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Texas Instruments LM2585T-5.0
- Part No.:
- LM2585T-5.0
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-5 Formed Leads
- Datasheet:
-
LM2585T-5.0.pdf
- Description:
- IC REG BST FLYBACK 5V 3A TO220-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,045
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Product details
Overview
LM2585T-5.0 from Texas Instruments is a monolithic 3-A step-up (boost) and flyback DC-DC converter IC with fixed 5.0-V output, 4-V to 40-V input range, 100-kHz fixed-frequency operation, NPN internal switch rated for 65-V standoff, and ±4% system output voltage tolerance over line and load. It enables compact, low-component-count isolated or non-isolated power supplies in industrial control and automotive subsystems.
For engineers reviewing the LM2585T-5.0 datasheet, LM2585T-5.0 pinout, LM2585T-5.0 application, or LM2585T-5.0 equivalent, key selection criteria include its 3-A NPN switch capability, current-mode control architecture for transient response, internal soft-start function, undervoltage lockout at 3.3 V, and thermal shutdown protection - all critical for reliable high-input-voltage boost/flyback designs.
Technical Context
The LM2585T-5.0 implements current-mode control using an internal error amplifier (transconductance = 0.75 mmho, voltage gain = 165 V/V), comparator, and 100-kHz oscillator to regulate output by modulating peak switch current. Its feedback pin references a trimmed 5.0-V internal reference (±1.5% over temperature), enabling stable regulation without external resistor dividers.
Operation relies on cycle-by-cycle current limiting, thermal shutdown at 150°C junction temperature, and undervoltage lockout that disables switching below 3.05 V input. The NPN switch exhibits 0.45-V saturation voltage at 3 A and sustains up to 65 V, supporting wide VIN applications including 24-V industrial rails and automotive battery-supplied systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0 V ±4% over full line/load/temperature range - eliminates external feedback resistors and simplifies layout. |
| Input Voltage Range | 4 V to 40 V - supports direct connection to 12-V/24-V battery systems and unregulated industrial supplies. |
| Switch Current Rating | 3 A continuous - enables ≥1.1 A output at 5 V in boost mode with typical efficiency of 80% at 12-V input. |
| Oscillator Frequency | 100 kHz ±15% - permits use of small, low-cost magnetics and reduces EMI compared to higher-frequency alternatives. |
| Reference Voltage | 5.0 V at FB pin - internally trimmed and temperature-compensated, enabling precise output regulation without calibration. |
| UVLO Threshold | 3.30 V (typ), 3.05–3.75 V (min/max) - prevents erratic startup during brownout and ensures clean enable/disable behavior. |
| Thermal Shutdown | 150°C junction temperature - protects device under overload or poor heatsinking; auto-recovery after cooldown. |
Pinout & Package
LM2585T-5.0 is available in TO-220 (NDH) and DDPAK/TO-263 (KTT) packages. Both are 5-pin thermally enhanced variants with exposed metal pads for heatsink attachment. Pin functions are identical across packages.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1: Input | Power input supply connection | Accepts 4–40 V; must be decoupled with ≥100 μF low-ESR capacitor near pin for stability. |
| Pin 2: Ground | Power and signal reference node | Low-impedance return path for switch current and feedback circuitry; requires dedicated copper pour. |
| Pin 3: Feedback | Output voltage sensing input | Internally referenced to 5.0 V; no external divider needed - connect directly to regulated output. |
| Pin 4: Output | Collector of internal NPN switch | Drives external inductor or transformer primary; handles 3-A peak current and 65-V transients. |
| Pin 5: Compensation | Error amplifier output | Connect RC network (e.g., 10 kΩ + 10 nF) to stabilize loop; sets bandwidth and phase margin. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode control | Enables fast transient response and inherent cycle-by-cycle current limiting without external sense resistor. |
| Internal soft-start | 11 μA soft-start current ramps output gradually, limiting inrush into output capacitors and preventing input rail sag. |
| Integrated 3-A NPN switch | Eliminates need for external transistor and driver; reduces BOM count and PCB area in boost/flyback topologies. |
| Fixed 5.0-V output | Removes feedback resistor network, improving accuracy, reducing component count, and enhancing long-term stability. |
| Thermal & fault protection | Combines undervoltage lockout, current limit, and thermal shutdown - ensures robust operation under fault conditions. |
Applications
| Industrial Power Supply | Automotive Body Control Module |
|---|---|
|
Use Scenario: Generating stable 5-V rail from 12-V vehicle battery for microcontrollers and sensors in door modules or lighting controllers. IC Role / Device Role / Timing Role: Primary DC-DC regulator providing isolated or non-isolated 5-V output with current-mode control for load-step immunity. Use Value: Delivers 1.1 A at 80% efficiency with built-in UVLO and thermal shutdown - meets automotive cold-crank (6-V) and load-dump (40-V) requirements. |
Use Scenario: Powering CAN transceivers and EEPROMs in body control units where input voltage varies from 9 V to 16 V. IC Role / Device Role / Timing Role: Fixed-output boost converter supplying regulated 5-V bus independent of battery fluctuations. Use Value: ±4% output tolerance and 100-kHz switching ensure low noise and compatibility with sensitive digital peripherals. |
| Flyback Isolated Bias Supply | Industrial Sensor Interface |
|
Use Scenario: Providing galvanically isolated 5-V bias for op-amps and ADCs in PLC analog input modules. IC Role / Device Role / Timing Role: Flyback controller driving transformer primary; regulates secondary-side output via optocoupler feedback. Use Value: Internal 65-V switch withstands reflected flyback spikes; current-mode control improves cross-regulation in multi-output designs. |
Use Scenario: Converting 24-V factory floor supply to clean 5-V for precision 4–20 mA transmitter circuits. IC Role / Device Role / Timing Role: Step-up regulator delivering low-noise, tightly regulated 5-V rail in harsh EMI environments. Use Value: Fixed 5.0-V reference and ±4% system tolerance eliminate post-regulation LDOs, reducing heat and 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-5.0 | Same pinout and electrical specs, but includes integrated diode - reduces external component count by one. | Preferred for space-constrained designs where board area is premium; slightly higher quiescent current (15.5 mA vs 11 mA). | Select LM2587T-5.0 when minimizing external diode BOM and layout complexity outweighs minor efficiency trade-off. |
| TPS55340RTER | Wider 3.5–36-V input, 5-A switch, adjustable output - requires external feedback resistors and compensation network. | Suitable for higher-current or programmable-output applications; lacks fixed 5-V option and integrated soft-start timing. | Choose TPS55340RTER only when >1.1 A output or output voltage flexibility is required; adds design complexity. |
Compared with LM2585T-5.0, LM2587T-5.0 offers integration advantage at minor efficiency cost, while TPS55340RTER trades simplicity for scalability - making LM2585T-5.0 optimal for cost-sensitive, fixed-output 5-V boost/flyback systems requiring minimal external components.
