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Texas Instruments LM2598T-ADJ
- Part No.:
- LM2598T-ADJ
- Manufacturer:
- Texas Instruments
- Package:
- TO-220-7 Formed Leads
- Datasheet:
-
LM2598T-ADJ.pdf
- Description:
- IC REG BUCK ADJ 1A TO220-7
- Quantity:
- Payment:
- Shipping:
Inventory:3,909
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Product details
Overview
LM2598T-ADJ from Texas Instruments is a monolithic 150 kHz step-down (buck) switching voltage regulator IC delivering up to 1A output current with adjustable output voltage from 1.2V to 37V, ±4% tolerance over line and load, operating from 4.5V to 40V input, and featuring internal soft-start, shutdown control, and out-of-regulation error flag - used in industrial power supplies and embedded DC-DC conversion.
For engineers reviewing the LM2598T-ADJ datasheet, LM2598T-ADJ pinout, LM2598T-ADJ application, or LM2598T-ADJ equivalent, key selection criteria include its fixed 150 kHz oscillator frequency, 1.23V feedback reference, thermal shutdown protection, 85 μA standby quiescent current, and compatibility with standard off-the-shelf inductors for rapid design implementation.
Technical Context
The LM2598T-ADJ implements a current-mode PWM buck topology with internal 150 kHz oscillator, two-stage current limiting, and built-in soft-start via external capacitor on the SS/SD pin. It uses a single N-channel MOSFET switch with 1.2 V saturation voltage at 1A and integrates error amplifier, reference, and protection circuitry.
Its feedback loop references a precise 1.230 V (±2.7%) bandgap voltage at the FB pin, enabling programmable output via resistor divider. The device supports external shutdown with 1.3 V threshold and provides an open-collector FLAG output with delay timing controlled by an external capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 1 A maximum continuous - sufficient to power microcontrollers, sensors, and analog circuitry without external boost stages. |
| Input Voltage Range | 4.5 V to 40 V - supports wide-input industrial and automotive battery-supplied systems. |
| Output Voltage Range | 1.2 V to 37 V (adjustable) - set precisely using external resistive divider referenced to 1.23 V FB pin. |
| Switching Frequency | 150 kHz fixed - enables use of compact, low-cost magnetic components and reduces EMI filtering complexity. |
| Feedback Reference | 1.230 V ±2.7% - determines output accuracy and stability; sets minimum practical output voltage. |
| Quiescent Current | 85 μA in shutdown - enables ultra-low-power standby operation in battery-backed systems. |
| Efficiency | 78% at VIN=12 V, VOUT=3 V, IOUT=1 A - balances thermal performance and component count for mid-power applications. |
| Thermal Resistance | θJA = 50 °C/W (TO-220, no heatsink) - defines maximum power dissipation before thermal shutdown at ambient. |
Pinout & Package
LM2598T-ADJ is housed in a 7-pin TO-220 package (package number NDZ0007B) with bent and staggered leads. The exposed tab is electrically connected to Pin 2 (Ground) and serves as the primary thermal path.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Power Input | Accepts 4.5–40 V DC; requires local 120 μF low-ESR input capacitor for ripple suppression. |
| 2 (GND) | Ground Reference | Common return for power, feedback, and control circuits; connects to exposed tab for thermal conduction. |
| 3 (OUT) | Switch Node | Drives external catch diode and inductor; carries high di/dt switching current - layout critical. |
| 4 (FB) | Feedback Input | Senses output via resistor divider; regulates output by comparing to 1.23 V internal reference. |
| 5 (SD/SS) | Shutdown/Soft-Start | Pulled low ≤0.6 V to shut down; open or pulled high ≥2 V to enable soft-start with external capacitor. |
| 6 (FLAG) | Error Flag Output | Open-collector output active low when output drops below 92–98% of nominal; delays via external capacitor. |
| 7 (DELAY) | Flag Delay Control | Connects external capacitor to set flag assertion delay time; threshold is 1.25 V. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Soft-Start | Controlled by external capacitor on SD/SS pin - prevents inrush current and stabilizes startup sequencing. |
| Out-of-Regulation Flag | Open-drain FLAG output with user-programmable delay - enables system-level fault monitoring and graceful shutdown. |
| Two-Stage Current Limit | Peak current limit (1.2–2.6 A) plus foldback - protects switch under overload while maintaining regulation margin. |
| Thermal Shutdown | Activates at +150°C junction temperature - prevents permanent damage during sustained overload or poor heatsinking. |
| Fixed-Frequency Oscillator | 150 kHz ±15% - simplifies EMI filter design and ensures predictable inductor sizing across temperature and supply. |
| Low Standby IQ | 85 μA typical shutdown current - extends battery life in always-on monitoring or sensor nodes. |
Applications
| Industrial Power Supply | Automotive Body Control Module |
|---|---|
Use Scenario: Converting 24 V vehicle battery to stable 5 V or 3.3 V for MCU and CAN transceivers in door modules or lighting controllers. IC Role / Device Role / Timing Role: Primary buck regulator providing isolated, regulated DC rail with fault reporting via FLAG pin. Use Value: Withstands 40 V transients and operates down to 4.5 V cold-crank, ensuring reliable start-up and brownout immunity. | Use Scenario: Generating 12 V intermediate rail from 48 V supply in ADAS camera power tree before LDO post-regulation. IC Role / Device Role / Timing Role: High-efficiency pre-regulator stepping down high-voltage bus to reduce LDO thermal stress. Use Value: 90% efficiency at 12 V output (per LM2598-12 data) minimizes heat generation in confined enclosures. |
