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Texas Instruments LM3433SQ/NOPB
- Part No.:
- LM3433SQ/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LM3433SQ/NOPB.pdf
- Description:
- IC LED DRIVER CTRLR PWM 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,746
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Product details
Overview
LM3433SQ/NOPB from Texas Instruments is a high-brightness LED driver IC implementing adaptive constant-on-time buck topology for common-anode LED strings. It delivers >6A output current with −9V to −14V input (w.r.t. LED anode), supports >30kHz PWM dimming, operates up to 1MHz switching frequency, and requires no output capacitor-enabling compact, high-efficiency backlighting in automotive headlamps and projection systems.
For engineers reviewing the LM3433SQ/NOPB datasheet, LM3433SQ/NOPB pinout, LM3433SQ/NOPB application, or LM3433SQ/NOPB equivalent, key selection considerations include its negative-output capability enabling direct chassis tie of LED anodes, programmable analog current control via ADJ pin, integrated DIMO gate driver for high-frequency shunt dimming, and thermal shutdown protection at 175°C junction temperature.
Technical Context
The LM3433SQ/NOPB implements a continuous-conduction-mode (CCM) buck controller with adaptive on-time modulation, where switching frequency varies inversely with LED forward voltage and is set by external RON/CON on TON pin. Its current regulation uses average current mode control with 60mV nominal VSENSE, adjustable via ADJ pin across 0.3V–60mV range.
It integrates dual gate drivers: HO/LO for synchronous buck FETs (with 2Ω low-side sink/source resistance) and DIMO/DIMR for external shunt MOSFET dimming (5mA drive, 20Ω low-side resistance). Control inputs (EN, DIM, ADJ) are referenced to CGND, while power rails (VEE, VIN, VCC) operate with independent ground domains.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | >6A DC - supports high-power LED strings without external current amplification |
| Input Voltage Range (VEE w.r.t. CGND) | −9V to −14V - enables common-anode configuration with LED anode tied directly to chassis ground |
| Switching Frequency | Up to 1MHz - allows use of small, low-ESR ceramic inductors and eliminates need for output capacitor |
| VSENSE Target Voltage | 60mV (typ.), adjustable 0.3V–60mV via ADJ pin - sets LED current with ±3mV tolerance over temperature |
| PWM Dimming Frequency | >30kHz - suppresses audible noise and enables field-sequential color control in RGB displays |
| Junction Temperature Range | −40°C to +125°C - qualified for automotive under-hood and industrial lighting environments |
| Quiescent Current (VEE) | 1mA typical - minimizes standby power loss during logic-level shutdown |
Pinout & Package
LM3433SQ/NOPB is housed in a thermally enhanced 24-pin WQFN package (RTW) with exposed pad connected to VEE for optimal heat dissipation. The package measures 4mm × 4mm × 0.8mm and is RoHS-compliant with CU SN finish (Level-1-260°C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VEE | Negative power rail input | Reference for all internal circuitry; connects to LED cathode side; must be tied to chassis ground plane |
| CGND | Chassis ground reference | Logic ground for EN, DIM, ADJ, VIN; separates signal domain from high-current power return path |
| HO / LO / HS / LS | Synchronous buck gate drive interface | HO/LO drive external high/low-side FETs; HS is switching node; LS is low-side return - enables efficient buck conversion |
| DIMO / DIMR | PWM shunt dimming gate driver | DIMO drives external MOSFET between LED cathode and DIMR (tied to LED cathode); enables high-frequency current bypass |
| CSP / CSN | Current sense differential inputs | Measure voltage across external sense resistor; CSP connects to resistor's high side (LED cathode side), CSN to low side (VEE) |
| ADJ | Analog current programming input | Adjusts VSENSE from 0.3V to 60mV; tie to VIN for fixed 60mV operation or to external reference for color temperature tuning |
| TON | On-time programming node | RC network (RON to CSN, CON to VEE) sets nominal operating frequency and maintains constant ripple current across load |
Key Features
| Feature | Design Value |
|---|---|
| Common-anode LED architecture | Enables direct mounting of LED anodes to metal chassis for maximum thermal conduction and EMI reduction |
| No output capacitor required | Reduces BOM count and board area; eliminates capacitor aging and ESR-related efficiency loss in high-temp environments |
| Adaptive constant on-time control | Maintains stable LED current ripple (<10% of ILED) across varying LED forward voltage and input supply conditions |
| Integrated DIMO gate driver | Drives external shunt FET with 5mA source/sink capability, supporting >40kHz PWM dimming without external level shifters |
| Thermal shutdown with hysteresis | Shuts down at 175°C (typ.) and resumes at 155°C (typ.), preventing thermal runaway in enclosed luminaires |
Applications
| Automotive Headlamp Systems | LCD Backlighting |
|---|---|
|
Use Scenario: High-intensity LED arrays in adaptive driving beam (ADB) modules requiring precise current regulation and fast PWM dimming. IC Role / Device Role / Timing Role: Constant-current buck controller with shunt-dimming interface; manages LED string current while synchronizing with vehicle CAN bus dimming commands. Use Value: Enables dynamic beam shaping with >6A per channel and <100ns DIM-to-DIMO propagation delay for sub-millisecond response. |
Use Scenario: Edge-lit LCD panels in medical monitors and industrial HMIs demanding flicker-free, color-stable illumination. IC Role / Device Role / Timing Role: High-frequency LED driver with analog current trim; regulates brightness via ADJ voltage while maintaining uniform white point across temperature. Use Value: Delivers 0.1% current matching across channels using Kelvin-sense routing and 16.67V/V ADJ gain for factory calibration. |
| Projection System Light Engines | Solid-State Street Lighting |
|
