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Texas Instruments LM3431QMH/NOPB
- Part No.:
- LM3431QMH/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 28-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3431QMH/NOPB.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,056
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Product details
Overview
LM3431QMH/NOPB from Texas Instruments is an automotive-grade 3-channel constant-current LED driver with integrated boost controller, supporting 5V–36V input, ±5 mV channel-to-channel current sense offset (–40°C to +125°C), and up to 25 kHz PWM dimming for high-contrast backlighting in infotainment displays.
For engineers reviewing the LM3431QMH/NOPB datasheet, LM3431QMH/NOPB pinout, LM3431QMH/NOPB application, or LM3431QMH/NOPB equivalent, this page delivers verified technical context, validated pin functions, confirmed automotive-grade thermal and fault protection behavior, and real-world dimming performance metrics - all specific to the LM3431QMH/NOPB variant.
Technical Context
The LM3431QMH/NOPB integrates a current-mode PWM boost controller (200 kHz–1 MHz adjustable via RT resistor) with three independent linear current regulators using NDRVx base/gate drives and SNSx feedback amplifiers. It employs cathode feedback (CFB) for headroom optimization and anode feedback (AFB) for output voltage regulation during LED-off periods.
Its dual-mode dimming supports analog voltage or digital PWM inputs (DIM pin), with MODE/F selecting control mode and FF pin enabling overshoot suppression. Fault management includes LED short/open detection (SC pin), programmable delay (DLY), thermal monitoring (THM), and cycle-by-cycle current limiting (ILIM).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 36 V - supports wide automotive battery range including cold-crank transients down to 4.5 V. |
| LED Current Accuracy | ±5 mV SNSx offset mismatch (–40°C to +125°C) - enables <1% inter-channel current variation across temperature. |
| Dimming Frequency | Up to 25 kHz - eliminates audible noise while maintaining >100:1 contrast ratio in PWM mode. |
| Boost Switching Freq | 200 kHz to 1 MHz (RT-programmable) - balances EMI, efficiency, and component size for space-constrained displays. |
| Thermal Shutdown | 160°C junction threshold - protects IC and external transistors during sustained overloads or poor heatsinking. |
| Operating Temp | –40°C to +125°C (AEC-Q100 Grade 1) - qualified for under-hood and dashboard-mounted display systems. |
| Package | TSSOP-28 with exposed pad - provides low θJA = 32°C/W for thermal management in compact PCB layouts. |
Pinout & Package
TSSOP-28 package with exposed thermal pad connected to SGND; 0.65 mm pitch, 9.7 mm × 4.4 mm body size per Package Number PWP0028A.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Main power input | Accepts 4.5–36 V supply; feeds internal UVLO and boost controller input. |
| PGND | Power ground return | Low-impedance return path for boost switch current and LED string sink currents. |
| NDRV1–NDRV3 | Channel drive outputs | Drive external NPN bases or NFET gates; each capable of 10–20 mA source / 4–8 mA sink. |
| SNS1–SNS3 | Current sense inputs | High-precision inputs for LED string current sensing; ±5 mV max offset mismatch ensures tight channel matching. |
| CFB | Cathode feedback | Regulates LED cathode voltage at ~1.71 V during LED-on time to minimize headroom loss and maximize efficiency. |
| AFB | Anode feedback | Regulates output voltage during LED-off periods (startup/dimming); sets OVP threshold via resistor divider. |
| DIM | Brightness control input | Accepts analog voltage (0–5 V) or digital PWM (up to 25 kHz); controls duty cycle of all three channels synchronously. |
| THM | LED thermal monitor | Enters standby when pulled below 1.23 V - enables direct connection to NTC thermistor for LED array overtemperature protection. |
Key Features
| Feature | Design Value |
|---|---|
| No audible noise during dimming | Maintains constant CFB-regulated cathode voltage across PWM cycles - eliminates mechanical vibration in ferrite components. |
| Integrated LED fault protection | SC pin detects short/open faults; DLY capacitor sets shutdown delay; LEDOFF pin signals external drivers during fault events. |
| Programmable soft-start | SS/SH pin charges external capacitor to ramp output voltage smoothly - prevents inrush current and false OVP triggering at startup. |
| High-accuracy linear regulation | REFIN reference input with 2.5 V ±50 mV tolerance and <30 µA bias current enables stable current setting across temperature and supply variations. |
| Automotive-ready thermal management | THM input with 1.23 V ±40 mV threshold and 9.6 µA hysteresis current supports precise NTC-based LED thermal foldback. |
Applications
| Automotive Infotainment Displays | Small to Medium Format Displays |
|---|---|
Use Scenario: Driving RGB LED backlights in 7–10 inch center-stack touchscreens with dynamic brightness control. IC Role / Device Role / Timing Role: LM3431QMH/NOPB acts as primary LED current controller and boost regulator, synchronizing three independent channels to match display grayscale requirements. Use Value: Achieves >100:1 contrast ratio at 25 kHz dimming frequency while maintaining <1% channel current mismatch across –40°C to +125°C. | Use Scenario: Powering white LED arrays in industrial HMI panels requiring AEC-Q100 compliance and long-term reliability. IC Role / Device Role / Timing Role: LM3431QMH/NOPB regulates constant current through external MOSFETs while managing boost output voltage via AFB/CFB feedback loops. Use Value: Eliminates need for separate boost IC and current controllers - reduces BOM count by ≥4 components and PCB area by >30%. |
| LED Backlight for Instrument Clusters | Automotive HUD Modules |
Use Scenario: Controlling segmented LED strings behind analog gauges and digital speedometers with fast transient response. IC Role / Device Role / Timing Role: LM3431QMH/NOPB uses DIM input for real-time brightness scaling and THM pin to throttle current during LED overheating events. Use Value: Enables thermal derating without firmware intervention - maintains functional safety integrity during prolonged high-ambient operation. | Use Scenario: Driving high-brightness micro-LED arrays in compact head-up display projection units with strict EMI limits. IC Role / Device Role / Timing Role: LM3431QMH/NOPB operates boost controller at 800 kHz (via RT resistor) to shift switching noise above sensitive audio bands while sustaining 200 mA/channel. Use Value: Reduces conducted EMI by >15 dB compared to 400 kHz operation - meets CISPR 25 Class 5 requirements without added filtering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-channel LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3431AMH/NOPB | Lower SNSx offset (±3 mV vs. ±5 mV) and reduced VOS_DELTA across temperature - higher accuracy for premium displays. | Targeted at high-end automotive clusters where <0.5% channel mismatch is required; same pinout and footprint. | Select LM3431AMH/NOPB when tighter current matching is critical and cost premium is acceptable. |
| TPS61165DRVR | Single-channel, integrated-FET boost LED driver with I²C interface - no external transistor support or multi-channel sync capability. | Suitable for simpler displays with uniform brightness; lacks THM, SC, and DLY pins for comprehensive fault handling. | Choose TPS61165DRVR only for cost-sensitive single-string designs without thermal/fault monitoring needs. |
Compared with LM3431AMH/NOPB, the LM3431QMH/NOPB trades 2 mV lower offset for broader automotive qualification scope and identical fault architecture; versus TPS61165DRVR, it offers true 3-channel independent control, external transistor flexibility, and full AEC-Q100 Grade 1 protection - making it irreplaceable for robust multi-string backlight systems.
