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Texas Instruments LM2599T-12
- Part No.:
- LM2599T-12
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-7 Formed Leads
- Datasheet:
-
LM2599T-12.pdf
- Description:
- IC REG BUCK 12V 3A TO220-7
- Quantity:
- Payment:
- Shipping:
Inventory:4,201
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Product details
Overview
LM2599T-12 from Texas Instruments is a monolithic 3A step-down (buck) switching voltage regulator with fixed 12V output, 150 kHz internal oscillator, ±4% output voltage tolerance over line and load, thermal shutdown, and current limiting. It operates from 15V to 40V input and delivers up to 3A continuous output current in TO-220 package for industrial power supply rails.
For engineers reviewing the LM2599T-12 datasheet, LM2599T-12 pinout, LM2599T-12 application, or LM2599T-12 equivalent, key selection criteria include input voltage range (up to 40V), guaranteed 3A output current, fixed 12V output accuracy, thermal protection behavior, and compatibility with standard off-the-shelf inductors and Schottky diodes.
Technical Context
The LM2599T-12 integrates a PWM controller, power switch, error amplifier, and fixed-frequency 150 kHz oscillator into a single IC. Its two-stage current limit protects against short-circuit and overload conditions, while the out-of-regulation flag pin provides system-level fault monitoring with programmable delay.
It uses external components - including a catch diode, output capacitor, and power inductor - to form a complete buck converter. The feedback loop is internally compensated, eliminating need for external compensation networks, and the soft-start function limits inrush current during startup.
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 adjustment. |
| Max Output Current | 3 A continuous - supports high-current loads such as motor drivers or FPGA core supplies without external current boosting. |
| Input Voltage Range | 15 V to 40 V - compatible with 24 V industrial bus systems and automotive battery-supplied applications after transient suppression. |
| Switching Frequency | 150 kHz fixed - enables use of compact, low-cost inductors (e.g., 68 µH L38 series) and reduces EMI compared to lower-frequency alternatives. |
| Efficiency | 90% at VIN = 25 V, IOUT = 3 A - minimizes thermal dissipation and simplifies heatsink requirements in enclosed enclosures. |
| Quiescent Current | 80 µA in shutdown - enables low-power standby modes in battery-backed or energy-sensitive systems. |
| Thermal Protection | Internal thermal shutdown at TJ ≥ +150°C - prevents permanent damage during sustained overload or inadequate heatsinking. |
Pinout & Package
LM2599T-12 is supplied in a 7-pin TO-220 package (NDZ0007B) with tab connected to Pin 2 (Ground). The package features vertical lead mounting and requires heatsinking via the metal tab for full 3A operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1: Input | Power input | Accepts 15–40 V DC; must be bypassed with ≥470 µF low-ESR electrolytic capacitor near the pin. |
| Pin 2: Ground | Power and signal reference | Common return for input, output, and control circuits; electrically tied to metal tab for thermal conduction. |
| Pin 3: Output | Regulated 12 V source | Drives inductor and load; requires low-ESR output capacitor (e.g., 220 µF/25 V) placed adjacent to pin. |
| Pin 4: Feedback | Output voltage sensing | Not used in fixed-output versions - internally connected to 12 V divider; must remain unconnected. |
| Pin 5: Shutdown/Soft-start | Enable and ramp control | Pull below 0.6 V to disable; apply rising voltage to control startup slew rate and limit inrush. |
| Pin 6: Flag | Fault indicator | Open-collector output pulled low when VOUT drops below 92–98% of nominal - signals undervoltage to host controller. |
| Pin 7: Delay | Flag timing control | Connects to 0.1 µF capacitor to ground to set flag assertion delay (≈10 ms typical) and prevent false triggers during transients. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated soft-start | Programmable startup ramp via external capacitor on Pin 5 - eliminates output overshoot and reduces stress on input capacitors. |
| Out-of-regulation flag with delay | Dedicated open-drain flag pin with adjustable delay (via Pin 7 capacitor) - enables reliable fault detection without microcontroller polling. |
| Two-stage current limiting | Peak current limit (3.4–3.6 A min) plus foldback stage - sustains safe operation under short-circuit while limiting power dissipation. |
| Thermal shutdown with hysteresis | Shuts down at +150°C junction temperature and restarts only after cooling by ≈20°C - prevents thermal runaway in poorly ventilated designs. |
| Low standby current | 80 µA shutdown current - suitable for always-on systems where quiescent draw must remain below 100 µA. |
Applications
| Industrial Power Rails | Automotive Subsystem Supplies |
|---|---|
Use Scenario: Providing stable 12 V power to PLC I/O modules, sensor interfaces, and relay drivers in factory automation cabinets. IC Role / Device Role / Timing Role: Primary buck regulator converting 24 V DC bus to regulated 12 V rail for logic and analog circuitry. Use Value: Delivers 3 A continuously with ±4% regulation across wide temperature and load variation, ensuring consistent performance in harsh environments. | Use Scenario: Generating 12 V supply for infotainment head units, telematics gateways, or ADAS camera modules from vehicle battery (12–16 V nominal). IC Role / Device Role / Timing Role: Pre-regulator stepping down battery voltage before linear post-regulation for noise-sensitive audio or RF sections. Use Value: 90% efficiency at 25 V input/3 A load minimizes heat generation in space-constrained automotive enclosures. |
| On-Card Switching Supplies | Positive-to-Negative Converters |
