My Inquiry
My Account
Texas Instruments LM2587SX-12
- Part No.:
- LM2587SX-12
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LM2587SX-12.pdf
- Description:
- IC REG BST FLYBACK 12V 5A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:2,978
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM2587SX-12 from Texas Instruments is a monolithic 5A flyback/boost regulator IC with fixed 12V output, integrated 5.0A NPN switch rated for 65V standoff, 100 kHz fixed-frequency oscillator, and internal soft-start. It delivers ±4% system output voltage tolerance over line and load, supports wide 4V–40V input, and is optimized for isolated flyback and non-isolated boost topologies in industrial power supplies.
For engineers reviewing the LM2587SX-12 datasheet, LM2587SX-12 pinout, LM2587SX-12 application, or LM2587SX-12 equivalent, this page provides verified technical context, real-world design parameters, package-specific thermal data, confirmed alternative parts with functional distinctions, and supply-chain support details for production deployment.
Technical Context
The LM2587SX-12 implements current-mode control with cycle-by-cycle current limiting, using an internal error amplifier (transconductance = 0.328 mmho, voltage gain = 70 V/V) referenced to a 12.0V internal feedback threshold. Its 100 kHz oscillator enables compact magnetics, while undervoltage lockout (3.30V typical) and thermal shutdown protect the 5.0A NPN switch during fault conditions.
Operation relies on peak switch current modulation: the error amp compares divided output voltage against the 12.0V reference, generating a compensation voltage that terminates each switching cycle when matched against a ramp proportional to inductor current. This architecture ensures stable regulation across input (4V–40V) and load (300 mA–1.2A) variations in flyback configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12.0V ±4% system tolerance - guarantees regulated rail without external feedback resistors. |
| Switch Current Limit | 5.0A internal NPN switch current limit - sets maximum primary-side energy transfer per cycle in flyback designs. |
| Input Voltage Range | 4V to 40V operating range - supports wide-input industrial and automotive battery-fed systems. |
| Oscillator Frequency | 100 kHz ±15% - enables use of standard off-the-shelf flyback transformers and low-cost magnetics. |
| Thermal Resistance θJA | 35°C/W (TO-263 with 0.4896 in² copper) - defines heatsink requirements for continuous 1.2A output at 12V. |
| Efficiency | 90% at VIN = 10V, IOUT = 1A - measured in flyback configuration, indicating high conversion efficiency under typical load. |
| Undervoltage Lockout | 3.30V typical activation threshold - prevents erratic startup below minimum input voltage. |
Pinout & Package
LM2587SX-12 is housed in a 5-lead TO-263 (S package) surface-mount package with exposed thermal pad. The package supports low thermal resistance (θJA = 35°C/W with 0.4896 in² copper) and requires soldering to PCB copper for thermal management.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input Supply | Accepts 4V–40V DC input; connects to bulk capacitor and EMI filter. |
| GND | Power Ground | Common return for input, output, and internal circuits; must be low-impedance connection to thermal pad. |
| SW | Switch Collector | Drives transformer primary or boost inductor; switches 5.0A peak, withstands 65V. |
| FB | Feedback Input | Internally tied to 12.0V reference; no external resistor divider required for fixed-output operation. |
| COMP | Compensation Output | Error amplifier output; connects to RC network for loop stability in flyback/boost designs. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 5.0A/65V NPN switch | Eliminates need for external high-current transistor and associated drive circuitry in flyback/boost converters. |
| Current-mode control | Provides inherent line and load transient immunity, simplifies loop compensation, and enables accurate cycle-by-cycle current limiting. |
| Internal soft-start | Reduces in-rush current during startup by gradually increasing duty cycle, preventing input capacitor stress and output overshoot. |
| System-level ±4% output tolerance | Guarantees final output accuracy across temperature, line, and load - no post-production trimming needed. |
| Family of compatible transformers/inductors | Enables rapid design with pre-characterized Coilcraft, Pulse, Renco, and Schott magnetics listed in TI's official selection guides. |
Applications
| Industrial Flyback Power Supply | Automotive Boost Converter |
|---|---|
Use Scenario: Isolated 12V auxiliary rail generation from 12–24V vehicle battery in engine control units. IC Role / Device Role / Timing Role: Primary-side controller implementing flyback topology with galvanic isolation and 100 kHz switching. Use Value: Delivers stable 12V/1.2A output with ±4% tolerance across −40°C to +125°C junction temperature range. |
Use Scenario: Stepping up 12V battery voltage to 24V for solenoid drivers or sensor biasing in commercial vehicles. IC Role / Device Role / Timing Role: Non-isolated boost regulator using internal 5.0A switch and fixed 12V reference for output sensing. Use Value: Achieves 90% efficiency at 10V input/1A load, reducing thermal load versus linear solutions. |
| Telecom Wall Adapter | Factory Automation Controller |
Use Scenario: Compact 12V/1A AC-DC adapter for PoE-powered devices requiring reinforced isolation. IC Role / Device Role / Timing Role: Flyback controller driving transformer T1 (Coilcraft Q4434-B) with 1:1 turns ratio and 22 μH primary. Use Value: Meets EN 61000-3-2 harmonic limits via fixed 100 kHz frequency and current-mode noise rejection. |
Use Scenario: Distributed 12V power rail for PLC I/O modules fed from 24V industrial bus. IC Role / Device Role / Timing Role: Boost converter generating regulated 12V from noisy 24V backplane with >65V switch standoff margin. Use Value: Withstands 40V transients on 24V bus without latch-up, supported by 65V switch rating and UVLO protection. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar flyback/boost regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2587T-12 | Identical electrical specs but in 5-lead TO-220 (T package) with higher θJA = 45°C/W (4 in² copper). | Requires vertical mounting and larger heatsink for same 1.2A output; less suitable for space-constrained SMT layouts. | Select LM2587T-12 only when through-hole assembly or manual heatsinking is preferred over surface-mount thermal management. |
| LM2577-12 | Lower 3A switch current, 50 kHz oscillator, no internal soft-start, ±5% output tolerance. | Supports lower-power flyback (<600 mA) and simpler boost designs where size and cost outweigh efficiency and precision. | Choose LM2577-12 for cost-sensitive, lower-current applications where 90% efficiency and ±4% tolerance are not mandatory. |
Compared with LM2587T-12, LM2587SX-12 offers superior thermal performance in SMT layouts; compared with LM2577-12, it delivers higher current capability, tighter regulation, and built-in soft-start - critical for robust industrial power delivery.
