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Texas Instruments LM2577M-ADJ
- Part No.:
- LM2577M-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
LM2577M-ADJ.pdf
- Description:
- IC REG BST FLYBACK ADJ 3A 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,260
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Product details
Overview
LM2577M-ADJ from Texas Instruments is a monolithic step-up (boost) switching voltage regulator IC featuring an integrated 3.0A NPN power switch, 52 kHz fixed-frequency oscillator, current-mode control, and adjustable output via external resistor divider. It operates from 3.5V to 40V input and delivers up to 60V output with internal current limit, thermal shutdown, and undervoltage lockout - used in industrial power supplies and battery-powered boost converters.
For engineers reviewing the LM2577M-ADJ datasheet, LM2577M-ADJ pinout, LM2577M-ADJ application, or LM2577M-ADJ equivalent, key selection criteria include its adjustable reference voltage (1.230 V), TO-263-5 (M) surface-mount package, 3.0A switch current rating, and compatibility with standard flyback/forward topologies requiring minimal external components.
Technical Context
The LM2577M-ADJ implements current-mode PWM control using an internal error amplifier with 800 V/V gain and 3700 μmho transconductance, comparing feedback voltage against a precision 1.230 V reference. Its 52 kHz oscillator drives the NPN switch with soft-start functionality to limit in-rush current during startup.
Protection circuitry includes undervoltage lockout (2.70–3.15 V threshold), thermal shutdown, and current limiting that restricts peak switch current to 3.0A under normal operation - critical for reliability in wide-input industrial and automotive auxiliary power designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output topology | Adjustable step-up (boost) DC-DC converter with external feedback resistors |
| Input voltage range | 3.5 V to 40 V - supports 12 V battery systems, wide-range industrial rails, and unregulated AC/DC inputs |
| Switch current rating | 3.0 A continuous - defines maximum inductor peak current and output power capability (~25 W typical) |
| Oscillator frequency | 52 kHz ±10% - enables use of low-cost, high-saturation-current inductors and reduces EMI filtering burden |
| Reference voltage | 1.230 V ±1.3% - sets output voltage accuracy when configured with R1/R2 feedback network per Figure 10 |
| Thermal resistance θJA | 100 °C/W (M package, 1 in² copper) - requires PCB thermal relief design for >1.5 W dissipation at full load |
| UVLO threshold | 2.70 V min / 3.15 V max - prevents erratic startup during brownout or cold-cranking conditions |
Pinout & Package
LM2577M-ADJ uses a 5-pin TO-263 (S) surface-mount package (Texas Instruments package code TS5B), with exposed metal tab thermally and electrically connected to Pin 2 (Ground). The package is optimized for high-power density and thermal performance on standard FR-4 PCBs.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: Input | Power input supply connection | Accepts 3.5–40 V DC; requires local ceramic bypass capacitor (≥100 nF) near pin |
| 2: Ground | Power and signal reference node | Internally tied to exposed thermal pad; must be soldered to ≥1 in² copper pour for thermal management |
| 3: Feedback | Resistor-divider input to error amplifier | Senses output voltage; sets regulated output as VOUT = 1.23 × (1 + R1/R2) |
| 4: Output | Collector of internal NPN switch | Drives external diode and inductor; voltage swings from VIN to ~65 V during off-time |
| 5: Compensation | Error amplifier output for loop stability | Connect RC network (e.g., 1 MΩ + 100 pF) to set phase margin and transient response |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 3.0A NPN switch | Eliminates need for external power transistor and driver, reducing BOM count and layout complexity |
| Current-mode control | Provides inherent cycle-by-cycle current limiting and improves line/load transient response without external compensation |
| Soft-start function | Reduces in-rush current by gradually increasing duty cycle over ~10 ms, preventing input rail collapse at startup |
| Fixed 52 kHz oscillator | Enables predictable EMI profile and simplifies filter design versus variable-frequency alternatives |
| Undervoltage lockout | Ensures clean startup only above 2.7 V, avoiding unstable operation during low-battery or power-up sequencing |
Applications
| Industrial Power Supply | Automotive Auxiliary Rail |
|---|---|
|
Use Scenario: Generating stable 24 V from 12 V vehicle battery in telematics modules. IC Role / Device Role / Timing Role: Primary boost controller regulating output via feedback pin; 52 kHz switching establishes timing baseline for passive component selection. Use Value: Enables compact, cost-effective 24 V rail without transformer-based isolation - critical for space-constrained infotainment ECUs. |
Use Scenario: Powering CAN transceivers and sensors from nominal 12 V battery with cold-crank tolerance down to 6 V. IC Role / Device Role / Timing Role: Adjustable-output boost regulator maintaining 5 V or 3.3 V despite input sag; UVLO ensures no dropout during cranking. Use Value: Delivers regulated voltage across wide input range (6–16 V), supporting robust operation in automotive environments. |
| Portable Instrumentation | LED Driver for Indicator Panels |
|
Use Scenario: Boosting single-cell Li-ion (3.0–4.2 V) to 5 V for microcontroller and analog front-end in handheld test equipment. IC Role / Device Role / Timing Role: High-efficiency step-up regulator with current-mode control ensuring stable output under dynamic load changes. Use Value: Achieves >80% efficiency at 800 mA load, extending battery life while minimizing thermal stress in sealed enclosures. |
Use Scenario: Driving series-connected white LEDs (12–18 V total VF) from 5 V logic rail in industrial HMI panels. IC Role / Device Role / Timing Role: Constant-voltage boost source with external current-setting resistor; switch saturation voltage (0.7 V max) minimizes conduction loss. Use Value: Provides precise, ripple-free LED current control without dedicated LED driver IC - lowering system cost and component count. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2577T-ADJ | Same die, TO-220-5 through-hole package; higher θJA (65 °C/W) limits power handling without heatsink | Better suited for prototyping or low-volume assemblies where manual soldering is preferred | Select when thermal budget allows larger footprint and mechanical mounting is required |
| MC34063AP | Lower switch current (1.5 A), 100 kHz oscillator, wider temp range (−40°C to +85°C); requires external NPN transistor for >1 A loads | More flexible for ultra-low-cost or multi-output designs but needs more external components | Choose when lower power (<10 W) and cost sensitivity outweigh integration benefits of LM2577M-ADJ |
Compared with LM2577T-ADJ, the LM2577M-ADJ offers superior thermal performance on PCBs with adequate copper area, while MC34063AP trades integration for broader operating temperature and design flexibility at reduced current capability.
