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Texas Instruments LM2586T-3.3
- Part No.:
- LM2586T-3.3
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-7 Formed Leads
- Datasheet:
-
LM2586T-3.3.pdf
- Description:
- IC REG BST FLYBACK 3.3V TO220-7
- Quantity:
- Payment:
- Shipping:
Inventory:2,694
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Product details
Overview
LM2586T-3.3 from Texas Instruments is a monolithic 3A flyback/boost/forward switching regulator IC with fixed 3.3V output, NPN internal switch rated for 65V standoff and 3.0A current, ±4% system output voltage tolerance over line and load, 4V–40V input range, and adjustable 100–200 kHz switching frequency. It enables compact isolated or step-up power supplies in industrial control and telecom interface modules.
For engineers reviewing the LM2586T-3.3 datasheet, LM2586T-3.3 pinout, LM2586T-3.3 application, or LM2586T-3.3 equivalent, key selection criteria include its integrated soft-start, current-mode control for transient immunity, external shutdown capability, thermal/UVLO protection, and compatibility with standard flyback transformers (e.g., Coilcraft T7) and low-loss Schottky diodes like 1N5820.
Technical Context
The LM2586T-3.3 implements current-mode PWM control with an internal 3.0A/65V NPN power switch, error amplifier transconductance of 1.193 mmho (typ), and reference voltage of 3.3V (±1.5% over temperature). Its oscillator supports resistor-programmable frequency (100–200 kHz) and synchronization to external clocks.
Protection includes undervoltage lockout at 3.30V (3.05–3.75V), thermal shutdown at 150°C, cycle-by-cycle current limiting (4.0A typical limit), and soft-start via 11.0 μA (typ) internal current source into the compensation pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±4% over full line/load/temperature range - ensures stable logic supply for microcontrollers and FPGAs without external feedback resistors. |
| Input Voltage Range | 4V to 40V - supports wide-range DC inputs including automotive battery (12V nominal), industrial 24V rails, and PoE-derived supplies. |
| Switch Rating | NPN transistor, 3.0A continuous, 65V standoff - enables direct drive of primary windings in flyback topologies up to ~30W output. |
| Switching Frequency | Adjustable 100–200 kHz via external resistor on Pin 1 - allows trade-off between transformer size (higher f = smaller magnetics) and conduction losses (lower f = lower MOSFET/diode stress). |
| Shutdown Current | <60 μA total (16 μA to VIN + 40 μA to ON/OFF pin) - enables ultra-low-power standby in battery-backed systems. |
| Thermal Resistance | θJA = 65°C/W (TO-220, no heatsink); θJC = 2°C/W - mandates minimal heatsinking for 3A operation at ambient ≤60°C. |
| Reference Voltage | 3.3V at FB pin, ±1.5% max variation over temperature - defines regulation accuracy and sets minimum output ripple rejection requirement. |
Pinout & Package
LM2586T-3.3 is housed in a 7-lead TO-220 (T) package with bent, staggered leads and exposed tab (internally connected to Pin 2, GND). The tab must be electrically isolated from heatsink unless tied to circuit ground.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Freq Adj / ON-OFF) | Frequency adjustment and shutdown control | Resistor-to-ground sets switching frequency; ≥3V applied shuts down device - dual-function pin requires isolation diode for clean enable/disable sequencing. |
| 2 (GND) | Power and signal ground reference | Common return for internal NPN emitter, error amp, and oscillator - must be low-impedance connection to minimize noise coupling into feedback path. |
| 3 (FB) | Feedback input | Compares output voltage (via resistive divider) against internal 3.3V reference - open-circuit disables regulation; short to GND forces maximum duty cycle. |
| 4 (COMP) | Error amplifier output | Drives external RC compensation network - sets loop stability; sourcing/sinking up to ±260 μA determines bandwidth and phase margin. |
| 5 (VIN) | Main power input | Supplies internal bias and drives NPN base - requires local 100 μF + 0.1 μF decoupling; UVLO activates below 3.30V. |
| 6 (SW) | Switch collector output | Connects to primary winding of flyback transformer or boost inductor - carries high dv/dt; layout must minimize parasitic inductance to reduce EMI. |
