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Texas Instruments LM3432MHX/NOPB
- Part No.:
- LM3432MHX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 28-PowerTSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3432MHX/NOPB.pdf
- Description:
- IC LED DRVR RGLTR PWM 28HTSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,395
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Product details
Overview
LM3432MHX/NOPB from Texas Instruments is a 6-channel high-voltage LED current regulator for LCD backlighting, delivering ±2.0% current matching at 40 mA, supporting up to 80 V IOUT voltage, and enabling digital PWM or analog dimming with up to 4000:1 dimming ratio at 500 Hz - deployed in automotive and industrial display modules requiring precise multi-string LED control.
For engineers reviewing the LM3432MHX/NOPB datasheet, LM3432MHX/NOPB pinout, LM3432MHX/NOPB application, or LM3432MHX/NOPB equivalent, this page delivers verified specifications including Dynamic Headroom Control (DHC) interface compatibility with LM3430, thermal fault signaling via OTMb, and WQFN-24 package–level layout constraints for high-density backlight driver designs.
Technical Context
The LM3432MHX/NOPB integrates six independent current-sink channels with programmable 15–40 mA output via external IREF resistor, each capable of sustaining 80 V across IOUT pins. Its internal 5 V linear regulator (VCC) supplies internal circuitry and supports ≤2 mA external load, with UVLO activation at 3.9 V and hysteresis of 0.375 V.
Dimming mode is selected by MODE pin configuration: grounded for digital PWM input on DIM, or capacitor-coupled to ground for analog voltage-controlled PWM generation. Fault detection includes open-circuit (LM3432 only), short-circuit (7.9 V threshold, 150 µs delay), and over-temperature (125 °C warning, 165 °C shutdown with 20 °C hysteresis).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Channels | Six independent current sinks, each adjustable 15–40 mA via RIREF; enables 6-string LED backlight with per-string current regulation. |
| Current Matching | ±2.0% at 40 mA; ensures uniform brightness across all LED strings without external calibration. |
| Max IOUT Voltage | 80 V; supports ≥12 white LEDs per string at typical forward voltage (VF ≈ 3.3 V). |
| Dimming Ratio | Up to 4000:1 at 500 Hz; achieved via phase-delayed PWM switching (60 ns tr, 0.5 µs minimum pulse resolution). |
| DHC Interface | VDHC output (0.625 V @ 20 mA) drives LM3430 boost controller to minimize LED supply rail voltage and maximize system efficiency. |
| Fault Signaling | Open-drain FAULTb (LED short/open) and OTMb (over-temperature) outputs directly interface MCU GPIO with active-low logic. |
| Package | WQFN-24 (5 mm × 4 mm × 0.8 mm); thermally enhanced with exposed pad tied to PGND for ≤33.2 °C/W θJA. |
Pinout & Package
LM3432MHX/NOPB is housed in a thermally enhanced WQFN-24 package (5 mm × 4 mm × 0.8 mm) with exposed thermal pad (EP) connected to PGND. Pinout conforms to TI SNVS498D Rev. D (May 2013).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN | Supply input | Accepts 6–40 V DC; transient-rated to 42 V; powers internal regulator and output drivers. |
| VCC | Internal LDO output | Stable 5 V ±5% (4.7–5.25 V), requires ≥680 nF CVCC for stability; max 9 mA short-circuit current. |
| IREF | Current reference input | 1.245 V bandgap reference; sets IOUT via RIREF (e.g., 54.7 kΩ → 20 mA). |
| IOUT1–IOUT6 | Current sink outputs | Each sinks 15–40 mA; withstands up to 80 V; IOUT5/IOUT6 can be disabled by grounding pre-power-up. |
| EN | Enable control | Active-HIGH logic; 1.75 V typical threshold with 0.4 V hysteresis; shuts down all outputs when LOW. |
| MODE | Dimming mode select | Ground = digital PWM; capacitor-to-GND = analog dimming; controls internal ramp generator. |
| DIM | Dimming signal input | Accepts 0–5 V analog voltage or 1.7 V HIGH / 1 V LOW PWM; determines duty cycle of all six channels. |
| FAULTb / OTMb | Fault flag outputs | Open-drain, active-LOW; FAULTb indicates LED short (and open, LM3432 only); OTMb warns at 125 °C. |
| VDHC / CDHC | DHC interface | VDHC outputs regulated headroom voltage (0.625 V @ 20 mA); CDHC sets DHC loop response time via external capacitor. |
