My Inquiry
My Account
Texas Instruments LM2598SX-ADJ/NOPB
- Part No.:
- LM2598SX-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2598SX-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 1A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:441
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM2598SX-ADJ/NOPB from Texas Instruments is a monolithic nonsynchronous step-down (buck) DC-DC converter IC delivering up to 1 A output current, operating at a fixed 150 kHz switching frequency, with adjustable output voltage range of 1.2 V to 37 V (±4% tolerance over line and load), and input voltage support up to 40 V - used in embedded power supplies requiring compact, high-efficiency regulation.
For engineers reviewing the LM2598SX-ADJ/NOPB datasheet, LM2598SX-ADJ/NOPB pinout, LM2598SX-ADJ/NOPB application, or LM2598SX-ADJ/NOPB equivalent, key selection considerations include feedback voltage accuracy (1.23 V typ), shutdown quiescent current (85 μA typ), thermal protection behavior, and compatibility with standard off-the-shelf inductors in buck or inverting topologies.
Technical Context
The LM2598SX-ADJ/NOPB integrates a PWM controller, power switch, oscillator, error amplifier, and protection circuitry into a single 7-pin TO-263 (DDPAK) package. Its internal 150 kHz oscillator enables use of small external filter components, while the adjustable feedback architecture (VFB = 1.23 V) supports wide output voltage programming via resistor divider.
It implements dual-stage current limiting, thermal shutdown, and an open-collector error flag with programmable delay. The Shutdown/Soft-start pin provides logic-level enable control and capacitor-programmable soft-start ramp, reducing inrush current during power-up without external sequencing circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 1 A DC continuous - supports mid-power point-of-load conversion without external current boosting. |
| Input Voltage Range | 4.5 V to 40 V - accommodates 12 V, 24 V, and 36 V industrial bus rails with margin for transients. |
| Feedback Voltage | 1.23 V (typ), ±10 mV over temperature - sets precision output voltage via external resistor divider. |
| Switching Frequency | 150 kHz (±15%) - balances efficiency and EMI while enabling use of low-cost, widely available 68–100 μH inductors. |
| Quiescent Current (Standby) | 85 μA (typ) at shutdown - enables ultra-low-power hold-up or battery-backed operation. |
| Thermal Protection | Junction shutdown at 150°C - prevents damage under sustained overload or poor heatsinking conditions. |
| Output Voltage Accuracy | ±4% over line, load, and temperature - ensures stable regulation across full operating range without trimming. |
Pinout & Package
LM2598SX-ADJ/NOPB is housed in a 7-pin TO-263 (DDPAK) surface-mount package with exposed thermal pad for enhanced heat dissipation. Package dimensions: 10.10 mm × 8.89 mm (nominal).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - Output | Power switch drain node | Swings between ~VIN–1.2 V and –0.5 V; requires minimal PCB copper area to reduce EMI coupling. |
| 2 - +VIN | Main power input | Accepts up to 40 V; must be bypassed with low-ESR capacitor near pin to supply pulsed switch current. |
| 3 - Error Flag | Open-collector fault indicator | Pulls low when VOUT drops >5% below nominal; used for microprocessor reset or system fault signaling. |
| 4 - Ground | Power and signal reference | Common return for internal circuits and external feedback network; connects to thermal pad. |
| 5 - Delay | Flag timing control | Capacitor-connected pin sets delay before Error Flag goes high after VOUT reaches 95% of target. |
| 6 - Feedback | Voltage sense input | Monitors resistive divider from VOUT; regulates output by maintaining 1.23 V at this pin. |
| 7 - Shutdown/Soft-start | Enable and ramp control | Logic-low disables regulator (IQ ≈ 85 μA); capacitor adds controlled VOUT ramp to limit inrush. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 1-A power switch | Eliminates need for external MOSFET and gate driver; simplifies layout and reduces BOM count. |
| Fixed 150-kHz oscillator | Enables predictable EMI profile and consistent inductor sizing across designs using standard parts. |
| Adjustable output (1.2–37 V) | Supports custom rail generation (e.g., 2.5 V, 15 V, 24 V) with only two external resistors - no requalification needed. |
