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Microchip Technology MIC4576-3.3BU
- Part No.:
- MIC4576-3.3BU
- Manufacturer:
- Microchip Technology
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
MIC4576-3.3BU.pdf
- Description:
- IC REG BUCK 3.3V 3A TO263-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,756
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Product details
Overview
MIC4576-3.3BU from Microchip Technology is a fixed-output 3.3V, 3A step-down (buck) switching regulator with 200 kHz switching frequency, ±3% output voltage accuracy over line/load, 4V–36V input range, and thermal/overcurrent protection - designed for high-efficiency power conversion in embedded microprocessor supply rails.
For engineers reviewing the MIC4576-3.3BU datasheet, MIC4576-3.3BU pinout, MIC4576-3.3BU application, or MIC4576-3.3BU equivalent, this page delivers verified technical context, package-specific pin functions, real-world application mappings, and validated alternative options for industrial-grade DC-DC design.
Technical Context
The MIC4576-3.3BU integrates a BiCMOS 3A NPN switch, 1.23V bandgap reference, and 200 kHz oscillator to deliver fixed 3.3V regulation via internal feedback divider. Its cycle-by-cycle current limiting and thermal shutdown operate independently of external components.
It requires only five external parts (input/output capacitors, inductor, Schottky diode, and optional shutdown pull-up), supports standard inductors at 25% the size of LM2576 equivalents, and achieves up to 72% efficiency at 3A load with 12V input.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 3.3V ±3% over 6V–36V input and 0.5A–3A load - ensures stable core logic supply for Intel Pentium™ and similar microprocessors. |
| Switching Frequency | 200 kHz ±10% - enables smaller output filter inductors (e.g., 33 µH vs. 68–100 µH for 52 kHz regulators) without compromising EMI profile. |
| Input Voltage Range | 4V to 36V - supports wide industrial input sources including 12V/24V battery systems and unregulated wall adapters. |
| Max Switch Current | Guaranteed 3A - sustains full-rated output under worst-case thermal conditions (TJ ≤ +85°C) without derating. |
| Shutdown Current | <200 µA typical - reduces system standby power in battery-backed or energy-sensitive applications. |
| Efficiency | 72% typical at 3A, 12VIN → 3.3VOUT - minimizes heat generation and simplifies thermal management in enclosed enclosures. |
| Oscillator Accuracy | ±10% - ensures predictable timing for loop stability and consistent ripple frequency across temperature and voltage. |
Pinout & Package
Package: 5-Lead TO-263 (DDPAK), surface-mount, thermally enhanced with exposed tab (GND-connected). Pin 1 (VIN) is located at the leftmost lead when viewing top side with tab down.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - VIN | Unregulated input supply | Accepts 4V–36V DC; must be decoupled with ≥470 µF low-ESR capacitor near pin to suppress switching transients. |
| 2 - SW | Switch node output | Drives external inductor; connects to cathode of Schottky diode (e.g., MBR360); high dv/dt node requiring short PCB trace. |
| 3 & Tab - GND | Power and signal ground | Common return for input cap, output cap, feedback network, and thermal path; tab must be soldered to large copper pour for θJC = 2°C/W. |
| 4 - FB | Feedback input | Internally tied to 3.3V output divider; connect directly to regulated output; no external resistors required for fixed version. |
| 5 - SHDN | Enable/disable control | TTL-compatible logic input; <1.2V enables regulator, >2.4V disables; draws <30 µA when active, <200 µA in shutdown. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3V output with ±3% tolerance | Eliminates external resistor selection and layout sensitivity - critical for noise-sensitive digital core supplies. |
| 200 kHz fixed-frequency operation | Enables use of compact, off-the-shelf inductors (e.g., 33 µH) while maintaining predictable EMI filtering requirements. |
| Integrated thermal shutdown and cycle-by-cycle current limit | Provides autonomous fault recovery without external sensing circuitry - protects against short-circuit, overload, and heatsink failure. |
| TO-263 (DDPAK) package with exposed GND tab | Delivers 2°C/W junction-to-case thermal resistance - supports continuous 3A operation in ambient ≤+60°C with minimal heatsinking. |
| Low 200 µA shutdown current | Reduces system-level quiescent power in always-on subsystems such as real-time clocks or sensor wake-up circuits. |
Applications
| Intel Pentium™ Core Supply | Industrial 24V-to-3.3V Conversion |
|---|---|
Use Scenario: Powering 3.3V I/O and core logic of legacy x86 microprocessors in industrial controllers. IC Role / Device Role / Timing Role: Primary buck regulator delivering regulated 3.3V at up to 3A with fast transient response to CPU load steps. Use Value: Meets ±3% output accuracy requirement across 6V–36V input variation and 0.5A–3A dynamic load, ensuring reliable boot and operation. | Use Scenario: Converting 24V factory bus voltage to 3.3V for PLC I/O modules and fieldbus interface ICs. IC Role / Device Role / Timing Role: High-current, wide-input DC-DC stage replacing linear regulators to reduce heat and improve system efficiency. Use Value: Delivers 72% efficiency at full load, cutting dissipation by >7W versus LDO-based solutions - enabling fanless enclosure design. |
| Battery-Powered Test Equipment | Ruggedized Embedded Networking |
Use Scenario: Supplying 3.3V to MCU, ADC, and RF front-end in portable calibration tools powered by 12V Li-ion packs. IC Role / Device Role / Timing Role: Main power converter with enable control synchronized to measurement cycles to minimize idle current. Use Value: <200 µA shutdown current extends battery life during sleep mode; 4V–36V input accommodates pack voltage sag and charger transients. | Use Scenario: Providing isolated 3.3V rail for Ethernet PHYs and CAN transceivers in railway signaling hardware. IC Role / Device Role / Timing Role: Robust primary regulator operating across –40°C to +85°C with built-in overtemperature and overcurrent protection. Use Value: TO-263 package with 2°C/W θJC maintains safe junction temperature under sustained 3A load in sealed, high-ambient environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MIC4576-3.3WT | Same electrical specs, but in TO-220 through-hole package with higher θJA (65°C/W) and no exposed thermal tab. | Suitable for prototyping or low-volume boards where manual assembly or heatsink mounting is preferred. | Select MIC4576-3.3WT if board assembly uses through-hole process or requires mechanical heatsink attachment. |
| LM2576-3.3 | 52 kHz switching frequency, larger inductor requirement (≈2×), ±4% output tolerance, same 3A rating and 40V abs max input. | Legacy designs requiring drop-in replacement with existing 52 kHz filter layouts and lower EMI sensitivity. | Choose LM2576-3.3 only when reusing proven 52 kHz magnetics or when EMI constraints favor lower fundamental frequency. |
Compared with MIC4576-3.3WT and LM2576-3.3, the MIC4576-3.3BU offers superior thermal performance via its TO-263 package and higher efficiency due to 200 kHz operation - making it optimal for space-constrained, high-reliability industrial PCBs where thermal headroom and component count matter.
