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Diodes Incorporated ZTX855STOA
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- Part No.:
- ZTX855STOA
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- E-Line-3
- Datasheet:
-
ZTX855STOA.pdf
- Description:
- TRANS NPN 150V 4A E-LINE
- Quantity:
- Payment:
- Shipping:
Inventory:5,132
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Product details
Overview
ZTX855STOA from Diodes Incorporated is a 150V NPN medium-power transistor in E-Line (TO-92 compatible) package, rated for 4A continuous collector current and 10A peak pulse current, with VCE(sat) ≤ 60 mV at IC = 4A/ IB = 400mA, qualified to AEC-Q101, and used in automotive power switching and industrial relay drivers.
For engineers reviewing the ZTX855STOA datasheet, ZTX855STOA pinout, ZTX855STOA application, or ZTX855STOA equivalent, key selection criteria include its 150V VCEO, 200°C maximum junction temperature, low saturation voltage under high-current drive, and AEC-Q101 qualification for automotive-grade reliability.
Technical Context
This NPN bipolar junction transistor operates as a medium-power switch with complementary pairing to ZTX955. Its BVCEO = 150 V and BVCBO = 250 V support high-voltage off-state blocking, while fT = 90 MHz enables moderate-frequency switching up to several hundred kHz.
Thermal design is enabled by RΘJC = 50 °C/W and operation up to TJ = +200°C. Saturation performance is specified across four IC/IB conditions, with VCE(sat) ≤ 210 mV at IC = 4A, supporting efficient conduction in DC-DC pre-regulators and motor control stages.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 150 V - Maximum collector-emitter voltage before breakdown; supports 125V rail switching with safety margin |
| IC (cont.) | 4 A - Continuous collector current rating; defines steady-state load-handling capability |
| VCE(sat) | ≤210 mV @ IC=4A/IB=400mA - Low conduction loss enabling <1W dissipation at full current |
| fT | 90 MHz - Current gain-bandwidth product; sets upper limit for small-signal amplification or fast switching |
| TJ max | +200°C - Maximum junction temperature; allows operation in under-hood automotive environments |
| hFE | 35–300 - DC current gain range across 10mA–10A; supports stable biasing in linear and saturated modes |
| RΘJC | 50 °C/W - Junction-to-lead thermal resistance; enables direct heatsinking via collector lead |
Pinout & Package
E-Line (TO-92 compatible) molded plastic package with matte tin-plated leads; 0.159 g weight; UL 94V-0 flammability rating; flat-face marking orientation with ejection mark.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Emitter (E) | Current sink terminal | Connected to ground or low-side return path; carries full load current in common-emitter configuration |
| Base (B) | Control input | Receives forward-biased drive current to saturate transistor; requires ~400 mA for full 4A conduction |
| Collector (C) | High-side output terminal | Connected to load and supply rail; thermally coupled to PCB pad or heatsink via lead |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including engine control modules and body electronics |
| 200°C maximum junction temperature | Enables reliable operation in high-ambient environments without derating below 150°C ambient |
| VCE(sat) ≤ 210 mV @ 4A | Reduces conduction losses to <0.85 W at full rated current, minimizing thermal stress |
| Complementary pair with ZTX955 | Supports push-pull and H-bridge topologies with matched voltage/current ratings |
| Halogen- and antimony-free "Green" construction | Meets IEC 61249-2-21 and JEDEC JS709B requirements for environmentally compliant manufacturing |
Applications
| Automotive Relay Drivers | Industrial DC-DC Pre-regulators |
|---|---|
Use Scenario: Driving 12V/24V automotive relays in body control modules and lighting systems. IC Role / Device Role / Timing Role: NPN switch controlling relay coil current with fast turn-on/turn-off (ton = 66 ns, toff = 2130 ns). Use Value: 150V VCEO withstands load-dump transients; AEC-Q101 qualification ensures field reliability. | Use Scenario: Regulating intermediate bus voltage in industrial PLC power supplies. IC Role / Device Role / Timing Role: Medium-power series pass transistor in linear pre-regulator stage. Use Value: Low VCE(sat) minimizes dropout and heat generation at 4A output current. |
| Motor Control Stages | High-Temperature Sensor Signal Conditioning |
Use Scenario: Low-side switching of brushed DC motors in HVAC actuators and seat adjusters. IC Role / Device Role / Timing Role: Saturated-mode current switch with ICM = 10A peak handling motor stall currents. Use Value: 200°C TJ max allows mounting near hot components without thermal shutdown. | Use Scenario: Amplifying and buffering analog sensor outputs in engine bay temperature sensors. IC Role / Device Role / Timing Role: High-gain (hFE ≥ 35 @ 4A) emitter-follower buffer stage. Use Value: Stable hFE over -55°C to +150°C ambient enables accurate signal scaling across full operating range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN medium-power transistor applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| ZTX851 | Lower VCEO = 100 V; same E-Line package and pinout | Not suitable for >100V transient-prone automotive loads | Select when cost sensitivity outweighs 150V requirement and thermal margin is lower |
| MJD122 | TO-220 package; higher PD = 20 W; VCEO = 100 V | Requires heatsink; incompatible footprint; better for >5A continuous loads | Choose for higher power dissipation needs where board space permits TO-220 mounting |
Compared with ZTX855STOA, ZTX851 trades voltage headroom for cost, while MJD122 offers higher power handling in a larger package-neither matches its combination of 150V rating, AEC-Q101 qualification, and E-Line compactness.
