My Inquiry
My Account
Texas Instruments LM2599SX-ADJ/NOPB
- Part No.:
- LM2599SX-ADJ/NOPB
- Manufacturer:
- Texas Instruments
- Package:
- TO-263-8, D2PAK (7 Leads + Tab), TO-263CA
- Datasheet:
-
LM2599SX-ADJ/NOPB.pdf
- Description:
- IC REG BUCK ADJ 3A TO263
- Quantity:
- Payment:
- Shipping:
Inventory:910
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LM2599SX-ADJ/NOPB from Texas Instruments is a monolithic 150-kHz nonsynchronous step-down DC-DC converter IC delivering up to 3 A output current, supporting adjustable output voltage from 1.2 V to 37 V (±4% tolerance), with input voltage range up to 40 V and standby quiescent current of 80 μA. It integrates internal frequency compensation, thermal shutdown, current-limit protection, and soft-start/shutdown control - used in board-level power conversion for industrial and embedded systems.
For engineers reviewing the LM2599SX-ADJ/NOPB datasheet, LM2599SX-ADJ/NOPB pinout, LM2599SX-ADJ/NOPB application, or LM2599SX-ADJ/NOPB equivalent, key selection considerations include feedback voltage accuracy (1.23 V), oscillator frequency stability (127–173 kHz), saturation voltage (1.16–1.5 V at 3 A), duty cycle range (0–100%), and thermal resistance (50 °C/W for TO-220, 20–30 °C/W for TO-263).
Technical Context
The LM2599SX-ADJ/NOPB implements a fixed-frequency (150 kHz) buck topology with integrated NPN switch, requiring only external diode, inductor, and input/output capacitors. Its feedback loop references a precise 1.23 V internal bandgap, enabling wide-range output adjustment via resistor divider on the Feedback pin.
It supports dual-function Shutdown/Soft-start control (logic-level enable + capacitor-programmable ramp), open-collector Error Flag with 5% dropout detection and programmable delay, and two-stage overcurrent protection with peak limit of 3.6–7.5 A depending on temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 3 A DC maximum - supports medium-power loads without external current boosting. |
| Input Voltage Range | 4.5 V to 40 V - accommodates 12 V, 24 V, and 36 V industrial rails with margin. |
| Adjustable Output Range | 1.2 V to 37 V ±4% - set by external resistive divider; 1.23 V feedback reference enables precision regulation. |
| Oscillator Frequency | 127–173 kHz (±15%) - fixed internal clock enables predictable EMI profile and standard inductor selection. |
| Quiescent Current | 80 μA in shutdown - enables low-power system sleep modes with minimal battery drain. |
| Saturation Voltage | 1.16–1.5 V at 3 A - defines conduction loss and impacts efficiency at high load currents. |
| Thermal Resistance | 50 °C/W (TO-220), 20–30 °C/W (TO-263) - determines heatsink requirements for continuous 3-A operation. |
Pinout & Package
LM2599SX-ADJ/NOPB is available in 7-pin TO-220 (NDZ) and 7-pin TO-263 (KTW) packages. Both use identical pin numbering and functional assignment.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: +VIN | Power Input | Primary DC input supply (up to 40 V); requires local bypass capacitor for switching current return path. |
| 2: Output | Switch Node | Internal NPN collector node; switches between ~(+VIN − VSAT) and ~−0.5 V; PCB copper area must be minimized to reduce EMI coupling. |
| 3: Error Flag | Open-Collector Output | Active-low flag asserting when VOUT drops >5% below nominal; includes built-in delay capacitor timing for power-up sequencing. |
| 4: Ground | Reference Node | Common return for internal circuitry and external components; must be low-impedance connection to minimize noise and offset. |
| 5: Delay | Capacitor Timing Node | Controls error flag assertion delay after VOUT reaches 95%; sets power-good timing window for microprocessor reset. |
| 6: Feedback | Analog Input | Senses output voltage via resistor divider; 1.23 V threshold sets regulation point; bias current ≤50 nA minimizes divider error. |
| 7: Shutdown/Soft-start | Dual-Function Control | Logic-low (≤0.6 V) disables regulator (80 μA IQ); capacitor adds controlled VOUT ramp to limit inrush current. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Soft-Start | Capacitor-programmable output voltage ramp reduces peak inrush current from 2.6 A to 650 mA during startup. |