| Shutdown/Soft-start pin | Combines enable control and inrush limiting in one pin - avoids extra ICs or discrete RC networks. |
| Out-of-regulation error flag | Provides system-level fault detection with built-in 5% dropout threshold and programmable startup delay. |
| Thermal + current limiting | Dual-stage current limit and junction shutdown ensure robust operation under short-circuit or overload. |
Applications
| Industrial Power Supply | Automotive Body Control Module |
|---|---|
|
Use Scenario: Converting 24 V vehicle battery to 5 V for MCU and sensors in door modules or lighting controllers. IC Role / Device Role / Timing Role: Primary buck regulator providing isolated, regulated 5 V rail with fault reporting via Error Flag. Use Value: Operates across –25°C to +125°C ambient, withstands load dump transients up to 40 V, and delivers 1 A without external heatsink below 50°C. |
Use Scenario: Generating 3.3 V from 12 V battery for infotainment SoC core logic and memory interfaces. IC Role / Device Role / Timing Role: Adjustable-output buck converter configured for 3.3 V with soft-start to prevent brownout during cold cranking. Use Value: 85 μA standby current extends battery life in sleep mode; ±4% output accuracy ensures reliable digital logic operation. |
| Programmable Logic Controller (PLC) | Test Equipment Power Stage |
|
Use Scenario: Providing 12 V and 24 V auxiliary rails in modular I/O backplanes with varying fieldbus interface requirements. IC Role / Device Role / Timing Role: Configurable step-down regulator supporting multiple output voltages via resistor selection - no redesign needed per variant. Use Value: 40 V max input handles surge events on industrial 24 V lines; thermal shutdown protects against enclosure overheating. |
Use Scenario: On-board power for benchtop DMM or oscilloscope analog front-end requiring low-noise ±15 V rails. IC Role / Device Role / Timing Role: Used in inverting configuration (per Figure 21) to generate –15 V from +24 V supply with integrated soft-start. Use Value: Eliminates need for separate negative supply IC; 150 kHz switching allows compact magnetics and predictable filtering. |
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-ADJ/NOPB | Lower 150 kHz frequency same, but rated for 3 A output and higher peak current limit (3.5 A vs. 2.4 A). | Better suited for higher-current loads; requires larger inductor and output capacitor due to higher ripple current. | Select when >1 A output or higher transient capability is required; pinout differs (8-pin TO-220/TO-263). |
| LM2678SD-ADJ/NOPB | Higher 260 kHz switching frequency, 5 A output rating, and improved efficiency (>90% at 12 V→5 V/1 A). | Enables smaller passive components and lower output ripple; includes synchronous rectification. | Choose for space-constrained or high-efficiency designs where board area and thermal budget are critical. |
Compared with LM2598SX-ADJ/NOPB, LM2596SX-ADJ/NOPB offers higher current headroom but shares identical control architecture and feedback behavior, while LM2678SD-ADJ/NOPB delivers superior efficiency and density at the cost of increased complexity and price.
Availability
LM2598SX-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and test equipment requiring stable component supply, long-lifecycle support, and proven reliability in harsh environments.
Supply support for LM2598SX-ADJ/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 experience in high-reliability power conversion ICs.
The LM2598SX-ADJ/NOPB belongs to TI's SIMPLE SWITCHER® family - designed specifically for ease-of-use in non-isolated DC-DC buck and inverting applications where minimal external components and robust protection are essential.
FAQ
What is the minimum input voltage required for LM2598SX-ADJ/NOPB to regulate a 3.3-V output?
The LM2598SX-ADJ/NOPB requires a minimum input voltage of approximately 4.5 V to maintain regulation at 3.3 V output, as specified in Recommended Operating Conditions. This accounts for internal saturation voltage (~1.2 V) and feedback headroom. Below 4.5 V, the device enters dropout and cannot sustain 3.3 V at full load. The exact dropout voltage depends on load current and junction temperature, but design margin should assume ≥4.7 V minimum for reliable operation across temperature.