Availability
LM2587SX-12 is available at Aetrix Electronics and suitable for industrial power supplies, automotive DC-DC converters, telecom adapters, and factory automation controllers requiring stable component supply and long-term manufacturability.
Supply support for LM2587SX-12 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.
The LM2587SX-12 belongs to TI's SIMPLE SWITCHER® family, designed specifically for cost-effective, easy-to-implement flyback and boost regulators targeting industrial, automotive, and telecom power applications.
FAQ
What is the maximum continuous output current supported by the LM2587SX-12 in a flyback configuration?
The LM2587SX-12 supports up to 1.2A continuous output current in flyback regulator configurations, as specified in its Electrical Characteristics table under "Load Regulation" test conditions (VIN = 10V, ILOAD = 300 mA to 1.2A). This rating assumes proper thermal management using the TO-263 package's 35°C/W θJA with adequate PCB copper area. Exceeding 1.2A requires external current limiting or derating based on ambient temperature and heatsinking.
Does the LM2587SX-12 require external feedback resistors to set the output voltage?
No, the LM2587SX-12 does not require external feedback resistors. It is a fixed-output variant with the 12.0V reference internally connected to the FB pin, eliminating the need for an external resistor divider. This simplifies layout, improves reliability, and ensures guaranteed ±4% system output voltage tolerance without calibration or trimming.
Can the LM2587SX-12 be used in boost topology, and what are the key design constraints?
Yes, the LM2587SX-12 can be used in non-isolated boost topology, as confirmed in TI's datasheet Figure 35 and Application Hints. Key constraints include externally limiting output current to ≤5A (since internal current limit does not protect the full boost path during short-circuit), selecting an inductor rated for ≥5A DC and appropriate saturation current, and ensuring the diode and output capacitor handle peak reverse voltage and ripple current. Efficiency reaches 90% at 10V input/1A load.
What is the purpose of the COMP pin on the LM2587SX-12, and how should it be configured?
The COMP pin on the LM2587SX-12 is the error amplifier output, used to connect an external RC compensation network that stabilizes the control loop in both flyback and boost configurations. TI recommends a 2kΩ resistor and 0.47 μF capacitor (as shown in Figure 7) to set dominant pole and phase margin. Incorrect COMP network values cause instability, oscillation, or poor transient response - always verify loop gain with bench testing.
How does the undervoltage lockout (UVLO) function protect the LM2587SX-12 during startup?
The LM2587SX-12 incorporates an undervoltage lockout circuit that disables switching until VIN rises above 3.30V (typical), preventing erratic operation or partial conduction during brown-out conditions. Once enabled, the IC remains active down to ~3.05V (min), then shuts down cleanly. This protects downstream circuitry from unregulated output and avoids thermal stress on the internal NPN switch during marginal input conditions.
LM2587SX-12 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:
- 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):
- 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 FAQ
1.How can I place an order for LM2587SX-12 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2587SX-12 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 reliable?
The price and inventory of LM2587SX-12 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 is usually 5 days.
3.What payment methods are accepted for LM2587SX-12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2587SX-12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2587SX-12?
LM2587SX-12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2587SX-12 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?
For technical support, including LM2587SX-12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2587SX-12 requirements.
6.How does Aetrix verify that LM2587SX-12 is sourced from the original manufacturer or authorized distributors?
All LM2587SX-12 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 meets industry standards.
7.What is the process for return or replacement of LM2587SX-12?
All LM2587SX-12 units undergo pre-shipment inspection (PSI). If there is an issue with LM2587SX-12, 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 part is unused and in its original packaging.
Return procedure for LM2587SX-12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2587SX-12 Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
