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Texas Instruments LM2598S-3.3/NOPB
- Part No.:
- LM2598S-3.3/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2598S-3.3/NOPB.pdf
- Description:
- IC REG BUCK 3.3V 1A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:2,249
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Product details
Overview
LM2598S-3.3/NOPB from Texas Instruments is a monolithic 150-kHz nonsynchronous step-down (buck) DC-DC converter delivering 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, and current limiting, and is used in embedded power supplies requiring compact, high-efficiency regulation.
For engineers reviewing the LM2598S-3.3/NOPB datasheet, LM2598S-3.3/NOPB pinout, LM2598S-3.3/NOPB application, or LM2598S-3.3/NOPB equivalent, key selection criteria include its 3.3-V fixed output, TO-263-7 (DDPAK) package, 150-kHz switching frequency, shutdown/soft-start capability, and error flag with delay - all critical for reliable board-level power conversion design.
Technical Context
The LM2598S-3.3/NOPB implements a nonsynchronous buck topology with an integrated 1-A N-channel DMOS switch and fixed-frequency 150-kHz oscillator. Its feedback loop uses a precision 1.23-V reference and senses output via internal resistive divider for 3.3-V regulation.
It features dual-function Shutdown/Soft-start pin enabling logic-controlled disable (ISTBY = 85 μA typical) and controlled output ramp-up via external capacitor; Error Flag and Delay pins provide regulated dropout detection with programmable delay timing, supporting microprocessor reset sequencing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±4% over full line/load/temperature range - ensures stable logic supply without external resistor network. |
| Max Output Current | 1 A DC - supports single-rail digital subsystems (e.g., microcontrollers, FPGAs) without external current boosting. |
| Input Voltage Range | 4.5 V to 40 V - accommodates wide-input industrial, automotive, and telecom power rails including unregulated 24-V systems. |
| Switching Frequency | 150 kHz ±15% - enables use of low-cost, standard off-the-shelf inductors (e.g., 68–100 μH) and reduces EMI filtering complexity. |
| Quiescent Current | 85 μA in shutdown mode - minimizes standby power loss in battery-backed or energy-sensitive applications. |
| Efficiency | 78% at VIN = 12 V, IOUT = 1 A - delivers high conversion efficiency without synchronous rectification or complex layout. |
| Thermal Protection | Internal thermal shutdown + two-stage current limit - prevents damage during overload or poor heatsinking conditions. |
Pinout & Package
LM2598S-3.3/NOPB is housed in a 7-pin TO-263 (DDPAK) surface-mount package with exposed thermal pad (10.10 mm × 8.89 mm nominal body size), optimized for PCB heat dissipation without external heatsink below 50°C ambient and <12-V output.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUT) | Switch node | Drives external catch diode and inductor; voltage swings between ~VIN–1.2 V and –0.5 V - requires minimal copper area to reduce EMI coupling. |
| 2 (+VIN) | Power input | Accepts 4.5–40 V DC; requires local 100-nF ceramic + bulk electrolytic bypass to handle high di/dt switching currents. |
| 3 (FLAG) | Error flag output | Open-collector signal pulled low when VOUT drops >5%; delays going high until VOUT reaches 95% - usable as µP reset. |
| 4 (GND) | Power ground | Common return for internal switch, control circuitry, and thermal pad - must be connected to large PCB copper pour for thermal performance. |
| 5 (DELAY) | Flag delay timing | Capacitor-connected pin sets time delay between VOUT reaching 95% and FLAG going high - enables precise power-good timing. |
| 6 (FB) | Feedback input | Internally tied to 3.3-V divider; not accessible in fixed-output version - eliminates external resistor selection and trimming. |
| 7 (SD/SS) | Shutdown/Soft-start | Logic-low disables regulator (ISTBY ≈ 85 μA); capacitor adds soft-start ramp - prevents inrush current and stabilizes startup. |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 3.3-V output with ±4% tolerance | Guarantees compliance with 3.3-V logic supply standards (e.g., LVCMOS, USB PHY) across temperature and load without calibration. |
| Integrated 150-kHz oscillator | Eliminates external timing components and enables predictable EMI profile - simplifies EMC filter design and layout. |
| Shutdown/Soft-start pin | Single-pin dual function reduces BOM count and supports both power sequencing (soft-start) and system-level power management (shutdown). |
| Error Flag with programmable delay | Provides deterministic power-good signaling for microcontrollers and FPGAs - delay capacitor allows synchronization with downstream clocks or resets. |
| Thermal shutdown + current limiting | Self-protecting operation under short-circuit, overtemperature, or excessive load - no external fault-handling circuitry required. |
Applications
| Industrial PLC Power Supply | Embedded Microcontroller Board |
|---|---|
Use Scenario: Providing clean 3.3-V rail to ARM Cortex-M4-based controller in DIN-rail mounted automation module with 24-V DC field power. IC Role / Device Role / Timing Role: Primary step-down regulator converting unregulated 24-V bus to isolated 3.3-V logic supply; operates continuously with thermal margin at 50°C ambient. Use Value: Eliminates need for external feedback resistors or compensation network - reduces component count and improves long-term stability vs. adjustable regulators. |
Use Scenario: Powering FPGA configuration memory, Ethernet PHY, and sensor interface on compact IoT edge node with limited PCB area. IC Role / Device Role / Timing Role: High-efficiency buck converter delivering 1-A peak current during boot; soft-start prevents brownout on shared 12-V input rail. Use Value: 78% efficiency at 12-V input enables passive cooling; 150-kHz frequency permits small 68-μH inductor footprint (<8 mm²). |
| Automotive Body Control Module | Point-of-Load Converter for Industrial HMI |
