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Texas Instruments LM3430SDX
- Part No.:
- LM3430SDX
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 12-WFDFN Exposed Pad
- Datasheet:
-
LM3430SDX.pdf
- Description:
- IC LED DRIVER CTRLR PWM 12WSON
- Quantity:
- Payment:
- Shipping:
Inventory:3,785
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Product details
Overview
LM3430SDX from Texas Instruments is a high-voltage, current-mode boost controller for LED backlighting applications, featuring 6V–40V input range, 1A peak gate drive, 90%+ duty cycle capability, and internal 40V startup regulator. It operates as a low-side N-channel MOSFET controller in non-isolated boost or SEPIC topologies, commonly paired with LM3432 for dynamic headroom control in LCD notebook backlight systems.
For engineers reviewing the LM3430SDX datasheet, LM3430SDX pinout, LM3430SDX application, or LM3430SDX equivalent, key selection considerations include VIN operating range, RT-set oscillator frequency up to 2 MHz, VDHC interface compatibility with LM3432, soft-start ramp control via external capacitor, and cycle-by-cycle current limiting with 0.5V CS threshold.
Technical Context
The LM3430SDX implements current-mode PWM control with built-in slope compensation (105 mV typical), enabling stable operation above 50% duty cycle while providing inherent input voltage feed-forward and simplified loop compensation. Its error amplifier features a fixed 1.25V reference and open-drain COMP output compatible with optocoupler feedback in isolated designs.
It integrates a high-speed gate driver (18 ns rise, 15 ns fall time into 1 nF), programmable UVLO with 20 µA hysteresis current source, thermal shutdown at 165°C (25°C hysteresis), and external synchronization capability via AC-coupled signal on RT/SYNC pin - all within a 12-lead LLP-12 (3 mm × 3 mm) thermally enhanced package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 6V to 40V - supports direct connection to automotive battery or multi-cell Li-ion stacks without external pre-regulator. |
| FB Reference Voltage | 1.25V ±25 mV - sets output regulation accuracy for LED string voltage feedback networks. |
| Oscillator Frequency | Up to 2 MHz - set by single RT resistor; enables compact magnetics and fast transient response. |
| CS Current Limit Threshold | 0.5V - triggers immediate gate turn-off per switching cycle; defines maximum MOSFET peak current. |
| OUT Peak Drive Current | 1A - drives standard N-channel MOSFETs with gate charge ≤18 nC at 600 kHz without external buffer. |
| Max Duty Cycle | 95% - supports high step-up ratios required for wide-input LED backlighting (e.g., 8V → 33V). |
| Thermal Shutdown | 165°C with 25°C hysteresis - protects IC during overload or poor PCB thermal design. |
Pinout & Package
LM3430SDX is housed in a thermally enhanced 12-lead LLP package (3 mm × 3 mm, DAP exposed pad), optimized for high-power density LED driver layouts. The exposed pad must be soldered to PCB ground for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VDHC | Dynamic Headroom Control Input | Accepts analog voltage from LM3432 to adjust output voltage in real time for LED efficiency optimization. |
| 2 VIN | Main Power Input | Supplies internal startup regulator; operates over full 6V–40V range without external bias. |
| 3 FB | Feedback Input | Inverting input of error amplifier referenced to 1.25V; connects to resistor divider from LED string output. |
| 4 COMP | Error Amplifier Output | Open-drain output for loop compensation network; interfaces with optocoupler in isolated configurations. |
| 5 VCC | Internal Regulator Output | 7V regulated supply for internal circuitry; requires 0.1–100 µF ceramic bypass capacitor to GND. |
| 6 OUT | MOSFET Gate Driver Output | 1A peak push-pull driver for low-side N-MOSFET; directly controls switch timing and slew rate. |
| 7 GND | System Ground Reference | Analog and power ground common point; connects to exposed pad for thermal conduction. |
| 8 UVLO | Under-Voltage Lockout Input | Programmable enable/disable via resistor divider; includes 20 µA hysteresis current source. |
