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Texas Instruments LM2585SX-5.0/NOPB
- Part No.:
- LM2585SX-5.0/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-6, D2PAK (5 Leads + Tab), TO-263BA
- Datasheet:
-
LM2585SX-5.0/NOPB.pdf
- Description:
- IC REG BOOST FLYBACK 5V 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:862
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Product details
Overview
LM2585SX-5.0/NOPB from Texas Instruments is a monolithic 5-V fixed-output step-up (boost) and flyback DC-DC converter IC with integrated 3-A NPN switch, 100-kHz fixed-frequency oscillator, current-mode control, and ±4% system output voltage tolerance over line and load. It operates from 4 V to 40 V input and supports isolated or non-isolated topologies in industrial power supplies and battery-backed systems.
For engineers reviewing the LM2585SX-5.0/NOPB datasheet, LM2585SX-5.0/NOPB pinout, LM2585SX-5.0/NOPB application, or LM2585SX-5.0/NOPB equivalent, key selection criteria include input voltage range (4–40 V), output current capability (≤1.1 A typical at 5 V), thermal performance in TO-263 package, and compatibility with standard flyback transformers or boost inductors.
Technical Context
The LM2585SX-5.0/NOPB implements current-mode control using an internal error amplifier (transconductance = 0.75 mmho typ., gain = 165 V/V typ.) and comparator that compares ramp voltage (proportional to switch current) against the error amp output. This architecture delivers improved line/load transient response and inherent cycle-by-cycle current limiting.
Its 100-kHz fixed-frequency oscillator enables predictable EMI filtering and small magnetics sizing. The device integrates undervoltage lockout (3.3 V threshold), thermal shutdown, soft-start (11 μA start-up current), and switch protection-enabling robust operation without external supervision circuitry in flyback or boost configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5.0 V ±4% over full line/load/temperature range - ensures stable rail for logic or analog circuitry without external feedback resistors. |
| Input Voltage Range | 4 V to 40 V - supports wide-input applications including automotive (cold-crank), industrial 24-V rails, and multi-cell battery systems. |
| Switch Current Rating | 3 A peak, 65-V blocking - enables high-power boost/flyback designs with external diode and transformer selection per TI's recommended guidelines. |
| Switching Frequency | 100 kHz (±15 kHz) - balances efficiency, magnetics size, and EMI filter complexity; fixed frequency simplifies layout and noise mitigation. |
| Reference Voltage | 5.0 V at FB pin (4.913–5.088 V min/max) - defines regulation setpoint; internal reference eliminates need for precision external divider in fixed-output version. |
| Efficiency | 80% at VIN = 12 V, IOUT = 0.6 A - reflects real-world performance in typical boost configuration with standard external components. |
| Thermal Resistance (θJA) | 35°C/W (DDPAK/TO-263, 0.4896 in² copper) - enables >1.5 W continuous dissipation without heatsink under defined PCB layout conditions. |
Pinout & Package
LM2585SX-5.0/NOPB is packaged in a 5-pin DDPAK/TO-263 (KTT) surface-mount package with exposed thermal pad (10.16 mm × 8.42 mm nominal body size). The package provides low thermal resistance and is optimized for high-current switching regulator layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN | Input Supply | Primary DC input connection (4–40 V); requires local ceramic bypass capacitor near pin for stability and EMI suppression. |
| SW | Switch Node | Collector of internal 3-A NPN transistor; connects to primary winding (flyback) or inductor (boost); high dv/dt node requiring careful routing. |
| GND | Power Ground | Common return for input capacitor, output rectifier, and control circuitry; must be tied to thermal pad for optimal thermal performance. |
| FB | Feedback Input | Senses regulated output via internal 5-V reference; in fixed 5-V version, internally connected to output divider - no external resistor required. |
| COMP | Error Amplifier Output | Provides compensation node for loop stability; connects to RC network between COMP and GND to tailor bandwidth and phase margin. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 3-A NPN Switch | Eliminates external transistor and driver, reducing BOM count and board area in cost-sensitive boost/flyback designs. |
| Current-Mode Control | Enables fast transient response and inherent current limiting without additional sensing resistors - critical for reliable overload handling. |
| Internal Soft-Start | 11 μA soft-start current limits in-rush during power-up, preventing input rail collapse and reducing stress on input capacitors and diodes. |
| Undervoltage Lockout (UVLO) | 3.3 V turn-on threshold prevents erratic operation during brownout or cold-crank conditions - improves system robustness in automotive environments. |
| Thermal Shutdown Protection | Activates at 150°C junction temperature and latches off until cool-down - safeguards device and surrounding components during sustained overload. |
Applications
| Industrial Power Supply | Battery-Backed Telemetry |
|---|---|
Use Scenario: Generating isolated 5-V rail from 12-V or 24-V industrial bus for PLC I/O modules and sensor interfaces. IC Role / Device Role / Timing Role: Flyback controller with fixed 5-V output; regulates secondary-side voltage using primary-side sensing and current-mode feedback. Use Value: Achieves ±4% output accuracy across −40°C to +125°C ambient without optocoupler or secondary-side references - reduces component count and calibration effort. |
Use Scenario: Boosting voltage from aging 3.6-V Li-ion battery to stable 5-V USB-powered telemetry module during discharge down to 3.0 V. IC Role / Device Role / Timing Role: Step-up (boost) regulator with 100-kHz fixed-frequency operation enabling compact inductor selection and predictable EMI profile. Use Value: Maintains regulated 5-V output at ≥0.6 A up to 40-V input transients (e.g., load dump), supporting uninterrupted data transmission in remote monitoring nodes. |
| Automotive Body Control | Legacy Equipment Retrofit |