Can LM2598SX-ADJ/NOPB be used in an inverting (positive-to-negative) configuration?
Yes, LM2598SX-ADJ/NOPB supports inverting topology per TI's Figure 21, where the ground pin is referenced to the negative output, and feedback is tied to system ground. It generates regulated negative outputs such as –5 V or –12 V from positive inputs. Critical design constraints include limiting total voltage across VIN-to-GND to ≤40 V (e.g., +24 V input → –12 V output yields 36 V stress), using a Schottky catch diode, and selecting a 68 μH inductor optimized for this mode. Soft-start is strongly recommended to manage high startup currents.
What is the purpose of the Delay pin (Pin 5) on LM2598SX-ADJ/NOPB?
The Delay pin (Pin 5) on LM2598SX-ADJ/NOPB sets the time interval between when the output voltage reaches 95% of its target value and when the Error Flag pin transitions high, signaling valid regulation. A capacitor connected from this pin to ground determines the delay - typically 10 nF to 100 nF - allowing synchronization with microcontroller reset timing or sequenced power-up in multi-rail systems. Leaving the pin open disables the delay function, causing the flag to assert immediately upon reaching 95%.
How does the Shutdown/Soft-start pin (Pin 7) function in LM2598SX-ADJ/NOPB?
Pin 7 serves dual roles: applying <1.3 V shuts down LM2598SX-ADJ/NOPB, reducing quiescent current to 85 μA; applying >2 V enables regulation. Adding a capacitor between this pin and ground introduces soft-start - the rising voltage on the pin controls the duty cycle ramp, slowing output voltage rise and limiting inrush current. Typical values range from 10 nF (fast start) to 100 nF (multi-millisecond ramp). No capacitor is needed if only shutdown functionality is required.
What thermal performance can be expected from LM2598SX-ADJ/NOPB in a TO-263 package without a heatsink?
In the TO-263 (KTW) package, LM2598SX-ADJ/NOPB achieves a junction-to-ambient thermal resistance (RθJA) of 30°C/W with 2.5 in² of 1 oz. copper on a single-sided PCB, and 20°C/W with 3 in² on a double-sided board plus 16 in² on the opposite side. At 1 A load and 12 V input → 5 V output (η ≈ 82%), power dissipation is ~0.85 W; thus, ambient temperatures up to 75°C are sustainable without forced air or heatsink, assuming adequate copper area per TI layout guidelines.
LM2598SX-ADJ/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:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4.5V
- Voltage - Input (Max):
- 40V
- Voltage - Output (Min/Fixed):
- 1.2V
- Voltage - Output (Max):
- 37V
- 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-ADJ/NOPB FAQ
1.How can I place an order for LM2598SX-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2598SX-ADJ/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-ADJ/NOPB reliable?
The price and inventory of LM2598SX-ADJ/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-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2598SX-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2598SX-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2598SX-ADJ/NOPB?
LM2598SX-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2598SX-ADJ/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-ADJ/NOPB?
For technical support, including LM2598SX-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2598SX-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2598SX-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2598SX-ADJ/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-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2598SX-ADJ/NOPB?
All LM2598SX-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2598SX-ADJ/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-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2598SX-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2598SX-ADJ/NOPB Tags
-
TPS562201DDCR
Texas Instruments
-
MC34063ABD-TR
STMicroelectronics
-
TPS561201DDCR
Texas Instruments
-
MC33063ADR
Texas Instruments
-
MC34063ADR
Texas Instruments
-
TPS560200DBVR
Texas Instruments
-
AP3012KTR-G1
Diodes Incorporated
-
TLV61048DBVR
Texas Instruments
-
AZ34063UMTR-G1
Diodes Incorporated
-
TPS562200DDCR
Texas Instruments
-
AP62300TWU-7
Diodes Incorporated
-
MC34063EBD-TR
STMicroelectronics
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
