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onsemi MMBT6521LT1
- Part No.:
- MMBT6521LT1
- Manufacturer:
- onsemi
- Category:
- Single Bipolar Transistors
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBT6521LT1.pdf
- Description:
- TRANS NPN 25V 0.1A SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:3,059
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Product details
Overview
MMBT6521LT1 from onsemi is an NPN silicon small-signal amplifier transistor in SOT-23 package, rated for VCEO = 25 V, IC = 100 mA, and hFE = 150–600 (at IC = 2–100 mA), optimized for low-noise audio preamplifier and RF front-end stages in portable consumer electronics.
For engineers reviewing the MMBT6521LT1 datasheet, pinout, applications, or equivalent options, key selection criteria include its 3.5 pF Cobo, 3.0 dB noise figure at 15.7 kHz bandwidth, VCE(sat) ≤ 0.5 V at IC/IB = 10, and AEC-Q101 qualification for automotive signal conditioning.
Technical Context
This NPN bipolar junction transistor operates in linear amplification mode with DC current gain spanning 150–600 across collector currents from 2 mA to 100 mA at VCE = 10 V. Its thermal resistance RJA is 556 °C/W on FR-5 board, enabling stable operation up to +150 °C junction temperature.
The device exhibits low output capacitance (Cobo ≤ 3.5 pF at VCB = 10 V) and narrowband noise figure as low as 2.0 dB at 100 Hz with optimal source impedance matching, supporting high-fidelity analog signal paths in battery-powered sensor interfaces and wireless receiver IF stages.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCEO | 25 V - Maximum safe collector-emitter voltage before breakdown; defines headroom for 3.3 V/5 V rail applications. |
| IC (continuous) | 100 mA - Continuous collector current rating; supports moderate-gain active loads in discrete amplifier stages. |
| hFE | 150–600 - DC current gain range at IC = 2–100 mA; enables predictable biasing in emitter-follower and common-emitter configurations. |
| VCE(sat) | ≤ 0.5 V at IC = 50 mA, IB = 5 mA - Low saturation voltage ensures minimal power loss in switching or saturated amplifier modes. |
| Cobo | ≤ 3.5 pF at VCB = 10 V - Low output capacitance preserves bandwidth in RF amplifier and oscillator buffer designs. |
| Noise Figure | ≤ 3.0 dB at IC = 10 mA, VCE = 5 V, 10 Hz–10 kHz - Quantifies added noise in low-level signal amplification; critical for microphone preamps. |
| RJA (FR-5) | 556 °C/W - Junction-to-ambient thermal resistance determines required PCB copper area for thermal management at full load. |
Pinout & Package
SOT-23 (TO-236) surface-mount package, 2.90 × 1.30 × 1.00 mm, 3-pin, Pb-free, RoHS compliant. Case outline: CASE 318, STYLE 6.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Base | Control terminal for forward-biased junction; requires current-limited drive to achieve target hFE-based gain. |
| 2 | Emiter | Common reference node in common-emitter configuration; connects to ground or emitter degeneration resistor. |
| 3 | Collector | Output terminal carrying amplified current; connects to load resistor or next-stage input via coupling capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive signal path use including body control modules and sensor interface ECUs. |
| Low noise figure (≤3.0 dB) | Enables high-SNR amplification of microvolt-level signals from MEMS microphones and piezoelectric sensors. |
| Pb-free, Halogen Free/BFR Free | Complies with global environmental regulations including RoHS and ELV; suitable for export-controlled industrial systems. |
| High hFE consistency (150–600) | Reduces need for binning or feedback trimming in production-grade discrete amplifier circuits. |
| Low Cobo (≤3.5 pF) | Minimizes Miller effect in high-frequency gain stages, supporting >100 MHz fT operation per typical curves. |
Applications
| Audio Preamp Stage | RF Signal Buffer |
|---|---|
|
Use Scenario: Amplifying weak output from electret condenser microphones in Bluetooth headsets and voice assistants. IC Role / Device Role / Timing Role: Discrete NPN transconductance amplifier in common-emitter topology with emitter degeneration. Use Value: 3.0 dB noise figure and hFE ≥ 150 at 1 mA ensure clean gain without introducing audible hiss or distortion. |
Use Scenario: Isolating and driving local oscillator signals between mixer and VCO in sub-GHz ISM band transceivers. IC Role / Device Role / Timing Role: Low-capacitance emitter follower providing impedance transformation and signal buffering. Use Value: Cobo ≤ 3.5 pF and fT > 100 MHz (per Fig. 16) preserve signal integrity and phase stability in 433/868 MHz paths. |
| Automotive Sensor Interface | Industrial Current Sink Driver |
|
Use Scenario: Conditioning analog output from temperature or pressure sensors in engine control units under AEC-Q101 requirements. IC Role / Device Role / Timing Role: Linear amplifier stage converting ratiometric sensor voltage to conditioned 0–5 V output. Use Value: AEC-Q101 qualification and −55 °C to +150 °C operating range guarantee reliability in under-hood environments. |
Use Scenario: Driving LED indicators or optocoupler inputs in programmable logic controllers and HMI panels. IC Role / Device Role / Timing Role: Saturated switch controlling up to 100 mA load current with VCE(sat) ≤ 0.5 V. Use Value: Low saturation voltage minimizes power dissipation (≤50 mW at 100 mA), reducing thermal stress on PCB traces. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar NPN small-signal amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BC846B,215 | hFE = 200–450 (IC = 10 mA); VCEO = 65 V; Cobo = 4.5 pF; no AEC-Q101 qualification | Higher voltage rating suits 12 V industrial rails; higher Cobo limits RF use; lacks automotive qualification | Select when higher VCEO margin is needed and AEC-Q101 is not required. |
| MPS6521RLRA | Same die, TO-92 package; identical electrical specs; RJA = 200 °C/W (free-air); no SMT compatibility | Through-hole assembly only; unsuitable for automated SMT lines; better natural convection cooling | Choose for prototyping or legacy through-hole designs where thermal performance outweighs footprint constraints. |
Compared with BC846B,215 and MPS6521RLRA, the MMBT6521LT1 uniquely combines AEC-Q101 compliance, SOT-23 footprint, and sub-3.5 pF output capacitance-making it the only option qualified for automotive SMT audio/RF signal chains requiring both reliability and high-frequency fidelity.
