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Texas Instruments LM2577T-12/NOPB
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- Part No.:
- LM2577T-12/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-5
- Datasheet:
-
LM2577T-12/NOPB.pdf
- Description:
- IC REG BST FLYBCK 12V 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,296
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Product details
Overview
LM2577T-12/NOPB from Texas Instruments is a monolithic step-up (boost) switching voltage regulator with fixed 12 V output, integrated 3.0 A NPN switch, 52 kHz oscillator, and current-mode control. It operates from 3.5 V to 40 V input, delivers up to 800 mA load current, and includes undervoltage lockout, thermal shutdown, and current limiting-used in industrial power supplies and battery-powered instrumentation.
For engineers reviewing the LM2577T-12/NOPB datasheet, LM2577T-12/NOPB pinout, LM2577T-12/NOPB application, or LM2577T-12/NOPB equivalent, key selection criteria include input voltage range compatibility, output current capability under thermal constraints, TO-220 package thermal resistance (θJA = 65°C/W), and fixed-output vs. adjustable topology trade-offs.
Technical Context
The LM2577T-12/NOPB implements current-mode control using an internal error amplifier with 12 V reference (for fixed-output variants), comparator, and 52 kHz oscillator to regulate output by modulating peak inductor current. Its NPN switch features 65 V breakdown voltage and 0.7 V saturation voltage at 2.0 A.
It supports boost, flyback, and forward converter topologies. The feedback pin is internally connected to the 12 V reference, eliminating external resistor dividers-unlike the ADJ variant-simplifying design for fixed-voltage applications requiring minimal external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12 V ±4% over 100–800 mA load and 3.5–10 V input; enables direct replacement of linear regulators in 12 V rail generation. |
| Input Voltage Range | 3.5 V to 40 V; supports wide-input industrial and automotive battery-supplied systems without pre-regulation. |
| Switch Current Rating | 3.0 A continuous (6.0 A absolute max); defines maximum inductor peak current and limits achievable output power at low input voltages. |
| Oscillator Frequency | 52 kHz (±8% over temperature); determines inductor size and EMI profile-lower than 100+ kHz ICs, easing filter design but increasing passive size. |
| Thermal Resistance | θJA = 65°C/W (TO-220 package); requires ≥1 in² copper pour for full 3.0 A operation at ambient ≤70°C per derating curves. |
| Protection Features | Integrated undervoltage lockout (2.7–3.1 V threshold), thermal shutdown, and current limiting-eliminates need for external fault management circuitry. |
Pinout & Package
LM2577T-12/NOPB uses a 5-lead TO-220 (T) package (NS package code T05A) with exposed tab electrically connected to Pin 2 (Ground). The tab must be thermally and electrically tied to PCB ground plane for proper thermal performance and safety.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: Input | Power input (VIN) | Accepts 3.5–40 V DC; requires local 100 μF low-ESR capacitor near pin for stability and transient response. |
| 2: Ground | Power and signal reference | Common return for input, output, feedback, and internal circuits; connects to exposed tab for thermal conduction. |
| 3: Feedback | Output voltage sense | Internally tied to 12 V reference-no external divider needed; open-circuit or short-circuit disables regulation. |
| 4: Switch | NPN collector output | Drives external inductor/diode; switches at 52 kHz; must withstand up to 65 V off-state voltage during boost operation. |
| 5: Output | Regulated 12 V supply | Delivers up to 800 mA; requires ≥680 μF output capacitor (low-ESR electrolytic) for ripple suppression and load transient response. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 3.0 A NPN switch | Enables single-chip boost conversion without external MOSFET driver or discrete transistor-reduces BOM count and layout complexity. |
| Current-mode control | Provides inherent cycle-by-cycle current limiting, improves line/load transient response, and simplifies loop compensation vs. voltage-mode designs. |
| 52 kHz fixed-frequency oscillator | Eliminates external timing components; ensures predictable EMI spectrum and simplifies input/output filter design with standard inductors. |
| Soft-start function | Reduces inrush current during startup by gradually increasing duty cycle-prevents input rail collapse and output overshoot in capacitive-loaded systems. |
| Undervoltage lockout (UVLO) | Disables operation below ~2.7 V input, preventing erratic switching and ensuring clean startup when input rises above valid operating range. |
Applications
| Industrial Power Supply | Portable Test Equipment |
|---|---|
|
Use Scenario: Generating stable 12 V rail from 5 V or 9 V battery or adapter in handheld multimeters and oscilloscope front-ends. IC Role / Device Role / Timing Role: Primary DC-DC boost regulator providing isolated, regulated 12 V for analog front-end and display drivers. Use Value: Eliminates need for bulky 12 V wall adapters; maintains regulation across battery discharge (6–9 V), extending runtime without voltage sag. |
Use Scenario: Powering 12 V relays, sensors, and signal conditioning circuits in field-deployable data loggers with Li-ion or alkaline inputs. IC Role / Device Role / Timing Role: Fixed-output step-up controller managing energy transfer via external inductor and Schottky diode in non-isolated boost stage. Use Value: Delivers consistent 12 V at up to 800 mA while surviving cold cranking (≥3.5 V) and hot idle (≤40 V) in mobile instrumentation. |
| Automotive Aftermarket Module | Legacy Industrial Control |
|
Use Scenario: Upgrading 5 V microcontroller-based CAN gateways to drive 12 V CAN transceivers and optocouplers from vehicle 12 V system. IC Role / Device Role / Timing Role: Input-tolerant boost regulator converting noisy 9–16 V automotive rail to clean, regulated 12 V for interface ICs. Use Value: Withstands load dump transients up to 40 V input and provides UVLO hysteresis to prevent brownout resets during engine cranking. |
