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Texas Instruments LM2598S-12
- Part No.:
- LM2598S-12
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2598S-12.pdf
- Description:
- IC REG BUCK 12V 1A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:4,290
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Product details
Overview
LM2598S-12 from Texas Instruments is a monolithic 150 kHz step-down (buck) switching regulator IC delivering a fixed 12 V output at up to 1 A, with ±4% output voltage tolerance over line and load, input voltage range up to 40 V, and thermal shutdown/current limit protection. It operates in TO-220 and DDPAK packages and is used in on-card DC/DC conversion for industrial power supplies.
For engineers reviewing the LM2598S-12 datasheet, LM2598S-12 pinout, LM2598S-12 application, or LM2598S-12 equivalent, key selection considerations include its fixed 12 V output, 150 kHz oscillator frequency, 1 A guaranteed output current, 85 μA standby quiescent current, and built-in soft-start/shutdown control - all critical for reliable mid-power buck converter design.
Technical Context
The LM2598S-12 integrates a PWM controller, power switch, and internal frequency compensation in a single IC. Its 150 kHz fixed-frequency oscillator enables use of standard off-the-shelf inductors and reduces filter size versus lower-frequency regulators. The device employs a two-stage current limit and thermal shutdown for fault protection.
It features an out-of-regulation error flag with programmable delay, shutdown/soft-start control via a dedicated pin, and feedback reference voltage of 1.23 V (for adjustable versions); the fixed-12V variant uses internal resistor divider. Input voltage range spans 15 V to 40 V for stable operation under varying supply conditions.
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 external feedback network. |
| Max Output Current | 1 A continuous - supports mid-power applications such as FPGA core supplies or sensor interface rails. |
| Switching Frequency | 150 kHz fixed - allows use of compact, low-cost 68 µH inductors (e.g., L30 code) and simplifies EMI filtering design. |
| Input Voltage Range | 15 V to 40 V - compatible with 24 V industrial bus systems and accommodates transient surges up to 45 V absolute max. |
| Quiescent Current | 85 µA in shutdown - enables low-power standby modes in battery-backed or energy-sensitive systems. |
| Efficiency | 90% typical at VIN = 25 V, IOUT = 1 A - minimizes thermal load and improves system power density. |
| Thermal Resistance | θJA = 50 °C/W (DDPAK, 0.5 in² copper) - defines heatsinking requirement; no external heatsink needed below ~50 °C ambient at full load. |
Pinout & Package
LM2598S-12 is available in a 7-pin DDPAK (surface-mount) package with exposed thermal pad for enhanced heat dissipation. Pin numbering follows TI standard KTW0007B outline.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Power Input | Accepts 15–40 V DC input; requires local 120 µF/35 V low-ESR capacitor for stability and ripple suppression. |
| 2 (OUT) | Switch Node | Drives external catch diode and inductor; high dv/dt node requiring short PCB traces and ground-plane isolation. |
| 3 (GND) | Power Ground | Common return for power stage and control circuitry; must be connected to thermal pad and low-inductance ground plane. |
| 4 (FB) | Feedback Input | Internally tied to 12 V divider; not accessible - distinguishes fixed-output version from adjustable LM2598-ADJ. |
| 5 (SD/SS) | Shutdown/Soft-Start | Pulled low (<0.6 V) disables regulator (85 µA IQ); rising voltage initiates controlled soft-start ramp. |
| 6 (FLAG) | Error Flag Output | Open-collector output pulled low when output drops below 92–98% of nominal - signals undervoltage fault after delay. |
| 7 (DELAY) | Flag Delay Control | Connects to 0.1 µF capacitor to ground to set flag assertion delay time (≈100 ms typical). |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Power Switch | Internal N-channel MOSFET with 1.2 V saturation voltage at 1 A - eliminates external switch and simplifies BOM. |
| Fixed-Frequency Oscillator | 150 kHz ±15% - enables predictable EMI spectrum and consistent inductor sizing across designs. |
| Self-Protection Circuitry | Two-stage current limit + thermal shutdown - prevents damage during overload, short-circuit, or high-ambient conditions. |
| Soft-Start Function | Externally programmable via SD/SS pin voltage ramp - prevents inrush current and output overshoot at startup. |
| Out-of-Regulation Detection | Dedicated FLAG pin with user-settable delay - provides system-level fault signaling without external monitoring circuitry. |
Applications
| Industrial DC/DC Conversion | Pre-Regulation for Linear Supplies |
|---|---|
Use Scenario: Converting 24 V factory bus to stable 12 V for PLC I/O modules and field transmitters. IC Role / Device Role / Timing Role: Primary buck regulator providing isolated, regulated 12 V rail with high efficiency and thermal robustness. Use Value: Delivers 1 A at 90% efficiency with no heatsink required below 50 °C ambient - reduces board area and system cost. | Use Scenario: Generating 12 V intermediate rail before low-noise LDOs powering precision ADCs or op-amps. IC Role / Device Role / Timing Role: Efficient pre-regulator reducing dropout and heat dissipation in linear post-regulation stages. Use Value: Low 85 µA shutdown current and tight ±4% output tolerance preserve accuracy and enable fast wake-up sequencing. |
| On-Card Power for Embedded Controllers | Positive-to-Negative Converter |
