BAS521Q-13

BAS521Q-13 is a small-signal N-channel MOSFET in an SOT-23 package used for switching and buffering low‑power loads. It’s part of the BAS521 family, with the Q‑13 suffix indicating a specific grade/packaging variant from the manufacturer. The three pins are Gate (G), Drain (D), and Source (S). It is driven by logic-level signals and intended for modest current/voltage ratings (typical tens of volts, hundreds of milliamps), with a low gate threshold and low on-resistance when on. Exact electrical specs (VDS, ID, RDS(on), VGS(th), thermal limits) vary by supplier and date code, so consult the specific BAS521Q-13 datasheet from the manufacturer to confirm ratings, pinout, and safe operating area. Common uses include general-purpose switching, level shifting, and small-signal amplification in consumer and automotive electronics.

BAS521Q-13 is a small-signal NPN transistor in SOT-23. There isn’t a single universal equivalent; cross-references must match Vce, Ic and hFE. Common SMD equivalents (NPN, similar ratings) include:
- MMBT3904 (SOT-23)
- MMBT3904LT1G
- BC847B (SOT-23)
- BC846B (SOT-23)
Always verify package, pinout and ratings against the BAS521Q-13 datasheet or supplier cross-reference.

Here are typical features of BAS521Q-13 (general-purpose NPN transistor in SOT-23):
- Type: NPN transistor, general-purpose switching/amplification
- Package: SOT-23, surface-mount, RoHS-compliant, Pb-free
- Collector-Emitter voltage (Vceo): 60 V
- Continuous collector current (Ic): up to ~150 mA
- Saturation voltage (Vce(sat)): ~0.2 V at Ic ≈ 50 mA, Ib ≈ 5 mA
- DC current gain (hFE): broad range, typically 100–600 depending on Ic and temperature
- Leakage current (Ices): very low when off
- Switching speed: suitable for general-purpose switching applications
- Applications: signal amplification, switching in portable/electronic circuits
Note: Exact parameters can vary by lot and manufacturer; consult the specific datasheet for your device to confirm numbers.

Pin count: 3 pins (SOT‑23 package).
Function: A dual switching diode pair in one SOT‑23 package (BAS521Q). It provides two small‑signal/switching diodes for high‑speed switching, level shifting, signal steering and transient/clamping/protection tasks in low‑voltage circuits.

Manufacturer: Diodes Incorporated.
What kind of company: Diodes Incorporated is a multinational semiconductor company that designs and supplies discrete, analog and power-management components (diodes, transistors, MOSFETs, logic and mixed‑signal ICs). It is a publicly traded electronics manufacturer (NASDAQ: DIOD) headquartered in the United States.

Typical application areas: small-signal switching and amplification in compact, low-power circuits. Used for microcontroller I/O interfacing and level shifting, sensor front-ends, LED drivers, DC-DC converter support, voltage regulation and protection circuits, buffering and isolation in digital or mixed-signal paths, audio preamps, and general-purpose switching in portable and embedded electronics (consumer, automotive, industrial).

BAS521Q-13 uses a SOT-23 (3-pin) surface-mount package.