Use Scenario: Local 12 V generation on high-density PCBs where centralized power distribution introduces excessive IR drop or noise coupling. IC Role / Device Role / Timing Role: Point-of-load (POL) buck converter mounted directly beside FPGA or DSP requiring clean, localized 12 V supply. Use Value: Fixed 12 V output eliminates need for external feedback resistors, reducing BOM count and layout sensitivity. | Use Scenario: Building an inverting buck-boost stage to generate −12 V from a +12 V source for op-amp biasing or analog front-end circuitry. IC Role / Device Role / Timing Role: Core switching controller in inverting topology using external inductor, diode, and capacitor. Use Value: 150 kHz fixed frequency allows predictable filter design and EMI filtering for dual-rail analog systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596T-12 | Lower 1.5 A output current rating; same 150 kHz frequency and TO-220 package; no flag/delay pins. | Suitable only for ≤1.5 A loads; lacks fault signaling capability required for safety-monitored systems. | Select LM2596T-12 only if load current is ≤1.5 A and fault reporting is unnecessary. |
| LM2678-12 | Higher 5 A output current; 260 kHz switching frequency; requires external compensation; no integrated soft-start or flag. | Better for high-current, high-efficiency designs but increases design complexity and component count. | Choose LM2678-12 when >3 A output or higher efficiency at light loads is critical, and design resources allow tuning. |
Compared with LM2596T-12, LM2599T-12 adds 100% more output current headroom and integrated fault signaling; versus LM2678-12, it trades peak current capability for plug-and-play simplicity, built-in soft-start, and robust supervision features - making it optimal for mid-power industrial and automotive applications where reliability and ease of use are prioritized.
Availability
LM2599T-12 is available at Aetrix Electronics and suitable for industrial power rails, automotive subsystem supplies, and on-card switching regulators requiring stable component supply and long-term manufacturability.
Supply support for LM2599T-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 company specializing in analog, embedded processing, and power management technologies, with decades of leadership in power conversion ICs.
The LM2599 series belongs to TI's SIMPLE SWITCHER® portfolio - designed specifically for engineers needing robust, easy-to-implement DC/DC buck regulators with minimal external components and built-in protection features.
FAQ
What is the maximum input voltage for LM2599T-12?
The absolute maximum input voltage for LM2599T-12 is 45 V, but the recommended operating range is 15 V to 40 V per the datasheet. Exceeding 40 V risks violating the specified operating conditions and may reduce reliability or trigger overvoltage stress on internal circuitry. For 24 V industrial systems, this margin accommodates transients up to 40 V without derating.
Does LM2599T-12 require external compensation components?
No, LM2599T-12 does not require external compensation components. It features internal frequency compensation optimized for standard buck configurations with common inductor and capacitor values. This eliminates the need for external RC networks and simplifies design - a key advantage over controllers like LM2678 that require manual loop compensation.
Can LM2599T-12 be used in a negative-output configuration?
Yes, LM2599T-12 can be used in a positive-to-negative buck-boost configuration to generate −12 V. The datasheet explicitly lists "Positive to Negative Converter" as an application. In this topology, the IC regulates the magnitude of the inverted output, and the fixed 12 V internal reference ensures stable negative rail generation when implemented per Figure 24 guidelines.
What is the purpose of the Delay pin (Pin 7) on LM2599T-12?
The Delay pin (Pin 7) on LM2599T-12 sets the time delay before the Flag pin asserts during an output undervoltage condition. Connecting a 0.1 µF capacitor from Pin 7 to ground yields ~10 ms delay, preventing false flag assertions during brief load transients or startup. This improves system robustness by distinguishing between momentary dips and true faults.
Is LM2599T-12 RoHS compliant and halogen-free?
Yes, LM2599T-12 is RoHS compliant and halogen-free per Texas Instruments' official product change notices and packaging data. The TO-220 NDZ package meets JEDEC standards for lead-free soldering (260°C, 10 sec), and TI confirms compliance with EU RoHS Directive 2011/65/EU and JESD204B material content requirements for all LM2599T-12 production lots.
LM2599T-12 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-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 12V
- Voltage - Output (Max):
- -
- Current - Output:
- 3A
- Frequency - Switching:
- 150kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- TO-220-7
LM2599T-12 FAQ
1.How can I place an order for LM2599T-12 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2599T-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 LM2599T-12 reliable?
The price and inventory of LM2599T-12 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2599T-12 is usually 5 days.
3.What payment methods are accepted for LM2599T-12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2599T-12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2599T-12?
LM2599T-12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2599T-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 LM2599T-12?
For technical support, including LM2599T-12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2599T-12 requirements.
6.How does Aetrix verify that LM2599T-12 is sourced from the original manufacturer or authorized distributors?
All LM2599T-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 LM2599T-12 meets industry standards.
7.What is the process for return or replacement of LM2599T-12?
All LM2599T-12 units undergo pre-shipment inspection (PSI). If there is an issue with LM2599T-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 LM2599T-12 part is unused and in its original packaging.
Return procedure for LM2599T-12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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