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Microchip Technology MIC4684YM
- Part No.:
- MIC4684YM
- Manufacturer:
- Microchip Technology
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MIC4684YM.pdf
- Description:
- IC REG BUCK ADJ 2A 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,385
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Product details
Overview
MIC4684YM from Micrel, Inc. is a 2A continuous-output, fixed-frequency (200 kHz) synchronous buck regulator in an 8-lead SO package, designed for high-efficiency step-down conversion from 4V–30V input to adjustable 1.235V output. It integrates an NPN power switch, bootstrap driver, and internal 1.235V bandgap reference, enabling compact, heatsink-free designs in industrial and embedded power supplies.
For engineers reviewing the MIC4684YM datasheet, MIC4684YM pinout, MIC4684YM application, or MIC4684YM equivalent, key selection criteria include its 2A output capability at 60°C ambient, 85%+ efficiency across load range, wide 4V–30V input with 34V transient tolerance, and thermal shutdown protection - all critical for reliable low-headroom DC/DC conversion.
Technical Context
The MIC4684YM uses voltage-mode PWM control with a 200 kHz oscillator and a 1.235 V ±2% internal bandgap reference. Its duty cycle is adjusted via feedback error amplifier comparison against a sawtooth waveform, supporting output regulation down to 1.235 V with external resistor divider.
It employs a bootstrap capacitor (pin 4) to elevate gate drive above VIN, reducing NPN saturation voltage to 0.59 V (typ.) and sustaining >85% efficiency without external heat sinking. Safety features include frequency-foldback short-circuit protection, over-current limiting at 2.2 A (typ.), and thermal shutdown at 160°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 2 A continuous at 60°C ambient - enables replacement of TO-220/TO-263 regulators in space-constrained PCBs |
| Input Voltage Range | 4 V to 30 V (34 V transient) - supports 5 V, 12 V, and 24 V rail inputs with robust transient immunity |
| Switching Frequency | 200 kHz (±12.5 kHz) - balances EMI performance and inductor size; folds back to 30–120 kHz under short circuit |
| Feedback Reference | 1.235 V ±2% - sets precise output voltage via external resistor divider; stable over –40°C to +125°C |
| Thermal Shutdown | 160°C junction - protects device during overload or poor thermal layout; recovers automatically after cooldown |
| Enable Threshold | 2.0 V min (ON), 0.8 V max (OFF) with hysteresis - ensures noise-immune TTL-compatible on/off control |
| Saturation Voltage | 0.59 V at 1 A - minimizes conduction loss and improves efficiency in low-VOUT applications (e.g., 1.8 V @ 2 A) |
Pinout & Package
Package: 8-lead SOP (M), also referred to as Power-SO-8 - features integrated thermal paddle connected to pins 2, 6, and 7 (GND) for enhanced heat dissipation (θJA = 75°C/W typical).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (SW) | Switch node (NPN emitter) | Connects to inductor and Schottky diode cathode; swings from –0.5 V to VIN – VCE(sat); critical for EMI-sensitive layout |
| 2, 6, 7 (GND) | Power and signal ground | Shared thermal and electrical return path; must be tied to large copper plane (>6 cm²) for thermal management and low-impedance current return |
| 3 (IN) | Main supply input (NPN collector) | Accepts 4–30 V unregulated input; connect input capacitor cathode here to minimize voltage spikes during switching |
| 4 (BS) | Bootstrap voltage node | Drives external bootstrap capacitor to generate gate bias > VIN; enables low VCE(sat) and high efficiency |
| 5 (FB) | Feedback input | Compares output voltage (via resistive divider) to 1.235 V reference; high-impedance (50 nA bias) for minimal divider loading |
| 8 (EN) | Enable logic input | TTL-compatible; pulls regulator into 150 µA shutdown state when <0.8 V; requires no pull-up if tied to VIN |
Key Features
| Feature | Design Value |
|---|---|
| Integrated bootstrap driver | Delivers 250–380 mA peak current to external capacitor, enabling efficient NPN saturation and eliminating need for external charge pump |
| Voltage-mode PWM control | Provides predictable loop response and stable operation with standard output capacitors; avoids subharmonic oscillation in continuous conduction mode |
| Frequency-foldback protection | Reduces switching frequency to 30–120 kHz during hard short, limiting energy per cycle and preventing thermal runaway |
| Internally compensated error amplifier | Enables fast transient response (<100 mV overshoot for 1 A step) without external compensation components |
| Wide operating junction temperature | Rated for –40°C to +125°C, with thermal shutdown at 160°C - suitable for automotive under-hood and industrial environments |
Applications
| Industrial PLC I/O Power | Embedded System Core Rail |
|---|---|
Use Scenario: Providing isolated 3.3 V/1.7 A power from 12 V bus in programmable logic controller modules. IC Role / Device Role / Timing Role: Primary buck regulator delivering tightly regulated core voltage with fast load-step response. Use Value: Achieves >88% efficiency at full load without heatsink, reducing board area and thermal design complexity. |
Use Scenario: Generating 1.8 V/2 A supply for FPGA or microprocessor core in network edge devices. IC Role / Device Role / Timing Role: Adjustable buck converter with feed-forward diode configuration for low headroom (4.2 V → 1.8 V). Use Value: Maintains regulation and 85%+ efficiency even at 10% duty cycle, enabling direct use of partially discharged battery rails. |
| Automotive Body Control Module | Test Equipment Auxiliary Supply |
Use Scenario: Converting 24 V vehicle battery (with 34 V load-dump transients) to 5 V/1.5 A for sensor interface circuitry. IC Role / Device Role / Timing Role: Input-transient-tolerant buck regulator with built-in overvoltage and thermal protection. Use Value: Eliminates need for upstream TVS or linear pre-regulator, simplifying BOM and improving system reliability. |
Use Scenario: Delivering stable 2.5 V/1.8 A output in portable benchtop test instruments powered by 6.5–23 V adapters. IC Role / Device Role / Timing Role: High-PSRR, low-noise adjustable buck stage supplying analog front-end and ADC reference rails. Use Value: Internal 1.235 V reference and low feedback bias current (50 nA) ensure <±1% output accuracy over line/load/temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MP2307DN-LF-Z | 3 A output, 340 kHz switching, MOSFET-based synchronous rectification; no bootstrap requirement | Better suited for higher-current, higher-frequency designs with lower quiescent current (260 µA vs. 6 mA) | Prefer MP2307DN-LF-Z when board space allows larger inductor and higher switching frequency is acceptable |
| LM2678SX-5.0/NOPB | Fixed 5 V output, 5 A capability, 260 kHz, external NPN switch; requires external diode and compensation | Designed for fixed-output, high-current applications where adjustable output is not required | Choose LM2678SX-5.0/NOPB only for cost-sensitive 5 V systems needing >2 A, accepting larger solution size |
Compared with MP2307DN-LF-Z and LM2678SX-5.0/NOPB, the MIC4684YM offers superior thermal performance in SO-8 due to its dedicated Power-SO-8 construction and integrated bootstrap, making it optimal for compact 2 A designs where layout area and thermal margin are constrained.
