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Texas Instruments LM3429MHX/NOPB
- Part No.:
- LM3429MHX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 14-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3429MHX/NOPB.pdf
- Description:
- IC LED DRIVER CTRLR PWM 14HTSSOP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LM3429MHX/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 operates from 4.5 V to 75 V input, features predictive off-time (PRO) control, high-side current sensing with 1.24 V adjustable sense threshold, and delivers up to 1-A peak gate drive for external NFETs in automotive and outdoor SSL applications.
For engineers reviewing the LM3429MHX/NOPB datasheet, LM3429MHX/NOPB pinout, LM3429MHX/NOPB application, or LM3429MHX/NOPB equivalent, key selection considerations include its 75-V VIN rating, PRO control architecture for stable current regulation without subharmonic oscillation, high-side differential current sense interface (HSP/HSN), programmable switching frequency up to 2 MHz, and thermal shutdown at 165°C.
Technical Context
The LM3429MHX/NOPB implements Predictive Off-Time (PRO) control - a hybrid of peak current-mode control and input-voltage-proportional off-timer - enabling inherent feed-forward compensation and eliminating current-mode instability above 50% duty cycle. Its high-side transconductance amplifier (20–119 mA/V) interfaces directly with LED-string sense resistors via HSP/HSN pins, while the CSH pin regulates to 1.235 V (±2.5 mV) for analog dimming.
Internal 6.9-V LDO supplies VCC (7.35 V max, 27 mA current limit) across 4.5–75 V VIN; overvoltage protection triggers at 1.24 V on OVP pin with 20 µA hysteresis source; nDIM enables UVLO (1.24 V threshold) and PWM dimming; IS pin provides cycle-by-cycle current limiting at 245 mV typical with 75–450 ns leading-edge blanking.
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. |
| Current Sense Threshold | 1.235 V ±2.5 mV at CSH - enables precise LED current regulation via external resistor network (RSNS/RCSH/RHSP). |
| GATE Drive Strength | 2 Ω sourcing / 4.5 Ω sinking - drives NFET gates with fast rise/fall times for high-efficiency switching up to 2 MHz. |
| Switching Frequency | Programmable up to 2 MHz via RCT pin - RT/CT network sets off-time; VIN-proportional timing ensures stable fSW in boost/buck-boost. |
| OVP Threshold | 1.24 V ±60 mV with 20 µA hysteresis source - protects output stage against overvoltage faults in open-circuit LED conditions. |
| Thermal Shutdown | 165°C with 25°C hysteresis - prevents device damage during sustained overload or poor heatsinking in enclosed luminaires. |
| Operating Junction Temp | –40°C to +125°C - qualified for under-hood automotive and high-ambient outdoor lighting environments. |
Pinout & Package
LM3429MHX/NOPB uses a thermally enhanced 14-lead HTSSOP package (5.00 mm × 4.40 mm) with exposed DAP pad connected to AGND/PGND for low-thermal-resistance PCB mounting (RθJA = 47.8°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Input voltage supply | High-voltage input rail (4.5–75 V); bypassed with 100 nF ceramic capacitor to AGND near pin. |
| COMP | Error amplifier output | Connects to compensation network (capacitor to AGND); sets loop stability for current regulation. |
| CSH | Current sense reference | Regulated to 1.235 V; used for analog dimming or low-side current sense when HSP/HSN grounded. |
| RCT | Timing control input | Accepts VIN/25 reference (565 mV typ); RT/CT network sets off-time and switching frequency. |
| AGND | Analog ground reference | Return for CSH, COMP, RCT; must be star-connected to DAP and PGND for noise immunity. |
| OVP | Overvoltage protection input | 1.24 V threshold; connects to resistor divider from LED output to disable driver during open-circuit fault. |
| nDIM | Digital dimming enable | Active-low PWM input; also programs UVLO threshold (1.24 V) for input undervoltage lockout. |
| NC | No connection | Pin 8 is unconnected; must remain floating per datasheet. |
| PGND | Power ground return | Return path for GATE driver; connects to DAP copper pad for thermal and EMI performance. |
| GATE | NFET gate drive output | Drives external N-channel MOSFET gate; 2 Ω sourcing resistance enables fast turn-on. |