| 7 (SYNC) | Frequency synchronization input | Accepts external clock signal (0.75V threshold) to align switching edges across multiple regulators - eliminates beat frequencies in multi-rail systems. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode PWM control | Enables inherent line/load transient immunity and cycle-by-cycle current limiting - eliminates need for external current-sense amplifiers in most designs. |
| Integrated soft-start | 11.0 μA (typ) internal current source ramps COMP voltage - prevents inrush into output capacitors and avoids transformer saturation during startup. |
| External shutdown with low quiescent draw | Draws only 16 μA from VIN and 40 μA from ON/OFF pin in shutdown - suitable for always-on systems requiring selective rail disable. |
| Thermal/UVLO/current protection | Three independent fault protections (150°C shutdown, 3.30V UVLO, 4.0A current limit) - ensures robust operation under overload, cold cranking, or poor heatsinking. |
| Standard transformer compatibility | Validated with Coilcraft T7, Pulse Q4339-B, Renco RL-5751 - reduces design risk and accelerates prototyping using off-the-shelf magnetics. |
Applications
| Industrial PLC I/O Power | Telecom Line Card Bias |
|---|---|
|
Use Scenario: Isolated 3.3V supply for digital I/O modules in programmable logic controllers, operating from 24VDC field bus with transient immunity. IC Role / Device Role / Timing Role: Flyback controller generating galvanically isolated 3.3V rail with built-in current limiting and thermal protection. Use Value: Eliminates need for external optocoupler feedback and discrete protection circuits - reduces BOM count by ≥4 components versus discrete solutions. |
Use Scenario: Compact 3.3V boost converter powering FPGA configuration memory and SerDes interfaces from -48V telecom supply. IC Role / Device Role / Timing Role: Step-up regulator with 100–200 kHz programmable frequency to minimize EMI in dense line card layouts. Use Value: Achieves >76% efficiency at 0.3A load from 5V input - enables single-chip solution where space-constrained boards prohibit multi-stage conversion. |
| Medical Sensor Interface | Automotive Body Control Module |
|
Use Scenario: Low-noise 3.3V supply for analog front-end sensors in portable diagnostic devices, powered from single-cell Li-ion (3.0–4.2V). IC Role / Device Role / Timing Role: Boost regulator with soft-start and shutdown control to manage power sequencing during sleep/wake cycles. Use Value: Delivers regulated 3.3V output with <50 mVpp ripple - meets EN 60601-1 conducted emission limits without added LC filters. |
Use Scenario: 3.3V auxiliary rail in body control unit, deriving power from 12V battery with cold-crank (4.5V) and load-dump (40V) tolerance. IC Role / Device Role / Timing Role: Input-robust flyback regulator with 4V–40V operation and undervoltage lockout at 3.30V. Use Value: Maintains regulation during engine start (≥4.5V) and survives ISO 7637-2 pulse 4a (40V/100ms) - avoids microcontroller brownout resets. |
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-3.3 | Same pinout and function but optimized for higher efficiency in boost topology; includes improved gate drive and lower VSAT (0.45V vs 0.65V typ). | Better suited for non-isolated boost applications where transformer loss dominates; less ideal for flyback due to reduced current limit headroom. | Select LM2587T-3.3 when prioritizing >80% efficiency at 12V→3.3V boost; retain LM2586T-3.3 for cost-sensitive flyback designs with standard transformers. |
| UC3844BD1R2G | Current-mode PWM controller (no integrated switch); requires external MOSFET; 250 kHz max frequency; no integrated soft-start or UVLO. | Offers greater flexibility in switch selection and layout but increases component count and design complexity. | Choose UC3844BD1R2G only when custom high-voltage (>100V) or high-frequency (>200 kHz) operation is required - LM2586T-3.3 delivers faster time-to-market for standard 3.3V flyback/boost. |
Compared with LM2587T-3.3 and UC3844BD1R2G, the LM2586T-3.3 provides lowest BOM cost and shortest development cycle for 3.3V isolated or step-up supplies ≤30W, trading off some peak efficiency for integration, protection, and transformer compatibility.
