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Texas Instruments LM2598SX-3.3/NOPB
- Part No.:
- LM2598SX-3.3/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2598SX-3.3/NOPB.pdf
- Description:
- IC REG BUCK 3.3V 1A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:266
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Product details
Overview
LM2598SX-3.3/NOPB from Texas Instruments is a monolithic 150-kHz nonsynchronous step-down (buck) DC-DC converter delivering up to 1 A output current with fixed 3.3-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 embedded power supplies where compact, high-efficiency regulation of 3.3-V logic rails is required.
For engineers reviewing the LM2598SX-3.3/NOPB datasheet, LM2598SX-3.3/NOPB pinout, LM2598SX-3.3/NOPB application, or LM2598SX-3.3/NOPB equivalent, key selection criteria include its 3.3-V fixed output accuracy, 1-A continuous load capability, TO-263-7 (DDPAK) surface-mount package, 150-kHz fixed-frequency operation enabling small external inductors, and integrated error flag with programmable delay for system reset sequencing.
Technical Context
The LM2598SX-3.3/NOPB implements a nonsynchronous buck topology with an internal NPN switch, operating at a fixed 150-kHz switching frequency (±15% tolerance). Its feedback loop uses a precision 1.23-V reference and senses output voltage via the Feedback pin, enabling stable regulation without external compensation components.
Control features include dual-function Shutdown/Soft-start pin (logic-level shutdown with ~85 μA standby current; capacitor-programmable soft-start ramp), open-collector Error Flag pin asserting low when output drops >5% below nominal, and Delay pin allowing user-defined flag assertion delay via external capacitor - all supporting robust power sequencing in microprocessor-based systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±4% over full line (4.75–40 V), load (0.1–1 A), and temperature (–25°C to +125°C) range - ensures reliable 3.3-V logic rail compliance. |
| Max Output Current | 1 A DC continuous - supports single-rail powering of microcontrollers, FPGAs, and peripheral ICs without external current boosting. |
| Switching Frequency | 150 kHz (typical), ±15% over temperature - enables use of standard, low-cost 68–100 μH shielded inductors and reduces EMI compared to higher-frequency alternatives. |
| Input Voltage Range | 4.75 V to 40 V - accommodates wide-input industrial, automotive, and telecom supply rails including 12-V and 24-V nominal systems. |
| Quiescent Current | 85 μA in shutdown mode - minimizes battery drain in always-on or low-power standby applications. |
| Efficiency | 78% typical at VIN = 12 V, IOUT = 1 A - delivers high conversion efficiency without requiring heatsinking below 50°C ambient for most PCB layouts. |
| Protection Features | Thermal shutdown, peak-current limiting (1.2–2.4 A), and undervoltage lockout - provides autonomous fault recovery without external circuitry. |
Pinout & Package
LM2598SX-3.3/NOPB is housed in a 7-pin TO-263 (DDPAK) surface-mount package with exposed thermal pad, measuring 10.10 mm × 8.89 mm. The package supports high-power dissipation via PCB copper area soldering and is RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUT) | Internal switch collector | Swings between ~VIN–1.2 V and –0.5 V; connects directly to external catch diode and inductor - requires minimal PCB copper area to reduce EMI coupling. |
| 2 (+VIN) | Positive input supply | Accepts 4.75–40 V input; requires local 100-μF low-ESR capacitor to handle high di/dt switching currents and suppress transients. |
| 3 (FLAG) | Error flag output | Open-collector output pulled low when VOUT falls >5% below 3.3 V; used as hardware reset signal for MCUs upon power failure. |
| 4 (GND) | Power and signal ground | Common return for internal circuitry, switch emitter, and feedback network - must be tied to thermal pad for optimal thermal performance. |
| 5 (DELAY) | Flag delay timing | Capacitor-connected pin setting delay time before FLAG goes high after VOUT reaches 95% of 3.3 V - enables controlled system boot timing. |
| 6 (FB) | Feedback input | Monitors regulated output via resistive divider; internally references 1.23 V - unused in fixed 3.3-V version (pin left open per datasheet). |
| 7 (SD/SS) | Shutdown/Soft-start control | Logic-low (<0.6 V) disables regulator (IQ ≈ 85 μA); capacitor to ground enables controlled VOUT ramp-up - prevents inrush current in sensitive loads. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3-V output | Eliminates external feedback resistor network, reducing BOM count and layout sensitivity while guaranteeing ±4% regulation across temperature and load. |
| Integrated soft-start | Capacitor-programmable output voltage ramp prevents input inrush current and stabilizes upstream supplies during cold start. |
| Open-collector error flag | Provides system-level power-good signaling with built-in 5% dropout threshold and user-adjustable delay - simplifies MCU reset circuit design. |
| Thermal shutdown + current limit | Two-stage protection automatically recovers after fault removal - avoids need for external thermal sensors or current-sense amplifiers. |
| 150-kHz fixed oscillator | Enables predictable EMI filtering and consistent inductor sizing across designs; eliminates need for external timing components. |
Applications
| Industrial PLC I/O Module | Automotive Body Control Unit |
|---|---|
Use Scenario: Powering isolated 3.3-V digital I/O channels in DIN-rail mounted programmable logic controllers with 24-V DC field bus input. IC Role / Device Role / Timing Role: Primary step-down regulator converting 24-V field supply to clean, regulated 3.3-V logic rail for microcontroller, CAN transceivers, and optocouplers. Use Value: Delivers 1-A continuous current with 78% efficiency at 24-V input, eliminating need for heatsink under typical 50°C ambient conditions. | Use Scenario: Generating 3.3-V supply for infotainment head-unit microprocessors and sensor interfaces from vehicle 12-V battery with load dump immunity. IC Role / Device Role / Timing Role: Buck converter front-end providing stable 3.3-V rail with error flag used as hardware reset to ensure safe boot after battery reconnection. Use Value: Withstands 40-V max input and includes thermal/current protection - survives ISO 7637-2 pulse 5a (load dump) when paired with input TVS. |