Availability
LM3431QMH/NOPB is available at Aetrix Electronics and suitable for automotive infotainment displays, instrument clusters, and HUD modules requiring stable component supply, AEC-Q100 compliance, and long-term production continuity.
Supply support for LM3431QMH/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 and embedded processing technologies, with decades of automotive-grade product development and manufacturing expertise.
The LM3431 product line delivers integrated LED backlight solutions for automotive displays, combining boost regulation and precision current control in a single AEC-Q100 qualified IC to reduce system complexity and improve thermal reliability.
FAQ
What is the maximum LED string current supported by the LM3431QMH/NOPB?
The LM3431QMH/NOPB supports LED string currents exceeding 200 mA per channel when used with appropriately rated external NPN transistors or MOSFETs. Its NDRVx outputs deliver up to 20 mA source current and 8 mA sink current, enabling robust drive of medium-power discrete switches. The actual current limit depends on external component selection, thermal design, and operating conditions - but the IC's architecture is validated for ≥200 mA/channel in TI reference designs.
Does the LM3431QMH/NOPB support analog dimming, and how is it configured?
Yes, the LM3431QMH/NOPB supports analog dimming via the DIM pin, which accepts a DC voltage from 0 V to 5 V. When MODE/F is held below 0.37 V (analog mode), the internal current reference scales linearly with DIM voltage - delivering proportional LED current reduction without PWM artifacts. This mode avoids EMI concerns associated with high-frequency switching and is ideal for noise-sensitive applications like audio-integrated dashboards.
How does the LM3431QMH/NOPB handle LED open-circuit faults?
The LM3431QMH/NOPB detects LED open circuits using the SC pin, which monitors cathode voltage through diodes connected to each LED string. During an open fault, SC voltage rises to ~3.5 V (clamped), triggering a fault condition. The DLY pin capacitor then determines whether the device shuts down permanently or auto-restarts after a programmable delay - configurable via external capacitance from DLY to SGND.
What is the purpose of the CFB and AFB pins on the LM3431QMH/NOPB?
The CFB (cathode feedback) pin regulates LED cathode voltage at ~1.71 V during LED-on periods to minimize headroom loss and maximize efficiency. The AFB (anode feedback) pin regulates output voltage during LED-off times (e.g., dimming off-cycles or startup) and sets the overvoltage protection threshold. Together, they enable stable output control across dynamic lighting states without requiring external op-amps or complex compensation networks.
Can the LM3431QMH/NOPB operate with input voltage equal to or greater than the LED string forward voltage?
No - the LM3431QMH/NOPB requires VIN to remain at least 1 V below the set output voltage to maintain proper boost operation. If VIN ≥ VOUT, the boost switch stops switching, causing unregulated output and increased NDRVx power dissipation. TI explicitly recommends restricting input voltage to ensure minimum on-time is not violated and continuous conduction mode is preserved for optimal current regulation.
LM3431QMH/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 28-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- DC DC Controller
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 3
- Voltage - Supply (Min):
- 4.5V
- Voltage - Supply (Max):
- 36V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 1MHz
- Dimming:
- Analog, PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-HTSSOP
LM3431QMH/NOPB FAQ
1.How can I place an order for LM3431QMH/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3431QMH/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 LM3431QMH/NOPB reliable?
The price and inventory of LM3431QMH/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3431QMH/NOPB is usually 5 days.
3.What payment methods are accepted for LM3431QMH/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3431QMH/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3431QMH/NOPB?
LM3431QMH/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3431QMH/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 LM3431QMH/NOPB?
For technical support, including LM3431QMH/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3431QMH/NOPB requirements.
6.How does Aetrix verify that LM3431QMH/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3431QMH/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 LM3431QMH/NOPB meets industry standards.
7.What is the process for return or replacement of LM3431QMH/NOPB?
All LM3431QMH/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3431QMH/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 LM3431QMH/NOPB part is unused and in its original packaging.
Return procedure for LM3431QMH/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3431QMH/NOPB Tags
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HV9910CLG-G
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CL2N8-G
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