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Texas Instruments LM2599S-3.3
- Part No.:
- LM2599S-3.3
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2599S-3.3.pdf
- Description:
- IC REG BUCK 3.3V 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:4,941
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Product details
Overview
LM2599S-3.3 from Texas Instruments is a monolithic 3A step-down (buck) switching voltage regulator with fixed 3.3V output, 150 kHz internal oscillator, input voltage range up to 40V, ±4% output voltage tolerance over line and load, and thermal/current protection. It delivers stable power in industrial power supplies and embedded system rails.
For engineers reviewing the LM2599S-3.3 datasheet, LM2599S-3.3 pinout, LM2599S-3.3 application, or LM2599S-3.3 equivalent, key selection considerations include its 3A continuous output capability, TO-263 surface-mount package, shutdown/soft-start control, out-of-regulation flag, and compatibility with standard off-the-shelf inductors.
Technical Context
The LM2599S-3.3 integrates a PWM controller, power switch, and internal frequency compensation operating at a fixed 150 kHz switching frequency. Its architecture uses a two-stage current limit for overload protection and includes an error amplifier with feedback reference of 1.23V internally connected for fixed-output variants.
It features dedicated pins for shutdown/soft-start (SD/SS), delay timing (DELAY), and regulation status flag (FLAG), enabling precise power sequencing and fault monitoring. The device supports low-power standby mode with 80 μA quiescent current and operates across −40°C to +125°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3 V ±4% over full line/load/temperature range - ensures stable logic rail without external feedback network. |
| Max Output Current | 3 A continuous - supports high-current digital subsystems without external current boosting. |
| Input Voltage Range | 4.5 V to 40 V - accommodates wide-input industrial or automotive-derived supplies. |
| Switching Frequency | 150 kHz fixed - enables use of compact, low-cost magnetic components with predictable EMI profile. |
| Efficiency | 73% at VIN = 12 V, IOUT = 3 A - balances thermal performance and component count for mid-power applications. |
| Quiescent Current | 80 μA in shutdown - minimizes battery drain in always-on or low-power standby systems. |
| Thermal Resistance | θJA = 30 °C/W (TO-263 on 2.5 in² copper) - enables 3A operation without external heatsink under typical PCB layout. |
Pinout & Package
LM2599S-3.3 is housed in a 7-lead TO-263 (KTW) surface-mount package with exposed thermal pad for enhanced heat dissipation. Pin 1 is marked by notch or dot; pin numbering follows standard counter-clockwise order starting from lead-1 tab side.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Input Power Supply | Accepts 4.5–40 V DC; requires local 470 μF low-ESR input capacitor for ripple suppression and transient response. |
| 2 (OUTPUT) | Switch Node / Power Switch Drain | Connects to catch diode anode and inductor; carries high di/dt pulsed current - must be routed with minimal loop area. |
| 3 (GND) | Power Ground | Main return path for high-current switch and control circuits; tied directly to thermal pad for thermal and noise integrity. |
| 4 (FEEDBACK) | Internal Reference Connection | Internally connected to 3.3V output - not accessible; no external resistor divider required for fixed version. |
| 5 (SD/SS) | Shutdown / Soft-Start Control | Pulled low (<0.6 V) disables regulator; rising voltage initiates controlled soft-start ramp - enables sequencing with other rails. |
| 6 (DELAY) | Flag Delay Timing | Connects to 0.1 μF capacitor to ground to set flag assertion delay - prevents false trip during startup transients. |
| 7 (FLAG) | Regulation Status Output | Open-collector output pulled low when VOUT drops below 92–98% nominal - signals undervoltage fault to host controller. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 3A Power Switch | Eliminates need for external MOSFET and gate driver - reduces BOM count and layout complexity. |
| Fixed-Frequency PWM Control | 150 kHz operation enables consistent filter design and predictable EMI filtering requirements. |
| Out-of-Regulation Flag with Programmable Delay | Provides reliable fault signaling with adjustable immunity to startup overshoot and load transients. |
| Thermal Shutdown + Two-Stage Current Limit | Prevents damage under sustained overload or short-circuit - allows safe recovery without latch-off. |
| Low Standby IQ (80 μA) | Enables energy-efficient power management in battery-backed or always-on systems. |
Applications
| Industrial PLC Power Rails | Embedded Microcontroller Core Supply |
|---|---|
Use Scenario: Providing clean, regulated 3.3V power to FPGA configuration memory and I/O banks in programmable logic controllers. IC Role / Device Role / Timing Role: Primary buck converter delivering 3A continuous current with tight output tolerance and fault reporting. Use Value: Maintains ±4% output accuracy across 4.5–40V input variation and 0.2–3A load steps - ensures reliable boot and operation of sensitive logic. | Use Scenario: Powering ARM Cortex-M7 microcontrollers and associated peripherals in edge IoT gateways. IC Role / Device Role / Timing Role: Main system regulator with soft-start and FLAG-based health monitoring integrated into firmware power-up sequence. Use Value: 80 μA shutdown current extends battery life during deep sleep; FLAG pin enables real-time undervoltage detection without external supervisor IC. |
| Automotive Body Control Module (BCM) | Test Equipment Auxiliary Supply |
