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Microchip Technology MIC4576-3.3WT
- Part No.:
- MIC4576-3.3WT
- Manufacturer:
- Microchip Technology
- Package:
- TO-220-5
- Datasheet:
-
MIC4576-3.3WT.pdf
- Description:
- IC REG BUCK 3.3V 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,888
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Product details
Overview
MIC4576-3.3WT from Microchip Technology is a fixed-output 3.3V, 3A step-down (buck) switching regulator in TO-220 package, operating at 200 kHz with ±3% output voltage accuracy over 6V–36V input and 0.5A–3A load, designed for Intel Pentium™-class microprocessor power rails and industrial DC-DC conversion.
For engineers reviewing the MIC4576-3.3WT datasheet, MIC4576-3.3WT pinout, MIC4576-3.3WT application, or MIC4576-3.3WT equivalent, key selection criteria include guaranteed 3A switch current, thermal shutdown protection, <200 µA shutdown current, 72% typical efficiency at 3A, and compatibility with standard inductors-critical for high-reliability embedded power designs.
Technical Context
The MIC4576-3.3WT integrates a BiCMOS NPN power switch, 1.23V bandgap reference, and fixed-gain error amplifier to regulate output via duty-cycle control of a 200 kHz oscillator. Its internal compensation eliminates external compensation components.
It features cycle-by-cycle current limiting, thermal shutdown at +150°C junction temperature, TTL-compatible SHDN logic interface (1.2V turn-on / 1.4V turn-off), and operates across –40°C to +85°C industrial temperature range with 65°C/W junction-to-air thermal resistance in TO-220 package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 3.3V ±3% (3.168V–3.432V) across 6V–36V input and 0.5A–3A load - ensures stable core voltage for 3.3V logic systems. |
| Switch Current | Guaranteed 3A peak switch current - supports continuous 3A load without derating under thermal limits. |
| Switching Frequency | 200 kHz ±10% - enables smaller output filter inductors (e.g., 33 µH vs. larger values in 52 kHz LM2576). |
| Efficiency | 72% typical at 3A load - reduces heat generation and improves system-level power budget in compact enclosures. |
| Shutdown Current | <200 µA typical (50 µA typical) - minimizes standby power in battery-backed or energy-sensitive applications. |
| Input Voltage Range | 4V to 36V - accommodates wide-input industrial supplies, automotive transients, and unregulated DC bus rails. |
| Thermal Protection | Thermal shutdown at +150°C junction temperature with 2°C/W junction-to-case resistance - prevents catastrophic failure during overload. |
Pinout & Package
Package: 5-Lead TO-220 (T), with exposed tab electrically connected to GND; suitable for through-hole mounting and heatsink attachment via tab.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: VIN | Unregulated input supply | Accepts +4V to +36V; must be decoupled with ≥470 µF low-ESR capacitor near pin for stability. |
| 2: SW | Switch node output | Drives external inductor and Schottky diode; high dv/dt node requiring short PCB trace routing. |
| 3 & Tab: GND | Power and signal ground reference | Common return path for input capacitor, output capacitor, feedback network, and heatsink thermal interface. |
| 4: FB | Feedback input | Internally tied to fixed 3.3V divider; connect directly to output for regulation - no external resistors required. |
| 5: SHDN | Enable/disable control | TTL-compatible input; ≤0.8V enables regulator, ≥2.4V disables it - allows system-level power sequencing. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3V output | Eliminates external feedback resistors, reducing BOM count and layout complexity for dedicated 3.3V rails. |
| 200 kHz switching frequency | Enables use of standard 33 µH inductors - cuts inductor size by ~50% versus legacy 52 kHz regulators like LM2576. |
| Integrated thermal shutdown | Automatically disables switching when junction exceeds +150°C - protects against sustained overload or poor heatsinking. |
| Cycle-by-cycle current limit | Clamps peak switch current to ≥4.2A - prevents MOSFET or inductor saturation during short-circuit or startup. |
| Low shutdown current | 50 µA typical shutdown quiescent current - extends battery life in always-on monitoring or backup power systems. |
Applications
| Intel Pentium™ Core Power | Industrial 24V-to-3.3V Conversion |
|---|---|
|
Use Scenario: Providing clean, regulated 3.3V supply to Intel Pentium™ and compatible microprocessors in embedded controllers. IC Role / Device Role / Timing Role: Primary step-down regulator delivering up to 3A continuous current with tight ±3% output tolerance. Use Value: Eliminates need for post-regulation LDOs; supports full CPU load without voltage droop or thermal throttling. |
Use Scenario: Converting 24V industrial bus to 3.3V for PLC I/O modules, sensor interfaces, and fieldbus transceivers. IC Role / Device Role / Timing Role: High-efficiency buck converter handling wide input transients (6V–36V) and load steps. Use Value: 72% efficiency at 3A reduces thermal stress in sealed enclosures; TO-220 tab enables direct heatsink mounting. |
| Battery Charger Pre-Regulator | POS Terminal Power Supply |
|
Use Scenario: Preregulating variable battery voltage (e.g., 8V–28V LiFePO₄ pack) before linear charging ICs. IC Role / Device Role / Timing Role: Efficient intermediate-stage buck regulator improving overall charger efficiency and thermal management. Use Value: Reduces power dissipation in downstream linear regulators by >60% compared to direct battery-to-3.3V linear drop. |
Use Scenario: Generating 3.3V rail for payment terminal logic, display, and secure element in retail POS systems. IC Role / Device Role / Timing Role: Single-chip 3.3V supply with shutdown control for low-power sleep mode. Use Value: <200 µA shutdown current enables multi-year battery backup; robust ESD and thermal protection ensure field reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MIC4576-3.3WU | Same electrical specs but in TO-263 (DDPAK) surface-mount package; θJC = 2°C/W identical, but θJA = 65°C/W same as TO-220. | Required for SMT production; lacks through-hole mounting and manual heatsink interface of TO-220. | Select MIC4576-3.3WU when board space or automated assembly mandates surface-mount packaging. |
| LM2576-3.3 | 52 kHz operation, larger inductor requirement (≈2×), ±4% output tolerance, higher dropout voltage, no integrated SHDN pin. | Suitable for cost-sensitive, lower-frequency designs where size and efficiency are secondary to legacy compatibility. | Choose LM2576-3.3 only if redesign is impractical and 200 kHz noise or inductor size is not critical. |
Compared with MIC4576-3.3WU and LM2576-3.3, the MIC4576-3.3WT delivers superior efficiency, tighter regulation, and built-in enable control in a serviceable through-hole package - making it optimal for industrial upgrades and new designs prioritizing thermal performance and design simplicity.
