My Inquiry
My Account
Microchip Technology LM2575-3.3WT
- Part No.:
- LM2575-3.3WT
- Manufacturer:
- Microchip Technology
- Package:
- TO-220-5
- Datasheet:
-
LM2575-3.3WT.pdf
- Description:
- IC REG BUCK 3.3V 1A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,302
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM2575-3.3WT from Micrel is a monolithic 52kHz fixed-frequency buck switching regulator delivering 3.3V at up to 1A output current, with ±3% output voltage tolerance over line and load, 4V–40V input range, and integrated thermal shutdown and cycle-by-cycle current limiting - used in on-card DC/DC conversion for industrial control and embedded power rails.
For engineers reviewing the LM2575-3.3WT datasheet, LM2575-3.3WT pinout, LM2575-3.3WT application, or LM2575-3.3WT equivalent, key selection criteria include guaranteed 1A output capability, TO-220 thermal performance (θJA = 65°C/W), 75% typical efficiency at 12VIN/1A, and compatibility with standard 330µH inductors and Schottky catch diodes.
Technical Context
The LM2575-3.3WT integrates a 52kHz oscillator, error amplifier, bandgap reference (1.23V), PWM comparator, and 1A NPN switch in a single TO-220 package. It operates in continuous conduction mode with internal frequency compensation and requires only four external components: input capacitor, output capacitor, inductor, and catch diode.
Feedback is internally connected to generate a fixed 3.3V output; no external resistors are needed. The ON/OFF pin enables logic-controlled shutdown with <200µA standby current, and protection includes thermal shutdown and peak current limiting at 1.7–3.2A.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±3% over 0.2–1A load and 8–40V input - ensures stable logic rail without trimming. |
| Max Output Current | 1A DC - supports microcontroller cores, FPGAs, and peripheral ICs without external current boosting. |
| Input Voltage Range | 4V to 40V - accommodates wide-input industrial supplies, automotive batteries (with transient margin), and unregulated wall adapters. |
| Switching Frequency | 52kHz ±10% - enables use of low-cost, off-the-shelf 330µH inductors and reduces EMI filtering complexity vs. MHz-range regulators. |
| Efficiency | 75% typical at 12VIN, 1A, 3.3VOUT - cuts heat dissipation by >50% versus linear regulators, often eliminating heatsinks. |
| Standby Current | <200µA when ON/OFF pin = 5V - enables low-power sleep modes in battery-backed or energy-conscious systems. |
| Thermal Resistance | θJA = 65°C/W (TO-220, minimal copper) - defines maximum power dissipation before thermal shutdown under natural convection. |
Pinout & Package
LM2575-3.3WT uses a 5-pin TO-220 package with exposed tab (pin 3) electrically connected to GND. The tab serves as primary thermal path and must be mounted to a heatsink or large copper pour for sustained 1A operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: VIN | Unregulated input supply connection | Accepts 4–40V DC; requires ≥100µF low-ESR input capacitor placed within 1 cm to minimize switching noise coupling. |
| 2: OUTPUT | Switch node and regulated output source | Drives inductor; connects to cathode of Schottky catch diode (e.g., MBR360); high di/dt node requiring short PCB traces. |
| 3: GND | Power ground and thermal tab | Common return for input/output capacitors and catch diode; tab must be soldered to ≥4 in² copper for θJA = 45°C/W. |
| 4: FEEDBACK | Internal voltage sense node | Internally tied to 3.3V reference; not accessible - no external resistor divider required for fixed-output operation. |
| 5: ON/OFF | Logic-controlled enable/disable input | Active-high: ≥2.2V enables regulation; ≤1.0V disables switch and reduces quiescent current to <200µA. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3V output | Eliminates feedback resistor network - reduces BOM count, layout area, and calibration risk in volume production. |
| Integrated 1A NPN switch | Removes need for external MOSFET and gate driver - simplifies design and improves reliability in space-constrained applications. |
| 52kHz fixed-frequency operation | Enables predictable EMI spectrum and use of low-cost, high-saturation-current inductors (e.g., 330µH, 2A). |
| Cycle-by-cycle current limit | Prevents destructive overcurrent during short-circuit or startup - sustains safe operation without external current-sense circuitry. |
| Thermal shutdown | Automatically disables regulator if junction temperature exceeds ~150°C - protects device and system during overload or poor heatsinking. |
Applications
| Industrial PLC I/O Module Power | Embedded Microcontroller Core Supply |
|---|---|
|
Use Scenario: Providing clean 3.3V power to digital I/O banks in programmable logic controllers operating from 24V DC field buses. IC Role / Device Role / Timing Role: Primary step-down regulator converting 24V bus to isolated 3.3V logic rail with ripple <100mVPP. Use Value: Replaces linear regulators to eliminate 20W+ heat dissipation, enabling fanless enclosure design and extended MTBF. |
Use Scenario: Powering ARM Cortex-M4 microcontrollers and associated peripherals (ADC, SPI, USB PHY) in portable test equipment. IC Role / Device Role / Timing Role: Main system regulator delivering 1A at 3.3V with fast load transient response (<100µs settling). Use Value: Achieves 75% efficiency at full load - extends battery life by >2× versus linear alternatives in 12V battery-powered units. |
| Automotive Body Control Unit (BCU) | Point-of-Load Converter for FPGA Config Rail |
|
Use Scenario: Generating 3.3V for CAN transceivers and sensor interfaces in 12V automotive body electronics with cold-crank tolerance. IC Role / Device Role / Timing Role: Input-capable down to 4V - maintains regulation during engine cranking (6.5V min) without brownout. Use Value: Wide 4–40V input range eliminates need for pre-regulator stage, reducing component count and board space in cost-sensitive modules. |
Use Scenario: Supplying configuration voltage to Xilinx Spartan-7 FPGA bank requiring stable 3.3V at up to 800mA during bitstream loading. IC Role / Device Role / Timing Role: Fixed-output buck converter with <2% output deviation across temperature and load - meets FPGA VCCO spec. Use Value: ±3% output tolerance and low 100mV ripple ensure reliable FPGA configuration and I/O initialization without retry cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2575-3.3T | Same electrical specs and TO-220 package, but non-RoHS compliant (lead-based solder compatible); no "W" suffix. | Approved for legacy industrial systems requiring Pb-containing assembly processes. | Select LM2575-3.3T only if RoHS exemption for high-melting-point solder is not required and legacy qualification applies. |
| MP1584EN-LF-Z | 40V input, 3A output, 1.5MHz switching - smaller magnetics but higher EMI; no integrated thermal pad. | Better suited for compact, high-density layouts where size outweighs EMI filter cost. | Choose MP1584EN-LF-Z when board space is critical and 1.5MHz EMI can be managed; LM2575-3.3WT remains preferred for robustness and thermal margin. |
Compared with LM2575-3.3T and MP1584EN-LF-Z, the LM2575-3.3WT offers superior thermal management via its exposed GND tab, proven 52kHz noise profile for industrial environments, and drop-in compatibility with existing TO-220 heatsink footprints - making it optimal for reliability-first designs.
