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Texas Instruments LM3406MHX/NOPB
- Part No.:
- LM3406MHX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 14-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3406MHX/NOPB.pdf
- Description:
- IC LED DRVR RGLTR PWM 14HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:5,350
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Product details
Overview
LM3406MHX/NOPB from Texas Instruments is a monolithic 1.5-A constant-current buck LED driver with integrated 2.0-A N-channel MOSFET, true average current control via external sense resistor, and dedicated PWM dimming logic input. It operates from 6 V to 42 V input, delivers stable current to high-power LED arrays in automotive headlamps and industrial lighting, and features thermal shutdown and cycle-by-cycle current limiting.
For engineers reviewing the LM3406MHX/NOPB datasheet, LM3406MHX/NOPB pinout, LM3406MHX/NOPB application, or LM3406MHX/NOPB equivalent, key selection considerations include its 200-mV CS reference accuracy over temperature, programmable on-time via RON, TSSOP-14 exposed-pad package thermal performance (θJA = 50°C/W), and dual-dimming support (DIM pin and VINS comparator).
Technical Context
The LM3406MHX/NOPB implements a controlled-on-time (COT) architecture with an integrator-based error amplifier that maintains 200 mV average at the CS pin. Its switching frequency varies inversely with VIN and VO but remains stable in continuous conduction mode (CCM), enabling accurate current regulation across wide input/output ranges.
It integrates a high-side N-MOSFET (RDS-ON = 0.75 Ω typ), bootstrap gate drive (22 nF CB required), 7-V internal linear regulator (VCC), and dual-dimming paths: TTL-compatible DIM pin (VIH = 2.2 V, VIL = 0.8 V) and VINS comparator for two-wire PWM dimming (70% VIN threshold).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 6 V to 42 V - supports 12 V/24 V automotive and industrial DC supplies without external step-down. |
| Output Current | Up to 1.5 A - set precisely by RSNS = 0.2 V / IF; minimum 1.7 A current limit ensures robustness under transient overload. |
| CS Reference Voltage | 200 mV (typ) - enables ±1% LED current accuracy with low-drift sense resistors and stable averaging loop. |
| Switching On-Time | 800–1800 ns (programmable via RON) - allows frequency tuning from ~100 kHz to >1 MHz while maintaining CCM operation. |
| Thermal Shutdown | 165°C (with 25°C hysteresis) - protects IC during sustained overload or poor PCB heatsinking; DAP must be soldered to ground plane. |
| Package | TSSOP-14 with exposed thermal pad (PWP0014A) - achieves 50°C/W θJA when mounted on ≥2 in² of 1-oz copper. |
| PWM Dimming Inputs | DIM pin (TTL-level) and VINS comparator (70% VIN threshold) - enable flexible dimming architectures without external controllers. |
Pinout & Package
TSSOP-14 package with exposed thermal pad (DAP), requiring 4–6 vias to bottom-layer ground plane for thermal integrity and EMI control.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1,2 SW | Power switch node | Connects to inductor and Schottky diode cathode; carries full switching current and high dv/dt. |
| 3 BOOT | Bootstrap supply rail | Drives high-side MOSFET gate; requires 22 nF ceramic capacitor to SW pins for proper gate voltage generation. |
| 4 NC | No connect | Internally unconnected; must remain floating per datasheet. |
| 5 VOUT | Output voltage sense | Monitors LED string anode node; used for open-circuit protection and output voltage clamping design. |
| 6 CS | Current sense feedback | Inputs 200 mV reference-controlled current signal; sets LED current via RSNS and enables OVP/OCP at 300 mV. |
| 7 GND | Power and signal ground | Common return for all analog and power circuits; must be low-impedance and tied to DAP. |
| 8 DIM | PWM dimming logic input | TTL-compatible enable/disable control; 75 µA internal pull-up eliminates need for external resistor. |
| 9 COMP | Error amplifier output | Drives external compensation network (0.1 µF X5R/X7R to GND); sets loop stability and transient response. |
| 10 RON | On-time programming | Resistor to VIN sets tON; determines base switching frequency and influences CCM boundary. |
| 11 VCC | Internal 7-V bias supply | Bypassed with 0.1 µF ceramic; regulates from VIN above 8.8 V; powers gate driver and analog circuitry. |
| 12 VINS | Input-voltage PWM dimming comparator | Detects 70% VIN drop to enable two-wire dimming; requires external input diode for isolation. |