Availability
MIC4576-3.3WT is available at Aetrix Electronics and suitable for Intel Pentium™ power delivery, industrial 24V-to-3.3V conversion, and battery-powered terminal equipment requiring stable component supply across extended product lifecycles.
Supply support for MIC4576-3.3WT 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 provider of microcontrollers, analog devices, and power management ICs, with leadership in embedded control and energy-efficient power solutions.
The MIC4576 series was engineered as a pin-compatible, higher-frequency upgrade to the LM2576 for industrial and computing power applications - emphasizing ease-of-use, minimal external components, and robust thermal protection.
FAQ
What is the maximum input voltage rating for the MIC4576-3.3WT?
The MIC4576-3.3WT has an absolute maximum input voltage rating of +40V, with recommended operating input range of +4V to +36V. Exceeding +40V risks permanent damage; operation above +36V voids guaranteed performance specifications including output regulation and thermal behavior. Always include transient voltage suppression on VIN in automotive or industrial environments.
Does the MIC4576-3.3WT require external feedback resistors?
No, the MIC4576-3.3WT does not require external feedback resistors. It integrates an internal resistive divider calibrated for 3.3V output; the FB pin must be connected directly to the output node. Adding external resistors will disrupt regulation and cause output voltage deviation beyond the specified ±3% tolerance.
What inductor value is recommended for the MIC4576-3.3WT in a 6V–24V input application?
For 6V–24V input to 3.3V/3A output, Microchip recommends a 33 µH shielded power inductor (e.g., Coiltronics PL52C-33-1000 or BI Magnetics HM77-30004) with DCR ≤ 0.045Ω. This value balances ripple current (<30% of IOUT), efficiency (>72%), and physical size - validated in Figures 4-1 and 4-2 of DS20006158A.
How does the SHDN pin function on the MIC4576-3.3WT?
The SHDN pin on the MIC4576-3.3WT is TTL-compatible: logic low (≤0.8V) enables regulation, while logic high (≥2.4V) disables switching and reduces quiescent current to <200 µA. The turn-on threshold is 1.2V and turn-off is 1.4V; leaving SHDN unconnected or floating may cause erratic operation - tie to GND or VCC via resistor if unused.
Can the MIC4576-3.3WT be used in parallel for higher current capability?
Yes, the MIC4576-3.3WT supports parallel operation as documented in Figure 4-6 of DS20006158A. Two units can deliver up to 4A with proper current-sharing design: matched inductors, shared output capacitors, and synchronized SHDN control. However, phase interleaving is not supported - output ripple increases without careful layout and component matching.
MIC4576-3.3WT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- TO-220-5
- Packaging:
- Tube
- Product Status:
- Active
- 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:
- Through Hole
- Supplier Device Package:
- TO-220-5
MIC4576-3.3WT FAQ
1.How can I place an order for MIC4576-3.3WT through Aetrix?
Please submit a Request for Quotation (RFQ) for MIC4576-3.3WT 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 MIC4576-3.3WT reliable?
The price and inventory of MIC4576-3.3WT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MIC4576-3.3WT is usually 5 days.
3.What payment methods are accepted for MIC4576-3.3WT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MIC4576-3.3WT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MIC4576-3.3WT?
MIC4576-3.3WT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MIC4576-3.3WT 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 MIC4576-3.3WT?
For technical support, including MIC4576-3.3WT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MIC4576-3.3WT requirements.
6.How does Aetrix verify that MIC4576-3.3WT is sourced from the original manufacturer or authorized distributors?
All MIC4576-3.3WT 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 MIC4576-3.3WT meets industry standards.
7.What is the process for return or replacement of MIC4576-3.3WT?
All MIC4576-3.3WT units undergo pre-shipment inspection (PSI). If there is an issue with MIC4576-3.3WT, 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 MIC4576-3.3WT part is unused and in its original packaging.
Return procedure for MIC4576-3.3WT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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