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Texas Instruments LM3431MH/NOPB
- Part No.:
- LM3431MH/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 28-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3431MH/NOPB.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:137
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Product details
Overview
LM3431MH/NOPB from Texas Instruments is a 3-channel constant-current LED driver IC with integrated boost controller, designed for space-constrained LED backlight panels. It delivers ±5 mV SNS amplifier offset voltage, 2 MHz bandwidth per channel, and supports up to 25 kHz PWM dimming with >100:1 contrast ratio in automotive infotainment displays.
For engineers reviewing the LM3431MH/NOPB datasheet, LM3431MH/NOPB pinout, LM3431MH/NOPB application, or LM3431MH/NOPB equivalent, key selection considerations include cathode feedback (CFB) regulation, programmable cycle-by-cycle current limit via ILIM, thermal shutdown at 160°C, and TSSOP-28 exposed-pad package compatibility with high-density PCB layouts.
Technical Context
The LM3431MH/NOPB integrates a current-mode PWM boost controller and three independent linear current regulators. Its CFB pin regulates LED cathode voltage at 1.71 V (typ) during LED-on periods, while AFB pin controls output voltage during LED-off intervals using sample-hold functionality on SS/SH.
It employs dual dimming control: MODE/F selects analog (0.37–2.5 V) or digital PWM mode (threshold 3.8 V), and DIM accepts either signal type with 0.4 µs minimum internal pulse width. Fault protection includes LED short detection (SC threshold 6.0 V), open-circuit clamping (3.50 V), and programmable delay via DLY capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 36 V - supports wide-range automotive and industrial supplies without external pre-regulation. |
| LED Current Accuracy | ±5 mV SNSx offset voltage - enables <±1% current matching across channels at 200 mA string current. |
| Dimming Frequency | Up to 25 kHz - eliminates audible noise while maintaining >100:1 contrast ratio in video applications. |
| Boost Switching Freq | 200 kHz to 1 MHz - adjustable via RT resistor; 700 kHz typical with 34.8 kΩ sets stable operation in continuous conduction mode. |
| Thermal Shutdown | 160°C junction - protects IC and external NPN/MOSFET drivers during sustained overloads or poor heatsinking. |
| Package | TSSOP-28 with exposed pad - provides low θJA = 32°C/W for thermal management in compact LED driver modules. |
| Operating Temp | –40°C to +125°C - qualified for automotive Grade 1 environments per AEC-Q100. |
Pinout & Package
TSSOP-28 exposed pad package (Package Number PWP0028A); exposed pad must be connected to SGND for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Power input | Accepts 4.5–36 V supply; feeds internal LDO for VCC and gate drivers. |
| PGND | Power ground | High-current return path for boost switch and LED string currents; separate from SGND. |
| VCC | Internal reference output | 5.0 V ±2.5% regulated output; requires ≥4.7 µF bypass capacitor to PGND. |
| LG | Boost gate driver | Drives external NFET switch with 0.35 A source / 0.70 A sink capability and 6.4 Ω on-resistance. |
| CFB | Cathode feedback | Senses LED cathode voltage during LED-on time; regulates at 1.71 V to minimize headroom loss. |
| AFB | Anode feedback | Regulates output voltage during LED-off time; sets OVP threshold via resistor divider. |
| SNS1–SNS3 | Channel current sense | Inputs to matched transconductance amplifiers; bias current <30 µA ensures minimal sensing error. |
| NDRV1–NDRV3 | Channel drive outputs | Drive external NPN bases or NFET gates; 3.7 V drive voltage and 10–20 mA source current support fast switching. |
| DIM | Dimming control | Accepts analog voltage (0–5 V) or digital PWM; 2.3 V threshold enables direct MCU GPIO interfacing. |
| EN | Enable/UVLO | Programmable UVLO (1.23 V threshold) allows system-level brownout protection with resistor divider. |
| THM | LED thermal monitor | Enters standby when pulled below 1.23 V; interfaces directly with NTC thermistor networks. |
| SC | Short-circuit detection | Flags LED short fault at 6.0 V; connects via diode to each LED cathode for shared fault sensing. |
