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Texas Instruments LM2577MX-ADJ
- Part No.:
- LM2577MX-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
LM2577MX-ADJ.pdf
- Description:
- IC REG BST FLYBACK ADJ 3A 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,703
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Product details
Overview
LM2577MX-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, soft-start, and protection circuitry including undervoltage lockout, thermal shutdown, and current limiting. It operates from 3.5V to 40V input and delivers adjustable output voltage (≥1.23V) with up to 80% efficiency in boost configurations - widely used in industrial power supplies and battery-powered instrumentation.
For engineers reviewing the LM2577MX-ADJ datasheet, LM2577MX-ADJ pinout, LM2577MX-ADJ application, or LM2577MX-ADJ equivalent, key selection considerations include its TO-263-5 (S) package thermal performance (θJA = 37°C/W with 1 in² copper), 1.230V internal reference accuracy (±1.3% over temperature), adjustable feedback network design, and compatibility with standard off-the-shelf flyback inductors per TI Application Note SNOS658C.
Technical Context
The LM2577MX-ADJ implements current-mode control using an error amplifier with 800 V/V gain and 3700 μmho transconductance, comparing feedback voltage against a precision 1.230V reference to modulate switch duty cycle. Its 52 kHz oscillator drives the NPN output switch directly, eliminating external timing components.
Protection functions are hardware-based: undervoltage lockout activates below 2.70V (min), thermal shutdown engages at 150°C junction temperature, and current limit responds to sensed switch current - with 3.0A nominal switch rating and 4.3A typical current-limit threshold under max-duty conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.5V to 40V - supports wide-range DC inputs including 5V, 12V, and 24V rails without pre-regulation. |
| Output Voltage | Adjustable ≥1.23V via external resistor divider - enables custom regulation points (e.g., 3.3V, 5V, 9V) using two precision resistors. |
| Switch Current Rating | 3.0A continuous - defines maximum inductor peak current capability in boost topology; requires external current limiting above 6.0A absolute max. |
| Oscillator Frequency | 52 kHz (±8%) - fixed frequency simplifies EMI filtering and inductor selection; stable across temperature and line variations. |
| Reference Voltage | 1.230V ±1.3% (−40°C to +125°C) - high-accuracy bandgap reference enabling tight output regulation in adjustable configurations. |
| Thermal Resistance | θJA = 37°C/W (with 1 in² PCB copper) - enables >2W dissipation at ΔT = 74°C, critical for high-current boost designs without heatsinks. |
| Protection Features | UVLO (2.70–3.15V), thermal shutdown (150°C), current limit (3.7–5.3A min/max) - fully autonomous fault recovery without external circuitry. |
Pinout & Package
LM2577MX-ADJ is housed in a 5-lead TO-263 (S) surface-mount package (NS Package Number TS5B), with exposed thermal pad for enhanced heat dissipation. The package measures 10.16 mm × 8.89 mm × 4.57 mm and is RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - Input | Power input supply connection | Accepts 3.5V–40V DC; requires local 100 μF low-ESR capacitor for stability and transient response. |
| 2 - Ground | Power and signal reference node | Must be low-impedance connection to PCB ground plane; ties internally to thermal pad for thermal conduction. |
| 3 - Feedback | Regulation sense input | Connects to resistor divider from output; compares against 1.230V reference to control duty cycle. |
| 4 - Output Switch | Collector of internal NPN transistor | Drives external boost diode and inductor; switches at 52 kHz; voltage swing up to 65V max. |
| 5 - Compensation | Error amplifier output | Used for loop compensation (e.g., RC network); sets phase margin and transient response characteristics. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 3.0A NPN switch | Eliminates need for external power transistor; reduces BOM count and layout complexity in boost/flyback topologies. |
| Current-mode control architecture | Provides inherent cycle-by-cycle current limiting, fast load/transient response, and simplified loop compensation. |
| Soft-start function | Reduces inrush current during startup by gradually increasing duty cycle - prevents input rail sag and output overshoot. |
| 52 kHz fixed-frequency oscillator | Enables predictable EMI profile and eliminates external timing components; compatible with standard off-the-shelf magnetics. |
| Thermal shutdown & UVLO | Hardware-level protection ensures safe operation under overload, short-circuit, or brownout conditions without software intervention. |
Applications
| Industrial Power Supply | Portable Instrumentation |
|---|---|
Use Scenario: Generating stable 5V or 9V from a single 3.7V Li-ion cell in handheld test equipment. IC Role / Device Role / Timing Role: Step-up regulator controlling energy transfer via 52 kHz PWM to maintain regulated output under variable load. Use Value: Enables extended battery runtime with >80% efficiency at 500 mA load and eliminates need for discrete switch/driver stages. |
Use Scenario: Providing isolated 12V bias for analog front-end sensors in field-deployed environmental monitors. IC Role / Device Role / Timing Role: Boost converter core in non-isolated auxiliary supply; feedback network sets precise 12.0V output. Use Value: Delivers stable sensor bias with <50 mV load/line regulation and built-in thermal protection for unattended operation. |
| Automotive Aftermarket | Legacy System Upgrade |