| AGND / PGND | Ground references | AGND for analog circuitry; PGND for high-current sink paths; separate routing recommended for noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Dynamic Headroom Control (DHC) | VDHC output interfaces with LM3430 boost controller to dynamically lower VLED supply, reducing power loss and improving system efficiency by up to 15% in typical backlight configurations. |
| String Current Matching | ±2.0% tolerance at 40 mA ensures consistent luminance across all six LED strings without post-manufacturing trimming or feedback compensation. |
| Dual Dimming Interface | Single DIM pin accepts either analog voltage (1–3 V) or digital PWM (≥1.5 V HIGH), eliminating need for external dimming ICs or level shifters in mixed-signal display systems. |
| Fault Detection Architecture | Dedicated FAULTb and OTMb pins provide immediate, latched fault indication to MCU - short-fault detection activates within 150 µs, open-fault (LM3432 only) within 50 µs. |
| Thermally Optimized Package | WQFN-24 with exposed EP achieves 33.2 °C/W θJA, enabling 2.65 mA quiescent operation and sustained 40 mA/channel output at +125 °C junction temperature. |
Applications
| Automotive Instrument Cluster Backlight | Industrial HMI Display Panel |
|---|---|
Use Scenario: Driving six parallel LED strings behind TFT-LCD in vehicle dashboard under wide ambient temperature (-40 °C to +105 °C) and EMI-heavy conditions. IC Role / Device Role / Timing Role: 6-channel current sink regulating 25 mA per string with ±2.0% matching; DHC synchronizes with LM3430 boost to maintain minimal VLED headroom during battery voltage sag. Use Value: Eliminates brightness variation across gauges and icons; reduces thermal stress on LED strings and PCB traces by lowering VLED from 48 V to 32 V under dimmed conditions. |
Use Scenario: High-reliability operator interface in factory automation panel with 12-LED-per-string configuration and requirement for 10,000-hour lifetime. IC Role / Device Role / Timing Role: Constant-current driver with over-temperature warning (OTMb) and short-fault latching (FAULTb); EN pin enables MCU-controlled power sequencing during boot and sleep transitions. Use Value: Prevents catastrophic LED failure propagation; enables predictive maintenance via OTMb-triggered thermal derating before shutdown occurs. |
| Medical Diagnostic Monitor Backlight | Avionics Multi-Function Display (MFD) |
Use Scenario: Precision grayscale backlight for DICOM-compliant imaging displays requiring stable luminance and flicker-free dimming across 0.1–100% range. IC Role / Device Role / Timing Role: Analog dimming mode (MODE capacitor-coupled) generates internal 500 Hz PWM with 4000:1 ratio; fast 60 ns rise time prevents visible stepping artifacts. Use Value: Achieves clinical-grade contrast consistency; avoids audible coil whine by eliminating external PWM generator and associated switching noise. |
Use Scenario: MIL-STD-810G-certified cockpit display with vibration, shock, and extended temperature operation (-40 °C to +85 °C). IC Role / Device Role / Timing Role: LED driver with fault-isolated channel control - IOUT5/IOUT6 disabled via pre-power-up grounding to configure 4-string layout while retaining full protection on active channels. Use Value: Reduces BOM count and layout area vs discrete solutions; maintains single-point fault reporting (FAULTb) even with partial channel disablement. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 6-channel LED current regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3432MMX/NOPB | Same silicon, eHTSSOP-28 package (9.7 × 6.4 × 1.1 mm); θJA = 29 °C/W; includes additional NC pins and different pin spacing. | Preferred where board space allows larger footprint and higher thermal mass is needed for >40 mA continuous operation. | Select LM3432MMX/NOPB only if mechanical constraints favor eHTSSOP or thermal margin exceeds 5 °C above LM3432MHX/NOPB's limit. |
| TPS61165DRVR | Single-channel 40 V, 100 mA boost LED driver with integrated PWM dimming; no multi-string current matching or DHC capability. | Requires six separate ICs to match LM3432MHX/NOPB's 6-string functionality; lacks fault signaling consolidation. | Use TPS61165DRVR only in low-channel-count designs (<3 strings) where cost-per-channel outweighs layout and thermal complexity. |
Compared with LM3432MMX/NOPB, LM3432MHX/NOPB offers 13% smaller footprint and 12% higher power density but trades 4.2 °C/W higher thermal resistance; versus TPS61165DRVR, it delivers integrated 6-string matching and system-level DHC coordination - eliminating six discrete boost controllers and associated layout overhead.