Availability
ZTX855STOA is available at Aetrix Electronics and suitable for automotive relay drivers, industrial DC-DC pre-regulators, and high-temperature motor control stages requiring stable component supply and long-term lifecycle support.
Supply support for ZTX855STOA 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability, application-optimized components for automotive, industrial, and computing markets.
ZTX855STOA belongs to Diodes' E-Line bipolar transistor product line, designed specifically for medium-power switching in space-constrained, high-temperature, and automotive-qualified applications.
FAQ
What is the maximum allowable collector-emitter voltage for ZTX855STOA?
The absolute maximum collector-emitter voltage (VCEO) is 150 V under DC conditions at TA = +25°C. This rating decreases with rising ambient temperature per the derating curve in DS33136 Rev. 4–2, and must not be exceeded even during transient events unless external clamping is applied.
Is ZTX855STOA pin-compatible with other E-Line transistors?
Yes - ZTX855STOA uses standard E-Line (TO-92 compatible) pinout: Emitter (E), Base (B), Collector (C) in flat-face view left-to-right. It shares mechanical and electrical pin compatibility with ZTX851, ZTX955, and ZTX1051, but voltage and current ratings differ.
Does ZTX855STOA require a heatsink in 4A continuous operation?
At 4A with VCE(sat) ≈ 210 mV, power dissipation is ~0.84 W. With RΘJA = 110 °C/W (min pad layout), junction rise is ~92°C above ambient - acceptable up to +108°C ambient. A small copper pour on the collector lead is recommended; no external heatsink required below 85°C ambient.
How does AEC-Q101 qualification impact ZTX855STOA's use in non-automotive designs?
AEC-Q101 qualification confirms robustness against temperature cycling, humidity, mechanical shock, and ESD (≥4 kV HBM). These tests enhance reliability in any demanding environment - including industrial controls, aerospace subsystems, and outdoor equipment - even when automotive certification isn't mandated.
ZTX855STOA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- E-Line-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 4 A
- Voltage - Collector Emitter Breakdown (Max):
- 150 V
- Vce Saturation (Max) @ Ib, Ic:
- 260mV @ 400mA, 4A
- Current - Collector Cutoff (Max):
- 50nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 100 @ 1A, 5V
- Power - Max:
- 1.2 W
- Frequency - Transition:
- 90MHz
- Operating Temperature:
- -55°C ~ 200°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- E-Line (TO-92 compatible)
ZTX855STOA FAQ
1.How can I place an order for ZTX855STOA through Aetrix?
Please submit a Request for Quotation (RFQ) for ZTX855STOA 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 ZTX855STOA reliable?
The price and inventory of ZTX855STOA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for ZTX855STOA is usually 5 days.
3.What payment methods are accepted for ZTX855STOA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for ZTX855STOA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for ZTX855STOA?
ZTX855STOA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your ZTX855STOA 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 ZTX855STOA?
For technical support, including ZTX855STOA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your ZTX855STOA requirements.
6.How does Aetrix verify that ZTX855STOA is sourced from the original manufacturer or authorized distributors?
All ZTX855STOA 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 ZTX855STOA meets industry standards.
7.What is the process for return or replacement of ZTX855STOA?
All ZTX855STOA units undergo pre-shipment inspection (PSI). If there is an issue with ZTX855STOA, 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 ZTX855STOA part is unused and in its original packaging.
Return procedure for ZTX855STOA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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