Availability
MMBT6521LT1 is available at Aetrix Electronics and suitable for audio preamplifier design, RF signal buffering, and automotive sensor interface applications requiring stable component supply and full traceability.
Supply support for MMBT6521LT1 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, and sensing solutions for automotive, industrial, and cloud infrastructure markets.
The MMBT6521LT1 belongs to onsemi's general-purpose NPN transistor product line, engineered for low-noise, high-gain analog signal conditioning in space-constrained, thermally sensitive applications.
FAQ
What is the maximum continuous collector current rating for MMBT6521LT1?
The MMBT6521LT1 has a maximum continuous collector current (IC) rating of 100 mA at TA = 25 °C. Derating applies above 25 °C at 1.8 mW/°C on FR-5 board. This rating ensures reliable operation in discrete amplifier and switching roles without exceeding thermal limits under standard PCB layout conditions. The MMBT6521LT1 must be used within this limit to maintain specified hFE, VCE(sat), and noise performance.
Is MMBT6521LT1 qualified for automotive applications?
Yes, the MMBT6521LT1 is AEC-Q101 qualified and PPAP capable, as explicitly stated in its datasheet features section. This qualification covers stress testing for temperature cycling, humidity, mechanical shock, and ESD robustness required for automotive electronic control units. The MMBT6521LT1 meets these standards in its SOT-23 package variant and is suitable for use in non-safety-critical automotive signal conditioning functions such as cabin sensor interfaces and infotainment system audio stages.
What is the noise figure specification for MMBT6521LT1 and under what conditions is it measured?
The MMBT6521LT1 has a maximum noise figure (NF) of 3.0 dB, measured at IC = 10 mA, VCE = 5.0 Vdc, with a power bandwidth of 15.7 kHz (3.0 dB points at 10 Hz and 10 kHz). This value reflects added noise in low-level amplification scenarios and is validated per the test setup shown in Figure 1. The MMBT6521LT1 achieves lower noise figures (e.g., 2.0 dB at 100 Hz) depending on source impedance and operating point, as shown in Figures 6–8 of the datasheet.
Does MMBT6521LT1 have a Pb-free and RoHS-compliant construction?
Yes, the MMBT6521LT1 is explicitly marked as Pb-free, halogen free/BFR free, and RoHS compliant per its datasheet features and ordering information. The "G" suffix in MMBT6521LT1G denotes the Pb-free version, and the device meets EU RoHS Directive 2011/65/EU and related global environmental regulations. This compliance is verified through material declarations and third-party testing, making the MMBT6521LT1 suitable for export-controlled and environmentally regulated electronics programs.
What is the pin configuration of MMBT6521LT1 in the SOT-23 package?
The MMBT6521LT1 uses SOT-23 package STYLE 6: Pin 1 is Base, Pin 2 is Emitter, and Pin 3 is Collector. This configuration is confirmed in the mechanical drawings on page 2 of the datasheet and matches the internal schematic symbol. Correct orientation is critical-reversing emitter and collector will prevent proper biasing and may cause device failure. The MMBT6521LT1 pinout is not interchangeable with STYLE 7 (Emitter/Base/Collector) or other SOT-23 variants without circuit redesign.
MMBT6521LT1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Transistor Type:
- NPN
- Current - Collector (Ic) (Max):
- 100 mA
- Voltage - Collector Emitter Breakdown (Max):
- 25 V
- Vce Saturation (Max) @ Ib, Ic:
- 500mV @ 5mA, 50mA
- Current - Collector Cutoff (Max):
- 500nA (ICBO)
- DC Current Gain (hFE) (Min) @ Ic, Vce:
- 300 @ 2mA, 10V
- Power - Max:
- 225 mW
- Frequency - Transition:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3 (TO-236)
MMBT6521LT1 FAQ
1.How can I place an order for MMBT6521LT1 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBT6521LT1 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 MMBT6521LT1 reliable?
The price and inventory of MMBT6521LT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBT6521LT1 is usually 5 days.
3.What payment methods are accepted for MMBT6521LT1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBT6521LT1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBT6521LT1?
MMBT6521LT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBT6521LT1 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 MMBT6521LT1?
For technical support, including MMBT6521LT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBT6521LT1 requirements.
6.How does Aetrix verify that MMBT6521LT1 is sourced from the original manufacturer or authorized distributors?
All MMBT6521LT1 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 MMBT6521LT1 meets industry standards.
7.What is the process for return or replacement of MMBT6521LT1?
All MMBT6521LT1 units undergo pre-shipment inspection (PSI). If there is an issue with MMBT6521LT1, 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 MMBT6521LT1 part is unused and in its original packaging.
Return procedure for MMBT6521LT1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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