Availability
MIC4576-3.3BU is available at Aetrix Electronics and suitable for Intel Pentium™ core supply, industrial 24V-to-3.3V conversion, and ruggedized embedded networking requiring stable component supply across extended temperature and long production lifecycles.
Supply support for MIC4576-3.3BU 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
Microchip Technology is a global semiconductor company specializing in microcontrollers, analog devices, and power management ICs, with a focus on industrial, automotive, and aerospace reliability standards.
The MIC4576 product line delivers easy-to-use, high-current buck regulators targeting cost-sensitive, thermally demanding applications where minimal external components and robust protection are essential.
FAQ
What is the maximum input voltage rating for the MIC4576-3.3BU?
The MIC4576-3.3BU has an absolute maximum input voltage rating of +40V, with recommended continuous operation up to +36V. Exceeding +40V risks permanent damage. The device operates reliably across 4V–36V input range, supporting common industrial and battery-derived supplies. Always include input transient suppression (e.g., TVS diode) when using near the 40V limit.
Does the MIC4576-3.3BU require external feedback resistors?
No, the MIC4576-3.3BU does not require external feedback resistors. As a fixed-output variant, it integrates an internal resistive divider referenced to the 1.23V bandgap, connecting the FB pin directly to the 3.3V output. This eliminates resistor selection errors and improves accuracy versus adjustable versions - confirmed in Electrical Characteristics tables on pages 5 and 9 of DS20006158A.
What thermal performance can be expected from the MIC4576-3.3BU in a typical PCB layout?
In a standard 4-layer PCB with 2 oz copper and 4 cm² exposed GND pour under the TO-263 tab, the MIC4576-3.3BU achieves θJA ≈ 35°C/W. With its 2°C/W θJC, this allows continuous 3A operation at ambient temperatures up to +60°C. Thermal shutdown activates at +150°C junction temperature, providing safety margin even under partial airflow restriction.
Can the MIC4576-3.3BU be used in negative-output (inverting buck-boost) configurations?
Yes, the MIC4576-3.3BU supports positive-to-negative conversion per Figure 4-7 in DS20006158A. Its SW pin drives the inductor in standard buck topology, and with proper component reorientation (e.g., grounding the output and referencing FB to –3.3V), it generates regulated negative rails. Output polarity reversal requires careful attention to diode orientation and capacitor polarity - application note AN14 provides design equations.
What is the shutdown threshold voltage for the MIC4576-3.3BU SHDN pin?
The MIC4576-3.3BU SHDN pin turns the regulator on when voltage falls below 1.2V (typical VSDTH_ON) and turns it off when voltage rises above 1.4V (typical VSDTH_OFF). Input logic levels are TTL-compatible: VIH ≥ 2.4V disables the part, while VIL ≤ 0.8V enables it. This hysteresis prevents chatter during slow-rising control signals.
MIC4576-3.3BU Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Bulk
- 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):
- 36V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 3A
- Frequency - Switching:
- 200kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-263-5
MIC4576-3.3BU FAQ
1.How can I place an order for MIC4576-3.3BU through Aetrix?
Please submit a Request for Quotation (RFQ) for MIC4576-3.3BU 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 MIC4576-3.3BU reliable?
The price and inventory of MIC4576-3.3BU are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MIC4576-3.3BU is usually 5 days.
3.What payment methods are accepted for MIC4576-3.3BU?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC4576-3.3BU transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MIC4576-3.3BU?
MIC4576-3.3BU orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MIC4576-3.3BU 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 MIC4576-3.3BU?
For technical support, including MIC4576-3.3BU datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC4576-3.3BU requirements.
6.How does Aetrix verify that MIC4576-3.3BU is sourced from the original manufacturer or authorized distributors?
All MIC4576-3.3BU 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 MIC4576-3.3BU meets industry standards.
7.What is the process for return or replacement of MIC4576-3.3BU?
All MIC4576-3.3BU units undergo pre-shipment inspection (PSI). If there is an issue with MIC4576-3.3BU, 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 MIC4576-3.3BU part is unused and in its original packaging.
Return procedure for MIC4576-3.3BU:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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