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Texas Instruments LM3432SQX
- Part No.:
- LM3432SQX
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LM3432SQX.pdf
- Description:
- IC LED DRV RGLTR PWM 40MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,035
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Product details
Overview
LM3432SQX from Texas Instruments is a 6-channel high-voltage LED current regulator IC designed for LCD backlight driving, featuring ±2.0% string-to-string current matching at 40 mA, 80 V maximum IOUT voltage rating, and dual digital PWM/analog dimming control with up to 4000:1 dimming ratio at 500 Hz.
For engineers reviewing the LM3432SQX datasheet, LM3432SQX pinout, LM3432SQX application, or LM3432SQX equivalent, this device supports thermally enhanced WQFN-24 (5×4×0.8 mm) packaging, Dynamic Headroom Control (DHC) interface with LM3430 boost controllers, and fault signaling (short circuit, over-temperature) to MCU via open-drain FAULTb/OTMb pins.
Technical Context
The LM3432SQX integrates six independent current-sink channels with programmable output (15–40 mA via external RIREF), each capable of sustaining up to 80 V across IOUT pins. Its internal 5 V linear regulator (VCC) provides stable biasing with UVLO (4.15 V rising threshold) and supports ≤2 mA external load.
Dimming is implemented either digitally (MODE = GND, PWM input on DIM) or analog (MODE capacitor-based ramp generation), with channel switching phased by 0.5 µs to limit supply surge currents. Fault detection includes LED short-circuit latching (7.9 V threshold, 150 µs delay) and over-temperature warning (125 °C) with thermal shutdown at 165 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IOUT Range | 15–40 mA per channel, set by external RIREF resistor; enables precise brightness tuning across LED strings. |
| Current Matching | ±2.0% at 40 mA; ensures uniform luminance in multi-string LCD backlight panels without per-string calibration. |
| Max IOUT Voltage | 80 V; supports up to ~24 white LEDs (3.3 V each) in series per string under typical forward voltage conditions. |
| Dimming Ratio | Up to 4000:1 at 500 Hz; achieves deep black levels in high-contrast display applications using PWM control. |
| Rise Time (tr) | 60 ns typical; enables fast, clean current transitions critical for flicker-free dimming and accurate pulse-width fidelity. |
| VDHC Output | 0.625 V regulation at 20 mA; interfaces with LM3430 boost controller to dynamically minimize LED supply voltage and maximize system efficiency. |
| Operating Temp | −40 °C to +125 °C junction; suitable for industrial and automotive display modules with extended thermal envelopes. |
Pinout & Package
LM3432SQX is packaged in a thermally enhanced 24-pin WQFN (5 mm × 4 mm × 0.8 mm) with exposed thermal pad (EP) connected to PGND. Pin count and layout match the LM3432B variant; the 'SQX' suffix denotes tape-and-reel packaging for automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Supply input | Accepts 6–40 V DC; withstands 42 V transients; powers internal regulator and output drivers. |
| VCC | Internal LDO output | Stable 5 V ±5% (4.7–5.25 V), requires ≥680 nF CVCC capacitor for stability; supplies internal logic and bias circuits. |
| IREF | Current reference input | 1.245 V bandgap reference node; connects to RIREF to set IOUT magnitude (IOUT ≈ 1.094×10⁶ / RIREF in mA). |
| IOUT1–IOUT6 | Current sink outputs | Six independent high-side referenced sinks; each handles up to 40 mA and 80 V; channels 5/6 can be disabled by grounding pre-power-up. |
| EN | Enable control | Active-HIGH logic input (1.75 V threshold); toggling resets fault latches and re-enables regulated output. |
| MODE | Dimming mode select | GND = digital PWM; capacitor to AGND = analog dimming; sets internal ramp generator frequency and modulation method. |
| DIM | Dimming signal input | Accepts 0–5 V analog voltage or 1.7 V min. PWM signal; directly controls duty cycle of all six channels synchronously. |
| FAULTb / OTMb | Fault indicator outputs | Open-drain, active-LOW signals: FAULTb asserts on LED short or (LM3432 only) open fault; OTMb asserts at 125 °C junction temp. |
| VDHC / CDHC | DHC interface | VDHC delivers regulated headroom voltage (0.625–1.25 V) to LM3430; CDHC sets DHC loop response time via external capacitor. |
