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Microchip Technology MIC4684-3.3BM TR
- Part No.:
- MIC4684-3.3BM TR
- Manufacturer:
- Microchip Technology
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MIC4684-3.3BM TR.pdf
- Description:
- IC REG BUCK 3.3V 2A 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,303
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Product details
Overview
MIC4684-3.3BM TR from Micrel, Inc. is a fixed-output 3.3V, 2A continuous current synchronous buck regulator in an 8-lead Power-SO-8 package, operating at 200kHz PWM with >85% efficiency across 4V–30V input range. It integrates an NPN power switch, bootstrap driver, and internal compensation for compact, high-efficiency step-down conversion in space-constrained industrial and embedded power rails.
For engineers reviewing the MIC4684-3.3BM TR datasheet, MIC4684-3.3BM TR pinout, MIC4684-3.3BM TR application, or MIC4684-3.3BM TR equivalent, key selection criteria include its fixed 3.3V output, thermal shutdown at 160°C, enable logic compatibility (2.0V/0.8V thresholds), 1.235V feedback reference, and SO-8 thermal design requiring ≥6 cm² ground plane area.
Technical Context
The MIC4684-3.3BM TR implements voltage-mode control using a 200kHz sawtooth oscillator and a transconductance error amplifier comparing FB voltage to a 1.235V bandgap reference. Its internal NPN switch is driven via a bootstrap capacitor (pin 4) to reduce saturation voltage-enabling high efficiency without external heat sinking.
It features frequency foldback during short-circuit conditions (reducing switching frequency to ~30–120 kHz), over-current protection with 2.2A current limit, and TTL-compatible EN pin with hysteresis (2.0V turn-on / 0.8V turn-off) for noise-immune sequencing. The device operates across –40°C to +125°C junction temperature with θJA = 75°C/W on standard PCB layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±2%, set internally-eliminates external feedback resistors and simplifies layout for stable point-of-load regulation. |
| Continuous Output Current | 2A at 60°C ambient-achieved via Power-SO-8 package with pins 2/6/7 tied to die paddle for low θJC = 25°C/W. |
| Input Voltage Range | 4V to 30V (34V transient rated)-supports wide industrial input rails including 5V, 12V, and 24V systems with transient robustness. |
| Switching Frequency | 200kHz nominal (180–225kHz)-enables use of small, cost-effective 27–68µH inductors while balancing EMI and efficiency. |
| Efficiency | >85% typical at 1.5A/3.3V output with 12V input-enabled by bootstrap-driven NPN switch reducing VCE(sat) to 0.59V. |
| Enable Thresholds | 2.0V min ON / 0.8V max OFF with hysteresis-ensures clean startup/shutdown under noisy supply conditions without external RC filtering. |
| Thermal Shutdown | 160°C junction trip-protects against sustained overload or poor thermal design; automatic recovery after cooldown. |
Pinout & Package
Package: 8-lead Power-SO-8 (SOP-8 M), thermally enhanced with exposed die-attach paddle connected to pins 2, 6, and 7 (GND). Requires ≥6 cm² copper ground plane for thermal management per Micrel Application Note.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch node (NPN emitter) | Connects to inductor and Schottky diode cathode; swings from –0.5V to VIN–VCE(sat); critical for EMI-sensitive routing. |
| 2, 6, 7 (GND) | Power and signal ground | Common return for input cap, output cap, and diode; must be tied directly to large ground plane-pins form low-impedance thermal path. |
| 3 (IN) | Input supply (NPN collector) | Accepts 4–30V unregulated input; connect input capacitor cathode as close as possible to minimize voltage spikes. |
| 4 (BS) | Bootstrap voltage node | Drives external 0.33µF/50V capacitor to generate gate drive >VIN-reduces VCE(sat) and improves efficiency. |
| 5 (FB) | Feedback input | Internally connected to 1.235V reference-no external divider needed for fixed 3.3V version; unused but must be left open or grounded per datasheet. |
