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Texas Instruments LM3431AQMHX/NOPB
- Part No.:
- LM3431AQMHX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 28-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3431AQMHX/NOPB.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,967
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Product details
Overview
LM3431AQMHX/NOPB from Texas Instruments is an automotive-grade 3-channel constant-current LED driver with integrated boost controller, delivering ±3 mV channel-to-channel offset voltage mismatch, 2.5 V reference accuracy, and programmable switching frequency up to 1 MHz for driving LED strings exceeding 200 mA per channel in space-constrained backlight systems.
For engineers reviewing the LM3431AQMHX/NOPB datasheet, LM3431AQMHX/NOPB pinout, LM3431AQMHX/NOPB application, or LM3431AQMHX/NOPB equivalent, key selection considerations include cathode feedback (CFB) regulation, analog/PWM dimming support up to 25 kHz, thermal shutdown at 160°C, LED short/open fault detection, and AEC-Q100 Grade 1 qualification (–40°C to +125°C).
Technical Context
The LM3431AQMHX/NOPB integrates a current-mode PWM boost controller and three independent linear current regulators with NDRVx base/gate drivers. It uses CFB-based cathode voltage regulation during LED-on periods and AFB-based anode regulation during LED-off intervals, enabling stable output voltage across dimming cycles without audible noise.
Its architecture supports dual dimming modes via MODE/F pin: digital PWM (≥3.8 V threshold) or analog control (0.37–2.5 V range), with DIM input accepting signals up to 25 kHz and achieving >100:1 contrast ratio. Fault protection includes programmable delay on DLY pin, SC pin-based short/open detection, THM-driven thermal standby, and cycle-by-cycle current limiting via ILIM.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5 V to 36 V - supports wide automotive battery rail variations including cold-crank transients. |
| LED Current Accuracy | ±3 mV channel-to-channel offset mismatch - ensures uniform brightness across 3 LED strings without external calibration. |
| Reference Voltage | 2.5 V ±0.05 V - high-precision internal reference enables accurate current setting via REFIN resistor divider. |
| Switching Frequency | 200 kHz to 1 MHz - adjustable via RT pin resistor; higher frequencies reduce inductor size but increase switching losses. |
| Dimming Frequency | Up to 25 kHz - eliminates visible flicker and audible noise in PWM dimming mode. |
| Thermal Shutdown | 160°C junction temperature - protects IC and external transistors under sustained overload or poor heatsinking. |
| Operating Temperature | –40°C to +125°C - qualified per AEC-Q100 Grade 1 for under-hood and infotainment display use. |
Pinout & Package
TSSOP-28 with exposed pad (Package Number PWP0028A); exposed pad must be connected to SGND for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power supply input | Accepts 5–36 V input; powers internal circuitry and boost switch driver. |
| PGND | Power ground | Low-impedance return path for boost switch and sense resistor currents. |
| VCC | Internal reference output | 5 V ±0.24 V regulated supply; requires ≥4.7 µF bypass capacitor to PGND. |
| LG | Boost gate driver | Drives external NFET gate; 0.35 A source / 0.7 A sink capability at 5.5 V VIN. |
| CS | Boost current sense | Monitors top-side voltage of boost sense resistor; used for PWM control and overcurrent protection. |
| ILIM | Current limit adjust | Sets peak inductor current threshold via resistor to CS; enables cycle-by-cycle limiting. |
| MODE/F | Dimming mode select | Pull high for digital PWM; connect capacitor to GND for analog dimming frequency setting. |
| RT | Frequency adjust | Resistor to GND sets boost switching frequency from 200 kHz to 1 MHz. |
| REF/REFIN | Reference voltage interface | REF provides 2.5 V reference; REFIN sets LED current via resistor divider from REF. |
| COMP | Error amplifier output | Connects to compensation network for boost loop stability; transconductance = 230 µmho. |
| SGND | Signal ground | Reference for analog blocks (SNSx, REFIN, COMP); separate from PGND to minimize noise coupling. |
| AFB/CFB | Anode/cathode feedback | AFB regulates output during LED-off; CFB regulates cathode voltage during LED-on for minimal headroom. |
| SNS1–SNS3 | Channel current sense | Inputs to current regulator amplifiers; bias current ≤30 µA, offset ≤±3 mV (LM3431A). |
| NDRV1–NDRV3 | Channel drive outputs | Drive external NPN bases or NFET gates; 3.7 V drive voltage, 4–8 mA sink, 10–20 mA source capability. |
| DIM | Brightness control | Accepts analog voltage (0–2.5 V) or digital PWM (1.9–2.3 V threshold); 0.4 µs minimum pulse width. |