| Programmable Power-Good Delay | Delay pin capacitor sets error flag assertion time after VOUT reaches 95%, enabling reliable microcontroller reset timing. |
| Two-Stage Overcurrent Protection | Peak current limit (3.6–7.5 A) plus thermal shutdown prevents damage under sustained overload or short-circuit conditions. |
| Low-IQ Shutdown Mode | 80 μA typical standby current allows integration into battery-powered systems requiring long idle periods. |
| Fixed 150-kHz Switching | Enables use of standard off-the-shelf inductors and simplifies EMI filter design versus variable-frequency alternatives. |
Applications
| Industrial Motor Drive Power Supply | Embedded System Core Voltage Regulator |
|---|---|
Use Scenario: Provides stable 5 V or 3.3 V rail for microcontrollers, FPGAs, and interface ICs in PLCs and motor control boards operating from 24 V DC bus. IC Role / Device Role / Timing Role: Primary step-down regulator converting unregulated 24 V input to tightly regulated logic supply; uses internal 150-kHz oscillator for deterministic switching timing. Use Value: ±4% output tolerance and 1.23 V feedback reference ensure consistent digital logic operation across line/load/temperature variations. | Use Scenario: Generates adjustable 1.8 V or 2.5 V core voltage for ARM-based SoCs in portable test equipment powered from 12 V battery or adapter. IC Role / Device Role / Timing Role: Adjustable buck controller delivering precise core voltage; soft-start function prevents brownout during cold boot. Use Value: Soft-start capacitor limits inrush to 650 mA, avoiding input rail collapse and enabling reliable SoC initialization. |
| Positive-to-Negative Inverting Converter | Preregulator for Linear Regulator |
Use Scenario: Converts +12 V input to −5 V bias supply for op-amp circuits in analog signal conditioning modules. IC Role / Device Role / Timing Role: Inverting buck-derived topology using bootstrapped ground; relies on fixed 150-kHz switching for stable closed-loop behavior. Use Value: Eliminates need for separate negative supply IC; achieves >85% efficiency at 1 A load with standard 33-μH inductor. | Use Scenario: Steps down 36 V vehicle battery voltage to 7 V intermediate rail feeding low-noise LDOs for sensor front-ends. IC Role / Device Role / Timing Role: High-efficiency preregulator reducing power dissipation in downstream linear regulators; operates continuously at 150 kHz. Use Value: Reduces LDO thermal load by >70% compared to direct 36 V → 3.3 V conversion, improving system reliability. |
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 3-A rating, 150-kHz frequency, but 37-V max input and 1.23-V feedback reference identical; TO-220/TO-263 pinout compatible. | Optimized for lower-cost, lower-power designs where 3-A capability is sufficient and thermal margin is less constrained. | Select when cost sensitivity outweighs need for higher current headroom or enhanced protection features. |
| LM2678SX-5.0/NOPB | Fixed 5-V output, 5-A rating, same 150-kHz frequency and TO-220/TO-263 package; lacks adjustable feedback and error flag functionality. | Used where fixed 5-V output suffices and higher current delivery is required without external feedback network. | Choose for 5-V-only systems needing >3 A, accepting loss of adjustability and monitoring features. |
Compared with LM2599SX-ADJ/NOPB, LM2596SX-ADJ/NOPB offers identical adjustability and pin compatibility at lower cost but reduced thermal robustness, while LM2678SX-5.0/NOPB trades flexibility for higher current and fixed output - making LM2599SX-ADJ/NOPB optimal for designs requiring wide-range programmability, error signaling, and proven 3-A performance in harsh environments.
Availability
LM2599SX-ADJ/NOPB is available at Aetrix Electronics and suitable for industrial motor drives, embedded computing power supplies, analog signal conditioning circuits, and automotive body electronics requiring stable component supply across extended temperature ranges (–40°C to +125°C).
