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Texas Instruments LM3431AQMH/NOPB
- Part No.:
- LM3431AQMH/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 28-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3431AQMH/NOPB.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,662
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Product details
Overview
LM3431AQMH/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, 25 kHz PWM dimming capability, and 5 V to 36 V input operation - used in infotainment display backlighting where thermal robustness and high-accuracy current regulation are critical.
For engineers reviewing the LM3431AQMH/NOPB datasheet, LM3431AQMH/NOPB pinout, LM3431AQMH/NOPB application, or LM3431AQMH/NOPB equivalent, this page provides verified pin functions, real-world dimming performance data, confirmed AEC-Q100 Grade 1 qualification (-40°C to +125°C), validated cathode feedback architecture, and direct alternative part comparisons for automotive display power design.
Technical Context
The LM3431AQMH/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 drive outputs and SNSx current-sense amplifiers. It employs LED cathode feedback (CFB) for headroom optimization and dual-mode dimming control via DIM and MODE/F pins.
Its protection architecture includes LED short/open detection (SC pin), thermal shutdown (THM input), programmable fault delay (DLY capacitor), cycle-by-cycle current limit (ILIM), and output overvoltage protection (AFB sensing). The device maintains constant CFB regulation during PWM dimming to eliminate audible noise.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5 V to 36 V - supports wide automotive battery rail variation including cold-crank transients. |
| LED Current Accuracy | ±3 mV channel-to-channel offset (–40°C to +125°C) - enables <0.5% inter-string current mismatch at 200 mA per string. |
| PWM Dimming Frequency | Up to 25 kHz - achieves >100:1 contrast ratio without audible coil whine. |
| Boost Switching Frequency | Adjustable 200 kHz to 1 MHz via RT resistor - balances EMI, efficiency, and inductor size. |
| Operating Temperature | –40°C to +125°C junction - AEC-Q100 Grade 1 qualified for under-hood and dashboard applications. |
| Package | TSSOP-28 with exposed pad - 32°C/W θJA enables 3.1 W power dissipation on standard 4-layer PCB. |
| Protection Features | LED short/open, thermal shutdown, overvoltage (AFB), fault delay, cycle-by-cycle current limit - reduces external fault-handling circuitry. |
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 supply input | Accepts 5–36 V input; feeds internal LDO and boost controller. |
| PGND | Power ground | High-current return path for boost switch and LED strings; separate from SGND. |
| VCC | Internal reference output | 5 V ±2.4% regulated supply; requires ≥4.7 µF bypass to PGND. |
| LG | Boost gate driver | Drives external NFET switch; 0.35 A source / 0.7 A sink capability. |
| SNS1–SNS3 | Channel current sense inputs | High-impedance inputs (≤30 µA bias) for precision current regulation per LED string. |
| NDRV1–NDRV3 | Linear regulator drive outputs | Drive external NPN bases or NFET gates; 3.7 V output swing at 5 mA load. |
| CFB | Cathode feedback | Regulates LED cathode voltage at 1.71 V (typical); minimizes headroom loss and improves efficiency. |
| AFB | Anode feedback | Sets output overvoltage threshold and controls soft-start; referenced to 2.0 V internal comparator. |
| DIM | Brightness control input | Accepts analog voltage (0–5 V) or digital PWM (up to 25 kHz); 2.3 V threshold with 0.8 V hysteresis. |
| EN | Enable/UVLO input | Programmable UVLO (1.23 V typical ON threshold); pulls low to shut down IC, reducing IQ to 23 µA. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated boost + 3-channel linear control | Single-chip solution eliminates discrete boost IC and three current regulators - reduces BOM count and layout area. |
| Cathode feedback regulation (CFB) | Maintains fixed 1.71 V reference at LED cathodes - cuts regulator headroom by up to 1.5 V per string vs. anode sensing. |
| AEC-Q100 Grade 1 qualification | Validated for –40°C to +125°C operation - suitable for automotive infotainment, instrument clusters, and HUD systems. |
| No-audible-noise dimming | Constant CFB regulation during PWM off-cycles prevents output voltage droop and eliminates inductor buzz. |
| Programmable fault response | DLY capacitor sets shutdown delay; LEDOFF pin enables automatic restart or latched fault mode - configurable per system safety requirements. |
Applications
| Automotive Infotainment Displays | Small to Medium Format Displays |
|---|---|
Use Scenario: Backlighting for 7–10 inch TFT LCD dashboards in vehicles operating across –40°C to +85°C ambient. IC Role / Device Role / Timing Role: LM3431AQMH/NOPB acts as primary LED current controller and boost regulator, synchronizing dimming with MCU PWM signals while maintaining stable cathode voltage. Use Value: ±3 mV channel offset ensures uniform brightness across all three LED strings; thermal shutdown protects against LED array overheating during prolonged sunlight exposure. | Use Scenario: Backlight for industrial HMI panels with variable dimming profiles and space-constrained PCB layouts. IC Role / Device Role / Timing Role: LM3431AQMH/NOPB delivers precise analog/digital dimming control and integrated fault detection - replacing discrete op-amps and comparators. Use Value: CFB-based regulation reduces power dissipation in linear pass devices by 15–20% versus anode-sensing architectures; TSSOP-28 footprint fits tight board areas. |
| Automotive Instrument Clusters | HUD (Heads-Up Display) Lighting |
Use Scenario: High-reliability backlighting for gauge clusters requiring fail-safe dimming and temperature-aware brightness control. IC Role / Device Role / Timing Role: LM3431AQMH/NOPB monitors THM pin for LED thermal feedback and adjusts current via analog dimming - enabling dynamic thermal derating. Use Value: THM input triggers standby mode below 1.23 V, preventing LED thermal runaway; AEC-Q100 qualification ensures long-term reliability in vibration-prone environments. | Use Scenario: Compact projection lighting module requiring ultra-low EMI and silent operation during night driving. IC Role / Device Role / Timing Role: LM3431AQMH/NOPB implements 25 kHz PWM dimming with constant CFB regulation - eliminating audible switching noise in quiet cabin environments. Use Value: No-audible-noise operation meets automotive NVH standards; 1 MHz max switching frequency allows use of small, low-profile inductors. |
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 |
|---|---|---|---|
| LM3431QMH/NOPB | Non-A grade version; ±5 mV channel offset (vs. ±3 mV), same pinout and functionality. | Lacks AEC-Q100 Grade 1 qualification; rated for –40°C to +105°C only. | Select when automotive qualification is not required and cost sensitivity outweighs thermal accuracy needs. |
| TPS61165DRVR | Single-channel boost LED driver with I²C interface; no integrated linear regulators or multi-string control. | Requires external current-setting resistors and additional drivers for 3-string operation; lacks THM, SC, DLY fault pins. | Choose only for simpler, lower-channel-count designs where digital control and smaller footprint are prioritized over integrated protection. |
Compared with LM3431QMH/NOPB, the LM3431AQMH/NOPB offers tighter current matching and extended temperature range essential for automotive displays; versus TPS61165DRVR, it provides full 3-channel integration, analog/digital dimming flexibility, and comprehensive fault handling - reducing total system component count by ≥7.
