BC547BTA - 45V NPN BJT 100mA TO-92 | onsemi
Référence : BC547BTA ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $0.2 | $0,20 |
| 10 | $0.16 | $1,60 |
| 100 | $0.09 | $9,00 |
| 500 | $0.06 | $30,00 |
| 1 000 | $0.04 | $40,00 |
| 10 000 | $0.03 | $300,00 |
BC547BTA Présentation
An NPN bipolar junction transistor (BJT) is a three-terminal semiconductor device consisting of an N-type collector, a P-type base, and an N-type emitter. BJTs are the foundational active components of analog electronics, used as small-signal amplifiers, switches, and current sources. In the wider component hierarchy, small-signal NPN BJTs like BC547 sit under discrete semiconductors > transistors > bipolar transistors > epitaxial silicon transistors, providing the gain and switching function for virtually every analog and digital control circuit.
The BC547BTA features a low-noise epitaxial silicon die with a typical DC current gain (hFE) of 330 at 2 mA, making it well-suited for audio pre-amplifier input stages, sensor signal conditioning, and general-purpose switching. It provides 300 MHz transition frequency (fT) for RF and high-speed pulse applications, 5 pF typical output capacitance, and a 5 ns storage time for fast switching. The TO-92-3 package with formed leads supports automatic insertion and is the de-facto industry standard for through-hole small-signal transistors.
The BC547BTA's PNP complement is the BC557, which shares the same TO-92 package and gain group nomenclature. The 'B' suffix designates the hFE bin (200-450), distinguishing it from BC547A (110-220) and BC547C (420-800). Designers typically select the BC547B as a balance between gain and stability for audio and general-purpose circuits.
Typical applications include audio pre-amplifiers, signal conditioning for sensors, general-purpose switching interfaces for microcontrollers, RF amplifier stages up to 300 MHz, oscillator circuits, and Darlington-pair drivers. The through-hole TO-92 package also makes it a popular choice for prototyping, education labs, and hobbyist projects.
When designing with the BC547BTA, ensure the collector current remains below 100 mA continuous and the junction temperature stays within -55C to +150C. Use a base resistor to limit base current and prevent excessive collector current, and add a flyback diode when driving inductive loads to protect against reverse-EMF.
This page synthesizes distributor pricing from DigiKey/Mouser, drop-in alternatives from the BC547/2N3904 family, and practical design notes not found on a single manufacturer datasheet, providing engineers with a complete sourcing and design reference in one place.
Alternatives de remplacement direct pour BC547BTA — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
BC547B
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
BC547C
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
BC547BTAR
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
2N3904BU
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
BC547B-AP
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
BC547BTAR
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
BC547BTA Valeurs maximales et caractéristiques électriques
| Type de transistor | NPN Bipolar Junction Transistor |
| Boîtier | TO-92-3 (Through Hole, formed leads) |
| Tension collecteur-émetteur (Vceo) | 45 V |
| Tension collecteur-base (Vcbo) | 50 V |
| Tension émetteur-base (Vebo) | 5 V (some sources 6 V) |
| Continuous Collector Current (IC) | 100 mA |
| Power Dissipation (PD) | 500 mW (some sources 625 mW) |
| DC Current Gain (hFE), Group B | 200 to 450 (typical 330 at 2 mA / 10 V) |
| Fréquence de transition (ft) | 300 MHz (typical) |
| Plage de température de fonctionnement | -55C to +150C (junction) |
| Type de montage | Through Hole |
| Lead Form | Formed leads (Ammo Pack / Tape & Reel suffix 'TA') |
| Gain Group | B (200-450 hFE) |
| Statut RoHS | Compliant |
| Niveau MSL | Not applicable (through-hole) |
Configuration des broches de BC547BTA
| Broche 1 | Collector — Collector terminal (C) |
| Broche 2 | Base — Base terminal (B) |
| Broche 3 | Emitter — Emitter terminal (E) |
Applications typiques
BC547BTA convient pour 7 applications: Audio Pre-Amplifier Input Stage, Sensor Signal Conditioning, Microcontroller GPIO Switching Interface, RF Amplifier Stage up to 100 MHz, Oscillator and Timer Circuits, Darlington Pair Driver Stage, Educational and Prototyping Applications.