| EN | Enable/UVLO | Shuts down device below 0.75 V; enables at 1.23 V with 165 mV hysteresis; UVLO programmable via resistor divider. |
| THM | LED thermal monitor | Pulls low when external thermistor voltage drops below 1.23 V; forces standby mode to protect LED array. |
| SC | LED short/open detect | Monitors cathode nodes via diodes; triggers fault at 6 V (short) or clamps at 3.5 V (open). |
| DLY | Fault delay timing | Capacitor to GND sets shutdown delay time; 2.8 V threshold, 39–73 µA source current. |
| SS/SH | Soft-start/sample-hold | Charges during startup to ramp output; holds reference during LED-off for stable AFB regulation. |
| LEDOFF | Fault signaling/output control | Drives external drivers during PWM off-time; connect to GND to enable automatic restart after fault. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated boost + 3-channel linear regulation | Eliminates need for separate boost IC and current controllers; reduces BOM count and PCB area in display backlight designs. |
| Cathode feedback (CFB) regulation | Maintains constant 1.71 V at CFB pin during LED-on, minimizing headroom loss and maximizing efficiency across varying LED Vf. |
| Programmable fault response | DLY pin capacitor selects shutdown delay; LEDOFF pin enables either latched shutdown or automatic restart after fault clearance. |
| No-audible-noise dimming | Constant output voltage regulation during PWM dimming prevents mechanical resonance in inductors and capacitors. |
| AEC-Q100 Grade 1 qualification | Validated for automotive operation from –40°C to +125°C junction temperature; includes enhanced offset voltage performance (±3 mV). |
Applications
| Automotive Infotainment Displays | Small to Medium Format Displays |
|---|---|
Use Scenario: Driving RGB LED backlight arrays in center-stack touchscreens and instrument clusters requiring uniform brightness and thermal robustness. IC Role / Device Role / Timing Role: LM3431AQMHX/NOPB acts as primary LED current controller and boost regulator, managing three independent channels while maintaining <±3 mV inter-channel mismatch. Use Value: Enables consistent color balance and luminance across display zones despite varying LED forward voltages and ambient temperature shifts. | Use Scenario: Powering monochrome or segmented LED backlights in industrial HMIs, medical panels, and portable test equipment. IC Role / Device Role / Timing Role: LM3431AQMHX/NOPB serves as compact, single-chip solution for multi-string LED current regulation with integrated fault diagnostics. Use Value: Reduces system-level component count by integrating boost controller, current regulators, and comprehensive protection features into one TSSOP-28 package. |
| Automotive Rear Seat Entertainment | Automotive Head-Up Display (HUD) Backlighting |
Use Scenario: Controlling LED strings in rear-seat tablets and fold-down displays where EMI and thermal constraints limit discrete solutions. IC Role / Device Role / Timing Role: LM3431AQMHX/NOPB delivers precise analog/PWM dimming up to 25 kHz while suppressing audible noise through constant-voltage regulation. Use Value: Achieves >100:1 contrast ratio without coil whine, meeting OEM acoustic requirements for passenger cabin environments. | Use Scenario: Regulating high-brightness LED arrays in HUD projection modules requiring stable current under wide input voltage swings (e.g., 9–16 V battery). IC Role / Device Role / Timing Role: LM3431AQMHX/NOPB functions as fault-tolerant LED driver with THM input monitoring LED die temperature and triggering standby before thermal damage occurs. Use Value: Prevents LED degradation and maintains optical output consistency over lifetime by actively throttling current based on real-time thermal feedback. |
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 |
|---|---|---|---|
| LM3431QMHX/NOPB | Standard automotive grade (AEC-Q100 Grade 1), ±5 mV channel offset vs. ±3 mV in LM3431AQMHX/NOPB. | Same pinout and functionality; suitable where tighter current matching is not required. | Select LM3431QMHX/NOPB for cost-sensitive automotive displays where ±5 mV inter-channel mismatch is acceptable. |
| TPS61165DRVR | Single-channel boost LED driver with I²C interface; no integrated linear regulators or multi-string current control. | Requires external current-setting components per string; lacks THM, SC, and DLY fault management features. | Choose TPS61165DRVR only for single-string applications needing digital control, not for 3-channel analog/PWM systems. |
Compared with LM3431QMHX/NOPB, the LM3431AQMHX/NOPB offers improved current matching for critical color fidelity; versus TPS61165DRVR, it provides full 3-channel integration, analog dimming, and automotive-grade fault handling-making it uniquely suited for space-constrained, safety-aware backlight systems.
