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Texas Instruments LM2587SX-12/NOPB
- Part No.:
- LM2587SX-12/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LM2587SX-12/NOPB.pdf
- Description:
- IC REG BST FLYBACK 12V 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:1,013
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Product details
Overview
LM2587SX-12/NOPB from Texas Instruments is a monolithic 5-A step-up (boost) and flyback switching regulator IC with fixed 12-V output, 4-V to 40-V input range, 100-kHz fixed-frequency oscillator, NPN internal switch rated for 65-V standoff and 5-A peak current, and ±4% system output voltage tolerance over line and load. It enables compact, low-component-count DC/DC conversion in industrial power supplies and battery-powered systems.
For engineers reviewing the LM2587SX-12/NOPB datasheet, LM2587SX-12/NOPB pinout, LM2587SX-12/NOPB application, or LM2587SX-12/NOPB equivalent, key selection considerations include its fixed 12-V output configuration, TO-263 (DDPAK) thermal performance, current-mode control for transient response, undervoltage lockout threshold of 3.3 V, and soft-start function limiting in-rush current during startup.
Technical Context
The LM2587SX-12/NOPB implements current-mode PWM control using an internal 100-kHz oscillator and cycle-by-cycle current limiting. Its error amplifier compares feedback voltage against a precision 12-V reference (derived from internal 1.23-V bandgap), generating a compensation signal that modulates switch duty cycle via a comparator driven by sensed switch current.
It integrates protection features including thermal shutdown, undervoltage lockout (3.3 V turn-on threshold), and internal current limit (6.5 A typical). The NPN output switch operates in flyback or boost topologies, requiring external diode, transformer or inductor, and output capacitor - with no need for external current-sense resistor due to integrated sensing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12 V ±4% over full line/load/temperature range - ensures stable rail for downstream logic or analog circuitry without external feedback resistors. |
| Input Voltage Range | 4 V to 40 V - supports wide-range inputs including 5-V, 12-V, 24-V, and 36-V battery or bus systems. |
| Switch Current Limit | 6.5 A typical (5.0–9.5 A min/max) - defines maximum peak inductor or primary winding current before cycle-by-cycle shutdown. |
| Oscillator Frequency | 100 kHz (75–125 kHz over temp) - enables use of standard, cost-effective magnetics with predictable EMI profile. |
| UVLO Threshold | 3.30 V (3.05–3.75 V) - prevents erratic operation during brownout or cold-start conditions. |
| Efficiency | 90% typical at 10 V input, 1 A load - reduces thermal load and extends battery life in portable applications. |
| Thermal Resistance (θJA) | 35°C/W (DDPAK on 0.4896 in² copper) - enables high-power operation without mandatory heatsink under moderate ambient conditions. |
Pinout & Package
LM2587SX-12/NOPB is housed in a 5-pin DDPAK/TO-263 package (body size 10.16 mm × 8.42 mm) with exposed thermal pad for enhanced heat dissipation. Pin 1 is Input Voltage (VIN), Pin 2 is Ground (GND), Pin 3 is Feedback (FB), Pin 4 is Output Switch (SW), and Pin 5 is Compensation (COMP).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Power input supply | Accepts 4–40 V DC; powers internal bias circuits and switch driver; requires local ceramic bypass capacitor. |
| GND (Pin 2) | Power and signal reference | Common return for input, output, and control circuitry; must be connected to low-impedance ground plane beneath thermal pad. |
| FB (Pin 3) | Output voltage sense input | Internally referenced to 12 V; connects to output divider only in adjustable versions - unused (open) for LM2587SX-12/NOPB. |
| SW (Pin 4) | NPN collector output | Drives primary winding of flyback transformer or boost inductor; switches at 100 kHz; requires snubber network for voltage spike suppression. |
| COMP (Pin 5) | Error amplifier output | Provides compensation node for loop stability; connects to RC network between COMP and FB in adjustable versions - left unconnected for fixed 12-V variant. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode PWM control | Enables fast transient response and inherent cycle-by-cycle current limiting without external sense resistor. |
| Internal 100-kHz oscillator | Eliminates external timing components and ensures consistent switching frequency across temperature and supply variations. |
| Integrated 5-A NPN switch | Reduces BOM count and layout complexity; supports up to 65-V blocking voltage for robust flyback operation. |
| Soft-start function | Gradually ramps COMP voltage at startup to limit in-rush current into output capacitors and prevent input rail sag. |
| System-level ±4% output tolerance | Guarantees regulated 12-V output accuracy across full operating range - no post-regulation LDO required for many loads. |
Applications
| Industrial Power Supply | Battery-Powered Telemetry |
|---|---|
Use Scenario: Generating isolated 12-V rail from 24-V industrial bus for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Flyback controller regulating isolated secondary output; provides galvanic isolation and voltage step-down via transformer turns ratio. Use Value: Enables single-chip solution with <1% output drift over −40°C to +85°C, eliminating need for trimming or secondary regulation. | Use Scenario: Boosting voltage from aging 9-V alkaline or 7.4-V Li-ion battery pack to stable 12-V for RF transmitter and microcontroller. IC Role / Device Role / Timing Role: Step-up (boost) regulator maintaining constant output as input decays from 10 V to 4 V. Use Value: Delivers >90% efficiency at 1-A load down to 4-V input, extending operational runtime by >25% versus linear solutions. |
| Automotive Aftermarket Lighting | Test Equipment Auxiliary Rail |
Use Scenario: Driving LED arrays requiring 12-V from variable 9–16-V vehicle battery with cold-crank immunity. IC Role / Device Role / Timing Role: Non-isolated boost converter with UVLO hysteresis preventing dropout during engine cranking transients. Use Value: Sustains regulated 12-V output even when input dips to 3.3 V, ensuring uninterrupted LED illumination during start-up. | Use Scenario: Providing clean, isolated 12-V auxiliary supply for analog front-end circuitry in benchtop multimeters and oscilloscopes. IC Role / Device Role / Timing Role: Flyback regulator with transformer-based isolation minimizing noise coupling into sensitive measurement paths. Use Value: Achieves <10 mVpp output ripple and ±4% accuracy without post-filtering, simplifying PCB layout and reducing component count. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-up/flyback regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2587T-12/NOPB | TO-220-5 package; higher θJA (65°C/W vs. 35°C/W); identical electrical specs. | Suitable for lower-power or forced-air-cooled designs where board space allows larger through-hole footprint. | Select LM2587T-12/NOPB when thermal budget permits larger package or socket mounting is preferred. |
| LM2588SX-12/NOPB | Higher 65-V switch rating (vs. 65-V same), 4-A switch current limit (vs. 5-A), same 12-V fixed output and 100-kHz frequency. | Optimized for higher-input-voltage flyback designs (e.g., 48-V telecom); lower current capability limits max output power. | Choose LM2588SX-12/NOPB only when input exceeds 40 V or when tighter switch SOA margin is required. |
Compared with LM2587T-12/NOPB, the LM2587SX-12/NOPB delivers superior thermal performance in surface-mount layouts, while LM2588SX-12/NOPB trades switch current headroom for extended input voltage robustness - making LM2587SX-12/NOPB optimal for high-current, space-constrained 12-V boost/flyback designs.