| VCC | Internal regulator output | 6.9 V LDO output; bypassed with 2.2–3.3 µF ceramic capacitor to PGND. |
| IS | Main switch current sense | Monitors NFET source/drain voltage drop; triggers cycle-by-cycle shutdown at 245 mV. |
| HSP / HSN | High-side LED current sense | Differential inputs to transconductance amplifier; enable floating LED-string current measurement. |
| DAP | Thermal pad | Exposed bottom pad; must be soldered to AGND/PGND copper pour for thermal dissipation and EMI reduction. |
Key Features
| Feature | Design Value |
|---|---|
| Predictive Off-Time (PRO) Control | Eliminates subharmonic oscillation at >50% duty cycle; enables stable operation in high-ratio boost and buck-boost LED drivers. |
| High-Side Differential Current Sensing | HSP/HSN interface supports floating LED strings without shunt-to-ground, preserving system efficiency and simplifying layout. |
| Adjustable Analog Dimming | CSH pin regulated to 1.235 V allows 0–100% LED current adjustment using external potentiometer or current source. |
| Integrated 1-A Peak Gate Driver | 2 Ω sourcing resistance reduces external gate-drive component count and improves MOSFET switching efficiency. |
| Programmable Overvoltage Protection | OVP pin accepts resistor divider from LED output; 1.24 V threshold with 20 µA hysteresis enables precise fault detection. |
Applications
| Automotive Headlamp Drivers | Outdoor Street Lighting |
|---|---|
Use Scenario: High-brightness LED headlamps requiring constant current regulation across 9–16 V battery range with cold-crank tolerance down to 4.5 V. IC Role / Device Role / Timing Role: N-channel controller managing external NFET in boost configuration to step up battery voltage for series-connected HBLED arrays. Use Value: PRO control maintains stable LED current despite wide VIN variation; 75 V absolute max rating withstands load-dump transients up to 76 V. | Use Scenario: Municipal streetlights powered from 120/277 VAC via PFC front-end, driving 36–72 V LED strings with analog/PWM dimming. IC Role / Device Role / Timing Role: Constant-current controller in buck-boost topology, regulating LED current independent of line fluctuations and temperature drift. Use Value: High-side sensing (HSP/HSN) eliminates ground-referenced shunt losses; thermal shutdown (165°C) ensures reliability in sealed pole-mounted enclosures. |
| Indoor Architectural Lighting | Industrial Machine Vision Illumination |
Use Scenario: Tunable-white LED fixtures with separate warm/cool channels requiring precise current matching and flicker-free dimming. IC Role / Device Role / Timing Role: Dual-channel controller (one per channel) using analog dimming via CSH pin and synchronized PWM dimming via nDIM. Use Value: 1.235 V CSH reference enables <±1% LED current matching between channels; 2 MHz max fSW supports ultra-low-profile magnetics. | Use Scenario: High-speed strobed illumination for factory automation cameras, requiring microsecond-level current turn-on/turn-off precision. IC Role / Device Role / Timing Role: Fast-response LED driver in SEPIC topology, delivering pulsed current to high-power LEDs with minimal delay. Use Value: Leading-edge blanking (75 ns min) and 245 mV IS threshold ensure accurate cycle-by-cycle current limiting during rapid PWM bursts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar N-channel LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3429-Q1MHX/NOPB | AEC-Q100 Grade 1 qualified; identical electrical specs but validated for automotive temperature range (–40°C to +125°C) and ESD robustness. | Required for production automotive lighting; not necessary for commercial indoor/outdoor use. | Select LM3429-Q1MHX/NOPB only when AEC-Q100 compliance is mandated by OEM specification. |
| LM3409HVMM/NOPB | Same PRO control architecture but wider VIN (4.5–100 V); includes integrated 1.5-A gate driver and different pinout (10-pin WSON). | Better suited for ultra-high-input applications (e.g., 48 V telecom or solar); lacks HSP/HSN high-side sensing. | Choose LM3409HVMM/NOPB when input exceeds 75 V or board space constraints favor WSON package. |
Compared with LM3429-Q1MHX/NOPB, the LM3429MHX/NOPB offers identical performance at lower qualification cost for non-automotive use; versus LM3409HVMM/NOPB, it provides superior high-side sensing for floating LED strings but limits max VIN to 75 V.