Use Scenario: Replacing aging linear regulators in PLC I/O modules where 24 V field power must generate internal 12 V logic rails. IC Role / Device Role / Timing Role: High-current, thermally robust switching regulator replacing inefficient 7812 in space-constrained DIN-rail enclosures. Use Value: Achieves >80% efficiency at 500 mA-cutting heat sink requirements by >60% versus linear solution-while maintaining TO-220 mounting compatibility. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-up regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2577T-15/NOPB | Fixed 15 V output; identical pinout, package, and electrical specs except reference voltage and load regulation bounds. | Requires redesign of downstream 12 V loads or LDO post-regulation; unsuitable where exact 12 V is mandated (e.g., RS-232 drivers). | Select only if system tolerates 15 V or uses external LDO; verify thermal margin remains sufficient at higher VOUT/VIN ratio. |
| MC34063AP1G | 3.0 A switch, 100 kHz oscillator, wider input (3–40 V), but requires external feedback resistors and has lower efficiency (~75%) at 12 V/500 mA. | Better high-frequency EMI performance but needs more external components; lacks integrated soft-start and tighter UVLO hysteresis. | Prefer for cost-sensitive, space-tolerant designs needing flexibility; avoid where board area or startup reliability is critical. |
Compared with LM2577T-12/NOPB, LM2577T-15/NOPB offers identical form-factor and protection but mismatches 12 V system requirements, while MC34063AP1G trades integration for frequency and configurability-making LM2577T-12/NOPB optimal for fixed 12 V, low-component-count, thermally constrained boost applications.
Availability
LM2577T-12/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, portable test equipment, and automotive aftermarket modules requiring stable component supply with long lifecycle support.
Supply support for LM2577T-12/NOPB 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
Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in power management ICs and industrial-grade reliability.
The LM2577 family was designed for cost-effective, robust DC-DC conversion in non-isolated boost, flyback, and forward topologies-targeting industrial, automotive, and instrumentation applications where simplicity and thermal resilience are critical.
FAQ
What is the maximum output current capability of the LM2577T-12/NOPB?
The LM2577T-12/NOPB delivers up to 800 mA continuous output current under typical conditions (VIN = 5 V, TA = 25°C, with adequate PCB copper). At higher ambient temperatures or lower input voltages, output current must be derated per the thermal resistance (θJA = 65°C/W) and maximum junction temperature (125°C). The internal 3.0 A switch supports peak inductor currents required for this output level in boost configuration.
Does the LM2577T-12/NOPB require external feedback resistors?
No. The LM2577T-12/NOPB has the feedback network internally configured for a fixed 12 V output-Pin 3 (Feedback) is internally connected to the 12 V reference. Unlike the LM2577T-ADJ variant, no external resistors are needed, reducing component count and layout sensitivity. Leaving Pin 3 unconnected or shorting it disrupts regulation.
Can the LM2577T-12/NOPB operate from a 3.3 V input source?
No. The LM2577T-12/NOPB has a minimum input voltage of 3.5 V per its operating ratings. At 3.3 V, undervoltage lockout activates and the device remains disabled. For 3.3 V input applications, consider the LM2577T-ADJ with appropriate feedback divider or alternative low-VIN boost regulators such as the TPS61040.
What package type does the LM2577T-12/NOPB use, and how is thermal management handled?
The LM2577T-12/NOPB uses a 5-lead TO-220 (T) package (NS code T05A) with the exposed tab electrically and thermally connected to Pin 2 (Ground). Effective thermal management requires soldering the tab to ≥1 square inch of PCB copper pour tied to ground. Without this, junction temperature exceeds 125°C at full load, triggering thermal shutdown.
Is the LM2577T-12/NOPB suitable for flyback converter designs?
Yes. The LM2577T-12/NOPB supports flyback topology per its datasheet, leveraging the same 3.0 A NPN switch and current-mode control. However, the fixed 12 V feedback connection limits output voltage adjustability-flyback designs requiring variable or isolated outputs should use the LM2577T-ADJ variant with external feedback network and transformer turns ratio optimization.
LM2577T-12/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-220-5
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Boost, Flyback, Forward Converter
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 12V
- Voltage - Output (Max):
- -
- Current - Output:
- 3A (Switch)
- 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
LM2577T-12/NOPB FAQ
1.How can I place an order for LM2577T-12/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2577T-12/NOPB 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 LM2577T-12/NOPB reliable?
The price and inventory of LM2577T-12/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2577T-12/NOPB is usually 5 days.
3.What payment methods are accepted for LM2577T-12/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2577T-12/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2577T-12/NOPB?
LM2577T-12/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2577T-12/NOPB 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 LM2577T-12/NOPB?
For technical support, including LM2577T-12/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2577T-12/NOPB requirements.
6.How does Aetrix verify that LM2577T-12/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2577T-12/NOPB 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 LM2577T-12/NOPB meets industry standards.
7.What is the process for return or replacement of LM2577T-12/NOPB?
All LM2577T-12/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2577T-12/NOPB, 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 LM2577T-12/NOPB part is unused and in its original packaging.
Return procedure for LM2577T-12/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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