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Texas Instruments LM3429MH/NOPB
- Part No.:
- LM3429MH/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 14-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3429MH/NOPB.pdf
- Description:
- IC LED DRIVER CTRLR PWM 14HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:6,317
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Product details
Overview
LM3429MH/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, 2-Ω/1-A gate drive, and high-side current sensing with 1.235 V adjustable sense threshold - enabling precise LED current regulation in automotive headlamps and outdoor SSL systems.
For engineers reviewing the LM3429MH/NOPB datasheet, LM3429MH/NOPB pinout, LM3429MH/NOPB application, or LM3429MH/NOPB equivalent, key selection considerations include its 75 V VIN rating, PRO control architecture for inherent input feed-forward and no sub-harmonic instability, high-side differential current sense interface (HSP/HSN), thermal shutdown at 165 °C, and compatibility with up to 2 MHz switching via RCT timing network.
Technical Context
The LM3429MH/NOPB implements Predictive Off-Time (PRO) control - combining peak current-mode regulation with an input-proportional off-timer - eliminating current-mode instability at all duty cycles and enabling stable operation in high-VIN boost and buck-boost LED drivers. Its high-side transconductance amplifier (119 mA/V typical) interfaces directly with floating LED strings via HSP/HSN, while the IS pin provides cycle-by-cycle overcurrent protection at 245 mV threshold.
Internal 6.9 V LDO regulator powers the controller core from VIN (4.5–75 V), and the GATE driver delivers 1-A peak sink/source with 2 Ω sourcing resistance. PWM dimming is implemented via the nDIM pin (1.24 V UVLO threshold), and analog dimming is enabled through CSH pin voltage modulation of the 1.235 V reference-controlled current sense loop.
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 external pre-regulation. |
| Switching Frequency | Up to 2 MHz - set by external RCT network; enables compact magnetics and low-profile designs. |
| Current Sense Threshold | 1.235 V (typ) at CSH - adjustable high-side sense reference enabling tight LED current regulation (±0.5% typical drift over temperature). |
| GATE Drive Strength | 2 Ω sourcing / 4.5 Ω sinking - drives large external N-FETs with fast turn-on/turn-off, minimizing conduction and switching losses. |
| Overvoltage Protection | 1.24 V threshold at OVP pin - programmable output overvoltage lockout with 20 µA hysteresis current source. |
| Thermal Shutdown | 165 °C with 25 °C hysteresis - protects against sustained overload or poor PCB thermal design. |
| Operating Junction Temp | –40 °C to +125 °C - qualified for under-hood automotive and outdoor lighting environments. |
Pinout & Package
LM3429MH/NOPB is housed in a thermally enhanced 14-lead HTSSOP package (5.00 mm × 4.40 mm) with exposed DAP pad for improved heat dissipation. The DAP must be connected to both AGND and PGND for optimal thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VIN | Main power input | High-voltage input rail (4.5–75 V); bypassed with 100 nF ceramic capacitor to AGND near pin. |
| 2 COMP | Error amplifier output | Compensation node for current loop stability; requires RC network to AGND per design requirements. |
| 3 CSH | Current sense reference | 1.235 V reference input for analog dimming and high-side current sense amplifier bias. |
| 4 RCT | Timing network input | Connects to switch node and AGND capacitor to set off-time and regulate switching frequency. |
| 5 AGND | Analog ground reference | Return path for CSH, COMP, RCT; must be tied to DAP and separated from PGND at single point. |
| 6 OVP | Overvoltage protection input | Monitors output voltage via resistor divider; triggers shutdown when >1.24 V with 20 µA hysteresis. |
| 7 nDIM | PWM dimming enable | Active-low input; 1.24 V threshold enables direct PWM signal connection for digital LED dimming. |
| 8 NC | No connection | Not internally bonded; must remain unconnected and unpopulated on PCB. |
| 9 PGND | Power ground return | High-current return for GATE driver and IS sense path; connects to DAP copper pad. |
| 10 GATE | N-FET gate driver output | Drives external N-channel MOSFET gate; 1-A peak current capability with 2 Ω source impedance. |
| 11 VCC | Internal LDO output | 6.9 V regulated supply; bypassed with 2.2–3.3 µF ceramic capacitor to PGND. |
| 12 IS | Main switch current sense | Inputs MOSFET RDS(on) or sense resistor voltage; triggers cycle-by-cycle limit at 245 mV. |