Availability
MIC4684YM is available at Aetrix Electronics and suitable for industrial PLCs, embedded computing power rails, automotive body electronics, test equipment auxiliary supplies, and battery-powered instrumentation requiring stable component supply and long-term lifecycle support.
Supply support for MIC4684YM 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 mixed-signal semiconductor company acquired by Microchip Technology in 2015; known for high-performance power management and timing solutions.
The MIC4684YM belongs to Micrel's SuperSwitcher™ family of integrated buck regulators, engineered specifically for high-current, low-profile DC/DC conversion in space- and thermally constrained industrial and embedded systems.
FAQ
What is the maximum continuous output current of the MIC4684YM at 85°C ambient?
The MIC4684YM delivers 2 A continuous output current at 60°C ambient temperature per datasheet specifications. At 85°C ambient, derating applies: based on θJA = 75°C/W and TJ(max) = 125°C, maximum sustainable output current drops to approximately 1.3 A assuming standard PCB layout with 6 cm² ground plane. The MIC4684YM must remain within its thermal limits to avoid activation of the 160°C thermal shutdown.
Can the MIC4684YM operate with a 3.3 V input voltage?
No - the MIC4684YM has a minimum input voltage of 4 V per Absolute Maximum Ratings and Operating Ratings. Operation below 4 V is not guaranteed and may result in failure to start or unstable regulation. For 3.3 V input applications, consider alternative regulators such as the MIC2280 or MP2101, which support lower VIN ranges. The MIC4684YM requires ≥4 V to properly bias its internal regulator and bootstrap circuitry.
Does the MIC4684YM require an external bootstrap capacitor, and what value is recommended?
Yes - the MIC4684YM requires an external ceramic bootstrap capacitor connected between BS (pin 4) and SW (pin 1). A 0.33 µF, 50 V X7R ceramic capacitor is specified in the Typical Application schematic and validated in evaluation boards. This value ensures sufficient charge storage to maintain gate drive during high-duty-cycle operation while minimizing ESR-related losses. The MIC4684YM will not function correctly without this capacitor.
How does the enable (EN) pin behave when left unconnected?
When the EN pin of the MIC4684YM is left floating, device behavior is undefined and may result in erratic startup or unintended shutdown due to noise coupling. The datasheet explicitly states: "connect the enable pin to the input if unused." Tying EN directly to VIN ensures reliable enablement with TTL-high logic level (>2.0 V), drawing only negligible current. Leaving EN unconnected violates recommended operating conditions and risks functional failure in noisy environments.
Is the MIC4684YM pin-compatible with the MIC4684BM variant?
Yes - the MIC4684YM and MIC4684BM share identical pinout, package (8-lead SOP-M), electrical specifications, and functional behavior. The sole difference is packaging compliance: MIC4684YM is the lead-free (Pb-free) version, while MIC4684BM is the standard leaded variant. Both operate identically across –40°C to +125°C junction temperature range and support the same input/output configurations. No PCB redesign is needed when substituting MIC4684YM for MIC4684BM.
MIC4684YM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- SuperSwitcher™
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 1.235V
- Voltage - Output (Max):
- 28.2V
- 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
MIC4684YM FAQ
1.How can I place an order for MIC4684YM through Aetrix?
Please submit a Request for Quotation (RFQ) for MIC4684YM 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 MIC4684YM reliable?
The price and inventory of MIC4684YM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MIC4684YM is usually 5 days.
3.What payment methods are accepted for MIC4684YM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC4684YM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MIC4684YM?
MIC4684YM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MIC4684YM 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 MIC4684YM?
For technical support, including MIC4684YM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC4684YM requirements.
6.How does Aetrix verify that MIC4684YM is sourced from the original manufacturer or authorized distributors?
All MIC4684YM 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 MIC4684YM meets industry standards.
7.What is the process for return or replacement of MIC4684YM?
All MIC4684YM units undergo pre-shipment inspection (PSI). If there is an issue with MIC4684YM, 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 MIC4684YM part is unused and in its original packaging.
Return procedure for MIC4684YM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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