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Texas Instruments LP8543SQ/NOPB
- Part No.:
- LP8543SQ/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LP8543SQ/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 60MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,193
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Product details
Overview
LP8543SQ/NOPB from Texas Instruments is a 7-channel SMBus/I²C-controlled white LED driver with integrated 38 V boost converter, adaptive output voltage control, and digital ambient light sensor interface. It delivers up to 60 mA per channel across 7 current sinks (OUT1–OUT7), supports 5.5–22 V input, and enables phase-shift PWM dimming for efficiency optimization in medium-sized LCD backlight systems.
For engineers reviewing the LP8543SQ/NOPB datasheet, LP8543SQ/NOPB pinout, LP8543SQ/NOPB application, or LP8543SQ/NOPB equivalent, key selection considerations include its 24-pin WQFN package, programmable EEPROM calibration for brightness/ALS response, thermal regulation with user-defined temperature threshold, LED open/short fault detection on all 7 outputs, and dual-mode PWM control (internal register-based or external duty-cycle-driven).
Technical Context
The LP8543SQ/NOPB integrates a high-efficiency inductive boost converter with adaptive output voltage control-dynamically adjusting VBOOST to the minimum required level based on real-time LED string forward voltage monitoring. This reduces power loss, especially under mismatched VF conditions across strings.
It implements Phase-Shift PWM (PSPWM) dimming: selectively turning off individual LED strings to lower average boost demand and battery peak current. PSPWM operates across 7 independently controllable current sinks, with programmable grouping (Display1: OUT1–OUT6; Display2: OUT7) and separate 8-bit current/PWM registers for each group.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5.5 V to 22 V - supports 2×, 3×, or 4× Li-ion battery stacks without external regulation. |
| Boost Output Voltage | Up to 38 V - sufficient for driving up to 10 LEDs in series per string at typical VF (3.0–3.8 V). |
| LED Current Range | 0–60 mA per channel (8-bit resolution, 0.23 mA step) - enables precise binning compensation and panel-to-panel brightness matching. |
| Current Matching (OUT1–OUT6) | ±0.5% to ±1.35% - ensures uniform luminance across main display backlight strings. |
| PWM Dimming Frequency | 229 Hz to 19.5 kHz - selectable via register; avoids audible noise while supporting high-speed camera synchronization. |
| Ambient Light Interface | Digital light-to-frequency sensor input (ALSI) with programmable prescaler and compensation curve - eliminates external ADC and reduces BOM count. |
| Thermal Regulation | User-programmable temperature threshold with automatic PWM reduction - protects LEDs and IC at junction temperatures >125°C. |
Pinout & Package
LP8543SQ/NOPB is housed in a 4.0 mm × 4.0 mm × 0.8 mm WQFN-24 package with 0.5 mm pitch and wettable flanks. The package supports high thermal dissipation (θJA = 35–50°C/W) and automated optical inspection (AOI).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND_SW (Pin 1) | Boost converter ground reference | Separate low-noise return path for high-current switch node; must be connected to power ground plane with minimal inductance. |
| PWM (Pin 2) | External PWM dimming input | Accepts 0.1–25 kHz duty-cycle signal; enables stand-alone operation without MCU or serial bus. |
| IF_SEL (Pin 3) | Interface mode select | Low = I²C-compatible; High = SMBus v2.0 compliant - determines timing, ACK behavior, and timeout handling. |
| EN (Pin 4) | Enable control input | Active-high logic input; asserts internal LDO and boost enable; supports system-level power sequencing. |
| ALSI (Pin 5) | Ambient light sensor frequency input | Accepts TTL/CMOS-compatible pulse train from light-to-frequency ALS; no external conditioning required. |
| ALSO (Pin 6) | Ambient light sensor enable output | Open-drain active-high output; powers external ALS only during measurement cycles to minimize quiescent current. |
| FAULT (Pin 7) | Fault status indicator | Open-drain active-low output signaling LED open/short, boost overcurrent, or thermal shutdown - directly drives MCU interrupt or LED indicator. |
| VDDIO (Pin 8) | Digital I/O supply reference | 1.65–5.5 V input powering SDA/SCLK/ADR/IF_SEL logic; decoupled internally to reduce noise coupling into analog blocks. |
| GND_S (Pin 9) | Signal ground | Reference for analog inputs (FB, ALSI) and digital I/O; isolated from GND_SW and GND_L to prevent switching noise injection. |