Audio Pre-Amplifier Input Stage
The BC547BTA's hFE bin B (200-450) and low-noise epitaxial silicon die make it a strong fit for audio pre-amplifier input stages. With a typical hFE of 330 at 2 mA and VCE of 5 V, the transistor provides ample gain for moving-magnet phono stages and microphone preamps, while its 5 pF output capacitance and 300 MHz fT preserve signal integrity across the audio band. Placed in a common-emitter configuration with a 10 kohm collector resistor and 100 kohm base bias, the BC547BTA delivers approximately 30 dB of voltage gain with noise figures below 2 dB. Unlike the higher-gain BC547C, bin B offers better thermal stability and lower base-emitter leakage, critical for low-hum audio designs. The TO-92 package allows easy through-hole mounting on prototyping boards and is well-suited for high-end tube preamp buffer circuits.
Recommandé
Sensor Signal Conditioning
For sensor signal conditioning, the BC547BTA's 100 mA collector current and 200-450 hFE range provide flexible biasing for thermistor, photodiode, and Hall-effect sensor front-ends. Its 45 V VCEO supports industrial 24 V supply rails common in PLC and process-control applications, while the 300 MHz fT ensures adequate bandwidth for fast-changing sensor signals. In a typical thermistor bridge circuit, the BC547BTA serves as a DC amplifier with a gain set by the collector resistor, delivering a buffered 0-10 V output to the ADC. The 500 mW dissipation rating and 200 C/W thermal resistance keep junction temperatures well below the 150C maximum even at 100 mA continuous load. Designers should add a base resistor (typically 10x the calculated Rb) to limit base current and protect against sensor short-circuit conditions.
Recommandé
Microcontroller GPIO Switching Interface
The BC547BTA excels as a low-side switch for interfacing microcontrollers to relays, solenoids, LEDs, and small DC loads. With 100 mA continuous collector current, it can directly drive most signal relays and high-brightness LEDs, while its 45 V VCEO handles inductive kickback from 12V/24V relay coils when paired with a flyback diode. Driven from a 3.3 V or 5 V GPIO pin via a 1 kohm base resistor, the transistor saturates fully (VCE(sat) typically < 200 mV) and delivers the full supply voltage to the load. The 5 ns storage time and 300 MHz fT support PWM dimming and audio-frequency switching up to 100 kHz. Unlike MOSFET switches, the BC547BTA requires no gate-charge drive and is fully controllable from any logic-level GPIO, making it ideal for legacy and low-cost microcontroller designs.
Recommandé
RF Amplifier Stage up to 100 MHz
The BC547BTA's 300 MHz transition frequency enables its use as an RF amplifier in the 1-100 MHz range, including IF stages for AM receivers, 27 MHz CB radio pre-amps, and low-power FM transmitter oscillators. Its low output capacitance (typically 5 pF) and small-signal characteristics are well-suited for tuned-collector and common-base RF topologies. In a 10.7 MHz IF amplifier configuration, the BC547BTA delivers 20-30 dB of stable gain with appropriate neutralization. Compared to dedicated RF transistors like the 2N5179, the BC547BTA offers lower cost and broader availability, though at the expense of lower gain-bandwidth product. Designers should add emitter degeneration (typically 10-100 ohm) for unconditional stability across temperature and unit-to-unit hFE variation.
Recommandé
Oscillator and Timer Circuits
The BC547BTA is a popular choice for astable multivibrator, bistable, and monostable timer circuits, where its 100 mA collector current drives timing capacitors and LED indicators directly. With consistent hFE binning (200-450), the BC547BTA produces predictable oscillation frequencies in RC-timed designs, making it superior to the wider-bin 2N3904 for precision timing. In a classic 555-replacement astable, a pair of BC547BTA and BC557B transistors with 100 kohm resistors and 10 uF capacitors produces a 1 Hz blink rate with stable duty cycle. The TO-92 package and through-hole leads make it ideal for educational lab kits and breadboard prototypes. For designs requiring tighter frequency stability, designers should add a 100 nF bypass capacitor across the supply rail and keep base resistors below 470 kohm to minimize leakage effects.
Recommandé
Darlington Pair Driver Stage
Cascading two BC547BTA transistors in a Darlington configuration produces a composite device with effective hFE of 40,000-200,000, ideal for driving high-current loads from low-current microcontroller GPIO pins. With 45 V VCEO (shared by both stages) and 100 mA continuous current, the Darlington handles relays, small motors, and high-brightness LED arrays. The trade-off is VCE(sat) doubling to 0.8-1.2 V and a 2x reduction in switching speed compared to a single transistor, limiting PWM frequencies to roughly 50 kHz. For motor-control and solenoid-driver applications, designers should add a 10 kohm resistor from base to emitter to ensure clean turn-off, and a 1N4001 flyback diode across the inductive load. The BC547BTA's well-defined hFE bin B ensures both Darlington stages operate in their linear region without saturation mismatch.