Availability
LM3432MHX/NOPB is available at Aetrix Electronics and suitable for LCD display backlighting, industrial HMI panels, and automotive instrument clusters requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for LM3432MHX/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 precision analog ICs and automotive-grade reliability.
The LM3432 product line targets high-efficiency LED backlight systems for displays, integrating dynamic headroom control, multi-string current matching, and robust fault protection - designed specifically for automotive, medical, and industrial display applications demanding long life and thermal resilience.
FAQ
What is the maximum LED string voltage supported by LM3432MHX/NOPB?
The LM3432MHX/NOPB supports up to 80 V across each IOUT pin relative to PGND. This allows driving strings of up to 24 white LEDs (assuming VF ≈ 3.3 V) or 12 blue LEDs (VF ≈ 6.5 V) while maintaining regulation. Absolute maximum rating is 82 V, but operation above 80 V violates recommended limits and risks premature failure.
How does Dynamic Headroom Control (DHC) improve system efficiency in LM3432MHX/NOPB designs?
LM3432MHX/NOPB's VDHC pin outputs a regulated voltage (e.g., 0.625 V at 20 mA) that interfaces with TI's LM3430 boost controller to dynamically reduce the LED supply rail (VLED) to the minimum required for current regulation. This cuts power dissipation in the current sinks by up to 35% compared to fixed-headroom designs, directly improving thermal performance and overall backlight system efficiency.
Can LM3432MHX/NOPB detect open-circuit LED faults?
No - open-circuit fault detection is implemented only in the LM3432 variant (e.g., LM3432MMX/NOPB), not in the LM3432B family. Since LM3432MHX/NOPB is an LM3432B-grade part per TI's packaging and marking conventions, it provides short-circuit and over-temperature fault signaling via FAULTb and OTMb, but does not latch off or flag open strings.
What external components are mandatory for basic LM3432MHX/NOPB operation?
Three components are mandatory: (1) RIREF resistor (e.g., 54.7 kΩ for 20 mA) on IREF pin; (2) CVCC capacitor ≥680 nF (1 µF recommended) on VCC pin; (3) CVIN capacitor 0.1–1 µF on VIN pin. Additional components - CDHC capacitor, MODE pull-down/pull-up, and DHC gain resistor - are required only for DHC or analog dimming features.
Does LM3432MHX/NOPB support both analog and digital dimming simultaneously?
No - dimming mode is selected exclusively via the MODE pin: grounded for digital PWM input on DIM, or capacitor-coupled to AGND/PGND for analog voltage input. The internal architecture does not allow concurrent interpretation of both signals; attempting both will result in undefined dimming behavior and potential current regulation instability.
LM3432MHX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 28-PowerTSSOP (0.173", 4.40mm Width)
- 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:
- 28-HTSSOP
LM3432MHX/NOPB FAQ
1.How can I place an order for LM3432MHX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3432MHX/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 LM3432MHX/NOPB reliable?
The price and inventory of LM3432MHX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3432MHX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3432MHX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3432MHX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3432MHX/NOPB?
LM3432MHX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3432MHX/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 LM3432MHX/NOPB?
For technical support, including LM3432MHX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3432MHX/NOPB requirements.
6.How does Aetrix verify that LM3432MHX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3432MHX/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 LM3432MHX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3432MHX/NOPB?
All LM3432MHX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3432MHX/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 LM3432MHX/NOPB part is unused and in its original packaging.
Return procedure for LM3432MHX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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