Availability
LM2575-3.3WT is available at Aetrix Electronics and suitable for industrial control systems, embedded microcontroller power supplies, and automotive body electronics requiring stable component supply, long-term lifecycle support, and RoHS-compliant manufacturing.
Supply support for LM2575-3.3WT 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
Micrel Inc. was a U.S.-based analog and mixed-signal semiconductor company headquartered in San Jose, CA, specializing in power management, timing, and interface solutions before its acquisition by Microchip Technology in 2015.
The LM2575 series was designed as a drop-in, high-efficiency replacement for three-terminal linear regulators - targeting cost-sensitive, thermally constrained applications in industrial, telecom, and consumer power supplies.
FAQ
What is the maximum input voltage rating for the LM2575-3.3WT?
The LM2575-3.3WT has an absolute maximum input voltage of 45V, with recommended continuous operation up to 40V. Exceeding 40V risks violating the specified operating conditions and may trigger overvoltage stress on internal circuitry, even if thermal limits are not exceeded. Always include input transient suppression (e.g., TVS diode) for automotive or industrial inputs.
Does the LM2575-3.3WT require external feedback resistors?
No, the LM2575-3.3WT does not require external feedback resistors. Its 3.3V output is internally trimmed and fixed; the FB pin is not accessible for adjustment. This differs from the adjustable LM2575 variant, which uses pins 4 (FB) and 3 (GND) to set output via resistor dividers - a configuration not applicable to the LM2575-3.3WT.
Can the LM2575-3.3WT drive a 1A load continuously at 40V input?
Yes, the LM2575-3.3WT is rated for 1A continuous output current across its full input range (4–40V), but thermal design is critical at high VIN. At 40V input and 3.3V/1A output, power dissipation exceeds 36W - requiring substantial heatsinking (e.g., ≥12 in² copper + finned heatsink) to maintain junction temperature below 125°C. Derating is recommended above 24V input for unassisted convection cooling.
What is the purpose of the ON/OFF pin on the LM2575-3.3WT?
Pin 5 (ON/OFF) provides logic-level enable/disable control for the LM2575-3.3WT. Driving it to ≥2.2V (VIH min) enables regulation; pulling it to ≤1.0V (VIL max) disables the internal switch and reduces quiescent current to <200µA. This allows system-level power sequencing and low-power sleep states without removing input voltage.
Which catch diode is recommended for use with the LM2575-3.3WT?
The LM2575-3.3WT datasheet specifies the MBR360 Schottky diode (3A, 60V, ~0.55V VF) as the reference part. Its low forward voltage minimizes conduction loss and improves efficiency, while its fast recovery avoids reverse-recovery spikes. For 1A operation, diodes rated ≥2A average current and ≥60V PIV (e.g., SS34, SB360) are acceptable alternatives if thermal and layout constraints permit.
LM2575-3.3WT 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):
- 40V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 1A
- Frequency - Switching:
- 52kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-5
LM2575-3.3WT FAQ
1.How can I place an order for LM2575-3.3WT through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2575-3.3WT 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 LM2575-3.3WT reliable?
The price and inventory of LM2575-3.3WT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2575-3.3WT is usually 5 days.
3.What payment methods are accepted for LM2575-3.3WT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2575-3.3WT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2575-3.3WT?
LM2575-3.3WT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2575-3.3WT 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 LM2575-3.3WT?
For technical support, including LM2575-3.3WT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2575-3.3WT requirements.
6.How does Aetrix verify that LM2575-3.3WT is sourced from the original manufacturer or authorized distributors?
All LM2575-3.3WT 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 LM2575-3.3WT meets industry standards.
7.What is the process for return or replacement of LM2575-3.3WT?
All LM2575-3.3WT units undergo pre-shipment inspection (PSI). If there is an issue with LM2575-3.3WT, 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 LM2575-3.3WT part is unused and in its original packaging.
Return procedure for LM2575-3.3WT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2575-3.3WT Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
