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Texas Instruments LM2598SX-12/NOPB
- Part No.:
- LM2598SX-12/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2598SX-12/NOPB.pdf
- Description:
- IC REG BUCK 12V 1A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:903
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Product details
Overview
LM2598SX-12/NOPB from Texas Instruments is a monolithic 150-kHz nonsynchronous step-down (buck) DC-DC converter delivering 1-A output current with fixed 12-V output, ±4% output voltage tolerance over line and load, and input voltage range up to 40 V. It integrates internal frequency compensation, thermal shutdown, current limiting, and soft-start/shutdown control - used in industrial power supplies and embedded system point-of-load regulation.
For engineers reviewing the LM2598SX-12/NOPB datasheet, LM2598SX-12/NOPB pinout, LM2598SX-12/NOPB application, or LM2598SX-12/NOPB equivalent, key selection criteria include its fixed 12-V output, TO-263-7 (DDPAK) package, 150-kHz switching frequency enabling compact filter design, and integrated error flag with programmable delay for system reset sequencing.
Technical Context
The LM2598SX-12/NOPB implements a nonsynchronous buck topology with an internal NPN power switch and fixed-frequency 150-kHz oscillator. Its feedback loop uses a precision 1.23-V reference and external resistor divider to regulate output, while the error flag pin provides open-collector dropout detection at 95% of nominal output with delay timing set by an external capacitor on the DELAY pin.
Shutdown/Soft-start functionality is implemented via a single dual-purpose pin that accepts logic-level signals for enable/disable control and supports capacitor-based ramp control of output voltage rise time. Protection includes two-stage current limiting, thermal shutdown, and internal clamping on all pins except OUT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 12 V ±4% over full line/load/temperature range - ensures stable rail for microcontrollers and analog circuitry without external feedback resistors. |
| Max Output Current | 1 A DC - supports moderate-power loads such as FPGAs, sensors, and communication interfaces without external current boosting. |
| Input Voltage Range | 4.5 V to 40 V - accommodates wide-input industrial and automotive supply rails including 12-V, 24-V, and 36-V nominal systems. |
| Switching Frequency | 150 kHz ±15% - enables use of low-cost, standard off-the-shelf inductors and reduces EMI compared to higher-frequency alternatives. |
| Quiescent Current (Standby) | 85 μA typical - minimizes battery drain in always-on or low-power monitoring applications when shutdown is asserted. |
| Efficiency | 90% typical at VIN = 25 V, IOUT = 1 A - reduces thermal load and improves power density in space-constrained designs. |
| Thermal Shutdown | Active at TJ ≥ 150°C - protects device under overload or poor heatsinking conditions without requiring external thermal management circuitry. |
Pinout & Package
LM2598SX-12/NOPB is housed in a 7-pin TO-263 (DDPAK) surface-mount package with exposed thermal pad for enhanced heat dissipation. The package measures 10.10 mm × 8.89 mm and is rated for junction temperatures up to 150°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUT) | Power Switch Output | Internal NPN collector node; switches between ~VIN–1.2 V and –0.5 V; requires minimal PCB copper area to reduce EMI coupling. |
| 2 (+VIN) | Input Supply | Main power input (4.5–40 V); must be bypassed with low-ESR capacitor close to pin to support high di/dt switching currents. |
| 3 (FLAG) | Error Flag Output | Open-collector signal pulled low when VOUT drops below 95% of 12 V; used for microprocessor reset or fault indication. |
| 4 (GND) | Power Ground | Common return for internal circuitry and power switch emitter; must be connected to thermal pad for optimal thermal performance. |
| 5 (DELAY) | Flag Delay Control | Sets time delay between VOUT reaching 95% and FLAG going high via external capacitor; enables controlled power-up sequencing. |
| 6 (FB) | Feedback Input | Not used in fixed-output versions - internally connected to 12-V divider; must be left open per datasheet guidance. |
| 7 (SD/SS) | Shutdown/Soft-start | Logic-level enable (low = shutdown, IQ ≈ 85 μA); adding capacitor provides controlled VOUT ramp to limit inrush current. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Soft-start | Capacitor-programmable output voltage ramp rate - prevents input inrush and stabilizes downstream LDOs or clock circuits during power-up. |
| Error Flag with Delay | Programmable delay before flag assertion ensures reliable power-good signaling after transient settling - avoids false resets during startup overshoot. |
| Nonsynchronous Buck Architecture | Single external Schottky catch diode required - simplifies BOM and layout versus synchronous designs while maintaining >90% efficiency at 1-A load. |
| Thermal & Current Protection | Two-stage current limit + thermal shutdown - eliminates need for external foldback or thermal sensors in rugged industrial environments. |
| Wide Input Range Support | Operates down to 4.5 V - enables compatibility with brownout-prone 12-V systems and battery-backed inputs without pre-regulation. |
Applications
| Industrial PLC Power Supply | Automotive Body Control Module |
|---|---|
Use Scenario: Providing regulated 12-V rail from vehicle battery (9–16 V) to power MCU, CAN transceivers, and sensor interfaces in body control units. IC Role / Device Role / Timing Role: Primary step-down regulator converting unregulated battery input to stable 12-V supply; operates at fixed 150-kHz frequency to avoid AM radio band interference. Use Value: Integrated shutdown allows MCU-controlled power cycling; error flag enables safe firmware-initiated reset before entering sleep mode. | Use Scenario: Generating clean 12-V supply from 24-V industrial bus for programmable logic controllers with isolated I/O modules. IC Role / Device Role / Timing Role: On-card buck converter delivering 1-A load current; fixed 12-V output eliminates feedback resistor calibration and improves long-term stability. Use Value: 40-V max input rating tolerates 24-V system transients (e.g., load dump); thermal shutdown protects against enclosure overheating in sealed enclosures. |