Availability
LM2587SX-12/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery-powered telemetry systems, and automotive aftermarket lighting requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.
Supply support for LM2587SX-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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and personal electronics markets.
The LM2587 product line was designed specifically for cost-sensitive, high-reliability flyback, boost, and forward converter applications - targeting engineers needing minimal external components, integrated protection, and proven thermal performance in TO-263 packages.
FAQ
What topology does the LM2587SX-12/NOPB support?
The LM2587SX-12/NOPB supports flyback, step-up (boost), and forward converter topologies. As a fixed 12-V output device, it is commonly used in non-isolated boost configurations (e.g., 5-V to 12-V conversion) or isolated flyback designs (e.g., 24-V input to isolated 12-V output). Its internal NPN switch, current-mode control, and 100-kHz oscillator make it adaptable to all three, with external component selection determining the final architecture. The LM2587SX-12/NOPB does not require external feedback resistors due to its factory-trimmed 12-V reference.
Does the LM2587SX-12/NOPB require an external feedback resistor divider?
No, the LM2587SX-12/NOPB does not require an external feedback resistor divider. It is a fixed-output variant with internal voltage reference set to 12 V, so the FB pin is left unconnected (open) in standard operation. This eliminates tuning errors and component count versus adjustable versions like LM2587MX-ADJ/NOPB. The LM2587SX-12/NOPB achieves ±4% output accuracy across temperature and load without any external resistive network.
What is the maximum output current achievable with the LM2587SX-12/NOPB?
The LM2587SX-12/NOPB's internal NPN switch is rated for 5-A peak current and 65-V standoff, but maximum continuous output current depends on topology, input voltage, efficiency, and thermal design. In boost mode, output current is limited externally by inductor saturation and diode rating; in flyback mode, it is internally limited. With proper heatsinking on the DDPAK package, the LM2587SX-12/NOPB reliably delivers ≥1.2 A at 12 V with 10-V input and >90% efficiency - verified per Figure 62 in the datasheet.
How does the soft-start function operate in the LM2587SX-12/NOPB?
The LM2587SX-12/NOPB incorporates an internal soft-start circuit that gradually charges the COMP pin voltage at power-up, ramping the peak switch current limit from zero to full scale over ~10 ms. This prevents large in-rush currents into output capacitors and avoids input rail collapse during startup. Because the LM2587SX-12/NOPB uses fixed 12-V internal feedback, no external soft-start capacitor is needed - the function is fully autonomous. This behavior is confirmed in Section 7.3.1 and Figure 16 of the LM2587 datasheet.
Is the LM2587SX-12/NOPB pin-compatible with other LM2587 variants?
Yes, the LM2587SX-12/NOPB shares identical pinout and package (5-pin DDPAK/TO-263) with all other LM2587X variants, including LM2587SX-3.3/NOPB, LM2587SX-5.0/NOPB, and LM2587SX-ADJ/NOPB. All share VIN, GND, FB, SW, and COMP pin assignments. However, FB and COMP connections differ: fixed-output versions leave FB open and COMP unconnected, while adjustable versions require external resistor divider and compensation network. Thus, board layout is reusable, but schematic design must match the selected variant's configuration. The LM2587SX-12/NOPB maintains full mechanical compatibility across the family.
LM2587SX-12/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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):
- 4V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 12V
- Voltage - Output (Max):
- -
- Current - Output:
- 5A (Switch)
- Frequency - Switching:
- 100kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-5)
LM2587SX-12/NOPB FAQ
1.How can I place an order for LM2587SX-12/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2587SX-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 LM2587SX-12/NOPB reliable?
The price and inventory of LM2587SX-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 LM2587SX-12/NOPB is usually 5 days.
3.What payment methods are accepted for LM2587SX-12/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2587SX-12/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2587SX-12/NOPB?
LM2587SX-12/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2587SX-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 LM2587SX-12/NOPB?
For technical support, including LM2587SX-12/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2587SX-12/NOPB requirements.
6.How does Aetrix verify that LM2587SX-12/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2587SX-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 LM2587SX-12/NOPB meets industry standards.
7.What is the process for return or replacement of LM2587SX-12/NOPB?
All LM2587SX-12/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2587SX-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 LM2587SX-12/NOPB part is unused and in its original packaging.
Return procedure for LM2587SX-12/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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