| 13 HSP | High-side sense positive | Positive input to differential amplifier for LED string current sensing; referenced to HSN. |
| 14 HSN | High-side sense negative | Negative input to differential amplifier; requires matched series resistor to cancel input bias current. |
| DAP | Thermal pad | Exposed bottom pad; must be soldered to large copper area connected to AGND and PGND. |
Key Features
| Feature | Design Value |
|---|---|
| Predictive Off-Time (PRO) Control | Eliminates sub-harmonic oscillation at all duty cycles; enables stable high-VIN boost/buck-boost operation without slope compensation. |
| High-Side Differential Current Sensing | HSP/HSN interface supports floating LED strings and avoids ground-referenced shunt limitations in high-side buck configurations. |
| Integrated 6.9 V LDO Regulator | Starts up directly from 4.5–75 V input; eliminates need for external bias supply and simplifies system BOM. |
| Programmable Overvoltage & Undervoltage Lockout | OVP and nDIM pins use 1.24 V thresholds with 20 µA hysteresis sources - enabling precise, resistor-programmable protection points. |
| 2 MHz Switching Capability | Supports ultra-compact magnetic designs and reduced EMI filtering requirements in space-constrained SSL applications. |
| Thermal Shutdown with Hysteresis | 165 °C trip with 25 °C hysteresis prevents thermal cycling; ensures safe recovery after fault conditions. |
Applications
| Automotive Headlamp Drivers | Outdoor Street Lighting |
|---|---|
|
Use Scenario: High-brightness LED arrays in vehicle forward lighting, requiring robust operation across 6–16 V battery range and load-dump transients. IC Role / Device Role / Timing Role: N-channel controller implementing boost topology to regulate 1–5 A LED current from variable automotive input; PRO control maintains stability during rapid VIN changes. Use Value: 75 V absolute max rating withstands 120 V load-dump events; high-side sensing avoids ground-loop interference in chassis-referenced systems. |
Use Scenario: Multi-string LED luminaires mounted on utility poles, operating continuously in ambient temperatures from –40 °C to +85 °C. IC Role / Device Role / Timing Role: Constant-current controller in buck-boost configuration powering 36–72 V LED strings from 120/277 VAC rectified input with PFC front-end. Use Value: Wide 4.5–75 V input range accommodates PFC output ripple; thermal shutdown protects against enclosure overheating in sealed fixtures. |
| Indoor Architectural Lighting | Industrial Machine Vision Illumination |
|
Use Scenario: Tunable-white and color-mixing LED modules in commercial buildings, requiring smooth analog and PWM dimming down to 0.1%. IC Role / Device Role / Timing Role: LED current controller supporting dual dimming modes - CSH-based analog adjustment and nDIM-based PWM with <100 ns response. Use Value: 1.235 V CSH reference enables precise dimming linearity; PRO control ensures flicker-free dimming even at low duty cycles. |
Use Scenario: High-intensity strobed LED arrays used in automated inspection systems, demanding microsecond-level current accuracy and repeatability. IC Role / Device Role / Timing Role: Precision current regulator in SEPIC topology driving pulsed LED loads with cycle-by-cycle current limiting and leading-edge blanking. Use Value: 245 mV IS threshold and 75 ns tON-MIN enable accurate short-pulse current control; high-side sensing isolates sensitive vision sensors from power ground noise. |
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 |
|---|---|---|---|
| LM3423MH/NOPB | Includes integrated high-side N-FET driver and current sense amplifier; lacks RCT-based frequency programming. | Better suited for lower-current (<1.5 A), fixed-frequency designs where integration reduces component count. | Select LM3423MH/NOPB when board space is critical and switching frequency stability over input variation is less important than simplicity. |
| TPS92691QPWPRQ1 | Features integrated op-amp, current mirror, and spread-spectrum clocking; supports I²C dimming and fault reporting. | Targeted at ASIL-B automotive lighting with diagnostics; higher BOM cost and larger footprint than LM3429MH/NOPB. | Choose TPS92691QPWPRQ1 only when functional safety compliance, digital control, or multi-channel synchronization is required. |
Compared with LM3429MH/NOPB, LM3423MH/NOPB trades external FET flexibility and PRO control for integration, while TPS92691QPWPRQ1 adds diagnostics and digital control at the expense of design simplicity and cost - making LM3429MH/NOPB optimal for high-efficiency, high-VIN analog/PWM dimmable LED drivers where reliability and thermal robustness are primary.