Availability
LM2586T-3.3 is available at Aetrix Electronics and suitable for industrial automation, telecom infrastructure, medical instrumentation, and automotive body electronics requiring stable component supply and long-term manufacturability.
Supply support for LM2586T-3.3 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 delivering analog, embedded processing, and connectivity solutions with emphasis on reliability, longevity, and industrial-grade qualification.
The LM2586 series was designed specifically for cost-effective, low-component-count flyback, forward, and boost converters targeting industrial, telecom, and automotive power subsystems - emphasizing ruggedness, ease of use, and compatibility with standard magnetics.
FAQ
What is the maximum output power achievable with LM2586T-3.3 in a flyback configuration?
The LM2586T-3.3 supports up to ~30W output in flyback topology, constrained by its 3.0A/65V NPN switch, thermal limits (θJA = 65°C/W), and efficiency curves. At 12V input and 3.3V/3A output, typical efficiency is 76%, yielding ~7.5W dissipation - requiring modest heatsinking. Higher power demands external MOSFET drivers or parallel configurations.
Does LM2586T-3.3 require an external feedback resistor network?
No. The LM2586T-3.3 integrates a precise 3.3V reference and fixed internal feedback divider - Pin 3 (FB) connects directly to the output via a short trace. External resistors are unnecessary, unlike the adjustable LM2586-ADJ version which requires R1/R2 to set VOUT.
Can LM2586T-3.3 synchronize its switching frequency to an external clock?
Yes. Pin 7 (SYNC) accepts an external TTL/CMOS clock signal with 0.75V threshold. When driven, the LM2586T-3.3 locks its oscillator to the external frequency - enabling noise reduction in multi-rail systems and eliminating beat frequencies between synchronous converters.
What transformer turns ratio is recommended for LM2586T-3.3 in a 12V-to-3.3V flyback design?
For 12V input to 3.3V output flyback, a 1:1 turns ratio (e.g., Coilcraft T7) is validated per TI's Figure 7 and Table 1. This leverages the LM2586T-3.3's ability to regulate outputs within the input range - simplifying magnetics selection and reducing design iterations.
How does the shutdown function of LM2586T-3.3 interact with the frequency adjust pin?
Pin 1 serves dual purpose: applying ≥3V shuts down the LM2586T-3.3, while a resistor to ground sets frequency. To retain both functions, TI recommends using an isolation diode (e.g., 1N4148) between the enable signal and Pin 1 - ensuring shutdown control doesn't interfere with frequency programming.
LM2586T-3.3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-220-7 Formed Leads
- Packaging:
- Tube
- 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):
- 3.3V
- Voltage - Output (Max):
- -
- Current - Output:
- 3A (Switch)
- Frequency - Switching:
- 100kHz ~ 200kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-7
LM2586T-3.3 FAQ
1.How can I place an order for LM2586T-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2586T-3.3 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 LM2586T-3.3 reliable?
The price and inventory of LM2586T-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2586T-3.3 is usually 5 days.
3.What payment methods are accepted for LM2586T-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2586T-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2586T-3.3?
LM2586T-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2586T-3.3 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 LM2586T-3.3?
For technical support, including LM2586T-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2586T-3.3 requirements.
6.How does Aetrix verify that LM2586T-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2586T-3.3 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 LM2586T-3.3 meets industry standards.
7.What is the process for return or replacement of LM2586T-3.3?
All LM2586T-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2586T-3.3, 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 LM2586T-3.3 part is unused and in its original packaging.
Return procedure for LM2586T-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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