Supply support for LM2599SX-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 LM2599 series belongs to TI's SIMPLE SWITCHER® family, designed specifically for ease-of-use in non-isolated DC-DC buck conversion - emphasizing minimal external components, internal compensation, and robust protection for industrial and automotive applications.
FAQ
What is the feedback reference voltage of the LM2599SX-ADJ/NOPB?
The LM2599SX-ADJ/NOPB has a precise internal feedback reference voltage of 1.23 V, specified from –40°C to +125°C with ±0.05 V tolerance. This value sets the regulation point for the adjustable output configuration and directly determines output voltage accuracy when used with external resistor dividers. The LM2599SX-ADJ/NOPB maintains this reference across line, load, and temperature variations to ensure stable regulation.
Can the LM2599SX-ADJ/NOPB operate with an input voltage below 4.5 V?
No, the LM2599SX-ADJ/NOPB has a minimum recommended input voltage of 4.5 V per its absolute operating conditions. Below this, the internal circuitry may not initialize correctly or sustain regulation. The device's undervoltage lockout is not internally implemented - external UVLO circuitry (e.g., Zener-based) is required if operation below 4.5 V is needed. The LM2599SX-ADJ/NOPB datasheet explicitly specifies 4.5 V as the lower bound for reliable operation.
How does the Error Flag pin function on the LM2599SX-ADJ/NOPB?
The Error Flag pin on the LM2599SX-ADJ/NOPB is an open-collector output that pulls low when the regulated output voltage falls more than 5% below its nominal value. At power-up, it remains low until VOUT reaches 95% of target and the Delay pin capacitor times out. This pin provides a hardware reset signal for microcontrollers and can be wired to interrupt lines. The LM2599SX-ADJ/NOPB guarantees flag saturation voltage ≤0.3 V at 3 mA sink current.
What is the maximum junction temperature specification for the LM2599SX-ADJ/NOPB?
The LM2599SX-ADJ/NOPB has a maximum junction temperature rating of 150°C, as defined in its Absolute Maximum Ratings table. Operation beyond this limit risks permanent damage. Thermal design must account for package-specific RθJA values: 50°C/W for TO-220 (NDZ) and 20–30°C/W for TO-263 (KTW) depending on PCB copper area. The LM2599SX-ADJ/NOPB includes internal thermal shutdown that activates before reaching 150°C to protect against overheating.
Does the LM2599SX-ADJ/NOPB support synchronous rectification?
No, the LM2599SX-ADJ/NOPB is a nonsynchronous buck regulator and does not support synchronous rectification. It uses an external Schottky or fast-recovery diode for the freewheeling path. The internal switch is a bipolar NPN transistor, and no gate drive signals are provided for an external synchronous MOSFET. Efficiency improvements require optimizing external diode selection and layout - the LM2599SX-ADJ/NOPB itself does not offer synchronous control capability.
LM2599SX-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):
- 1.23V
- Voltage - Output (Max):
- 37V
- 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)
LM2599SX-ADJ/NOPB FAQ
1.How can I place an order for LM2599SX-ADJ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM2599SX-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 LM2599SX-ADJ/NOPB reliable?
The price and inventory of LM2599SX-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 LM2599SX-ADJ/NOPB is usually 5 days.
3.What payment methods are accepted for LM2599SX-ADJ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM2599SX-ADJ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM2599SX-ADJ/NOPB?
LM2599SX-ADJ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM2599SX-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 LM2599SX-ADJ/NOPB?
For technical support, including LM2599SX-ADJ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM2599SX-ADJ/NOPB requirements.
6.How does Aetrix verify that LM2599SX-ADJ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM2599SX-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 LM2599SX-ADJ/NOPB meets industry standards.
7.What is the process for return or replacement of LM2599SX-ADJ/NOPB?
All LM2599SX-ADJ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM2599SX-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 LM2599SX-ADJ/NOPB part is unused and in its original packaging.
Return procedure for LM2599SX-ADJ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM2599SX-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…
