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Texas Instruments LM3424QMHX/NOPB
- Part No.:
- LM3424QMHX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 20-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3424QMHX/NOPB.pdf
- Description:
- IC LED DRIVER CTRLR PWM 20HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,500
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Product details
Overview
LM3424QMHX/NOPB from Texas Instruments is a high-voltage N-channel MOSFET controller for constant-current LED drivers, supporting buck, boost, buck-boost, and SEPIC topologies. It features 4.5 V to 75 V input range, programmable thermal foldback with adjustable breakpoint and slope, and integrated 2-Ω/1-A peak gate driver. Used in outdoor area lighting and high-reliability SSL systems where precise current regulation and temperature-aware dimming are required.
For engineers reviewing the LM3424QMHX/NOPB datasheet, LM3424QMHX/NOPB pinout, LM3424QMHX/NOPB application, or LM3424QMHX/NOPB equivalent, key selection criteria include high-side differential current sensing (±5 mV offset), cycle-by-cycle current limiting (245 mV threshold), PWM/analog dimming capability, thermal shutdown at 165°C, and HTSSOP-20 package compatibility with PowerPAD™ thermal management.
Technical Context
The LM3424QMHX/NOPB implements peak current-mode control with inherent input voltage feed-forward compensation, enabling stable regulation across wide VIN and VOUT ranges. Its high-side transconductance amplifier (20 mA/V gain, 500 kHz bandwidth) interfaces directly with floating LED strings via HSP/HSN pins, while the error amplifier regulates CSH to 1.24 V with ±125 mV linear input range.
Thermal foldback is implemented via external resistor networks on TSENSE, TREF, TGAIN, and VS pins - allowing programmable breakpoint (via RREF1/RREF2 divider) and foldback slope (via RGAIN) independent of LED current setpoint. The internal 2.45 V reference (VS) and precision 1.24 V CSH reference enable accurate analog dimming and temperature compensation without external references.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4.5 V to 75 V - supports wide-input industrial and automotive LED systems without pre-regulation. |
| Switching Frequency | Up to 2.0 MHz (RT = 12 kΩ) - enables compact magnetics and high-frequency PWM dimming. |
| Current Sense Threshold | 245 mV typical at IS pin - sets cycle-by-cycle overcurrent limit with 75 ns response delay. |
| GATE Driver Strength | 2 Ω sourcing / 1.3 Ω sinking (25°C) - drives N-channel MOSFETs up to 5 A LED current with fast edge rates. |
| Thermal Shutdown | 165°C with 25°C hysteresis - protects IC and external FET during sustained overload or ambient rise. |
| CSH Reference Voltage | 1.24 V ±25 mV - defines LED current setpoint accuracy when used with external sense resistors. |
| VS Reference Output | 2.45 V ±50 mV - provides stable bias for thermal foldback circuitry and external monitoring. |
Pinout & Package
LM3424QMHX/NOPB is housed in a thermally enhanced HTSSOP-20 package (6.50 mm × 4.40 mm) with exposed PowerPAD™ thermal pad soldered to PCB ground plane for efficient heat dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main power input | Bypassed with 100 nF capacitor near pin; powers internal LDO and startup regulator (4.5–75 V). |
| EN | Enable control | Active-high logic input; >2.4 V enables operation, <0.8 V forces low-power shutdown (ISD ≤1 µA). |
| COMP | Error amplifier output | Connects to RC network for loop compensation; sinks/sources up to 35 µA for stability tuning. |
| CSH | Current sense reference node | Regulated to 1.24 V; sums high-side amplifier current and thermal foldback current (ITF) for ILED control. |
| RT/SYNC | Oscillator timing/synchronization | Resistor-to-ground sets fSW (164–669 kHz); accepts external clock for synchronization. |
| nDIM | PWM dimming & UVLO input | Accepts PWM signal for dimming; also programs input undervoltage lockout via resistor divider. |
| SS | Soft-start control | Capacitor-to-ground extends startup time to prevent inrush; ISS = 10 µA constant current source. |
| TGAIN | Foldback slope programming | Resistor-to-ground sets ITF ramp slope; determines how rapidly LED current decreases per °C above TBK. |
| TSENSE | Temperature sense input | Connects to thermistor/resistor divider; senses ambient or heatsink temperature for foldback activation. |
| TREF | Foldback reference input | Resistor divider from VS sets thermal foldback breakpoint voltage; defines TBK temperature threshold. |
| VS | Internal 2.45 V reference | Stable output for TREF, TSENSE, and external circuitry; load current ≤1 mA, ±50 mV tolerance. |
| OVP | Output overvoltage protection | Resistor divider from LED string cathode triggers shutdown if VO exceeds programmed threshold (1.24 V). |
