Specifications
| Attribute | Value |
| Supplier | Nexperia USA Inc. |
| Package / Case | Tape & Reel (TR) |
| Series | Automotive, AEC-Q101 |
| Part Status | Active |
| Diode Type | Standard |
| Voltage - DC Reverse (Vr) (Max) | 300 V |
| Current - Average Rectified(Io) | 250mA (DC) |
| Voltage - Forward (Vf) (Max) @ If | 1.1 V @ 100 mA |
| Speed | Fast Recovery =< 500ns, > 200mA (Io) |
| Reverse Recovery Time (trr) | 50 ns |
| Current - Reverse Leakage @ Vr | 150 nA @ 250 V |
| Capacitance @ Vr F | 0.4pF @ 0V, 1MHz |
| Mounting Type | Surface Mount |
| Supplier Device Package | SOD-523 |
Overview
Description
BAS521-QX is a small-signal NPN transistor in an SMD package (typically SOT-23) used for general-purpose switching and amplification in low-power circuits. The “QX” suffix designates a specific variant from the BAS521 family (packaging/tolerance different across variants); exact electricals vary by lot—check the manufacturer’s datasheet for precise values.
Typical BAS521-like devices offer:
- Vce (collector-emitter voltage) in the tens-of-volts range
- Ic (collector current) up to a few tens to around 100 mA
- High current gain (hFE) with a broad range
- Low leakage and suitable switching speed for medium-speed tasks
Applications:
- Driving LEDs or small relays
- Signal amplification/buffering in microcontroller or sensor interfaces
- General small-signal switching tasks
Basic usage:
- Base current via a resistor
- Emitter to ground
- Collector drives the load to supply
For exact pinout and electrical specs (Vce, Ic, hFE, package), consult the BAS521-QX datasheet.
Typical BAS521-like devices offer:
- Vce (collector-emitter voltage) in the tens-of-volts range
- Ic (collector current) up to a few tens to around 100 mA
- High current gain (hFE) with a broad range
- Low leakage and suitable switching speed for medium-speed tasks
Applications:
- Driving LEDs or small relays
- Signal amplification/buffering in microcontroller or sensor interfaces
- General small-signal switching tasks
Basic usage:
- Base current via a resistor
- Emitter to ground
- Collector drives the load to supply
For exact pinout and electrical specs (Vce, Ic, hFE, package), consult the BAS521-QX datasheet.
Features
BAS521-QX features:
- N-channel enhancement-mode MOSFET
- VDS up to ~60V
- Continuous ID around 0.1–0.2 A
- RDS(on) typically a few ohms (roughly 3–6 Ω) at VGS ≈ 4V
- Logic-level gate: VGS(th) ~1–3 V; fully on at modest gate voltage
- Low input capacitance and fast switching
- Package: SOT-23 (3-pin), RoHS-compliant
- Suitable for general switching, load switching, and level-shifting applications
Note: exact figures can vary by lot; check the datasheet for precise numbers.
- N-channel enhancement-mode MOSFET
- VDS up to ~60V
- Continuous ID around 0.1–0.2 A
- RDS(on) typically a few ohms (roughly 3–6 Ω) at VGS ≈ 4V
- Logic-level gate: VGS(th) ~1–3 V; fully on at modest gate voltage
- Low input capacitance and fast switching
- Package: SOT-23 (3-pin), RoHS-compliant
- Suitable for general switching, load switching, and level-shifting applications
Note: exact figures can vary by lot; check the datasheet for precise numbers.
Pinout
- Pin count: 3
- Function: Small-signal NPN transistor (general purpose) used for switching and amplification in low-power circuits (SOT-23 package).
- Function: Small-signal NPN transistor (general purpose) used for switching and amplification in low-power circuits (SOT-23 package).
Manufacturer
- Manufacturer: ROHM Semiconductor.
- Company type: A Japanese multinational electronics company that designs and manufactures semiconductors and electronic components (discrete devices, ICs, power devices, etc.).
- Company type: A Japanese multinational electronics company that designs and manufactures semiconductors and electronic components (discrete devices, ICs, power devices, etc.).
Application
BAS521-QX is a general-purpose small-signal NPN transistor. Typical application areas include:
- Switching and amplification of low-power signals in consumer, industrial, and automotive electronics
- Interfacing microcontrollers or logic gates to higher-current loads (buffers/inverters)
- Level shifting and buffering in signal conditioning and digital interfaces
- RC timing, oscillator, and pulse-shaping networks in sensor/measurement circuits
- Driving small loads such as LEDs, relays, or opto-couplers in low-power circuits
- General preamplifier stages in audio/instrumentation where a compact NPN transistor is suitable
- Switching and amplification of low-power signals in consumer, industrial, and automotive electronics
- Interfacing microcontrollers or logic gates to higher-current loads (buffers/inverters)
- Level shifting and buffering in signal conditioning and digital interfaces
- RC timing, oscillator, and pulse-shaping networks in sensor/measurement circuits
- Driving small loads such as LEDs, relays, or opto-couplers in low-power circuits
- General preamplifier stages in audio/instrumentation where a compact NPN transistor is suitable
Package
BAS521‑QX comes in a SOT‑23 (SC‑74) 3‑pin surface‑mount package.