Availability
LM3431AQMH/NOPB is available at Aetrix Electronics and suitable for automotive infotainment displays, instrument clusters, and HUD lighting requiring stable component supply, long lifecycle support, and AEC-Q100-compliant sourcing.
Supply support for LM3431AQMH/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 and automotive electronics.
The LM3431 product line was designed specifically for high-accuracy, thermally robust LED backlighting in automotive and industrial displays - integrating boost conversion and multi-channel linear regulation into a single AEC-Q100-qualified IC.
FAQ
What is the AEC-Q100 qualification status of the LM3431AQMH/NOPB?
The LM3431AQMH/NOPB is AEC-Q100 Grade 1 qualified, meaning it is tested and certified for operation from –40°C to +125°C junction temperature. This qualification covers stress testing for temperature cycling, humidity, mechanical shock, and ESD - confirming suitability for automotive infotainment and instrument cluster applications. LM3431AQMH/NOPB meets all requirements specified in the SNVS547G datasheet revision May 2013.
How does the CFB pin function in the LM3431AQMH/NOPB during PWM dimming?
The CFB pin in the LM3431AQMH/NOPB maintains a regulated 1.71 V (typical) reference at the LED cathodes during both on and off PWM cycles. This constant cathode voltage regulation prevents output droop and eliminates audible noise from inductor vibration. During LED-off periods, the AFB pin takes over output voltage control via sample-and-hold, while CFB remains active to preserve current regulation readiness. This dual-feedback behavior is intrinsic to the LM3431AQMH/NOPB architecture.
Can the LM3431AQMH/NOPB drive MOSFETs directly, or is it limited to NPN transistors?
The LM3431AQMH/NOPB can drive both external NPN transistors and N-channel MOSFETs via its NDRV1–NDRV3 outputs. Each NDRV pin provides 3.7 V drive voltage at 5 mA load and supports 10–20 mA source current, sufficient to fully enhance logic-level NFETs. The datasheet explicitly states "drives 3 external NPN transistors or MOSFETs" and confirms NDRVx sink/source capability - making LM3431AQMH/NOPB compatible with either topology depending on thermal and efficiency requirements.
What is the minimum recommended input voltage for reliable startup of the LM3431AQMH/NOPB?
The LM3431AQMH/NOPB requires a minimum input voltage of 4.5 V to ensure proper VCC regulation and enable circuit activation, as specified in the Recommended Operating Conditions table. Below 4.5 V, internal UVLO may prevent startup; the EN pin's 1.23 V ON threshold and VCC's 4.4 V UVLO threshold jointly enforce this limit. For automotive cold-crank scenarios, the LM3431AQMH/NOPB remains functional down to 5 V input - verified in typical application schematics and startup waveforms in Figure 15 of SNVS547G.
How is LED open-circuit protection implemented in the LM3431AQMH/NOPB?
LED open-circuit protection in the LM3431AQMH/NOPB is implemented via the SC (short-circuit) pin, which monitors cathode voltage through diodes connected to each LED string. When all strings open, cathode voltage rises until SC exceeds 3.50 V (typical), triggering a fault. The DLY capacitor then sets a programmable delay before shutdown or automatic restart (if LEDOFF is grounded). This mechanism is confirmed in the Electrical Characteristics table (VSC_OPEN = 3.16–3.87 V) and block diagram - no external comparators are needed for basic open detection in LM3431AQMH/NOPB.
LM3431AQMH/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
LM3431AQMH/NOPB FAQ
1.How can I place an order for LM3431AQMH/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3431AQMH/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 LM3431AQMH/NOPB reliable?
The price and inventory of LM3431AQMH/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3431AQMH/NOPB is usually 5 days.
3.What payment methods are accepted for LM3431AQMH/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3431AQMH/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3431AQMH/NOPB?
LM3431AQMH/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3431AQMH/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 LM3431AQMH/NOPB?
For technical support, including LM3431AQMH/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3431AQMH/NOPB requirements.
6.How does Aetrix verify that LM3431AQMH/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3431AQMH/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 LM3431AQMH/NOPB meets industry standards.
7.What is the process for return or replacement of LM3431AQMH/NOPB?
All LM3431AQMH/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3431AQMH/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 LM3431AQMH/NOPB part is unused and in its original packaging.
Return procedure for LM3431AQMH/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3431AQMH/NOPB Tags
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