| 8 (EN) | Enable input | TTL-compatible; logic high ≥2.0V enables regulator; logic low ≤0.8V reduces quiescent current to 150µA; tie to VIN if unused. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3V output | Eliminates external resistor network-reduces BOM count, layout area, and potential drift from resistor tolerance/temperature. |
| Integrated bootstrap driver | Supplies >5.5V bias to NPN base-lowers saturation voltage to 0.59V at 1A, enabling 2A output in SO-8 without heatsink. |
| Frequency foldback protection | Reduces switching frequency to 30–120kHz during short circuit-limits peak switch current and thermal stress during fault conditions. |
| Thermal shutdown with hysteresis | Trips at 160°C junction and holds off until cooldown-prevents thermal runaway while allowing safe auto-recovery in intermittent overload. |
| Wide input range with transient rating | Operates from 4V to 30V DC with 34V transient capability-suitable for automotive, industrial, and battery-backed systems without upstream clamping. |
Applications
| Industrial PLC I/O Module | Embedded Network Router |
|---|---|
|
Use Scenario: Powering FPGA I/O banks and microcontroller peripherals from 12V or 24V backplane rails in DIN-rail mounted controllers. IC Role / Device Role / Timing Role: Primary 3.3V point-of-load regulator delivering up to 2A with fast transient response to handle burst logic loads. Use Value: High efficiency (>85%) minimizes board heating in sealed enclosures; fixed output eliminates tuning effort during production calibration. |
Use Scenario: Generating stable 3.3V for Ethernet PHYs, switch ASICs, and DDR memory interfaces in fanless edge routers. IC Role / Device Role / Timing Role: Compact, thermally robust DC-DC converter replacing TO-220 solutions-fits dense 2-layer PCB layouts. Use Value: Power-SO-8 package with GND-connected paddle enables 2A operation at 60°C ambient without heatsink or airflow. |
| Medical Diagnostic Handheld | Automotive Infotainment Display |
|
Use Scenario: Converting 5V USB or battery-derived input to regulated 3.3V for ARM Cortex-M microcontrollers and sensor ADCs. IC Role / Device Role / Timing Role: Low-noise, enable-controlled power stage supporting sleep/wake sequencing and battery life optimization. Use Value: 150µA shutdown current extends battery runtime; EN hysteresis prevents false wake-up from supply ripple. |
Use Scenario: Supplying 3.3V to display timing controllers and touch ICs in 12V automotive systems subject to load dump transients. IC Role / Device Role / Timing Role: Input-transient-tolerant buck regulator with 34V absolute max rating-survives ISO 7637-2 pulse 5a without external TVS. Use Value: Integrated over-current and thermal protection ensures reliability in high-temperature dash environments (TA up to 85°C). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MIC24045-3.3WU | Pin-compatible 3.3V 3A buck with integrated MOSFETs; higher current, smaller 2mm×2mm QFN-12 package; requires external bootstrap capacitor. | Supports higher load currents and tighter space constraints; lacks feed-forward diode support for ultra-low headroom. | Select when >2A output or QFN thermal performance is required; verify PCB rework for QFN vs SO-8 footprint. |
| LM2675-3.3 | 5-pin SO-8 buck controller (no internal switch); requires external N-channel MOSFET and bootstrap circuit; 1.5A typical output. | Offers greater flexibility in FET selection and thermal layout; lower integration increases component count and layout complexity. | Select when discrete FET optimization (e.g., low RDS(on), high-speed switching) is prioritized over BOM simplicity. |
Compared with MIC4684-3.3BM TR, MIC24045-3.3WU delivers higher current in a smaller footprint but demands more careful layout for bootstrap stability, while LM2675-3.3 trades integration for design flexibility-neither offers the same combination of fixed 3.3V, 2A SO-8 integration, and feed-forward diode support.