Use Scenario: Generating 3.3V rail for CAN transceivers and sensor interfaces in 12V automotive body electronics. IC Role / Device Role / Timing Role: Robust buck regulator handling load dump (up to 40V) and cold-crank (down to 4.5V) conditions. Use Value: Withstands 45V absolute max input and −40°C to +125°C operating range - meets AEC-Q100 stress requirements for non-safety-critical modules. | Use Scenario: On-board 3.3V supply for digital logic and ADC reference in portable benchtop test instruments. IC Role / Device Role / Timing Role: High-efficiency pre-regulator feeding low-noise LDOs for analog signal chains. Use Value: 73% efficiency at 3A reduces thermal load on compact enclosures; 150 kHz switching avoids interference with sensitive measurement bandwidths. |
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 | Lower 1.5A output current; same 150 kHz frequency and TO-263 package; no FLAG or DELAY pins. | Lacks regulation monitoring and programmable fault delay - unsuitable where system-level fault reporting is required. | Select LM2596S-3.3 only for cost-sensitive, lower-current designs without supervision needs. |
| MP2307DN-LF-Z | 3A output, 340 kHz switching, smaller SO-8 package; no integrated FLAG/DELAY; requires external feedback resistors even for fixed 3.3V. | Higher frequency enables smaller magnetics but increases EMI filtering complexity; no built-in fault signaling. | Choose MP2307DN-LF-Z when board space is constrained and FLAG functionality is handled externally. |
Compared with LM2596S-3.3 and MP2307DN-LF-Z, the LM2599S-3.3 uniquely combines 3A capability, integrated fault flag with delay, and fixed-output simplicity - making it optimal for industrial and automotive systems requiring robust, self-monitoring power conversion without added supervisory ICs.
Availability
LM2599S-3.3 is available at Aetrix Electronics and suitable for industrial PLC power rails, embedded microcontroller core supplies, and automotive body control modules requiring stable component supply and long-term production continuity.
Supply support for LM2599S-3.3 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 switching regulator design.
The LM2599 series was developed to deliver high-current, easy-to-use buck conversion for industrial and automotive applications - emphasizing reliability, thermal robustness, and integrated protection features without external complexity.
FAQ
What is the maximum input voltage rating for the LM2599S-3.3?
The LM2599S-3.3 has an absolute maximum input voltage rating of 45 V, with recommended operating range from 4.5 V to 40 V. Exceeding 45 V risks permanent damage. The device maintains regulation and protection functions across the full 4.5–40 V range, including automotive cold-crank and load-dump conditions. Always verify input transient clamping in the final design per TI's Application Report SLVA005.
Does the LM2599S-3.3 require external feedback resistors?
No, the LM2599S-3.3 does not require external feedback resistors. As a fixed-output variant, its feedback node is internally connected to the 3.3 V output. Unlike the adjustable LM2599-ADJ, the LM2599S-3.3 integrates the reference and divider - simplifying layout and eliminating resistor tolerance errors. This internal connection is confirmed in the Electrical Characteristics table and Figure 24 test circuit for fixed versions.
How does the FLAG pin function on the LM2599S-3.3?
The FLAG pin on the LM2599S-3.3 is an open-collector output that pulls low when the regulated output falls below 92–98% of nominal 3.3 V. It asserts after a user-programmable delay set by a capacitor on the DELAY pin. This provides immunity to startup transients while enabling reliable undervoltage detection for system-level fault handling - a feature absent in many competing 3A buck regulators.
What package type is used for the LM2599S-3.3?
The LM2599S-3.3 is supplied exclusively in the 7-lead TO-263 (KTW) surface-mount package, featuring an exposed thermal pad for efficient heat transfer to the PCB. This package differs from the through-hole TO-220 (NDZ) variant used in the LM2599T-3.3. The KTW package supports higher power density and automated assembly, with θJA as low as 30 °C/W when mounted on 2.5 in² of 1 oz. copper.
Can the LM2599S-3.3 be used in battery-powered applications?
Yes, the LM2599S-3.3 is suitable for battery-powered applications due to its 80 μA shutdown quiescent current and operation down to 4.5 V input - compatible with 2-cell Li-ion (6–8.4 V) or 3-cell alkaline/nickel-based (3.6–4.5 V) sources when paired with appropriate input conditioning. Its thermal shutdown and current limiting protect against battery over-discharge faults, and the FLAG pin enables battery voltage monitoring via host MCU.
LM2599S-3.3 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:
- Obsolete
- 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:
- 3A
- 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)
LM2599S-3.3 FAQ
1.How can I place an order for LM2599S-3.3 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2599S-3.3 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 LM2599S-3.3 reliable?
The price and inventory of LM2599S-3.3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM2599S-3.3 is usually 5 days.
3.What payment methods are accepted for LM2599S-3.3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2599S-3.3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2599S-3.3?
LM2599S-3.3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2599S-3.3 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 LM2599S-3.3?
For technical support, including LM2599S-3.3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2599S-3.3 requirements.
6.How does Aetrix verify that LM2599S-3.3 is sourced from the original manufacturer or authorized distributors?
All LM2599S-3.3 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 LM2599S-3.3 meets industry standards.
7.What is the process for return or replacement of LM2599S-3.3?
All LM2599S-3.3 units undergo pre-shipment inspection (PSI). If there is an issue with LM2599S-3.3, 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 LM2599S-3.3 part is unused and in its original packaging.
Return procedure for LM2599S-3.3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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