Recommandé
Educational and Prototyping Applications
The BC547BTA is a staple of electronics education and prototyping due to its robust TO-92 package, forgiving electrical characteristics, and broad availability. In hobbyist and classroom settings, it teaches fundamental BJT concepts including common-emitter amplification, common-collector emitter-follower buffering, and common-base RF stages. With 100 mA IC and 500 mW PD, it can directly drive most indicator LEDs, piezo buzzers, and small signal relays without additional driver stages. The through-hole leads are breadboard-friendly and easy to solder, making the BC547BTA a favorite for student projects from simple blink circuits to AM radio receivers. Compared to surface-mount alternatives, the TO-92 package survives repeated insertion cycles and student handling without lead damage. Universities worldwide stock BC547 series transistors as the standard NPN BJT for electronics laboratories.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour BC547BTA — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | BC547B | BC547C | 2N3904BU | BC547B-AP |
|---|---|---|---|---|---|
| Package | TO-92-3 (formed leads, Ammo Pack) | TO-92-3 - same | TO-92-3 - same | TO-92-3 - same | TO-92-3 - same |
| Brand | onsemi | onsemi | onsemi | onsemi | Micro Commercial Components |
| VCEO (V) | 45 | 45 | 45 | 40 | 45 |
| IC Continuous (mA) | 100 | 100 | 100 | 200 | 100 |
| hFE Bin / Range | B / 200-450 | B / 200-450 | C / 420-800 | Unbinned / 100-300 | B / 200-450 |
| fT (MHz) | 300 | 300 | 300 | 300 | 300 |
| PD (mW) | 500 | 500 | 500 | 625 | 500 |
| Packaging Format | Ammo Pack (TA suffix) | Bulk | Bulk | Bulk (BU suffix) | Ammo Pack (AP suffix) |
| Pinout | C-B-E (flat side, leads down) | C-B-E - same | C-B-E - same | E-B-C (note pinout difference) | C-B-E - same |
Principaux différenciateurs
- hFE B-bin for balanced gain and stability (vs BC547C)
- Ammo Pack packaging for automation (vs BC547B (bulk))
- Higher VCEO voltage headroom (vs 2N3904BU)
- Tighter hFE binning for matched-pair designs (vs 2N3904BU (unbinned 100-300))
Notes de conception
The BC547BTA's TO-92 package has a thermal resistance of approximately 200 C/W junction-to-ambient. At 100 mA collector current with 5 V VCE, the device dissipates 500 mW, raising junction temperature 100C above a 25C ambient - close to the 150C absolute maximum. Estimated using PD = VCE * IC and Tj = Tamb + PD * theta_JA. For continuous operation near maximum ratings, derate by 50% or improve PCB copper area around the leads to drop theta_JA to roughly 150 C/W.
When using the BC547BTA in through-hole designs, bend the leads at least 2 mm from the package body to avoid stress on the glass-lead seal. Maintain a 1.5 mm pad-to-pad pitch to match standard TO-92 footprints, and route collector and emitter traces away from the base trace to minimize parasitic feedback. For switching applications above 10 kHz, add a 100 nF supply bypass capacitor within 10 mm of the collector pin.
Do not confuse the BC547BTA's pinout with the 2N3904 - the BC547BTA is C-B-E (collector-base-emitter) when viewed from the flat side with leads down, while the 2N3904 is E-B-C. Substituting these parts without checking pinout will cause circuit malfunction. Also note that VCE(sat) can exceed 300 mV at 50 mA, which may cause unacceptable voltage drop in low-voltage LED-driver circuits - consider a MOSFET like the 2N7002 for sub-100 mV drop applications.
For low-noise audio pre-amplifier designs using the BC547BTA, source degeneration via a 100-ohm emitter resistor improves linearity and stabilizes the operating point across temperature. The BC547B bin (200-450 hFE) provides lower base-spreading resistance than the BC547C bin, yielding noise figures 1-2 dB lower at 1 kHz. For ultra-low-noise applications below 1 nV/sqrt(Hz), consider the MPSA18 or 2SD786 specialty transistors.
Informations de conformité
RoHS and REACH compliant per onsemi product page. Lead-free TO-92 packaging. Not AEC-Q100 qualified - this is a commercial/industrial-grade part. For automotive designs, source AEC-Q100 qualified parts separately.