| AGND / PGND | Ground references | Separate analog and power grounds minimize noise coupling between sensitive reference circuitry and high-current sink paths. |
Key Features
| Feature | Design Value |
|---|---|
| Dynamic Headroom Control (DHC) | Reduces LED supply voltage to minimum required level (e.g., 0.625 V overhead at 20 mA), cutting boost converter losses and improving total system efficiency by up to 15% in typical backlight designs. |
| String Current Matching | ±2.0% matching at full scale (40 mA) eliminates visible brightness gradients across multi-string LCD panels without post-manufacture trimming. |
| Dual Dimming Interface | Hardware-selectable mode (MODE pin) supports either direct PWM control or analog voltage input-enabling compatibility with both microcontroller GPIO and DAC-based dimming systems. |
| Fault Detection & Reporting | Dedicated open-drain FAULTb and OTMb outputs provide immediate, latchable status to host MCU-reducing firmware polling overhead and enabling rapid system-level fault response. |
| Thermally Optimized Packaging | WQFN-24 with exposed pad achieves θJA = 33.2 °C/W, allowing >1.5 W continuous dissipation at TA = 85 °C without forced airflow-critical for compact, sealed display enclosures. |
Applications
| LCD TV Backlight | Automotive Instrument Cluster |
|---|---|
|
Use Scenario: Driving six parallel LED strings (12 white LEDs/string) in a 55-inch LCD TV panel with local dimming zones. IC Role / Device Role / Timing Role: Primary current-regulated LED driver; provides synchronized PWM dimming across all strings with <0.5 µs inter-channel skew. Use Value: Enables uniform edge-lit illumination with <2% luminance variation across panel, supporting HDR contrast ratios >1000:1. |
Use Scenario: Illuminating segmented TFT display and analog gauge LEDs in vehicle dashboard under −40 °C to +105 °C ambient conditions. IC Role / Device Role / Timing Role: High-reliability current sink managing mixed-color (white/red/green) LED strings with integrated thermal fault monitoring. Use Value: Eliminates need for discrete current-setting resistors and external fault comparators-reducing BOM count by 12 components per module. |
| Industrial HMI Display | Medical Imaging Monitor |
|
Use Scenario: Backlighting a sunlight-readable 10.1-inch resistive touch display in factory automation panel with EMI-sensitive analog sensors nearby. IC Role / Device Role / Timing Role: Low-noise LED driver with separated AGND/PGND and fast 60 ns rise time to suppress conducted emissions into adjacent signal chains. Use Value: Meets CISPR-22 Class B radiated emissions limits without additional ferrite beads or shielding-cutting EMC debug time by 3 weeks. |
Use Scenario: Precision grayscale backlight for DICOM-compliant 21.5-inch diagnostic monitor requiring <1% ΔE color shift across 0–100% brightness range. IC Role / Device Role / Timing Role: Stable current source with ±2.0% matching and 4000:1 dimming resolution-enabling 14-bit luminance control via PWM frequency scaling. Use Value: Supports clinical-grade grayscale rendering without gamma correction firmware, reducing display calibration labor by 70%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED current regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3432TME/NOPB | Same silicon die and specs; differs only in eHTSSOP-28 packaging (9.7×6.4×1.1 mm) and lead finish (NiPdAu vs. matte Sn). | Requires PCB redesign due to larger footprint and 4 additional NC pins; better thermal performance (θJA = 29 °C/W) but higher assembly cost. | Select when board space allows larger package and higher continuous power (>1.8 W) is needed without heatsinking. |
| TPS61165DRVR | Single-channel 40 V, 30 mA LED driver with integrated boost converter; no DHC, no multi-string matching, no FAULTb reporting. | Only suitable for single-string or paralleled-LED applications; lacks system-level fault visibility and string uniformity control. | Choose only for cost-sensitive, low-channel-count designs where DHC and matching are non-critical. |
Compared with LM3432TME/NOPB, LM3432SQX offers identical electrical performance in a smaller, lower-inductance WQFN package optimized for high-density layouts; versus TPS61165DRVR, it delivers true multi-string regulation with diagnostic signaling-making it the sole option for precision backlight architectures requiring uniformity, efficiency, and fault awareness.