Key Features
| Feature | Design Value |
|---|---|
| No audible noise during dimming | Maintains constant output voltage regulation across PWM cycles-eliminates coil whine in display backlight systems. |
| Integrated cathode feedback | CFB pin reduces required headroom by ~0.7 V vs. anode-sensing architectures-improves efficiency by up to 8% at 12 V input. |
| Programmable fault response | DLY pin sets shutdown delay (via capacitor); LEDOFF pin enables automatic restart or latched fault mode. |
| Channel-to-channel current mismatch | ≤5.5 mV offset mismatch at 25°C-ensures uniform brightness across multi-string RGB or white LED arrays. |
| Robust protection suite | Combines LED short/open detection, overvoltage (AFB), thermal shutdown (IC + LED), and cycle-by-cycle current limiting. |
Applications
| Automotive Infotainment Displays | Small to Medium Format Displays |
|---|---|
Use Scenario: TFT-LCD backlight in dashboard clusters and center consoles operating from 9–16 V battery supply with thermal cycling from –40°C to +125°C. IC Role / Device Role / Timing Role: LM3431MH/NOPB acts as primary LED current controller and boost regulator, synchronizing dimming with display frame rate via DIM input. Use Value: Enables >100:1 contrast ratio at 25 kHz dimming while maintaining ±1% string current matching-critical for color fidelity in daylight-readable UIs. | Use Scenario: Backlight for portable medical monitors and industrial HMIs where EMI and acoustic noise must be minimized. IC Role / Device Role / Timing Role: LM3431MH/NOPB provides constant-current drive for 3 parallel LED strings, with CFB feedback ensuring stable regulation despite varying forward voltages. Use Value: Integrated soft-start (SS/SH) prevents inrush current spikes during power-up, reducing stress on input capacitors and extending system lifetime. |
| LED Video Wall Modules | Avionics Display Backlights |
Use Scenario: High-brightness indoor video walls requiring precise brightness uniformity across hundreds of tiles with local dimming zones. IC Role / Device Role / Timing Role: LM3431MH/NOPB serves as per-module LED driver, accepting PWM commands from central controller via isolated digital interface. Use Value: Programmable ILIM pin allows dynamic current limit adjustment per tile-enabling adaptive brightness scaling without hardware changes. | Use Scenario: Cockpit LCD backlighting in commercial aircraft, subject to DO-160 lightning-induced transient and temperature extremes. IC Role / Device Role / Timing Role: LM3431MH/NOPB functions as fault-tolerant LED driver with dual protection paths: SC pin detects shorted LEDs, THM monitors array temperature. Use Value: AEC-Q100 Grade 1 qualification and 160°C thermal shutdown ensure compliance with aviation safety-critical design requirements. |
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 |
|---|---|---|---|
| LM3431AQMH/NOPB | Enhanced version with ±3 mV SNSx offset voltage and reduced channel mismatch (3.5 mV max). | Required for designs demanding tighter than ±0.5% string current matching across temperature. | Select LM3431AQMH/NOPB when higher accuracy is needed; pinout and footprint are identical. |
| TPS61165DRVR | Single-channel boost LED driver with integrated MOSFET; no external NPN/NFET support or multi-string regulation. | Suitable only for single-string applications; lacks CFB feedback, THM input, and channel synchronization. | Choose TPS61165DRVR for cost-sensitive, low-channel-count designs where board area is less constrained. |
Compared with LM3431AQMH/NOPB, the LM3431MH/NOPB trades 2 mV higher offset for broader legacy compatibility and lower unit cost; versus TPS61165DRVR, it offers true 3-channel independent control, cathode feedback, and automotive-grade thermal/fault robustness-making it irreplaceable in multi-string backlight systems.
Availability
LM3431MH/NOPB is available at Aetrix Electronics and suitable for automotive infotainment displays, small-to-medium format displays, LED video wall modules, and avionics display backlights requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LM3431MH/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 specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and high-reliability ICs.
