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Diodes Incorporated BST61TA
- Part No.:
- BST61TA
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Bipolar Transistors
- Package:
- TO-243AA
- Datasheet:
-
BST61TA.pdf
- Description:
- TRANS PNP DARL 60V 0.5A SOT-89-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,745
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Product details
Overview
BST61TA from Nexperia is a PNP silicon planar Darlington transistor in SOT89 package, rated for -60 V VCEO, -500 mA continuous collector current, and -1.3 V VCE(sat) at IC = -500 mA / IB = -0.5 mA. It delivers high DC current gain (hFE ≥ 1000 at IC = -150 mA) and fast switching (ton = 400 ns, toff = 1.5 µs), used in low-voltage DC-DC converter output stage switching and relay driver circuits.
For engineers reviewing the BST61TA datasheet, BST61TA pinout, BST61TA application, or BST61TA equivalent, key selection criteria include verified Darlington saturation voltage under load, guaranteed hFE minimum at operating current, thermal derating behavior above 25°C, and SOT89 thermal resistance performance in PCB-constrained layouts.
Technical Context
This device implements a monolithic PNP Darlington pair with integrated base-emitter shunt resistor network to ensure reliable turn-off. Its VCE(sat) remains ≤ -1.3 V up to Tj = 150°C, supporting operation in thermally demanding industrial control modules.
The transistor exhibits low leakage: ICES ≤ -10 µA at VCE = -60 V and IEBO ≤ -10 µA at VEB = -8 V, enabling stable biasing in high-impedance sensor interface front-ends and battery-powered standby circuits.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | -60 V - Maximum safe collector-emitter blocking voltage in open-base configuration |
| IC (cont.) | -500 mA - Continuous DC collector current rating at Tamb = 25°C with adequate heatsinking |
| VCE(sat) | -1.3 V @ IC = -500 mA, IB = -0.5 mA - Low saturation voltage minimizes power loss in switching loads |
| hFE | ≥ 1000 @ IC = -150 mA, VCE = -10 V - High current gain reduces required base drive current |
| toff | 1.5 µs typical - Fast turn-off enables PWM operation up to ~200 kHz in discrete power stages |
| Ptot | 1 W @ Tamb = 25°C - Total package power dissipation limit before thermal shutdown or degradation |
Pinout & Package
SOT89 package: 3-pin surface-mount plastic case with exposed emitter pad for thermal conduction; pin 1 = Collector, pin 2 = Base, pin 3 = Emitter (C-B-E layout as marked on top-side silkscreen).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (Collector) | Main current sink terminal | Connected to load return path; requires trace width ≥ 0.5 mm for 500 mA continuous routing |
| Pin 2 (Base) | Control input node | Driven by microcontroller GPIO or logic-level signal; series resistor needed to limit IB ≤ -100 mA |
| Pin 3 (Emitter) | Common reference terminal | Internally bonded to exposed metal pad; must be soldered to ≥ 100 mm² copper pour for thermal management |
Key Features
| Feature | Design Value |
|---|---|
| Darlington architecture | Monolithic PNP pair with integrated base-shunt resistor ensures predictable turn-off without external pull-down |
| High hFE stability | hFE ≥ 1000 maintained across -40°C to +125°C junction range, reducing base drive variability in automotive environments |
| Low VCE(sat) at temperature | VCE(sat) ≤ -1.3 V up to Tj = 150°C supports sustained operation in enclosed industrial enclosures |
| Fast switching speed | Combined ton + toff < 2 µs enables efficient operation in 100–200 kHz DC-DC feedback loops |
Applications
| Relay Driver Module | Linear Regulator Pass Element |
|---|---|
Use Scenario: Driving 12 V/500 mA electromagnetic relay coil in PLC I/O module with 3.3 V MCU GPIO control. IC Role / Device Role / Timing Role: High-gain PNP Darlington switch providing galvanic isolation and current amplification between logic and inductive load. Use Value: Enables direct MCU interface without level-shifting; VCE(sat) ≤ -1.3 V limits coil power loss to < 650 mW at full load. | Use Scenario: Pass transistor in adjustable 5 V linear regulator supplying FPGA configuration circuitry. IC Role / Device Role / Timing Role: Series pass element regulating output voltage via base bias control from error amplifier. Use Value: High hFE allows low-error-amplifier output current (< 50 µA), improving regulation accuracy and noise immunity. |
| DC Motor Brake Circuit | Industrial Sensor Power Switch |
Use Scenario: Shorting motor terminals during dynamic braking in 24 V brushed DC motor controller. IC Role / Device Role / Timing Role: Low-saturation switch sinking motor back-EMF current during brake activation. Use Value: -1.3 V VCE(sat) limits peak brake power dissipation to 650 mW, compatible with SOT89 thermal design. | Use Scenario: Enabling/disabling 5 V supply to analog pressure sensor in hazardous-area transmitter. IC Role / Device Role / Timing Role: Load switch isolating sensor supply rail to meet intrinsic safety current limits during fault conditions. Use Value: ICES ≤ -10 µA ensures < 1 µA leakage into isolated sensor domain, preserving safety certification margins. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PNP Darlington switching applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMBT6427 | VCEO = -60 V, hFE = 500–1500 (min 500), SOT23 package, Ptot = 350 mW | Lower power rating limits use to < 200 mA continuous loads; unsuitable for 500 mA relay drivers | Select when board space is critical and load current ≤ 200 mA; verify thermal margin with 0.5 mm² copper pad |
| ZTX951 | VCEO = -60 V, hFE = 1000–4000, TO-92 package, Ptot = 1 W, toff = 2.5 µs | Through-hole mounting only; slower turn-off increases switching loss in >100 kHz PWM | Choose for legacy through-hole assembly or where manual rework access is required; avoid in high-frequency SMPS |
Compared with BST61TA, MMBT6427 trades power handling for footprint reduction, while ZTX951 offers higher hFE but sacrifices switching speed and surface-mount compatibility-making BST61TA optimal for thermally constrained, medium-current SMT relay and brake applications.