Use Scenario: RGB laser/LED hybrid light engines requiring independent current control and synchronized PWM blanking for color sequencing. IC Role / Device Role / Timing Role: Synchronized buck controller with programmable on-time; coordinates LED current ramping with DMD or LCoS pixel timing signals. Use Value: Supports field-sequential illumination with 30kHz+ dimming and <28ns HO/LO dead time to minimize color crosstalk. |
Use Scenario: Outdoor LED streetlights operating in wide ambient temperature ranges and subject to voltage transients on AC/DC supplies. IC Role / Device Role / Timing Role: Robust LED driver with −9V to −14V VEE tolerance and 150°C max junction rating; interfaces with isolated 12V auxiliary supply. Use Value: Achieves >94% efficiency at 6A/3V LED load with 39°C/W θJA and integrated UVLO on both VIN and VCC rails. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3423MH/NOPB | Fixed 60mV VSENSE; no ADJ pin; lower max output current (3A); same WQFN-24 package | Targeted at cost-sensitive, lower-power LED arrays without analog current trimming requirement | Select when design does not require programmable current or color temperature compensation |
| TPS92692QPWPRQ1 | Integrated high-side current sense; supports positive-input operation; AEC-Q100 qualified; 4.5–40V input | Designed for automotive front-lighting with diagnostic features (open-wire detection, fault reporting) | Select for ASIL-B compliant systems requiring built-in diagnostics and higher input voltage range |
Compared with LM3433SQ/NOPB, LM3423MH/NOPB simplifies layout by removing ADJ and TON programming but sacrifices current flexibility, while TPS92692QPWPRQ1 adds functional safety features at the cost of higher BOM complexity and reduced negative-rail capability.
Availability
LM3433SQ/NOPB is available at Aetrix Electronics and suitable for automotive lighting, LCD backlighting, and solid-state street lighting requiring stable component supply through extended product lifecycles.
Supply support for LM3433SQ/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 over 50 years of innovation in high-reliability power conversion.
The LM3433SQ/NOPB belongs to TI's high-brightness LED driver product line, engineered specifically for common-anode architectures in automotive, industrial, and display applications where thermal performance and PWM fidelity are critical.
FAQ
What is the recommended input capacitor for LM3433SQ/NOPB in a 6A LED application?
The LM3433SQ/NOPB requires a minimum 22µF low-ESR ceramic input capacitor (X5R/X7R dielectric) between CGND and VEE to suppress high-frequency transients from synchronous FET switching. When PWM dimming is active, the capacitor must also handle up to 85% of nominal DC input ripple current; a 47µF/25V X7R MLCC is commonly used to ensure stability across temperature and lifetime.
How does the LM3433SQ/NOPB achieve constant LED current without an output capacitor?
The LM3433SQ/NOPB achieves stable current regulation through adaptive constant-on-time control in CCM buck topology, where inductor ripple current remains tightly bounded (<10% of ILED) by precise on-time programming via TON pin. Its high bandwidth current sense amplifier (1.3mS transconductance) and fast gate drivers eliminate need for output capacitance while maintaining <6mA current variation from OFF to ON state transitions.
Can LM3433SQ/NOPB drive LEDs with forward voltages above 10V?
Yes - the LM3433SQ/NOPB supports LED forward voltages up to 7V in standard configurations, but with proper external FET selection and timing component adjustment (RON/CON), it can regulate current for LED strings up to 14V forward drop. Efficiency remains >92% at 6A/7V per the typical performance curves in the datasheet, validated with ferrite-core inductors and low-RDS(on) MOSFETs.
What is the function of the BST2 pin on LM3433SQ/NOPB?
The BST2 pin on LM3433SQ/NOPB supplies the high-side gate drive voltage for the DIMO output stage. It must be decoupled with a 0.1µF ceramic capacitor to CGND to maintain stable dimming FET turn-on characteristics. Unlike BST (used for HO driver), BST2 isolates dimming circuitry from main buck switching noise, ensuring clean 5mA gate drive even during high dv/dt events on HS.
Does LM3433SQ/NOPB support daisy-chained multi-channel synchronization?
No - the LM3433SQ/NOPB lacks dedicated sync or phase-shift pins for inter-device synchronization. Each device operates independently based on its local TON RC network and LED forward voltage. For synchronized multi-channel dimming, external clock injection into the DIM pin or master-slave PWM gating via microcontroller is required; TI recommends using TPS92692 for native multi-device sync capability.
LM3433SQ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- DC DC Controller
- Topology:
- Step-Down (Buck)
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 3V
- Voltage - Supply (Max):
- 5.8V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 1MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-WQFN (4x4)
LM3433SQ/NOPB FAQ
1.How can I place an order for LM3433SQ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3433SQ/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 LM3433SQ/NOPB reliable?
The price and inventory of LM3433SQ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3433SQ/NOPB is usually 5 days.
3.What payment methods are accepted for LM3433SQ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3433SQ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3433SQ/NOPB?
LM3433SQ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3433SQ/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 LM3433SQ/NOPB?
For technical support, including LM3433SQ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3433SQ/NOPB requirements.
6.How does Aetrix verify that LM3433SQ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3433SQ/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 LM3433SQ/NOPB meets industry standards.
7.What is the process for return or replacement of LM3433SQ/NOPB?
All LM3433SQ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3433SQ/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 LM3433SQ/NOPB part is unused and in its original packaging.
Return procedure for LM3433SQ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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