| Medical Diagnostic Sensor Hub | Test & Measurement Equipment |
Use Scenario: Powering analog front-end circuitry (ADC drivers, op-amps) in portable ultrasound or ECG devices requiring low-noise, stable 12-V bias. IC Role / Device Role / Timing Role: Preregulator feeding low-dropout linear regulators; 150-kHz switching frequency allows effective LC filtering to meet stringent analog noise requirements. Use Value: Soft-start prevents voltage overshoot into sensitive analog stages; ±4% output tolerance ensures consistent gain calibration across temperature. | Use Scenario: Supplying 12-V rail to FPGA configuration circuitry and high-speed ADCs in benchtop oscilloscopes and signal analyzers. IC Role / Device Role / Timing Role: Point-of-load regulator located near FPGA power pins; TO-263 package enables direct thermal coupling to PCB copper pour for passive cooling. Use Value: 1-A current capability supports FPGA core + I/O bank loads; error flag synchronizes FPGA configuration with power-good status. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596SX-12/NOPB | Same family, 150-kHz, 3-A output current, larger TO-263-5 package; no DELAY or FLAG pins. | Lacks error flag and programmable delay - unsuitable where power-good sequencing or fault reporting is required. | Select when higher output current is needed and flag/delay features are unnecessary; requires different PCB footprint. |
| LM2678SX-12/NOPB | Higher 2.5-A output, 260-kHz switching frequency, improved efficiency (92%), but no integrated soft-start or error flag delay. | Higher frequency demands tighter layout control and smaller inductors; lacks dedicated delay timing for reset coordination. | Choose for higher current and efficiency where soft-start timing and flag delay are managed externally. |
Compared with LM2596SX-12/NOPB and LM2678SX-12/NOPB, the LM2598SX-12/NOPB uniquely combines 1-A output with integrated error flag delay and soft-start - making it optimal for applications requiring deterministic power-up sequencing and compact, feature-complete buck regulation without external supervision circuitry.
Availability
LM2598SX-12/NOPB is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and medical instrumentation requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for LM2598SX-12/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 leader specializing in analog, embedded processing, and power management ICs, with decades of expertise in high-reliability power conversion solutions.
The LM2598 series belongs to TI's SIMPLE SWITCHER® portfolio - designed specifically for ease-of-use in cost-sensitive, medium-power DC-DC applications where minimal external components and robust protection are essential.
FAQ
What is the maximum input voltage rating for the LM2598SX-12/NOPB?
The LM2598SX-12/NOPB has an absolute maximum input voltage rating of 45 V, with recommended operating range from 4.5 V to 40 V. Exceeding 40 V continuously may trigger internal protection or reduce reliability; operation at 40 V is validated in datasheet test conditions for the 12-V version with 1-A load.
Does the LM2598SX-12/NOPB require external feedback resistors?
No - the LM2598SX-12/NOPB is a fixed-output variant with internal resistor divider set for 12 V. Pin 6 (FB) is not connected internally to the output and must be left open per TI's datasheet guidance; adding external resistors would disrupt regulation.
How does the error flag (FLAG) pin function on the LM2598SX-12/NOPB?
The FLAG pin on the LM2598SX-12/NOPB is an open-collector output that pulls low when the regulated 12-V output falls below 95% (11.4 V). It remains low until VOUT reaches 95% and the DELAY pin capacitor charges - providing a programmable power-good assertion window for system reset coordination.
Can the LM2598SX-12/NOPB be used in negative voltage applications?
Yes - the LM2598SX-12/NOPB supports inverting configurations (e.g., +12 V to –12 V) using the standard buck topology with ground pin bootstrapped to the negative output. Datasheet Figure 21 confirms this use case, though output current is reduced due to increased voltage stress across the switch.
What thermal considerations apply to the LM2598SX-12/NOPB in TO-263 package?
In the TO-263 (KTW) package, the LM2598SX-12/NOPB achieves RθJA ≈ 30°C/W with 2.5 in² of 1-oz copper and ≈20°C/W with 3 in² double-sided copper. Thermal pad must be soldered to PCB ground plane; ambient temperature must stay ≤125°C, and junction temperature must not exceed 150°C under continuous 1-A load.
LM2598SX-12/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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)
LM2598SX-12/NOPB FAQ
1.How can I place an order for LM2598SX-12/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2598SX-12/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 LM2598SX-12/NOPB reliable?
The price and inventory of LM2598SX-12/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2598SX-12/NOPB is usually 5 days.
3.What payment methods are accepted for LM2598SX-12/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2598SX-12/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2598SX-12/NOPB?
LM2598SX-12/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2598SX-12/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 LM2598SX-12/NOPB?
For technical support, including LM2598SX-12/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2598SX-12/NOPB requirements.
6.How does Aetrix verify that LM2598SX-12/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2598SX-12/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 LM2598SX-12/NOPB meets industry standards.
7.What is the process for return or replacement of LM2598SX-12/NOPB?
All LM2598SX-12/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2598SX-12/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 LM2598SX-12/NOPB part is unused and in its original packaging.
Return procedure for LM2598SX-12/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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