Availability
LM2577M-ADJ is available at Aetrix Electronics and suitable for industrial power supplies, automotive auxiliary rails, portable instrumentation, and LED indicator panels requiring stable component supply and long-term production continuity.
Supply support for LM2577M-ADJ 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 high-reliability industrial solutions.
The LM2577 family was designed as part of TI's SIMPLE SWITCHER® portfolio to deliver easy-to-use, highly integrated DC-DC conversion for cost-sensitive and space-constrained applications across industrial, automotive, and consumer markets.
FAQ
What is the maximum output voltage achievable with LM2577M-ADJ?
The LM2577M-ADJ supports output voltages up to 60 V, limited by the 65 V switch voltage rating and safe operating area constraints. When configured with appropriate external components - including a Schottky diode rated ≥60 V and an inductor with sufficient saturation current - the device reliably regulates outputs such as 24 V, 36 V, or 48 V from lower input sources. Always verify thermal performance and switch stress at high VOUT/ILOAD combinations using TI's Switchers Made Simple design tool.
How does the feedback pin (Pin 3) determine output voltage in LM2577M-ADJ?
The LM2577M-ADJ uses an internal 1.230 V reference voltage applied to the error amplifier's inverting input. The feedback pin (Pin 3) connects to the junction of two external resistors (R1 and R2) forming a voltage divider from VOUT to GND. At regulation, the voltage at Pin 3 equals 1.230 V, so VOUT = 1.23 × (1 + R1/R2). For example, R1 = 48.7 kΩ and R2 = 5.62 kΩ yields ~12 V output, as specified in the LM2577M-ADJ test circuit (Figure 10).
Can LM2577M-ADJ be used in flyback or forward converter topologies?
Yes, the LM2577M-ADJ is explicitly designed for flyback and forward converter configurations per its datasheet description and Application Hints section. In flyback mode, it replaces the primary-side switch in isolated designs, using transformer coupling and optocoupler feedback for regulation. Its current-mode architecture and built-in protection features ensure stable operation across these topologies - unlike basic boost-only controllers. External component selection (e.g., transformer turns ratio, snubber network) must follow TI's recommended guidelines in SNOS658C.
What thermal considerations apply to LM2577M-ADJ in the TO-263 package?
The LM2577M-ADJ in the TO-263-5 (M) package has a junction-to-ambient thermal resistance (θJA) of 100 °C/W with 1 in² PCB copper. To maintain TJ ≤125 °C at full load, PCB layout must include direct soldering of the exposed thermal pad to ≥1 in² copper pour with multiple thermal vias. Without adequate copper, power dissipation is limited to ~1.25 W. For higher power, consider forced air cooling or derating based on measured board temperature rise.
Does LM2577M-ADJ require an external compensation network?
Yes, the LM2577M-ADJ requires an external RC network on the compensation pin (Pin 5) to stabilize the control loop. A typical configuration uses a 1 MΩ resistor and 100 pF capacitor between Pin 5 and ground, as recommended in TI's application notes. This network sets dominant pole location and phase margin - omitting it causes oscillation or poor transient response. The error amplifier's high transconductance (3700 μmho) makes proper compensation essential for reliable regulation across line and load variations.
LM2577M-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Boost, Flyback, Forward Converter
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.23V
- Voltage - Output (Max):
- 60V (Switch)
- Current - Output:
- 3A (Switch)
- Frequency - Switching:
- 52kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
LM2577M-ADJ FAQ
1.How can I place an order for LM2577M-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2577M-ADJ 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 LM2577M-ADJ reliable?
The price and inventory of LM2577M-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2577M-ADJ is usually 5 days.
3.What payment methods are accepted for LM2577M-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2577M-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2577M-ADJ?
LM2577M-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2577M-ADJ 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 LM2577M-ADJ?
For technical support, including LM2577M-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2577M-ADJ requirements.
6.How does Aetrix verify that LM2577M-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2577M-ADJ 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 LM2577M-ADJ meets industry standards.
7.What is the process for return or replacement of LM2577M-ADJ?
All LM2577M-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2577M-ADJ, 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 LM2577M-ADJ part is unused and in its original packaging.
Return procedure for LM2577M-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2577M-ADJ Tags
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