Use Scenario: Generating 3.3-V supply for CAN transceiver and MCU in vehicle door module powered from 12-V battery with load-dump transients. IC Role / Device Role / Timing Role: Input-tolerant buck regulator handling up to 40-V transient surges; thermal shutdown protects against enclosure overheating during summer parking. Use Value: 40-V max input rating and built-in current limit enable direct connection to automotive battery without pre-regulator - lowers system cost and complexity. |
Use Scenario: Local 3.3-V regulation for touch-screen controller IC on 7-inch industrial display powered from 24-V main rail. IC Role / Device Role / Timing Role: On-card switching regulator placed near load to minimize IR drop and noise; error flag signals power-fail to display driver ASIC. Use Value: FLAG output provides hardware-level power-good status with user-defined delay - replaces discrete supervisor IC and saves board space. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596S-3.3/NOPB | Lower 150-kHz frequency same, but rated for 3-A output and higher 45-V max input; larger TO-263-5 package (no DELAY/FLAG pins). | Lacks error flag and delay functionality - unsuitable where power-good sequencing is required. | Select when higher output current or wider input range is needed, and FLAG/DELAY signals are unused. |
| TPS54331DR | 3-A synchronous buck with 570-kHz switching, integrated high-side FET, and adjustable output; requires external feedback resistors. | Higher efficiency (≥90%) and smaller solution size, but lacks fixed 3.3-V option and dedicated error flag pin. | Select for space-constrained designs needing >1-A current or tighter regulation; requires redesign of feedback and timing networks. |
Compared with LM2596S-3.3/NOPB, LM2598S-3.3/NOPB offers integrated FLAG/DELAY for power sequencing but lower current rating; versus TPS54331DR, it trades efficiency and integration for simplicity, fixed output, and hardware reset capability - making it optimal for cost-sensitive, medium-current applications requiring robust power-good signaling.
Availability
LM2598S-3.3/NOPB is available at Aetrix Electronics and suitable for industrial automation, embedded computing, and automotive body electronics requiring stable component supply, long-lifecycle support, and proven reliability in harsh environments.
Supply support for LM2598S-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 leader specializing in analog, embedded processing, and power management technologies, with decades of expertise in high-reliability power conversion ICs.
The LM2598S-3.3/NOPB belongs to TI's SIMPLE SWITCHER® family - designed specifically for engineers seeking easy-to-use, robust, and layout-friendly DC-DC converters that minimize design iterations and qualification risk in industrial and automotive applications.
FAQ
What is the maximum input voltage rating for the LM2598S-3.3/NOPB?
The LM2598S-3.3/NOPB has an absolute maximum input voltage rating of 45 V, with recommended operating range from 4.5 V to 40 V. Operation above 40 V is permissible only for brief transients such as automotive load dump, provided thermal limits and SOA are respected. The device includes internal clamping and current limiting to sustain these conditions without damage.
Does the LM2598S-3.3/NOPB require external feedback resistors?
No, the LM2598S-3.3/NOPB does not require external feedback resistors. It is a fixed-output variant with internal resistor divider set for 3.3 V, eliminating component count, layout sensitivity, and drift-related regulation errors. The FB pin is internally connected and not accessible for adjustment.
How does the Error Flag pin function on the LM2598S-3.3/NOPB?
The Error Flag pin on the LM2598S-3.3/NOPB is an open-collector output that pulls low when the regulated output falls more than 5% below 3.3 V. At startup, it remains low until VOUT reaches 95% of nominal and the DELAY capacitor times out - providing a synchronized power-good signal usable for microprocessor reset assertion.
Can the LM2598S-3.3/NOPB be used in a negative-output (inverting) configuration?
Yes, the LM2598S-3.3/NOPB can be configured as an inverting regulator to generate a negative output (e.g., –3.3 V) from a positive input, using the standard inverting buck-boost topology. This requires repositioning the ground reference and adding an isolation diode; however, output current capability decreases with increasing |VIN| + |VOUT|, and startup inrush is higher than in buck mode.
What thermal considerations apply to the LM2598S-3.3/NOPB in TO-263 package?
In the TO-263-7 (DDPAK) package, the LM2598S-3.3/NOPB achieves θJA ≈ 30°C/W with 2.5 in² of 1-oz copper on one side, or ≈20°C/W with 3 in² on the component side plus 16 in² on the opposite layer. For 1-A operation at 12-V input, junction temperature rise is typically <40°C at 25°C ambient - often eliminating need for external heatsink below 50°C ambient.
LM2598S-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:
- Tube
- 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)
LM2598S-3.3/NOPB FAQ
1.How can I place an order for LM2598S-3.3/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2598S-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 LM2598S-3.3/NOPB reliable?
The price and inventory of LM2598S-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 LM2598S-3.3/NOPB is usually 5 days.
3.What payment methods are accepted for LM2598S-3.3/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2598S-3.3/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2598S-3.3/NOPB?
LM2598S-3.3/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2598S-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 LM2598S-3.3/NOPB?
For technical support, including LM2598S-3.3/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2598S-3.3/NOPB requirements.
6.How does Aetrix verify that LM2598S-3.3/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2598S-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 LM2598S-3.3/NOPB meets industry standards.
7.What is the process for return or replacement of LM2598S-3.3/NOPB?
All LM2598S-3.3/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2598S-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 LM2598S-3.3/NOPB part is unused and in its original packaging.
Return procedure for LM2598S-3.3/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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