Use Scenario: Providing 5-V logic supply in body control unit (BCU) where input may dip to 4 V during cranking or surge to 40 V during load dump. IC Role / Device Role / Timing Role: Wide-VIN boost/flyback controller with UVLO (3.3 V) and thermal shutdown - ensures safe startup and fault recovery. Use Value: Operates continuously across full automotive temperature range (−40°C to +125°C) with no derating, meeting OEM reliability requirements for under-hood electronics. |
Use Scenario: Replacing obsolete linear regulators in legacy test equipment requiring 5-V/1-A output from variable 6–18-V DC input. IC Role / Device Role / Timing Role: Drop-in replacement for inefficient 7805-based solutions; uses same footprint as TO-220 variants but offers higher efficiency and thermal headroom. Use Value: Reduces heat sink size by >50% versus linear solution while delivering identical 5-V output - extends equipment service life and lowers cooling costs. |
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 |
|---|---|---|---|
| LM2585T-5.0/NOPB | TO-220-5 package (14.986 mm × 10.16 mm); higher θJA (65°C/W, no heatsink) vs. LM2585SX-5.0/NOPB (35°C/W with 0.4896 in² copper). | Preferred for prototyping, through-hole assembly, or lower-power applications (<0.8 A continuous) where thermal mass of TO-220 suffices. | Select LM2585T-5.0/NOPB when manual soldering, socket testing, or mechanical mounting constraints favor through-hole form factor. |
| LM2587SX-5.0/NOPB | Higher 5-A switch rating, 65-V blocking, and identical 5-V fixed output; shares pinout and functional block diagram with LM2585 family. | Supports higher output current (up to 2.5 A typical) and heavier loads - suitable for applications needing greater power headroom or future scalability. | Choose LM2587SX-5.0/NOPB when design requires >1.1 A continuous output or anticipates increased load in next revision - same layout, no redesign needed. |
Compared with LM2585T-5.0/NOPB, LM2585SX-5.0/NOPB offers superior thermal performance in surface-mount production; compared with LM2587SX-5.0/NOPB, it delivers identical 5-V regulation at lower cost and smaller footprint where 1.1-A output suffices.
Availability
LM2585SX-5.0/NOPB is available at Aetrix Electronics and suitable for industrial power supplies, battery-backed telemetry systems, and automotive body control units requiring stable component supply and long-term manufacturability.
Supply support for LM2585SX-5.0/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, specializing in analog, embedded processing, and power management technologies with over 50 years of innovation in power conversion ICs.
The LM2585 series was designed specifically for cost-effective, low-component-count flyback, boost, and forward converter applications - targeting industrial, automotive, and telecom power systems where reliability and wide input range are critical.
FAQ
What is the maximum continuous output current supported by the LM2585SX-5.0/NOPB in boost configuration?
The LM2585SX-5.0/NOPB supports up to 1.1 A continuous output current in boost topology at VIN = 12 V, as specified in Section 6.6 of the datasheet. Output current is limited by internal switch current (3 A peak), thermal dissipation, and external component selection - exceeding 1.1 A requires careful thermal design and may reduce reliability.
Does the LM2585SX-5.0/NOPB require external feedback resistors to set the 5-V output?
No. The LM2585SX-5.0/NOPB is a fixed-output variant with internal feedback divider configured for 5.0 V regulation. The FB pin is internally connected to the reference; no external resistors are needed - simplifying design and improving accuracy versus adjustable versions.
Can the LM2585SX-5.0/NOPB be used in flyback topology with primary-side regulation only?
Yes. The LM2585SX-5.0/NOPB is explicitly designed for flyback operation with primary-side sensing. Its current-mode control and internal 5-V reference enable accurate output regulation without optocouplers or secondary-side feedback - as demonstrated in Figure 22–27 of the datasheet.
What is the purpose of the COMP pin on the LM2585SX-5.0/NOPB, and how is it used?
The COMP pin is the error amplifier output, used to connect external compensation components (typically RC network to GND) that stabilize the control loop. Proper COMP network design ensures adequate phase margin (>45°) and transient response - TI provides design guidelines and example values in Section 8.2.1 and Figure 18–21.
How does the LM2585SX-5.0/NOPB handle input undervoltage conditions?
The LM2585SX-5.0/NOPB incorporates an undervoltage lockout (UVLO) circuit with 3.3 V turn-on threshold and hysteresis. When input drops below ~3.05 V, the device disables switching and enters low-current standby mode (IS ≈ 11 mA), preventing erratic operation and ensuring clean restart once VIN exceeds 3.75 V.
LM2585SX-5.0/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):
- 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:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-5)
LM2585SX-5.0/NOPB FAQ
1.How can I place an order for LM2585SX-5.0/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2585SX-5.0/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 LM2585SX-5.0/NOPB reliable?
The price and inventory of LM2585SX-5.0/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2585SX-5.0/NOPB is usually 5 days.
3.What payment methods are accepted for LM2585SX-5.0/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2585SX-5.0/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2585SX-5.0/NOPB?
LM2585SX-5.0/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2585SX-5.0/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 LM2585SX-5.0/NOPB?
For technical support, including LM2585SX-5.0/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2585SX-5.0/NOPB requirements.
6.How does Aetrix verify that LM2585SX-5.0/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2585SX-5.0/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 LM2585SX-5.0/NOPB meets industry standards.
7.What is the process for return or replacement of LM2585SX-5.0/NOPB?
All LM2585SX-5.0/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2585SX-5.0/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 LM2585SX-5.0/NOPB part is unused and in its original packaging.
Return procedure for LM2585SX-5.0/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2585SX-5.0/NOPB Tags
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