Availability
LM3429MHX/NOPB is available at Aetrix Electronics and suitable for automotive headlamps, outdoor street lighting, indoor architectural fixtures, and industrial machine vision systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LM3429MHX/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 company headquartered in Dallas, Texas, specializing in analog, embedded processing, and power management ICs for industrial, automotive, and consumer markets.
The LM3429MHX/NOPB belongs to TI's LED lighting controller product line, designed specifically for high-efficiency, high-voltage constant-current drivers supporting multiple topologies and advanced dimming methods in harsh environments.
FAQ
What is the maximum input voltage supported by the LM3429MHX/NOPB?
The LM3429MHX/NOPB supports an absolute maximum input voltage of 76 V and a recommended operating range of 4.5 V to 75 V. This wide VIN capability enables direct integration into 48 V industrial systems and 24/36 V automotive platforms without pre-regulation, while maintaining safe margin against load-dump transients.
How does the LM3429MHX/NOPB implement high-side current sensing?
The LM3429MHX/NOPB uses dedicated HSP and HSN pins to interface with a differential current-sense resistor placed in the LED-string return path. Its internal transconductance amplifier forces VHSP = VHSN, converting LED current into a proportional signal current (ICSH) at the CSH pin, which is regulated to 1.235 V for precise closed-loop control.
Can the LM3429MHX/NOPB be used for PWM dimming?
Yes, the LM3429MHX/NOPB supports PWM dimming via its active-low nDIM pin. Applying a PWM signal directly to nDIM enables fast, flicker-free LED brightness control without external circuitry. The device also supports analog dimming through the CSH pin, allowing hybrid dimming strategies for enhanced flexibility.
What is the purpose of the RCT pin on the LM3429MHX/NOPB?
The RCT pin on the LM3429MHX/NOPB accepts a resistor-capacitor network to set the off-time and thus the switching frequency. It references VIN/25 (565 mV typical), making off-time proportional to input voltage - a key feature enabling near-constant fSW in boost and buck-boost topologies despite wide VIN variation.
Does the LM3429MHX/NOPB include thermal protection?
Yes, the LM3429MHX/NOPB incorporates thermal shutdown that activates at 165°C junction temperature with 25°C hysteresis. This protection disables the GATE driver until die temperature falls below 140°C, preventing permanent damage during sustained overload, poor heatsinking, or ambient temperature excursions in enclosed luminaires.
LM3429MHX/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 Controller
- Topology:
- 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:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-HTSSOP
LM3429MHX/NOPB FAQ
1.How can I place an order for LM3429MHX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3429MHX/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 LM3429MHX/NOPB reliable?
The price and inventory of LM3429MHX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3429MHX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3429MHX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3429MHX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3429MHX/NOPB?
LM3429MHX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3429MHX/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 LM3429MHX/NOPB?
For technical support, including LM3429MHX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3429MHX/NOPB requirements.
6.How does Aetrix verify that LM3429MHX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3429MHX/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 LM3429MHX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3429MHX/NOPB?
All LM3429MHX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3429MHX/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 LM3429MHX/NOPB part is unused and in its original packaging.
Return procedure for LM3429MHX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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