| SCLK (Pin 10) | Serial clock input | I²C/SMBus clock line; supports 100 kHz (SMBus) or 400 kHz (I²C Fast Mode); requires external pull-up. |
| SDA (Pin 11) | Serial data I/O | Bidirectional open-drain bus line; supports read/write of 128-byte register map and EEPROM configuration space. |
| OUT1–OUT7 (Pins 12–14, 16–19) | Constant-current LED sink outputs | Seven independent 60 mA capable current sinks; OUT1–OUT6 assigned to Display1, OUT7 configurable for Display2 or sub-display lighting. |
| GND_L (Pin 15) | LED current sink ground | Dedicated return path for all OUTx currents; routed separately to minimize IR drop and improve current accuracy. |
| ADR (Pin 20) | I²C/SMBus address select | Configures slave address (0x2C or 0x2D) by tying to VDDIO or GND; enables multi-device bus topology. |
| FB (Pin 21) | Boost feedback input | Monitors output voltage for adaptive regulation; connects to resistive divider from VBOOST to set target voltage. |
| VLDO (Pin 22) | Internal 5 V LDO output | Supplies 5 V @ 5 mA for external ALS or other peripherals; requires 470 nF ceramic capacitor for stability. |
| VIN (Pin 23) | Main power input | 5.5–22 V DC input; powers boost converter, LDO, and internal logic; requires ≥10 µF low-ESR ceramic input capacitance. |
| SW (Pin 24) | Boost switch node | Connects to external inductor (L1) and Schottky diode (D1); handles peak currents up to 2.5 A; requires tight layout for EMI control. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive Boost Voltage Control | Reduces VBOOST to minimum required level based on real-time LED string voltage sensing - cuts power loss by up to 30% vs. fixed-output boost converters. |
| Phase-Shift PWM (PSPWM) | Sequentially disables LED strings to lower average boost load and battery peak current - improves efficiency by 15–25% under VF mismatch conditions. |
| On-Chip EEPROM Calibration | Stores factory-set current values, ALS compensation curves, temperature thresholds, and fault detection limits - eliminates post-assembly trimming and ensures unit-to-unit consistency. |
| 7-Channel Independent Control | Supports flexible grouping: OUT1–OUT6 for main display backlight, OUT7 for sub-display or keyboard lighting - enables single-IC solutions for dual-display systems. |
| Comprehensive Fault Detection | Reports open-circuit, short-circuit (≥2 LEDs), and thermal faults via FAULT pin and status register - increases manufacturing yield and field reliability. |
| Dual-Mode PWM Interface | Accepts either internal register-based PWM (229 Hz–19.5 kHz) or external duty-cycle input (100 Hz–25 kHz) - simplifies integration in MCU-constrained or MCU-less designs. |
Applications
| LCD Main Display Backlight | Sub-Display or Status Lighting |
|---|---|
|
Use Scenario: Driving 6–7 LED strings (up to 10 LEDs/chain) for 10–15 inch LCD panels in industrial HMIs, medical monitors, and automotive infotainment displays. IC Role / Device Role / Timing Role: Primary WLED driver with adaptive boost, PSPWM dimming, and ALS-based auto-brightness - manages power delivery, luminance uniformity, and ambient adaptation. Use Value: Achieves >85% system efficiency at full brightness and maintains <±1% luminance variation across temperature (-40°C to +85°C) using EEPROM-trimmed current matching. |
Use Scenario: Powering secondary display backlight (e.g., rear-view camera overlay), keyboard illumination, or status indicators in portable computing and IoT edge devices. IC Role / Device Role / Timing Role: Secondary LED controller with independent 8-bit current and PWM registers - enables synchronized or asynchronous dimming relative to main display. Use Value: Eliminates need for second LED driver IC; OUT7's dedicated control allows dynamic brightness scaling without affecting main display performance. |
| ALS-Enabled Adaptive Backlighting | Thermally Protected LED Lighting |
|
Use Scenario: Implementing ambient-adaptive brightness in kiosks, point-of-sale terminals, and outdoor tablets exposed to variable lighting conditions. IC Role / Device Role / Timing Role: Integrated ALS interface with programmable compensation curve - converts light-sensor frequency to calibrated backlight intensity without external microcontroller intervention. Use Value: Reduces system power consumption by up to 40% in low-light environments while preserving readability; EEPROM-stored curves support OEM-specific human-factor tuning. |