The LM3431 product line was developed specifically for high-accuracy, multi-string LED backlighting in automotive and industrial displays-emphasizing thermal resilience, noise-free dimming, and integrated fault protection.
FAQ
What is the maximum LED string current supported by the LM3431MH/NOPB?
The LM3431MH/NOPB supports LED string currents exceeding 200 mA per channel when used with appropriately rated external NPN transistors or MOSFETs. Its NDRVx outputs deliver 10–20 mA source current and 4–8 mA sink current, enabling direct drive of small-signal NPNs or level-shifting for power NFETs. The actual current limit depends on external component selection, thermal design, and PCB copper area-TI's typical application circuit achieves 200 mA per string with <1% variation across channels.
How does the CFB pin function in the LM3431MH/NOPB?
The CFB pin in the LM3431MH/NOPB senses the LED cathode voltage during LED-on periods and regulates it at 1.71 V (typical), minimizing required headroom between boost output and LED string forward voltage. This cathode feedback architecture improves efficiency by up to 8% compared to anode-sensing topologies. During LED-off time, CFB is inactive and AFB takes over output regulation via the SS/SH sample-hold circuit.
Can the LM3431MH/NOPB operate without an external boost inductor?
No, the LM3431MH/NOPB requires an external boost inductor, NFET switch, and output diode to form the step-up converter. It does not integrate power switches or magnetics. The boost controller drives the LG pin to switch the external NFET, and inductor selection must satisfy continuous conduction mode criteria-TI specifies minimum inductance based on input voltage range, output voltage, and switching frequency to ensure stability and current regulation accuracy.
What protection features are built into the LM3431MH/NOPB?
The LM3431MH/NOPB includes LED short-circuit detection (SC pin, 6.0 V threshold), open-circuit protection (AFB-based OVP), thermal shutdown at 160°C, cycle-by-cycle current limiting (programmed via ILIM), and LED over-temperature monitoring (THM pin, 1.23 V threshold). It also features soft-start with fault blanking, UVLO on EN and VCC, and latchable or auto-restart fault modes selectable via LEDOFF pin configuration.
Is the LM3431MH/NOPB pin-compatible with the LM3431AQMH/NOPB?
Yes, the LM3431MH/NOPB is fully pin-compatible and footprint-compatible with the LM3431AQMH/NOPB. Both use the same TSSOP-28 exposed-pad package and share identical pin functions, electrical connections, and recommended external circuitry. The LM3431AQMH/NOPB is an enhanced variant offering improved SNS amplifier offset voltage (±3 mV vs. ±5 mV) and lower channel-to-channel mismatch, but requires no layout or schematic changes for drop-in replacement.
LM3431MH/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:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-HTSSOP
LM3431MH/NOPB FAQ
1.How can I place an order for LM3431MH/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3431MH/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 LM3431MH/NOPB reliable?
The price and inventory of LM3431MH/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3431MH/NOPB is usually 5 days.
3.What payment methods are accepted for LM3431MH/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3431MH/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3431MH/NOPB?
LM3431MH/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3431MH/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 LM3431MH/NOPB?
For technical support, including LM3431MH/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3431MH/NOPB requirements.
6.How does Aetrix verify that LM3431MH/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3431MH/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 LM3431MH/NOPB meets industry standards.
7.What is the process for return or replacement of LM3431MH/NOPB?
All LM3431MH/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3431MH/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 LM3431MH/NOPB part is unused and in its original packaging.
Return procedure for LM3431MH/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3431MH/NOPB Tags
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BCR402RE6327HTSA1
Infineon Technologies
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
Infineon Technologies
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BCR420UE6327HTSA1
Infineon Technologies
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BCR421UE6327HTSA1
Infineon Technologies
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LYT1604D-TL
Power Integrations
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HV9910CLG-G
Microchip Technology
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CL2N8-G
Microchip Technology
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
Diodes Incorporated
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
Diodes Incorporated
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