| DDRV | Dimming MOSFET gate driver | 2.5 V CMOS output; drives external N-MOSFET for high-speed PWM dimming (700 ns rise/fall). |
| GND | Signal and power ground | Must be connected to PowerPAD™; serves as return path for all analog and power circuits. |
| GATE | Main switching MOSFET driver | 2 Ω sourcing / 1.3 Ω sinking (25°C); drives gate of external N-channel FET in high-side or low-side configuration. |
| VCC | Internal regulator output | 7.35 V regulated output; bypassed with 2.2–3.3 µF ceramic capacitor for gate drive and internal logic. |
| IS | Main switch current sense | Monitors RDS-ON or external sense resistor; triggers cycle-by-cycle limit at 245 mV threshold. |
| SLOPE | Slope compensation input | Resistor-to-ground adds artificial ramp to COMP signal; prevents subharmonic oscillation above 50% duty cycle. |
| HSN / HSP | High-side LED current sense | Differential inputs for floating LED string; enable accurate current regulation without ground-referenced sense resistor. |
Key Features
| Feature | Design Value |
|---|---|
| Programmable thermal foldback | Independent adjustment of foldback breakpoint (via TREF) and slope (via TGAIN) enables precise LED junction temperature control without firmware. |
| High-side differential current sensing | HSP/HSN inputs support floating LED strings with ±5 mV input offset and 10 µA input bias - eliminates ground-loop errors in multi-string designs. |
| Integrated 2.45 V reference (VS) | Stable, low-drift reference for thermal foldback circuitry and external monitoring - removes need for discrete voltage reference IC. |
| 2-Ω/1-A peak gate driver | Drives N-channel MOSFETs with fast turn-on/turn-off (sub-100 ns propagation delay), reducing switching losses in high-frequency LED drivers. |
| PWM and analog dimming support | nDIM accepts 100–1000 Hz PWM signals; CSH node allows analog dimming by injecting current - supports hybrid dimming schemes. |
Applications
| Street Lighting | Industrial High-Bay Lighting |
|---|---|
|
Use Scenario: Outdoor LED street luminaires operating from 12–48 V DC or rectified AC line with ambient temperatures from −40°C to +85°C. IC Role / Device Role / Timing Role: Constant-current controller managing buck-boost topology to maintain 700 mA LED current despite wide input variation and thermal drift. Use Value: Thermal foldback reduces LED current above 85°C ambient, extending lumen maintenance life by 35% per IES LM-80 data. |
Use Scenario: 150-W high-bay fixtures in warehouses using 24 V DC PoE or 277 V AC input with active cooling. IC Role / Device Role / Timing Role: High-side current controller in SEPIC configuration driving parallel LED strings with individual current regulation. Use Value: High-side sensing (HSP/HSN) eliminates ground-referenced shunt losses, improving system efficiency by 2.1% at full load. |
| Architectural Facade Lighting | UV-C Disinfection Systems |
|
Use Scenario: RGBW color-tunable facade modules requiring synchronized PWM dimming across multiple channels. IC Role / Device Role / Timing Role: Controller providing synchronized switching frequency (via RT/SYNC) and independent DDRV outputs for per-channel dimming MOSFETs. Use Value: External synchronization eliminates beat frequencies between adjacent luminaires, eliminating visible flicker in video capture. |
Use Scenario: Pulsed UV-C LED arrays (275 nm) requiring precise current control and thermal derating during 100-ms on-time bursts. IC Role / Device Role / Timing Role: Peak current-mode controller with 75 ns overcurrent response and programmable soft-start (SS) to manage inrush during burst mode. Use Value: Cycle-by-cycle current limiting prevents catastrophic failure of expensive UV-C LEDs during transient overloads. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3423QMHX/NOPB | Lower VIN max (60 V vs. 75 V); no thermal foldback; fixed 1.25 V CSH reference | Suitable for lower-voltage indoor lighting only; lacks temperature-aware current regulation | Select when thermal management is handled externally and input voltage stays below 60 V. |
| LT3762EFE#PBF | Higher integration (integrated 5.5 V/200 mA bias supply); 100 V VIN rating; no dedicated thermal foldback pins | Supports higher input voltages and eliminates need for external VCC regulator; requires external thermal compensation | Choose for ultra-wide VIN (>75 V) or when board space constraints favor integrated bias supply. |
Compared with LM3424QMHX/NOPB, LM3423QMHX/NOPB offers reduced feature set but lower BOM cost for non-thermal-critical applications, while LT3762EFE#PBF provides higher voltage headroom and integrated bias at the expense of dedicated thermal foldback flexibility.
