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Texas Instruments LM2577N-ADJ/NOPB
- Part No.:
- LM2577N-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- 16-DIP (0.300", 7.62mm)
- Datasheet:
-
LM2577N-ADJ/NOPB.pdf
- Description:
- IC REG BST FLYBACK ADJ 3A 16PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,503
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Product details
Overview
LM2577N-ADJ/NOPB 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, and adjustable output via external resistor divider. It operates from 3.5V to 40V input, delivers up to 60V output, and includes current limiting, thermal shutdown, and undervoltage lockout. It is used in compact DC-DC boost converters for industrial sensors and portable instrumentation.
For engineers reviewing the LM2577N-ADJ/NOPB datasheet, LM2577N-ADJ/NOPB pinout, LM2577N-ADJ/NOPB application, or LM2577N-ADJ/NOPB equivalent, key selection criteria include its adjustable reference voltage (1.230 V), 3.0A switch current rating, TO-220-5 package thermal performance (θJA = 85°C/W), and compatibility with standard flyback inductors per TI's recommended part list.
Technical Context
The LM2577N-ADJ/NOPB implements current-mode control using an internal error amplifier with 800 V/V gain and 3700 μmho transconductance, comparing feedback voltage against a precise 1.230 V reference to regulate output. Its 52 kHz oscillator drives the NPN switch with soft-start functionality to limit in-rush current during startup.
It supports boost, flyback, and forward converter topologies. The adjustable version requires external R1/R2 feedback network to set output voltage; regulation accuracy depends on reference voltage line regulation (0.5 mV over 3.5–40 V input) and load regulation (≤100 mV over 100–800 mA load).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output topology | Adjustable step-up (boost) regulator; requires external inductor, diode, and feedback resistors to set output voltage. |
| Input voltage range | 3.5 V to 40 V; enables direct operation from 5 V, 12 V, or 24 V rails without pre-regulation. |
| Reference voltage | 1.230 V ±16 mV; sets output via R1/R2 divider; determines minimum practical output (e.g., ~1.25 V) and scaling precision. |
| Switch current rating | 3.0 A continuous; defines maximum peak inductor current and limits achievable output power at given VIN/VOUT ratio. |
| Oscillator frequency | 52 kHz ±10 kHz; fixes switching period; enables use of low-cost, high-saturation-current inductors and reduces EMI filtering burden. |
| Thermal resistance | θJA = 85°C/W (TO-220-5 package); requires ≥1 in² copper pour for safe operation at full load near max ambient temperature. |
| Protection features | Current limit, thermal shutdown, and undervoltage lockout (UVLO at 2.7–3.15 V); prevent damage during fault or brownout conditions. |
Pinout & Package
LM2577N-ADJ/NOPB uses a 16-pin DIP (N) package (NS package code N16A), with pins 1–5 and 12–16 assigned; pins 6–11 are no-connect. The package is through-hole mounted and rated for industrial temperature range (−40°C to +125°C junction).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Input supply | Primary DC input connection; must be bypassed with ≥100 μF electrolytic capacitor close to pin. |
| 2 (GND) | Power ground | Common return for input, output, and internal circuitry; requires low-impedance PCB trace to minimize noise coupling. |
| 3 (FEEDBACK) | Regulation sense | Connects to resistor divider from output; internal 1.230 V reference compares here to set output voltage. |
| 4 (SWITCH) | NPN collector output | Drives external inductor; switches at 52 kHz; must connect to cathode of Schottky diode in boost configuration. |
| 5 (COMP) | Error amplifier output | Provides compensation node for loop stability; typically connected to RC network between COMP and FEEDBACK. |
| 12–16 | No internal connection | Unbonded; electrically isolated; no routing or soldering required. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 3.0A NPN switch | Eliminates need for external power transistor; simplifies layout and reduces BOM count in boost designs. |
| 52 kHz fixed-frequency oscillator | Enables predictable EMI profile and eliminates timing component variability; supports standard off-the-shelf inductors. |
| Soft-start function | Reduces in-rush current at startup by gradually increasing duty cycle; prevents input rail sag and output overshoot. |
| Current-mode control architecture | Improves transient response and line/load regulation; provides inherent cycle-by-cycle current limiting for robustness. |
| 1.230 V precision reference | Enables accurate output setting across temperature (±16 mV over −40°C to +125°C); supports stable 3.3 V, 5 V, or higher outputs. |
Applications
| Industrial Sensor Power Supply | Portable Instrumentation Boost Converter |
|---|---|
|
Use Scenario: Powers 5 V or 12 V analog front-end circuits from a single 3.7 V Li-ion cell in handheld test equipment. IC Role / Device Role / Timing Role: Step-up regulator providing regulated output; controls energy transfer via 52 kHz PWM and current-mode feedback. Use Value: Enables extended battery life by operating down to 3.5 V input while maintaining tight output regulation (≤100 mV load/line variation). |
Use Scenario: Generates 24 V bias for piezoelectric actuators in portable ultrasonic cleaners. IC Role / Device Role / Timing Role: Adjustable boost controller; sets output via R1/R2; manages inductor current with internal 3.0A NPN switch. Use Value: Delivers up to 24 V at 300 mA with <80% efficiency from 12 V input, leveraging low-component-count design and built-in UVLO protection. |
| Automotive Aftermarket Lighting | Legacy Industrial Control Interface |
|
Use Scenario: Supplies stable 12 V to LED driver modules from variable 9–16 V vehicle battery rail. IC Role / Device Role / Timing Role: Input-voltage-tolerant boost regulator; regulates output despite cold-crank dips to 6 V. Use Value: Maintains operation during engine cranking due to 3.5 V UVLO threshold and 40 V max input rating. |