| 13,14 VIN | Main power input | Accepts 6–42 V; supplies both power stage and internal regulators; requires local CIN decoupling. |
| DAP | Thermal pad | Must be soldered to PCB ground plane; primary thermal path; contributes significantly to θJA rating. |
Key Features
| Feature | Design Value |
|---|---|
| True average current control | Maintains 200 mV average at CS pin across temperature and line/load variations, enabling ±1% LED current accuracy without complex compensation. |
| Integrated 2.0-A N-MOSFET | Eliminates external high-side switch; RDS-ON = 0.75 Ω typ reduces conduction loss and simplifies layout in space-constrained LED modules. |
| Dual PWM dimming interface | Supports both logic-level DIM pin (fast response) and VINS comparator (two-wire compatibility), enabling flexible system-level dimming without added ICs. |
| Programmable on-time architecture | RON-resistor sets tON from 800–1800 ns, allowing frequency optimization for efficiency (low fSW) or size (high fSW) without sacrificing CCM stability. |
| Open-circuit and overvoltage protection | VOUT pin withstands VO(MAX) ≤ VIN; CS OVP comparator limits peak current to 300 mV / RSNS, preventing LED overcurrent during transients. |
| Low-power shutdown | Grounding RON reduces IIN to 240–350 µA; compatible with logic-level MOSFETs (e.g., 2N7000) for system-level power sequencing. |
Applications
| Automotive Headlamp Driver | Industrial High-Bay Lighting |
|---|---|
Use Scenario: Driving 3–6 series-connected InGaN LEDs in 12 V/24 V vehicle electrical systems with ambient temperatures up to +125°C. IC Role / Device Role / Timing Role: Constant-current buck regulator delivering 1.5 A with true average sensing, thermal shutdown, and PWM dimming for adaptive front-lighting. Use Value: Eliminates external current-sense amplifier and gate driver; 50°C/W θJA enables compact heatsinkless designs in sealed headlamp housings. |
Use Scenario: Powering multi-string LED arrays in warehouse high-bay fixtures operating continuously at 40–60°C ambient. IC Role / Device Role / Timing Role: Primary LED current controller with programmable on-time and all-ceramic output capacitor support for long-life, low-maintenance lighting. Use Value: Supports capacitor-less outputs to reduce BOM cost and failure points; cycle-by-cycle current limit prevents damage during LED string faults. |
| General Illumination Retrofit Module | Machine Vision LED Array |
Use Scenario: Replacing fluorescent tubes in commercial ceiling fixtures using universal AC/DC input with DC bus feeding LM3406MHX/NOPB. IC Role / Device Role / Timing Role: Buck-stage current regulator accepting 24–42 V DC bus, providing dimmable constant current to parallel LED strings. Use Value: Dual-dimming (DIM + VINS) enables compatibility with legacy 0–10 V and DALI-2 drivers; TSSOP-14 footprint fits narrow retrofit PCBs. |
Use Scenario: Driving high-speed pulsed LED arrays in automated inspection systems requiring precise current slew control and minimal ripple. IC Role / Device Role / Timing Role: Precision current source with <280 ns minimum on-time and fast DIM pin response (<1 µs turn-off) for strobed illumination. Use Value: Enables sub-millisecond LED on/off transitions; CS comparator OVP limits overshoot to ≤±5% during rapid dimming cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current buck LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3406HV/NOPB | Wider 6–75 V VIN range; identical pinout and functionality; higher VOUT capability for longer LED strings. | Suitable for 48 V industrial or 60 V telecom-powered LED systems where LM3406MHX/NOPB's 42 V max is insufficient. | Select LM3406HV/NOPB only when input exceeds 42 V; otherwise LM3406MHX/NOPB offers better cost and thermal margin at 24 V. |
| TPS92630QPWPRQ1 | AEC-Q100 Grade 0 automotive LED driver; 3.5-A switch; integrated PWM generator; I2C interface; different pinout and control scheme. | Targeted at ASIL-B automotive clusters requiring diagnostics and programmability; not pin-compatible or functionally drop-in. | Choose TPS92630QPWPRQ1 only for safety-critical automotive applications needing fault reporting; LM3406MHX/NOPB remains optimal for cost-sensitive, non-diagnostic LED drivers. |
Compared with LM3406HV/NOPB, LM3406MHX/NOPB trades input voltage headroom for lower cost and improved thermal efficiency at 24 V; versus TPS92630QPWPRQ1, it offers simpler analog control and proven reliability in non-ASIL applications without communication overhead.