Availability
LM3424QMHX/NOPB is available at Aetrix Electronics and suitable for street lighting, industrial high-bay fixtures, and UV-C disinfection systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LM3424QMHX/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 over 50 years of innovation in high-reliability power conversion ICs.
The LM3424QMHX/NOPB belongs to TI's LED lighting controller product line, designed specifically for thermally adaptive constant-current regulation in high-voltage, high-efficiency solid-state lighting systems.
FAQ
What is the maximum LED current achievable with LM3424QMHX/NOPB?
The LM3424QMHX/NOPB is a controller-not a driver IC-so maximum LED current depends on external components. With appropriate N-channel MOSFET, inductor, and sense resistor selection, designs routinely achieve 3–5 A LED current in boost or buck-boost configurations. The IS pin current limit threshold is 245 mV, and the GATE driver supports 1-A peak sourcing, enabling robust switching at high currents. Actual current is determined by system-level design, not internal limits.
Does LM3424QMHX/NOPB support both PWM and analog dimming simultaneously?
Yes, LM3424QMHX/NOPB supports hybrid dimming: nDIM accepts standard PWM signals (100–1000 Hz) for coarse intensity control, while the CSH pin allows analog dimming by injecting current to reduce the effective 1.24 V reference. This dual-path approach enables fine-grained brightness adjustment without flicker, especially useful in architectural and video-compatible lighting. The DDRV output provides dedicated gate drive for external dimming MOSFETs.
How is thermal foldback configured on LM3424QMHX/NOPB?
Thermal foldback on LM3424QMHX/NOPB uses four dedicated pins: TSENSE (temperature input), TREF (breakpoint reference), TGAIN (slope gain), and VS (2.45 V reference). A thermistor/resistor divider connects to TSENSE; TREF sets the foldback onset temperature via resistor ratio to VS; TGAIN adjusts the current ramp slope injected into CSH. Full configuration details-including breakpoint calculation and slope calibration-are provided in Section 7.3.4 of the LM3424QMHX/NOPB datasheet.
What package type and thermal performance does LM3424QMHX/NOPB use?
LM3424QMHX/NOPB uses the HTSSOP-20 PowerPAD™ package (6.50 mm × 4.40 mm) with an exposed thermal pad soldered to PCB ground. Its junction-to-board thermal resistance (RθJB) is 18°C/W, and junction-to-ambient (RθJA) is 36.7°C/W with 2-in² 2-oz copper. This enables reliable operation at 125°C ambient when properly mounted-critical for enclosed LED luminaires. The PowerPAD™ must be electrically and thermally connected to GND for specified performance.
Can LM3424QMHX/NOPB operate in buck, boost, and SEPIC topologies without hardware changes?
Yes, LM3424QMHX/NOPB is topology-agnostic: its high-side current sense (HSP/HSN), programmable slope compensation (SLOPE), and flexible gate drive (GATE) allow direct implementation in buck, boost, buck-boost, and SEPIC configurations using only external passive component changes. TI provides reference designs for all four topologies (e.g., SNVA397 for buck-boost, SNVA398 for boost), confirming single-IC reuse across diverse LED driver architectures.
LM3424QMHX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 20-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Controller
- Topology:
- Flyback, SEPIC, Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 4.5V
- Voltage - Supply (Max):
- 75V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 2MHz
- Dimming:
- Analog, PWM
- Applications:
- -
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-HTSSOP
LM3424QMHX/NOPB FAQ
1.How can I place an order for LM3424QMHX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3424QMHX/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 LM3424QMHX/NOPB reliable?
The price and inventory of LM3424QMHX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3424QMHX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3424QMHX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3424QMHX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3424QMHX/NOPB?
LM3424QMHX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3424QMHX/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 LM3424QMHX/NOPB?
For technical support, including LM3424QMHX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3424QMHX/NOPB requirements.
6.How does Aetrix verify that LM3424QMHX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3424QMHX/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 LM3424QMHX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3424QMHX/NOPB?
All LM3424QMHX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3424QMHX/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 LM3424QMHX/NOPB part is unused and in its original packaging.
Return procedure for LM3424QMHX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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