Use Scenario: Upgrades obsolete 78Lxx linear regulators in PLC I/O modules requiring 15 V from 5 V logic rail. IC Role / Device Role / Timing Role: High-efficiency switching alternative to linear regulators; replaces heat-generating solutions. Use Value: Reduces thermal load by >70% vs. linear solution; TO-220-5 package allows direct retrofit into existing footprints. |
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-ADJ | Same die, TO-220-5 package with bent leads; θJA = 65°C/W (vs. 85°C/W for N-package); higher thermal performance. | Better suited for higher ambient or continuous 3 A loads; requires different PCB footprint and mounting. | Select when thermal headroom is constrained and board space permits TO-220 mounting. |
| MC34063AP | Lower switch current (1.5 A), 100 kHz oscillator, wider input range (2.5–40 V); no soft-start or current-limit foldback. | Supports lower-input designs (e.g., 3 V systems); less robust under short-circuit but more flexible frequency tuning. | Choose for cost-sensitive, lower-power (<1.5 A) boost applications where soft-start is noncritical. |
Compared with LM2577T-ADJ, the LM2577N-ADJ/NOPB trades thermal performance for DIP compatibility and legacy board reuse; versus MC34063AP, it offers higher current capability, integrated soft-start, and tighter reference tolerance-critical for precision output regulation.
Availability
LM2577N-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial sensor power supplies, portable instrumentation boost converters, automotive aftermarket lighting, and legacy industrial control interface upgrades requiring stable component supply and long-term obsolescence management.
Supply support for LM2577N-ADJ/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, embedded processing, and power management ICs, with decades of expertise in switching regulator design and manufacturing.
The LM2577 family was developed as a SIMPLE SWITCHER® solution for cost-sensitive, medium-power DC-DC conversion-targeting industrial, automotive, and instrumentation applications needing minimal external components and proven reliability.
FAQ
What is the minimum input voltage required for stable operation of the LM2577N-ADJ/NOPB?
The LM2577N-ADJ/NOPB has an undervoltage lockout (UVLO) threshold of 2.70 V minimum, but stable regulation requires ≥3.5 V input per datasheet operating ratings. Below 3.5 V, the device may not sustain oscillation or maintain output regulation, especially under load. For reliable boost operation, ensure VIN remains ≥3.5 V across all operating conditions, including battery discharge or line sag.
How do I calculate the output voltage for LM2577N-ADJ/NOPB using the feedback resistors?
The LM2577N-ADJ/NOPB output voltage is set by VOUT = 1.230 V × (1 + R1/R2), where R1 connects from output to FEEDBACK pin and R2 connects from FEEDBACK to GND. Use 1% tolerance resistors; TI recommends R2 ≥5.62 kΩ (e.g., 5.62 kΩ) to limit bias current error. For example, R1 = 48.7 kΩ and R2 = 5.62 kΩ yields ~12 V output, as shown in Figure 10 of the datasheet.
Can LM2577N-ADJ/NOPB be used in flyback or forward converter topologies?
Yes, the LM2577N-ADJ/NOPB is explicitly designed for boost, flyback, and forward converter topologies per its datasheet description. In flyback mode, the transformer primary replaces the inductor, and the secondary delivers isolated output. Current limiting and thermal protection remain active. However, external snubber networks and transformer design must comply with TI Application Hints to avoid switch overstress.
What is the maximum achievable output voltage with LM2577N-ADJ/NOPB?
The LM2577N-ADJ/NOPB supports output voltages up to 60 V, as specified in the Absolute Maximum Ratings for output switch voltage. However, system-level limitations apply: VOUT ≤ 10 × VIN(min) per design guidelines, and external components (diode, capacitor, inductor) must be rated accordingly. For example, with VIN(min) = 5 V, max practical VOUT is 50 V; exceeding this risks instability or insufficient duty cycle margin.
Does LM2577N-ADJ/NOPB require an external compensation network?
Yes, the LM2577N-ADJ/NOPB requires an external RC compensation network between the COMP and FEEDBACK pins to ensure loop stability. Typical values are a 10 nF capacitor and 10 kΩ resistor, but exact values depend on inductor value, output capacitance, and load. TI's "Switchers Made Simple" software or Application Note SNVA005 provides design guidance; omitting compensation risks oscillation or poor transient response.
LM2577N-ADJ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 16-DIP (0.300", 7.62mm)
- 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:
- Through Hole
- Supplier Device Package:
- 16-PDIP
LM2577N-ADJ/NOPB FAQ
1.How can I place an order for LM2577N-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2577N-ADJ/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 LM2577N-ADJ/NOPB reliable?
The price and inventory of LM2577N-ADJ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2577N-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2577N-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2577N-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2577N-ADJ/NOPB?
LM2577N-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2577N-ADJ/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 LM2577N-ADJ/NOPB?
For technical support, including LM2577N-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2577N-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2577N-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2577N-ADJ/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 LM2577N-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2577N-ADJ/NOPB?
All LM2577N-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2577N-ADJ/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 LM2577N-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2577N-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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