Availability
LM3432SQX is available at Aetrix Electronics and suitable for LCD backlight modules, automotive instrument clusters, and medical imaging displays requiring stable component supply, long-term lifecycle support, and RoHS-compliant WQFN packaging.
Supply support for LM3432SQX 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 IC design and manufacturing.
The LM3432SQX belongs to TI's LED backlight driver product line, engineered specifically for energy-efficient, high-uniformity LCD and OLED display systems demanding tight current matching, dynamic voltage optimization, and robust fault handling.
FAQ
What is the maximum LED string voltage supported by the LM3432SQX?
The LM3432SQX supports up to 80 V across each IOUT pin relative to PGND. This allows driving strings containing up to approximately 24 standard white LEDs (3.3 V VF each) or 18 high-VF blue LEDs (4.4 V VF) while maintaining regulation margin. Absolute maximum rating is 82 V, but operation above 80 V is not guaranteed per datasheet specifications.
Does the LM3432SQX support open-circuit LED fault detection?
No-the LM3432SQX does not support open-circuit LED fault detection. That feature is exclusive to the base LM3432 part. The LM3432SQX is functionally identical to the LM3432B variant, which omits open-fault sensing while retaining short-circuit and over-temperature detection via FAULTb and OTMb pins.
How is LED current adjusted on the LM3432SQX?
LED current is set by an external resistor (RIREF) connected between IREF and AGND. The relationship is IOUT ≈ 1.094×10⁶ / RIREF (in mA). For example, 54.7 kΩ yields 20 mA per string. A ±1% tolerance, low-TCR resistor is recommended to maintain accuracy across temperature.
Can multiple LM3432SQX outputs be paralleled for higher per-string current?
Yes-outputs such as IOUT1 and IOUT2 can be wired in parallel to deliver up to 80 mA to a single LED string. However, this reduces total channel count (e.g., 3 strings at 80 mA instead of 6 at 40 mA) and may slightly degrade matching due to minor process variations between channels.
What is the purpose of the CDHC pin on the LM3432SQX?
The CDHC pin connects to an external capacitor that sets the time constant of the Dynamic Headroom Control loop. A larger CDHC value slows the VDHC response, preventing interference with the LM3430 boost converter's feedback loop-ensuring stable, ripple-free LED supply voltage adjustment during dimming transitions.
LM3432SQX 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 Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 6
- Voltage - Supply (Min):
- 6V
- Voltage - Supply (Max):
- 40V
- Voltage - Output:
- 80V
- Current - Output / Channel:
- 40mA
- Frequency:
- -
- Dimming:
- Analog, PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-WQFN (4x5)
LM3432SQX FAQ
1.How can I place an order for LM3432SQX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3432SQX 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 LM3432SQX reliable?
The price and inventory of LM3432SQX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3432SQX is usually 5 days.
3.What payment methods are accepted for LM3432SQX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3432SQX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3432SQX?
LM3432SQX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3432SQX 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 LM3432SQX?
For technical support, including LM3432SQX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3432SQX requirements.
6.How does Aetrix verify that LM3432SQX is sourced from the original manufacturer or authorized distributors?
All LM3432SQX 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 LM3432SQX meets industry standards.
7.What is the process for return or replacement of LM3432SQX?
All LM3432SQX units undergo pre-shipment inspection (PSI). If there is an issue with LM3432SQX, 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 LM3432SQX part is unused and in its original packaging.
Return procedure for LM3432SQX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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