Use Scenario: Local 12 V supply on CPU carrier boards where space and thermal management are constrained. IC Role / Device Role / Timing Role: Compact surface-mount (DDPAK) buck regulator enabling high-density power delivery directly on processor board. Use Value: 7-pin DDPAK package with thermal pad achieves θJA = 20 °C/W with double-sided copper - supports 1 A continuous in tight layouts. | Use Scenario: Generating −12 V rail from +12 V input for op-amp biasing or analog signal conditioning. IC Role / Device Role / Timing Role: Buck topology reconfigured as inverting buck-boost via external inductor/diode arrangement. Use Value: Leverages same 150 kHz oscillator and current-limit architecture - enables dual-rail generation with minimal component count. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596S-12 | Same pinout, 150 kHz, but rated for 3 A output and higher peak current limit (4.5 A vs 2.4 A). | Better suited for higher-current loads; larger inductor (100 µH) typically required. | Select LM2596S-12 if future design scaling or margin beyond 1 A is needed; otherwise LM2598S-12 offers tighter footprint and lower cost. |
| MP1584EN-LF-Z | 34 V max input, 1.5 MHz switching, 3 A output, requires external feedback resistors even for fixed 12 V. | Higher frequency enables smaller magnetics but increases EMI sensitivity and layout complexity. | Choose MP1584EN-LF-Z only when board space is extremely limited and 1.5 MHz operation is acceptable; LM2598S-12 provides simpler, more robust 150 kHz solution. |
Compared with LM2596S-12 and MP1584EN-LF-Z, the LM2598S-12 delivers optimal balance of proven reliability, fixed 12 V simplicity, and thermal performance in industrial environments - making it ideal for cost-sensitive, thermally constrained 1 A applications where design reuse and long-term availability matter.
Availability
LM2598S-12 is available at Aetrix Electronics and suitable for industrial automation, embedded controller power, and instrumentation applications requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.
Supply support for LM2598S-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, embedded processing, and power management technologies, with decades of expertise in high-reliability power conversion ICs.
The LM2598 series was designed specifically for simple, robust, mid-power DC/DC buck conversion in industrial, automotive, and telecom infrastructure - emphasizing ease of use, thermal resilience, and long-term manufacturability.
FAQ
What is the maximum input voltage rating for the LM2598S-12?
The LM2598S-12 has an absolute maximum input voltage rating of 45 V, but its recommended operating input voltage range is 15 V to 40 V. Operation above 40 V risks exceeding safe operating area limits and may trigger overvoltage stress; sustained use beyond 40 V is not advised per TI's Electrical Characteristics table and Absolute Maximum Ratings section.
Does the LM2598S-12 require an external feedback resistor network?
No, the LM2598S-12 does not require an external feedback resistor network. As a fixed-output variant, it integrates the 12 V feedback divider internally. The FB pin is not accessible for adjustment - unlike the LM2598-ADJ version - ensuring consistent 12 V regulation without external component dependencies.
Can the LM2598S-12 operate without a heatsink at full 1 A load?
Yes, the LM2598S-12 in DDPAK package can operate without an external heatsink at 1 A load when ambient temperature remains ≤50 °C and PCB copper area meets minimum thermal requirements (e.g., 2.5 in² of 1 oz. copper). TI's datasheet confirms this in the "Typical Applications" section and thermal resistance table (θJA = 30 °C/W with 2.5 in² copper).
What is the purpose of the DELAY pin on the LM2598S-12?
The DELAY pin on the LM2598S-12 sets the response time of the FLAG output. Connecting a capacitor (typically 0.1 µF) between DELAY and GND introduces a delay before the FLAG pin asserts low during output undervoltage events. This prevents false triggering from transient dips and ensures only sustained regulation loss activates the fault signal.
How does the LM2598S-12 handle thermal overload conditions?
The LM2598S-12 incorporates internal thermal shutdown that disables the power switch when junction temperature exceeds +150 °C. Once temperature falls below the hysteresis threshold (~135 °C), normal operation resumes automatically. This protection is independent of current limit and operates continuously - safeguarding the LM2598S-12 during prolonged overload or poor heatsinking scenarios.
LM2598S-12 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- 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:
- 1A
- Frequency - Switching:
- 150kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TO-263 (DDPAK-7)
LM2598S-12 FAQ
1.How can I place an order for LM2598S-12 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2598S-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 LM2598S-12 reliable?
The price and inventory of LM2598S-12 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2598S-12 is usually 5 days.
3.What payment methods are accepted for LM2598S-12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2598S-12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2598S-12?
LM2598S-12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2598S-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 LM2598S-12?
For technical support, including LM2598S-12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2598S-12 requirements.
6.How does Aetrix verify that LM2598S-12 is sourced from the original manufacturer or authorized distributors?
All LM2598S-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 LM2598S-12 meets industry standards.
7.What is the process for return or replacement of LM2598S-12?
All LM2598S-12 units undergo pre-shipment inspection (PSI). If there is an issue with LM2598S-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 LM2598S-12 part is unused and in its original packaging.
Return procedure for LM2598S-12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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