Availability
MIC4684-3.3BM TR is available at Aetrix Electronics and suitable for industrial PLCs, embedded networking equipment, medical handhelds, and automotive infotainment displays requiring stable component supply with long lifecycle visibility.
Supply support for MIC4684-3.3BM TR 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
Micrel, Inc. was a U.S.-based analog and power management semiconductor company founded in 1978 and acquired by Microchip Technology in 2015; known for high-performance SuperSwitcher™ DC-DC regulators and precision analog ICs.
The MIC4684 family was designed as a high-efficiency, thermally optimized buck regulator series targeting space-constrained industrial and embedded applications where SO-8 integration replaces larger TO-220/TO-263 solutions.
FAQ
What is the maximum continuous output current of the MIC4684-3.3BM TR?
The MIC4684-3.3BM TR delivers 2A continuous output current at 60°C ambient temperature when mounted on a PCB with ≥6 cm² ground plane area. This rating assumes proper thermal design per Micrel's Power-SO-8 layout guidelines-exceeding this current without enhanced cooling risks thermal shutdown at 160°C junction temperature.
Does the MIC4684-3.3BM TR require external feedback resistors?
No, the MIC4684-3.3BM TR is a fixed-output variant with internal feedback divider set to 3.3V. Pin 5 (FB) is internally connected to the 1.235V reference and must be left unconnected or grounded per datasheet guidance-no external resistors are needed, simplifying design and improving output accuracy.
Can the MIC4684-3.3BM TR operate from a 5V input to deliver 3.3V output?
Yes, the MIC4684-3.3BM TR supports 4V–30V input, making it suitable for 5V-to-3.3V conversion. For optimal efficiency and stability at low input-to-output differentials, Micrel recommends adding a feed-forward diode from VIN to BS pin-reducing saturation losses and enabling reliable operation down to ~4.2V input.
What is the purpose of the bootstrap capacitor on pin 4 of the MIC4684-3.3BM TR?
The bootstrap capacitor (typically 0.33µF/50V) on pin 4 (BS) provides gate drive voltage exceeding VIN to the internal NPN transistor's base. This reduces saturation voltage (VCE(sat)) from ~1.8V to 0.59V, directly enabling higher efficiency and 2A output in the SO-8 package without external heatsinking.
How does the enable (EN) pin function on the MIC4684-3.3BM TR?
The EN pin is TTL-compatible: a logic high ≥2.0V enables regulation, while a logic low ≤0.8V places MIC4684-3.3BM TR in shutdown mode, reducing quiescent current to 150µA. Its built-in hysteresis prevents oscillation near threshold-no external pull-up is required, though tying EN to VIN is recommended if unused.
MIC4684-3.3BM TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- SuperSwitcher™
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 2A
- Frequency - Switching:
- 200kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MIC4684-3.3BM TR FAQ
1.How can I place an order for MIC4684-3.3BM TR through Aetrix?
Please submit a Request for Quotation (RFQ) for MIC4684-3.3BM TR 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 MIC4684-3.3BM TR reliable?
The price and inventory of MIC4684-3.3BM TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MIC4684-3.3BM TR is usually 5 days.
3.What payment methods are accepted for MIC4684-3.3BM TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC4684-3.3BM TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MIC4684-3.3BM TR?
MIC4684-3.3BM TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MIC4684-3.3BM TR 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 MIC4684-3.3BM TR?
For technical support, including MIC4684-3.3BM TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC4684-3.3BM TR requirements.
6.How does Aetrix verify that MIC4684-3.3BM TR is sourced from the original manufacturer or authorized distributors?
All MIC4684-3.3BM TR 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 MIC4684-3.3BM TR meets industry standards.
7.What is the process for return or replacement of MIC4684-3.3BM TR?
All MIC4684-3.3BM TR units undergo pre-shipment inspection (PSI). If there is an issue with MIC4684-3.3BM TR, 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 MIC4684-3.3BM TR part is unused and in its original packaging.
Return procedure for MIC4684-3.3BM TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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