Availability
LM3406MHX/NOPB is available at Aetrix Electronics and suitable for automotive headlamps, industrial high-bay lighting, and general illumination retrofit modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM3406MHX/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 ICs, with decades of expertise in LED driver innovation and automotive-grade reliability.
The LM3406 family was designed specifically as a monolithic constant-current buck regulator for high-power LED lighting, emphasizing integration, thermal robustness, and dual-dimming flexibility in harsh environments.
FAQ
What is the maximum LED string voltage supported by LM3406MHX/NOPB?
The LM3406MHX/NOPB does not regulate output voltage directly-it regulates current-so maximum string voltage depends on minimum input voltage and minimum off-time (230 ns). For VIN(MIN) = 6 V, VO(MAX) ≈ 5.9 V; for VIN = 24 V, VO(MAX) ≈ 23.5 V. Always verify VO(MAX) = VIN(MIN) × (1 − fSW × tOFF-MIN) in your specific design. The LM3406MHX/NOPB itself withstands VO up to 45 V relative to GND.
Can LM3406MHX/NOPB operate without an output capacitor?
Yes, the LM3406MHX/NOPB supports capacitor-less outputs due to its direct inductor-to-LED connection and controlled-on-time architecture. This reduces BOM cost and improves reliability, especially in high-temperature environments. However, an output capacitor may still be needed for EMI suppression or to limit voltage overshoot during open-circuit events-TI recommends evaluating both configurations per application requirements.
How is LED current accuracy affected by temperature in LM3406MHX/NOPB?
The LM3406MHX/NOPB maintains LED current accuracy via true average current sensing with a 200 mV CS reference that drifts only ±1.5% over −40°C to +125°C junction temperature. Combined with low-tempco external RSNS resistors, this enables ±2% total current variation across full operating range-critical for color consistency in multi-LED arrays.
What is the purpose of the RON pin on LM3406MHX/NOPB?
The RON pin on LM3406MHX/NOPB sets the controlled on-time (tON) by connecting an external resistor to VIN. tON determines base switching frequency and influences CCM operation: higher RON yields longer tON and lower fSW. Typical values range from 100 kΩ to 1 MΩ. Grounding RON forces shutdown (IIN-SD ≈ 350 µA), making it usable for system-level enable control.
Does LM3406MHX/NOPB require a bootstrap capacitor, and what value is recommended?
Yes, LM3406MHX/NOPB requires a 22 nF ceramic capacitor between BOOT and SW pins to sustain gate drive for its integrated high-side N-MOSFET. TI specifies X7R or C0G dielectric with 16 V rating; placement must be adjacent to the IC with short, low-inductance traces. Omitting or undersizing this capacitor causes erratic switching, gate drive collapse, and potential device failure.
LM3406MHX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Down (Buck)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 6V
- Voltage - Supply (Max):
- 42V
- Voltage - Output:
- -
- Current - Output / Channel:
- 1.5A
- Frequency:
- 10kHz ~ 1MHz
- Dimming:
- PWM
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-HTSSOP
LM3406MHX/NOPB FAQ
1.How can I place an order for LM3406MHX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3406MHX/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 LM3406MHX/NOPB reliable?
The price and inventory of LM3406MHX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3406MHX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3406MHX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3406MHX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3406MHX/NOPB?
LM3406MHX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3406MHX/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 LM3406MHX/NOPB?
For technical support, including LM3406MHX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3406MHX/NOPB requirements.
6.How does Aetrix verify that LM3406MHX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3406MHX/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 LM3406MHX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3406MHX/NOPB?
All LM3406MHX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3406MHX/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 LM3406MHX/NOPB part is unused and in its original packaging.
Return procedure for LM3406MHX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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