Use Scenario: Upgrading 12V vehicle electrical systems to support 24V accessories (e.g., LED lighting controllers). IC Role / Device Role / Timing Role: High-input-voltage boost stage accepting 9–16V automotive rail and delivering regulated 24V output. Use Value: Operates reliably across cold-crank (6.5V) to load-dump (40V) transients due to 40V max input rating and UVLO hysteresis. |
Use Scenario: Retrofitting obsolete linear regulators in aging PLC I/O modules with higher-efficiency switching solution. IC Role / Device Role / Timing Role: Direct replacement for 78xx-style regulators in space-constrained PCBs using TO-263 footprint. Use Value: Reduces thermal load by >60% versus linear regulation at 500 mA, enabling use of existing heatsink area. |
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 | TO-220-5 through-hole package; θJA = 65°C/W; same electrical specs and pinout. | Better suited for prototyping, low-volume assembly, or legacy through-hole boards requiring manual soldering. | Select when mechanical mounting or thermal mass from TO-220 heatsink is preferred over surface-mount thermal management. |
| MC34063AP | 3.0A switch, 100 kHz oscillator, wider temp range (−40°C to +85°C), but lower reference accuracy (1.25V ±2%). | More suitable for cost-sensitive consumer applications where ±2% output tolerance is acceptable. | Choose when higher switching frequency allows smaller magnetics, and tighter reference voltage is not required. |
Compared with LM2577T-ADJ and MC34063AP, the LM2577MX-ADJ offers superior thermal performance in SMT layouts, tighter 1.230V reference accuracy for precision outputs, and optimized 52 kHz frequency for industrial-grade EMI compliance - making it the preferred choice for production-grade embedded power designs.
Availability
LM2577MX-ADJ is available at Aetrix Electronics and suitable for industrial power supplies, portable instrumentation, automotive aftermarket electronics, and legacy system upgrades requiring stable component supply and long-term lifecycle support.
Supply support for LM2577MX-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, embedded processing, and power management technologies, with decades of expertise in switching regulator design and manufacturing.
The LM2577 family was engineered specifically for cost-effective, robust DC-DC conversion in industrial, automotive, and instrumentation applications - emphasizing simplicity, reliability, and minimal external component count.
FAQ
What is the maximum output voltage achievable with LM2577MX-ADJ?
The LM2577MX-ADJ supports output voltages up to 60V, constrained by its 65V switch voltage rating and the requirement that VOUT ≤ 10 × VIN(min). For example, with a minimum input of 3.5V, the practical upper limit is 35V. Designers must ensure external components - especially the boost diode and output capacitor - are rated for the selected VOUT and associated ripple current.
Does LM2577MX-ADJ require an external diode in boost configuration?
Yes, the LM2577MX-ADJ requires an external Schottky or fast-recovery diode connected between the Output Switch pin and output capacitor. This diode provides the freewheeling path during switch-off time. TI recommends diodes with ≤0.5V forward voltage (e.g., MBR0520L) to maximize efficiency and minimize thermal stress on the IC.
How is output voltage set on LM2577MX-ADJ?
Output voltage is set using a two-resistor feedback divider from VOUT to the Feedback pin, referenced to the internal 1.230V bandgap. The formula is VOUT = 1.230V × (1 + R1/R2), where R2 connects from FB to GND. Precision 1% resistors are recommended to maintain regulation accuracy within datasheet limits.
Can LM2577MX-ADJ be used in flyback or forward converter topologies?
Yes, the LM2577MX-ADJ is explicitly designed for flyback and forward converter applications per its datasheet description and application circuits. In flyback mode, it uses transformer coupling and achieves internal current limiting - unlike boost mode, where external current limiting is required above 3.0A switch current.
What thermal design guidance applies to LM2577MX-ADJ in TO-263 package?
For optimal thermal performance, the LM2577MX-ADJ's exposed thermal pad must be soldered to ≥1 in² of inner-layer or bottom-side copper pour. With this layout, θJA drops to 37°C/W. Without adequate copper, junction temperature rise may exceed 150°C under full load - triggering thermal shutdown. Thermal vias under the pad are strongly recommended.
LM2577MX-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- 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
LM2577MX-ADJ FAQ
1.How can I place an order for LM2577MX-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2577MX-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 LM2577MX-ADJ reliable?
The price and inventory of LM2577MX-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2577MX-ADJ is usually 5 days.
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LM2577MX-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2577MX-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 LM2577MX-ADJ?
For technical support, including LM2577MX-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2577MX-ADJ requirements.
6.How does Aetrix verify that LM2577MX-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2577MX-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 LM2577MX-ADJ meets industry standards.
7.What is the process for return or replacement of LM2577MX-ADJ?
All LM2577MX-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2577MX-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 LM2577MX-ADJ part is unused and in its original packaging.
Return procedure for LM2577MX-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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