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Texas Instruments LM3432BSQ/NOPB
- Part No.:
- LM3432BSQ/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LM3432BSQ/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 40MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:4,209
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Product details
Overview
LM3432BSQ/NOPB from Texas Instruments is a 6-channel high-voltage LED current regulator IC for LCD backlighting, delivering ±2.0% current matching at 40 mA across all strings, supporting up to 80 V IOUT voltage, and enabling dynamic headroom control (DHC) with external LM3430 boost controllers in automotive and industrial display systems.
For engineers reviewing the LM3432BSQ/NOPB datasheet, LM3432BSQ/NOPB pinout, LM3432BSQ/NOPB application, or LM3432BSQ/NOPB equivalent, this page provides verified current regulation specs, DHC interface details, fault signaling behavior (short/over-temperature only), WQFN-24 package layout, and real-world dimming performance data - all confirmed from TI's SNVS498D revision May 2013 datasheet.
Technical Context
The LM3432BSQ/NOPB integrates six independent current-sink channels with bandgap-referenced IREF control (1.245 V typical), each capable of sinking 15–40 mA set by an external resistor (RIREF). Its internal 5 V linear regulator (VCC) supplies internal circuitry and supports ≤2 mA external load, with UVLO activation at 4.15 V rising threshold.
Digital PWM dimming operates with MODE grounded and DIM accepting 1.7 V HIGH / 1.0 V LOW signals; analog dimming uses MODE capacitor-coupled to ground and DIM voltage (1–3 V) to generate internal PWM. Short-fault detection triggers at 7.9 V (typical) on any IOUT pin for >150 µs; over-temperature warning activates at 125 °C (OTMb active low), shutdown at 165 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IOUT Range | 15–40 mA per channel, set by RIREF; enables flexible LED string design with 12 white LEDs/string at 20 mA. |
| Current Matching | ±2.0% at 40 mA, ±2.25% at 20 mA - ensures uniform brightness across 6 LED strings without per-string compensation. |
| Max IOUT Voltage | 80 V - supports high-LED-count strings (e.g., 12× white LEDs @ ~3.3 V each) without external cascoding. |
| Dimming Ratio | Up to 4000:1 at 500 Hz PWM - meets contrast requirements for premium LCD panels in medical and industrial displays. |
| Rise Time (tr) | 60 ns typical - minimizes current transient distortion during fast PWM switching, preserving dimming linearity. |
| VCC Regulator | 5.0 V ±2.5%, 9 mA short-circuit limit - powers internal logic and supports small external bias networks without secondary LDO. |
| Thermal Shutdown | 165 °C with 20 °C hysteresis - protects die during sustained overloads; resumes operation at ~145 °C. |
Pinout & Package
LM3432BSQ/NOPB is housed in a thermally enhanced 24-pin WQFN package (5 mm × 4 mm × 0.8 mm) with exposed thermal pad (EP) tied to PGND. Pin 1 is VCC; pin 24 is VIN; EP must be soldered to PCB ground plane for thermal performance (θJA = 33.2 °C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VCC (Pin 1) | Internal 5 V regulator output | Stable supply for internal logic; requires ≥680 nF CVCC capacitor for stability; max 2 mA external load. |
| IREF (Pin 2) | Current reference input | 1.245 V (typ) reference sets IOUT via RIREF; tolerance directly impacts string current accuracy. |
| AGND (Pin 3) | Analog ground reference | Separate from PGND to minimize noise coupling into IREF and VDHC circuits. |
| CDHC (Pin 4) | DHC time constant capacitor node | External capacitor to ground sets DHC loop response; prevents interference with LM3430 boost controller bandwidth. |
| VDHC (Pin 5) | DHC voltage output | 0.625 V (at 20 mA) or 1.25 V (at 40 mA) feedback signal sent to LM3430 VDHC pin to minimize LED supply voltage. |
| EN (Pin 6) | Enable control input | Active-HIGH logic; 1.75 V threshold with 0.4 V hysteresis; toggling resets latched fault conditions. |
| MODE (Pin 7) | Dimming mode select | Ground = digital PWM; capacitor-to-ground = analog dimming; determines internal PWM generation path. |
| DIM (Pin 8) | Dimming signal input | Accepts 1–3 V DC for analog mode or 1.7 V/1.0 V PWM for digital mode; defines ON duty factor. |
| FAULTb (Pin 9) | Open-drain fault indicator | Active-low signal for LED short or over-temperature; requires external pull-up; no open-fault reporting (LM3432B only). |
| OTMb (Pin 10) | Open-drain over-temp flag | Active-low at 125 °C; non-latching warning - system must reduce power before thermal shutdown at 165 °C. |
| IOUT1–IOUT6 (Pins 12,13,15,17,19,20) | Current sink outputs | Each sinks 15–40 mA; withstands 80 V; pins 5/6 can be grounded pre-power-up to disable channels 5/6. |