| 9 CS | Current Sense Input | Monitors MOSFET source current via sense resistor; triggers cycle-by-cycle limit at 0.5V. |
| 10 RT/SYNC | Oscillator & Sync Input | Single-resistor frequency setting (up to 2 MHz); accepts AC-coupled external clock ≥3.8V peak. |
| 11 SS | Soft-Start Control | 10 µA current source charges external capacitor to ramp COMP voltage and limit inrush current. |
| 12 NC | No Connect | Not internally bonded; must remain unconnected and floating. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Soft-Start | External capacitor on SS pin controls ramp time and limits inrush current during power-up. |
| Internal 40V Startup Regulator | Eliminates need for external bias supply; delivers regulated 7V to VCC across full 6V–40V VIN range. |
| Slope Compensation | 105 mV sawtooth ramp prevents subharmonic oscillation in continuous conduction mode above 50% duty. |
| Programmable UVLO with Hysteresis | 20 µA current source enables precise, noise-immune input voltage monitoring and remote ON/OFF control. |
| External Synchronization | AC-coupled sync input allows system-level clock alignment for EMI reduction in multi-converter designs. |
| Thermal Shutdown Protection | Auto-recovery shutdown at 165°C with 25°C hysteresis ensures robust operation under sustained overload. |
Applications
| LED Backlight Driver | Automotive Display Power |
|---|---|
|
Use Scenario: Driving 6 parallel strings of white LEDs (7× per string) in notebook PC LCD panels using boost topology. IC Role / Device Role / Timing Role: Low-side N-MOSFET controller implementing current-mode boost regulation with dynamic headroom control via VDHC pin. Use Value: Enables >90% efficiency across 8V–21V input range while maintaining ±2% output voltage regulation and real-time dimming coordination with LM3432. |
Use Scenario: Powering TFT-LCD instrument cluster displays in 12V/24V automotive systems with cold-crank tolerance down to 6V. IC Role / Device Role / Timing Role: High-voltage boost controller managing LED string voltage with UVLO hysteresis and thermal protection for under-hood reliability. Use Value: Sustains operation during engine cranking (6V minimum) and rejects load-dump transients up to 40V without external clamping. |
| Industrial Panel Lighting | SEPIC LED Driver |
|
Use Scenario: Providing constant-current LED illumination for industrial HMIs where input varies between 9V–36V DC due to unregulated PSUs. IC Role / Device Role / Timing Role: Current-mode controller regulating output via FB pin while compensating for line variations using inherent feed-forward behavior. Use Value: Delivers stable LED brightness despite ±40% input variation, eliminating need for secondary regulation stages. |
Use Scenario: Driving high-brightness LEDs from variable input sources (e.g., solar-charged batteries) where input may exceed output voltage. IC Role / Device Role / Timing Role: Controller configured in SEPIC topology to support VIN > VOUT or VIN < VOUT operation with single inductor. Use Value: Maintains regulation across wide input range (6V–40V) while avoiding polarity reversal issues of traditional buck-boost converters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3430MMX | Same die, MSOP-10 package (4.9 mm × 3.0 mm); lacks VDHC pin and NC pin; no exposed thermal pad. | Lower thermal performance; unsuitable for >1A continuous drive or high ambient temperature environments. | Select LM3430SDX when board space permits 3 mm × 3 mm footprint and thermal management is critical. |
| TPS40210DGQ | Current-mode controller with integrated 1.5A gate driver; wider 4.5V–52V VIN range; no VDHC or slope compensation auto-tuning. | Requires external slope compensation network; lacks dynamic headroom interface for LED-specific dimming. | Choose TPS40210DGQ for general-purpose boost/SEPIC where LED-specific features are not required. |
Compared with LM3430MMX, LM3430SDX offers superior thermal dissipation and VDHC functionality for LED systems; compared with TPS40210DGQ, it provides integrated slope compensation and seamless LM3432 interoperability but narrower VIN max rating.