| Programmable Lab Power Supply | IoT Edge Sensor Hub |
Use Scenario: Adjustable output stage in benchtop supply where users dial 3–30 V output via front-panel potentiometer. IC Role / Device Role / Timing Role: Core adjustable buck controller with precision 1.23 V reference enabling <1% output setting resolution. Use Value: ±4% output tolerance over full line/load range ensures calibrated accuracy without trimming. | Use Scenario: Powering mixed-signal sensor subsystems (ADC, RF, MCU) from a single Li-ion or 12 V wall adapter. IC Role / Device Role / Timing Role: Single-chip DC-DC solution delivering multiple rails via cascaded regulators or discrete outputs. Use Value: 85 μA shutdown current enables multi-week battery runtime in sleep mode between sensor readings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buck regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM2596T-ADJ | Same pinout, 150 kHz, but lower 3.5 A current limit and higher 5 mA operating IQ. | Better suited for higher-current designs; less efficient at light loads due to higher quiescent current. | Select LM2596T-ADJ only if >1 A output current or higher peak surge capability is required. |
| MP1584EN-LF-Z | 34 V max input, 1.5 A output, 1.8 MHz switching, smaller SOT-23-8 package, no FLAG pin. | Enables ultra-compact layouts but lacks fault-flagging and has reduced input voltage headroom. | Choose MP1584EN-LF-Z when board space is constrained and FLAG functionality is not needed. |
Compared with LM2596T-ADJ, LM2598T-ADJ offers tighter output tolerance (±4% vs ±5%), lower standby IQ (85 μA vs 75 μA typical but higher max), and integrated FLAG signaling; versus MP1584EN-LF-Z, it trades higher-frequency operation and miniaturization for robust fault reporting and wider input range.
Availability
LM2598T-ADJ is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, and programmable lab equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM2598T-ADJ 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 switching regulator design and manufacturing.
The LM2598 series belongs to TI's SIMPLE SWITCHER® portfolio - engineered for ease-of-use in cost-sensitive, medium-power DC-DC applications where minimal external components and proven reliability are critical.
FAQ
What is the minimum input voltage required for stable operation of the LM2598T-ADJ?
The LM2598T-ADJ requires a minimum input voltage of 4.5 V to maintain regulation across its full output range. Below this, dropout occurs and output voltage collapses proportionally. This specification is verified over temperature and load per the Electrical Characteristics table in the official SNVS125C datasheet.
Can the LM2598T-ADJ be used without a heatsink in a 1A, 12V-out application?
Yes - the LM2598T-ADJ in TO-220 package can deliver 1A at 12V output without a heatsink when ambient temperature remains below 50°C and input voltage is ≤24V, as confirmed by TI's thermal data showing θJA = 50°C/W and typical power dissipation <1.5 W under those conditions.
How is the output voltage programmed on the LM2598T-ADJ?
The LM2598T-ADJ output voltage is set using a resistor divider from output to FB pin and from FB pin to ground. With a precise 1.230 V internal reference at FB, VOUT = 1.23 × (1 + R1/R2); TI recommends R1 ≈ 1 kΩ and 1% tolerance resistors for optimal stability and accuracy.
Does the LM2598T-ADJ support synchronous rectification?
No - the LM2598T-ADJ uses an internal N-channel MOSFET switch and requires an external Schottky catch diode (e.g., 1N5822) connected from OUT to output capacitor ground. It does not integrate or drive a synchronous rectifier MOSFET.
What is the purpose of the DELAY pin on the LM2598T-ADJ?
The DELAY pin on the LM2598T-ADJ sets the response time of the FLAG output: connecting a capacitor here introduces a delay before the FLAG pin asserts low during undervoltage events. Its 1.25 V threshold and internal current source enable precise, user-adjustable fault detection timing - a feature unique to the LM2598 family.
LM2598T-ADJ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- SIMPLE SWITCHER®
- Package/Case:
- TO-220-7 Formed Leads
- Packaging:
- Bulk
- Product Status:
- Obsolete
- 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:
- Through Hole
- Supplier Device Package:
- TO-220-7
LM2598T-ADJ FAQ
1.How can I place an order for LM2598T-ADJ through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2598T-ADJ 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 LM2598T-ADJ reliable?
The price and inventory of LM2598T-ADJ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2598T-ADJ is usually 5 days.
3.What payment methods are accepted for LM2598T-ADJ?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2598T-ADJ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2598T-ADJ?
LM2598T-ADJ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2598T-ADJ 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 LM2598T-ADJ?
For technical support, including LM2598T-ADJ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2598T-ADJ requirements.
6.How does Aetrix verify that LM2598T-ADJ is sourced from the original manufacturer or authorized distributors?
All LM2598T-ADJ 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 LM2598T-ADJ meets industry standards.
7.What is the process for return or replacement of LM2598T-ADJ?
All LM2598T-ADJ units undergo pre-shipment inspection (PSI). If there is an issue with LM2598T-ADJ, 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 LM2598T-ADJ part is unused and in its original packaging.
Return procedure for LM2598T-ADJ:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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