| PGND (Pin 22) | Power ground return | High-current return path for all IOUT sinks; separate from AGND to avoid ground bounce in precision current paths. |
| VIN (Pin 24) | Main supply input | 6–40 V DC input; transient-rated to 42 V; powers internal VCC regulator and DHC circuitry. |
Key Features
| Feature | Design Value |
|---|---|
| Dynamic Headroom Control (DHC) | Reduces LED supply voltage to minimum required headroom (e.g., 0.625 V at 20 mA), cutting boost converter losses by up to 15% in full-brightness operation. |
| Fast current switching | 60 ns typical rise time enables clean 500 Hz PWM dimming with <0.5% duty-cycle quantization error at 0.5 µs resolution. |
| Dual dimming interface | Hardware-selectable mode (MODE pin) supports either direct PWM input or analog voltage control - simplifies MCU firmware and reduces BOM count. |
| String current programmability | Single RIREF resistor sets all six channels identically; eliminates per-string calibration and reduces layout complexity. |
| Fault diagnostics | Dedicated FAULTb and OTMb open-drain outputs provide immediate MCU visibility into LED short and thermal events - no software polling required. |
Applications
| Automotive Instrument Clusters | Industrial HMI Displays |
|---|---|
|
Use Scenario: Driving 6 parallel LED strings (12 white LEDs each) behind TFT-LCD in vehicle dashboards with ambient temperature range −40°C to +125°C. IC Role / Device Role / Timing Role: Current sink regulator maintaining ±2.0% string matching under wide VIN (6–40 V) and thermal variation; DHC interface synchronizes with LM3430 boost to minimize power loss. Use Value: Eliminates brightness drift across display zones during engine cranking or thermal soak, meeting ISO 16750-2 electrical stress and AEC-Q200 reliability requirements. |
Use Scenario: Backlighting ruggedized 10.1″ industrial panel PCs used in factory automation with frequent on/off cycling and ESD exposure. IC Role / Device Role / Timing Role: Fault-aware LED driver providing short-circuit latching and OTMb warning to PLC controller; EN pin allows safe soft-start sequencing. Use Value: Reduces field failures from LED shorts caused by mechanical shock or connector arcing - FAULTb signal triggers immediate UI alert and backlight disable. |
| Medical Diagnostic Monitors | Avionics Display Systems |
|
Use Scenario: High-contrast backlight for 1920×1200 diagnostic imaging displays requiring 4000:1 dimming ratio and flicker-free operation at 500 Hz. IC Role / Device Role / Timing Role: Precision current regulator with 60 ns tr and 0.5 µs phase delay between channels - suppresses PWM-induced beat frequencies and image artifacts. Use Value: Enables DICOM GSDF compliance by eliminating temporal non-uniformity in grayscale rendering during clinical review sessions. |
Use Scenario: LED backlight for certified cockpit multifunction displays operating in −55°C to +85°C extended temperature environments. IC Role / Device Role / Timing Role: High-voltage (80 V) current sink supporting long LED strings (15× AlInGaP) while maintaining ±2.0% matching across thermal extremes. Use Value: Meets DO-160G Section 22 lightning-induced transient immunity by withstanding 42 V transients on VIN without latch-up or parameter shift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED current regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3432SQ/NOPB | Includes LED open-fault detection (LM3432B lacks this); identical pinout, same WQFN-24 package and DHC capability. | Required where open-circuit monitoring is mandated (e.g., safety-critical medical displays); adds fault coverage but no dimming or efficiency benefit. | Select LM3432SQ/NOPB if open-fault reporting is needed; otherwise LM3432BSQ/NOPB reduces MCU interrupt load and simplifies fault-handling firmware. |
| TPS61165DRVR | Single-channel 40 V, 30 mA LED driver with integrated boost; no multi-string current matching or DHC interface. | Suitable for low-cost single-string designs; cannot replace 6-channel regulation or synchronize with external boost controllers. | Use TPS61165DRVR only for cost-sensitive, low-channel-count applications; not a functional substitute for LM3432BSQ/NOPB's 6-string matched regulation. |
Compared with LM3432SQ/NOPB, LM3432BSQ/NOPB removes open-fault detection to simplify fault signaling and reduce MCU overhead, while retaining identical current matching, DHC, and thermal protection. Compared with TPS61165DRVR, LM3432BSQ/NOPB delivers true 6-channel synchronized regulation with system-level efficiency optimization - not achievable with discrete single-channel drivers.
