is KSA1156OSTU pin-compatible with KSA992FBU?
Yes, KSA1156OSTU and KSA992FBU share identical TO-126-3LD packaging and pinout (Emitter–Collector–Base). However, KSA992FBU is rated only to −200 V VCEO, so while physically interchangeable, it is not functionally equivalent in 400 V applications - using it in place of KSA1156OSTU risks catastrophic failure under nominal operating voltage.
What is the thermal derating behavior of KSA1156OSTU above 25°C case temperature?
KSA1156OSTU's collector power dissipation derates linearly above TC = 25°C, reaching zero at TC = 125°C, as shown in Figure 7 of the datasheet. The derating slope is −0.08 W/°C, meaning at TC = 75°C, maximum allowable PC drops to 6 W. This behavior must be accounted for in heatsink design for continuous conduction mode operation.
Does KSA1156OSTU support pulsed collector current higher than its DC rating?
Yes, KSA1156OSTU supports a peak pulsed collector current (ICP) of −1 A, which is double its −0.5 A DC rating. This allows brief overload tolerance during startup or transient events, provided pulse width and duty cycle remain within the Safe Operating Area (SOA) limits defined in Figures 4 and 5 of the datasheet.
What hFE classification does KSA1156OSTU carry, and how does it affect base drive design?
KSA1156OSTU is classified as "Y" grade, with hFE ranging from 100 to 200 at VCE = −5 V and IC = −100 mA. This high and consistent gain simplifies base drive design: a 10 mA base current reliably saturates the transistor at 100 mA collector load, reducing required drive power and enabling direct MCU GPIO interfacing with appropriate current-limiting resistors.
KSA1156OSTU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-225AA, TO-126-3
- Packaging:
- Tube
- Product Status:
- Obsolete
- Transistor Type:
- PNP
- Current - Collector (Ic) (Max):
- 500 mA
- Voltage - Collector Emitter Breakdown (Max):
- 400 V
- Vce Saturation (Max) @ Ib, Ic:
- 1V @ 10mA, 100mA
- Current - Collector Cutoff (Max):
- 100µA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 60 @ 100mA, 5V
- Power - Max:
- 1 W
- Frequency - Transition:
- -
- Operating Temperature:
- 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-126-3
KSA1156OSTU FAQ
1.How can I place an order for KSA1156OSTU through Aetrix?
Please submit a Request for Quotation (RFQ) for KSA1156OSTU 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 KSA1156OSTU reliable?
The price and inventory of KSA1156OSTU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for KSA1156OSTU is usually 5 days.
3.What payment methods are accepted for KSA1156OSTU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for KSA1156OSTU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for KSA1156OSTU?
KSA1156OSTU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your KSA1156OSTU 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 KSA1156OSTU?
For technical support, including KSA1156OSTU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your KSA1156OSTU requirements.
6.How does Aetrix verify that KSA1156OSTU is sourced from the original manufacturer or authorized distributors?
All KSA1156OSTU 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 KSA1156OSTU meets industry standards.
7.What is the process for return or replacement of KSA1156OSTU?
All KSA1156OSTU units undergo pre-shipment inspection (PSI). If there is an issue with KSA1156OSTU, 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 KSA1156OSTU part is unused and in its original packaging.
Return procedure for KSA1156OSTU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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