Availability
LM3429MH/NOPB is available at Aetrix Electronics and suitable for automotive headlamps, outdoor street lighting, indoor architectural lighting, and industrial machine vision illumination requiring stable component supply across extended temperature and voltage ranges.
Supply support for LM3429MH/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 expertise in LED driver innovation and automotive-grade IC design.
The LM3429MH/NOPB belongs to TI's high-voltage LED controller product line, engineered specifically for constant-current regulation in buck, boost, buck-boost, and SEPIC topologies - targeting demanding SSL applications where efficiency, thermal resilience, and dimming fidelity are critical.
FAQ
What topology configurations does the LM3429MH/NOPB support?
The LM3429MH/NOPB supports buck, boost, buck-boost, and SEPIC topologies by leveraging its high-side current sense (HSP/HSN), predictive off-time control, and external N-FET gate drive. Its flexible architecture allows implementation in ground-referenced boost or floating-load buck-boost configurations - confirmed in TI's SNVA403 and SNVA404 evaluation boards. The LM3429MH/NOPB does not integrate power switches, preserving design freedom across voltage and current classes.
How does the LM3429MH/NOPB achieve stable LED current regulation without slope compensation?
The LM3429MH/NOPB uses Predictive Off-Time (PRO) control - a hybrid of peak current-mode regulation and input-proportional off-timing - which inherently avoids sub-harmonic oscillation at all duty cycles. Unlike standard current-mode controllers, PRO eliminates the need for external slope compensation components. This behavior is verified in the LM3429MH/NOPB datasheet Figure 12 and application note AN-1985, ensuring stable regulation even in high-duty-cycle boost configurations.
Can the LM3429MH/NOPB be used for analog dimming, and how is it implemented?
Yes, the LM3429MH/NOPB supports analog dimming via the CSH pin, which references the 1.235 V internal error amplifier threshold. Dimming is achieved by injecting current into or varying resistance in the CSH path - altering the effective current sense voltage (VSNS) and thus the regulated LED current. TI application note SNVA403 details two validated methods: potentiometer-based resistance adjustment and PNP current mirror sourcing, both preserving linearity and noise immunity in the LM3429MH/NOPB design.
What is the purpose of the RCT pin on the LM3429MH/NOPB, and how is it configured?
The RCT pin on the LM3429MH/NOPB sets the off-time (tOFF) and thus regulates switching frequency using an external resistor-capacitor network. For boost and buck-boost topologies, RCT connects to the switch node and AGND - enabling VIN-proportional timing that yields near-constant fSW across input voltage. The LM3429MH/NOPB datasheet specifies 1 nF CT and recommends close placement to minimize parasitic inductance, with typical frequencies ranging from 100 kHz to 2 MHz depending on RT value.
Does the LM3429MH/NOPB include built-in protection features, and what are their thresholds?
Yes, the LM3429MH/NOPB integrates overvoltage protection (OVP) with 1.24 V threshold at the OVP pin, input undervoltage lockout (UVLO) at 1.24 V on nDIM, cycle-by-cycle current limiting at 245 mV on the IS pin, and thermal shutdown at 165 °C with 25 °C hysteresis. All protection functions are hardware-based and operate independently of the control loop - confirmed in Section 6.5 Electrical Characteristics and Section 7.3.6 of the LM3429MH/NOPB datasheet.
LM3429MH/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-HTSSOP
LM3429MH/NOPB FAQ
1.How can I place an order for LM3429MH/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3429MH/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 LM3429MH/NOPB reliable?
The price and inventory of LM3429MH/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3429MH/NOPB is usually 5 days.
3.What payment methods are accepted for LM3429MH/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3429MH/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3429MH/NOPB?
LM3429MH/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3429MH/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 LM3429MH/NOPB?
For technical support, including LM3429MH/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3429MH/NOPB requirements.
6.How does Aetrix verify that LM3429MH/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3429MH/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 LM3429MH/NOPB meets industry standards.
7.What is the process for return or replacement of LM3429MH/NOPB?
All LM3429MH/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3429MH/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 LM3429MH/NOPB part is unused and in its original packaging.
Return procedure for LM3429MH/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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