Availability
LM3432BSQ/NOPB is available at Aetrix Electronics and suitable for automotive instrument clusters, industrial HMI displays, medical diagnostic monitors, and avionics display systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LM3432BSQ/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 analog ICs.
The LM3432BSQ/NOPB belongs to TI's LED backlight driver product line, designed specifically for high-efficiency, multi-string LCD backlighting in automotive, industrial, and medical displays where precision current matching and thermal robustness are critical.
FAQ
What is the maximum LED string voltage supported by the LM3432BSQ/NOPB?
The LM3432BSQ/NOPB supports up to 80 V across each IOUT pin relative to PGND, enabling configurations with up to 12 white LEDs (3.3 V each) or 15 AlInGaP LEDs (2.7 V each) per string. This rating is absolute maximum; recommended operating voltage is ≤80 V to ensure long-term reliability under thermal stress.
Does the LM3432BSQ/NOPB support analog dimming, and how is it configured?
Yes, the LM3432BSQ/NOPB supports analog dimming via the DIM pin when MODE is connected to ground through a capacitor (CMODE). A 1–3 V DC voltage applied to DIM generates internal PWM with frequency determined by CMODE value (e.g., 5.6 nF yields ~3 kHz). The LM3432BSQ/NOPB does not require external PWM generation hardware.
How does Dynamic Headroom Control (DHC) improve system efficiency in LM3432BSQ/NOPB designs?
DHC in the LM3432BSQ/NOPB reduces the LED supply rail voltage to the minimum needed for regulation - e.g., 0.625 V headroom at 20 mA - by feeding VDHC to an external LM3430 boost controller. This cuts boost converter conduction and switching losses, improving total system efficiency by up to 15% compared to fixed-rail operation.
What fault conditions does the LM3432BSQ/NOPB detect, and how are they signaled?
The LM3432BSQ/NOPB detects LED short circuits (triggered at 7.9 V on any IOUT pin for >150 µs) and over-temperature events (OTMb active low at 125 °C). Both faults assert open-drain FAULTb or OTMb pins low. Unlike the LM3432, the LM3432BSQ/NOPB does not detect or report open-circuit LED faults.
Can multiple LM3432BSQ/NOPB IOUT channels be paralleled to increase per-string current?
Yes, LM3432BSQ/NOPB IOUT channels can be paralleled (e.g., IOUT1+IOUT2) to achieve higher per-string current - up to 80 mA with two channels. However, current matching degrades slightly (±2.5% typical), and thermal derating must be applied due to increased power dissipation in shared PCB copper area.
LM3432BSQ/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 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)
LM3432BSQ/NOPB FAQ
1.How can I place an order for LM3432BSQ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3432BSQ/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 LM3432BSQ/NOPB reliable?
The price and inventory of LM3432BSQ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3432BSQ/NOPB is usually 5 days.
3.What payment methods are accepted for LM3432BSQ/NOPB?
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LM3432BSQ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3432BSQ/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 LM3432BSQ/NOPB?
For technical support, including LM3432BSQ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3432BSQ/NOPB requirements.
6.How does Aetrix verify that LM3432BSQ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3432BSQ/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 LM3432BSQ/NOPB meets industry standards.
7.What is the process for return or replacement of LM3432BSQ/NOPB?
All LM3432BSQ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3432BSQ/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 LM3432BSQ/NOPB part is unused and in its original packaging.
Return procedure for LM3432BSQ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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