Availability
LM3431AQMHX/NOPB is available at Aetrix Electronics and suitable for automotive infotainment displays, small-to-medium format industrial HMIs, and rear-seat entertainment systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LM3431AQMHX/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 broad automotive and industrial design expertise.
The LM3431 product line delivers integrated LED backlight drivers for automotive and industrial displays, combining boost conversion and precision current regulation to simplify high-reliability lighting subsystems.
FAQ
What is the operating temperature range of the LM3431AQMHX/NOPB?
The LM3431AQMHX/NOPB is AEC-Q100 Grade 1 qualified with a guaranteed operating junction temperature range of –40°C to +125°C. This specification is validated across all electrical parameters in the datasheet, including reference voltage stability, current regulation accuracy, and thermal shutdown activation at 160°C. The LM3431AQMHX/NOPB maintains full functionality within this range without derating.
How does the LM3431AQMHX/NOPB achieve no-audible-noise dimming?
The LM3431AQMHX/NOPB achieves no-audible-noise dimming by maintaining constant output voltage regulation during PWM dimming cycles. Unlike conventional boost controllers that modulate output voltage, it uses CFB feedback to regulate LED cathode voltage and AFB/SS/SH to hold reference during off-time-eliminating inductor and capacitor vibration caused by large ripple currents. This design is confirmed in Figure 11 (Dimming Transient Response) of the SNVS547G datasheet.
What is the difference between LM3431AQMHX/NOPB and LM3431QMHX/NOPB?
The LM3431AQMHX/NOPB features reduced SNS amplifier offset voltage (±3 mV vs. ±5 mV) and tighter channel-to-channel offset mismatch (≤4 mV over –40°C to +125°C vs. ≤6 mV), resulting in superior current matching across LED strings. Both share identical pinout, package (TSSOP-28), AEC-Q100 Grade 1 qualification, and functional block diagram. The 'A' suffix denotes enhanced analog performance for high-fidelity backlight applications.
Can the LM3431AQMHX/NOPB drive MOSFETs or only bipolar transistors?
Yes, the LM3431AQMHX/NOPB can drive both external NPN bipolar transistors and N-channel MOSFETs via its NDRV1–NDRV3 outputs. Each NDRV pin provides 3.7 V drive voltage, 10–20 mA source current, and 4–8 mA sink current-sufficient to fully enhance logic-level NFETs or saturate medium-power NPNs. The datasheet explicitly states "drives 3 external NPN transistors or MOSFETs" in the device description.
What protection features does the LM3431AQMHX/NOPB include?
The LM3431AQMHX/NOPB includes LED short and open detection (via SC pin), thermal shutdown (160°C), LED over-temperature monitoring (THM input), programmable fault delay (DLY pin), cycle-by-cycle current limiting (ILIM pin), output overvoltage protection (AFB-based), and enable-controlled undervoltage lockout (EN pin). All protections are hardware-based with defined thresholds and response times documented in the Electrical Characteristics table.
LM3431AQMHX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 28-PowerTSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- 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
LM3431AQMHX/NOPB FAQ
1.How can I place an order for LM3431AQMHX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3431AQMHX/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 LM3431AQMHX/NOPB reliable?
The price and inventory of LM3431AQMHX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3431AQMHX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3431AQMHX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3431AQMHX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3431AQMHX/NOPB?
LM3431AQMHX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3431AQMHX/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 LM3431AQMHX/NOPB?
For technical support, including LM3431AQMHX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3431AQMHX/NOPB requirements.
6.How does Aetrix verify that LM3431AQMHX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3431AQMHX/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 LM3431AQMHX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3431AQMHX/NOPB?
All LM3431AQMHX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3431AQMHX/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 LM3431AQMHX/NOPB part is unused and in its original packaging.
Return procedure for LM3431AQMHX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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