Availability
LM3430SDX is available at Aetrix Electronics and suitable for LED backlighting, automotive display power, and industrial panel lighting requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM3430SDX 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 ICs and LED driver solutions.
The LM3430SDX belongs to TI's LED backlight controller product line, designed specifically for high-efficiency, dynamically adjustable boost drivers in portable and automotive LCD displays.
FAQ
What is the function of the VDHC pin on the LM3430SDX?
The VDHC pin on the LM3430SDX is a proprietary analog input that accepts a control voltage from the LM3432 to dynamically adjust the output voltage in real time. This enables optimal LED efficiency by minimizing excess headroom across varying forward voltages and temperatures. When not used with LM3432, the VDHC pin must be left open-circuited. The LM3430SDX will operate normally in standard boost mode without VDHC connection.
Can the LM3430SDX operate without an external VCC supply?
Yes, the LM3430SDX can operate without an external VCC supply because it integrates a high-voltage startup regulator that powers internal circuitry from VIN (6V–40V). The VCC pin outputs a regulated ~7V supply and must be bypassed with a ceramic capacitor to GND. An external bias (7.5V–14V) may be applied to VCC and VIN together to disable the internal regulator and improve efficiency, but it is not required for basic operation of the LM3430SDX.
What is the maximum switching frequency supported by the LM3430SDX?
The LM3430SDX supports oscillator frequencies up to 2 MHz, set by a single resistor from RT/SYNC to GND. At RT = 16.2 kΩ, typical fSW is 990 kHz; at RT = 8.25 kΩ, it reaches ~1.8 MHz. Propagation delays remain below 100 ns across the range, enabling fast transient response. For reliable operation above 1.5 MHz, layout must minimize parasitic inductance on RT, CS, and OUT traces to prevent jitter or false triggering in the LM3430SDX.
How does the LM3430SDX implement cycle-by-cycle current limiting?
The LM3430SDX implements cycle-by-cycle current limiting by comparing the voltage on the CS pin against a 0.5V internal threshold. When sensed current through the MOSFET source resistor exceeds this level, the gate driver immediately terminates the current cycle. A 65 ns leading-edge blanking window suppresses noise during switch turn-on. The LM3430SDX also includes internal discharge circuitry on the CS pin to reset residual voltage before each new cycle, ensuring accurate per-cycle detection.
Is the LM3430SDX pin-compatible with other TI LED controllers like LM3432?
No, the LM3430SDX is not pin-compatible with LM3432 or other TI LED controllers. LM3432 is a multi-channel LED current regulator with I²C interface, while LM3430SDX is a boost controller with gate driver output. They are functionally complementary - LM3430SDX supplies regulated voltage, LM3432 sinks precise current - and connect via VDHC and fault signaling. Their pinouts, packages, and electrical roles are entirely distinct; interchanging them is not possible.
LM3430SDX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 12-WFDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Type:
- DC DC Controller
- Topology:
- SEPIC, Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 6V
- Voltage - Supply (Max):
- 40V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 2MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 12-WSON (3x3)
LM3430SDX FAQ
1.How can I place an order for LM3430SDX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3430SDX 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 LM3430SDX reliable?
The price and inventory of LM3430SDX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3430SDX is usually 5 days.
3.What payment methods are accepted for LM3430SDX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3430SDX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3430SDX?
LM3430SDX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3430SDX 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 LM3430SDX?
For technical support, including LM3430SDX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3430SDX requirements.
6.How does Aetrix verify that LM3430SDX is sourced from the original manufacturer or authorized distributors?
All LM3430SDX 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 LM3430SDX meets industry standards.
7.What is the process for return or replacement of LM3430SDX?
All LM3430SDX units undergo pre-shipment inspection (PSI). If there is an issue with LM3430SDX, 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 LM3430SDX part is unused and in its original packaging.
Return procedure for LM3430SDX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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