| Medical Point-of-Care Device | Networking Edge Router |
Use Scenario: Supplying 3.3-V power to ARM Cortex-M based patient monitoring subsystems powered from 12-V sealed lead-acid backup battery. IC Role / Device Role / Timing Role: Main DC-DC regulator enabling low-quiescent operation (85 μA shutdown) and soft-start to prevent brownout during battery switchover. Use Value: Soft-start limits inrush to <240 mA, avoiding voltage sag on shared 12-V rail that could disrupt other analog sensor circuits. | Use Scenario: Providing 3.3-V core voltage to Ethernet PHYs and packet processors in fanless enterprise edge routers with strict thermal envelope. IC Role / Device Role / Timing Role: High-efficiency buck regulator using TO-263 thermal pad soldered to 2.5 in² copper pour to maintain junction temp <100°C at full load. Use Value: Achieves 90°C max junction temperature at 1-A load with 2.5 in² PCB copper - meets EN 60950 touch-safe requirements without forced air. |
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-3.3/NOPB | Same pinout, 150-kHz frequency, but lower 3-A current rating and higher 1.2-V dropout - requires larger inductor for same ripple. | Supports higher current loads; less suitable for space-constrained 1-A designs due to larger thermal footprint. | Select when >1-A output or higher input-to-output differential is needed; not drop-in for LM2598SX-3.3/NOPB PCBs due to different thermal pad layout. |
| TPS5430DDAR | 3-A synchronous buck with 500-kHz switching, integrated high-side MOSFET, and adjustable soft-start - no error flag or delay pin. | Lacks dedicated power-good signaling; requires external resistor divider for 3.3-V output and additional components for reset generation. | Choose for higher efficiency (>90%) and smaller magnetics at cost of added design complexity and loss of integrated fault signaling. |
Compared with LM2596SX-3.3/NOPB and TPS5430DDAR, the LM2598SX-3.3/NOPB offers unique integration of error flag with programmable delay and soft-start in a compact TO-263-7 package - ideal for cost-sensitive, space-constrained 1-A applications requiring simple, robust power sequencing without external supervision circuitry.
Availability
LM2598SX-3.3/NOPB is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and medical portable devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM2598SX-3.3/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, designing and manufacturing analog ICs, embedded processors, and power management solutions for industrial, automotive, and consumer markets.
The LM2598 series belongs to TI's SIMPLE SWITCHER® power converter family, engineered for ease-of-use in non-isolated DC-DC buck applications where minimal external components, integrated protection, and fixed-output simplicity are prioritized over ultra-high efficiency or synchronous rectification.
FAQ
What is the maximum input voltage rating for the LM2598SX-3.3/NOPB?
The LM2598SX-3.3/NOPB has an absolute maximum input voltage rating of 45 V, with recommended operating range from 4.75 V to 40 V. Operation above 40 V risks exceeding thermal limits and triggering internal protection; sustained use at 45 V is not advised per datasheet stress ratings.
Does the LM2598SX-3.3/NOPB require external feedback resistors?
No - the LM2598SX-3.3/NOPB is a fixed-output variant with internal resistor divider set to 3.3 V. Pin 6 (FB) must be left unconnected per datasheet guidance; adding external resistors would disrupt regulation and is not supported.
How does the Error Flag pin function on the LM2598SX-3.3/NOPB?
The Error Flag pin on the LM2598SX-3.3/NOPB is an open-collector output that pulls low when the regulated 3.3-V output drops more than 5% (to <3.135 V). It remains low until VOUT reaches 95% of nominal and the Delay pin capacitor times out - commonly used as a hardware reset signal for microcontrollers.
Can the LM2598SX-3.3/NOPB be used in a negative voltage configuration?
Yes - the LM2598SX-3.3/NOPB can be configured as an inverting regulator to generate a negative output (e.g., –3.3 V) from a positive input, as documented in TI's application notes. This requires re-referencing GND and FB pins and adding an isolation diode; output current capability depends on input/output voltage ratio and is reduced versus buck mode.
What thermal considerations apply to the LM2598SX-3.3/NOPB in TO-263 package?
The LM2598SX-3.3/NOPB in TO-263 (KTW) package achieves θJA ≈ 30°C/W with 2.5 in² of 1-oz copper on a single-sided PCB. For 1-A operation at 12-V input, junction temperature rise is ~23°C above ambient - typically eliminating need for heatsink below 75°C ambient when thermal pad is fully soldered to copper pour.
LM2598SX-3.3/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):
- 3.3V
- 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-3.3/NOPB FAQ
1.How can I place an order for LM2598SX-3.3/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2598SX-3.3/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-3.3/NOPB reliable?
The price and inventory of LM2598SX-3.3/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-3.3/NOPB is usually 5 days.
3.What payment methods are accepted for LM2598SX-3.3/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2598SX-3.3/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2598SX-3.3/NOPB?
LM2598SX-3.3/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2598SX-3.3/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-3.3/NOPB?
For technical support, including LM2598SX-3.3/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2598SX-3.3/NOPB requirements.
6.How does Aetrix verify that LM2598SX-3.3/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2598SX-3.3/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-3.3/NOPB meets industry standards.
7.What is the process for return or replacement of LM2598SX-3.3/NOPB?
All LM2598SX-3.3/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2598SX-3.3/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-3.3/NOPB part is unused and in its original packaging.
Return procedure for LM2598SX-3.3/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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