Availability
LM2585T-5.0 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, isolated sensor interfaces, and PLC auxiliary rails requiring stable component supply and long-term manufacturability.
Supply support for LM2585T-5.0 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, specializing in analog, embedded processing, and power management technologies with broad industrial and automotive reach.
The LM2585 series was designed specifically for cost-effective, low-component-count flyback, boost, and forward converter applications - targeting engineers needing robust, thermally protected DC-DC solutions for wide-input-voltage industrial and transportation systems.
FAQ
What topology configurations does the LM2585T-5.0 support?
The LM2585T-5.0 supports boost (step-up), flyback, and forward converter topologies. In boost mode, it generates 5 V from inputs as low as 4 V; in flyback mode, it provides isolated outputs using a transformer and optocoupler feedback. Its current-mode architecture and 65-V switch rating make it especially suited for flyback designs requiring tight cross-regulation and high input voltage tolerance. All configurations use the same LM2585T-5.0 IC without modification.
Does the LM2585T-5.0 require external feedback resistors to set the output voltage?
No, the LM2585T-5.0 does not require external feedback resistors. It features an internal 5.0-V reference connected directly to the feedback (FB) pin, enabling fixed 5-V output regulation. The FB pin must be connected to the regulated output node - no resistor divider is needed, reducing component count, layout area, and potential drift sources. This distinguishes LM2585T-5.0 from adjustable versions like LM2585T-ADJ.
What thermal management is required for the LM2585T-5.0 in continuous 1-A output operation?
At 1-A output from 12-V input, LM2585T-5.0 dissipates ~1.5 W. With the TO-220 package (θJA = 65°C/W), junction temperature rise is ~98°C above ambient - requiring a heatsink to stay below 125°C max operating junction temperature. A 10°C/W heatsink reduces rise to ~25°C, enabling safe operation at 70°C ambient. The DDPAK/TO-263 version (θJA = 35°C/W) performs better on PCB copper but still benefits from thermal vias and 1–2 oz. copper pours.
How does the LM2585T-5.0 handle input voltage transients such as automotive load dump?
The LM2585T-5.0 withstands input transients up to 45 V absolute maximum, and its 65-V switch rating allows safe operation during 40-V load dump events common in 12-V automotive systems. Combined with undervoltage lockout (3.05–3.75 V), thermal shutdown, and cycle-by-cycle current limiting, it maintains regulation through cold-crank (down to 4 V) and load-dump surges without latch-up or damage - provided input filtering and clamping meet ISO 7637-2 requirements.
Can the LM2585T-5.0 be used in a SEPIC configuration?
No, the LM2585T-5.0 is not designed for SEPIC operation. Its internal NPN switch and control architecture are optimized for boost, flyback, and forward topologies - all of which rely on unidirectional switch current and specific transformer/inductor polarity relationships. SEPIC requires complementary switch control and bidirectional energy transfer not supported by the LM2585T-5.0's current-mode oscillator and error amplifier structure. Use dedicated SEPIC controllers like LM5122 for such applications.
LM2585T-5.0 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-220-5 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):
- 5V
- Voltage - Output (Max):
- -
- Current - Output:
- 3A (Switch)
- Frequency - Switching:
- 100kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-5
LM2585T-5.0 FAQ
1.How can I place an order for LM2585T-5.0 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2585T-5.0 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 LM2585T-5.0 reliable?
The price and inventory of LM2585T-5.0 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2585T-5.0 is usually 5 days.
3.What payment methods are accepted for LM2585T-5.0?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2585T-5.0 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2585T-5.0?
LM2585T-5.0 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2585T-5.0 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 LM2585T-5.0?
For technical support, including LM2585T-5.0 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2585T-5.0 requirements.
6.How does Aetrix verify that LM2585T-5.0 is sourced from the original manufacturer or authorized distributors?
All LM2585T-5.0 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 LM2585T-5.0 meets industry standards.
7.What is the process for return or replacement of LM2585T-5.0?
All LM2585T-5.0 units undergo pre-shipment inspection (PSI). If there is an issue with LM2585T-5.0, 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 LM2585T-5.0 part is unused and in its original packaging.
Return procedure for LM2585T-5.0:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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