Availability
BST61TA is available at Aetrix Electronics and suitable for industrial control modules, programmable logic controller (PLC) I/O stages, and 24 V DC motor brake circuits requiring stable component supply and long-term obsolescence management.
Supply support for BST61TA 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
Nexperia is a global semiconductor expert focused on essential efficiency technologies, delivering high-performance, reliable discrete and logic devices for automotive, industrial, and consumer markets.
BST61TA belongs to Nexperia's general-purpose bipolar transistor product line, engineered for robust DC switching and linear regulation in cost-sensitive industrial equipment where thermal reliability and parameter consistency are critical.
FAQ
What is the maximum allowable base current for BST61TA?
The absolute maximum base current is -100 mA per datasheet Absolute Maximum Ratings. Exceeding this risks metallization failure or bond wire lift. For reliable 500 mA collector operation, design base drive to deliver -0.5 mA (typical) with margin; use series resistor to limit peak IB during transients.
Can BST61TA replace a standard PNP BJT in existing designs?
Yes, but only if the original design accommodates Darlington characteristics: higher VBE(sat) (-1.9 V), slower switching than single BJTs, and higher hFE. Verify base drive capability supports -1.9 V VBE(sat) and that toff = 1.5 µs meets timing requirements before substitution.
Is BST61TA suitable for automotive under-hood applications?
No-BST61TA is qualified to industrial temperature range (-65°C to +150°C), but lacks AEC-Q101 qualification, PPAP documentation, or automotive-specific reliability testing. Use only in non-safety-critical, non-under-hood industrial systems unless fully requalified per customer requirements.
How does SOT89 thermal performance compare to TO-92 for BST61TA?
SOT89 provides ~2× lower thermal resistance (RθJA ≈ 125 K/W vs. TO-92's ~250 K/W) due to exposed emitter pad soldered to PCB copper. At 500 mA and 1.3 V VCE(sat), SOT89 dissipates 650 mW with ~81°C rise above ambient-achievable with ≥ 100 mm² 2-oz copper; TO-92 would exceed safe junction temperature.
BST61TA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- TO-243AA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Transistor Type:
- PNP - Darlington
- Current - Collector (Ic) (Max):
- 500 mA
- Voltage - Collector Emitter Breakdown (Max):
- 60 V
- Vce Saturation (Max) @ Ib, Ic:
- 1.3V @ 500µA, 500mA
- Current - Collector Cutoff (Max):
- 10µA
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 1000 @ 150mA, 10V
- Power - Max:
- 1 W
- Frequency - Transition:
- -
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-89-3
BST61TA FAQ
1.How can I place an order for BST61TA through Aetrix?
Please submit a Request for Quotation (RFQ) for BST61TA 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 BST61TA reliable?
The price and inventory of BST61TA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for BST61TA is usually 5 days.
3.What payment methods are accepted for BST61TA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for BST61TA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for BST61TA?
BST61TA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your BST61TA 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 BST61TA?
For technical support, including BST61TA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your BST61TA requirements.
6.How does Aetrix verify that BST61TA is sourced from the original manufacturer or authorized distributors?
All BST61TA 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 BST61TA meets industry standards.
7.What is the process for return or replacement of BST61TA?
All BST61TA units undergo pre-shipment inspection (PSI). If there is an issue with BST61TA, 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 BST61TA part is unused and in its original packaging.
Return procedure for BST61TA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
BST61TA Tags
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MMBT3906LT1G
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Diodes Incorporated
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Nexperia USA Inc.
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