Use Scenario: Deploying high-brightness LED arrays in enclosed enclosures (e.g., industrial control panels, avionics displays) where thermal derating is critical. IC Role / Device Role / Timing Role: On-die thermal sensor with user-configurable dimming threshold - automatically reduces LED current above defined junction temperature to extend lifetime. Use Value: Prevents thermal runaway and LED lumen depreciation; programmable threshold (e.g., 90°C) allows trade-off between brightness retention and reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar WLED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61165DRVR | Single-channel 40 V boost WLED driver; no integrated ALS interface, no EEPROM, no PSPWM; 1.2 MHz fixed-frequency switching. | Limited to single-string applications; requires external ALS solution and MCU-based dimming control. | Choose when cost sensitivity outweighs multi-string flexibility and ambient adaptation requirements. |
| LM3409QMY/NOPB | External-FET LED controller with 65 V max input; no integrated boost FET, no ALS, no EEPROM; analog/digital dimming only. | Requires discrete MOSFET, gate driver, and external current sense; suited for high-power (>1 A) or custom topologies. | Prefer for designs needing >60 mA per string or >38 V output, where board space and thermal management allow discrete implementation. |
Compared with TPS61165DRVR and LM3409QMY/NOPB, the LP8543SQ/NOPB uniquely integrates 7-channel current sinks, adaptive boost, PSPWM, on-chip ALS interface, and EEPROM calibration - enabling compact, self-contained backlight solutions for medium-format displays without external support components.
Availability
LP8543SQ/NOPB is available at Aetrix Electronics and suitable for industrial HMIs, medical display modules, and automotive infotainment systems requiring stable component supply, long-term lifecycle support, and validated thermal performance across -40°C to +85°C ambient.
Supply support for LP8543SQ/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 decades of expertise in LED driver innovation and automotive-grade reliability.
The LP8543SQ/NOPB belongs to TI's high-efficiency backlight driver product line, designed specifically for medium-format LCD displays requiring adaptive dimming, ambient light responsiveness, and robust fault diagnostics in space-constrained applications.
FAQ
What is the maximum number of LEDs the LP8543SQ/NOPB can drive per string?
The LP8543SQ/NOPB supports up to 10 LEDs per string when operating at 38 V maximum boost output and typical forward voltages of 3.0–3.8 V. Its 7 current sinks (OUT1–OUT7) allow parallel string configurations - for example, six strings of 10 LEDs each for a 60-LED main display, plus one string for sub-display lighting. The actual count depends on total string VF and desired current, but the device's 38 V rail and 60 mA per channel capability define the practical upper limit.
Does the LP8543SQ/NOPB require external components for basic operation?
Yes - the LP8543SQ/NOPB requires an external inductor (L1), Schottky diode (D1), input capacitor (CIN ≥10 µF), output capacitor (COUT ≥4.7 µF), and VLDO decoupling capacitor (CVLDO = 470 nF). These are mandatory for boost converter stability, EMI control, and LDO regulation. No external current-sense resistors or ALS signal-conditioning circuitry are needed due to integrated current sinks and digital ALS interface.
How does the Phase-Shift PWM (PSPWM) feature improve efficiency in the LP8543SQ/NOPB?
PSPWM in the LP8543SQ/NOPB improves efficiency by dynamically disabling individual LED strings to lower the required boost output voltage. When strings with higher forward voltage are turned off, the boost regulator reduces VBOOST to match the remaining active strings - minimizing conduction losses. This also lowers peak battery current, reducing stress on input capacitors and PCB traces, particularly beneficial under VF mismatch conditions common in mass-produced LED panels.
Can the LP8543SQ/NOPB operate without a microcontroller?
Yes - the LP8543SQ/NOPB supports stand-alone operation using its PWM input pin (Pin 2). An external PWM signal (100 Hz–25 kHz) directly controls LED brightness, and the chip powers up automatically when PWM goes high. Internal EEPROM stores default current, ALS curve, and fault thresholds, enabling fully autonomous function in systems lacking serial bus infrastructure or firmware resources.
What fault conditions does the LP8543SQ/NOPB detect and report?
The LP8543SQ/NOPB detects and reports LED open-circuit faults (disconnected or broken string), LED short-circuit faults (≥2 LEDs shorted in a string), boost overcurrent events, thermal overload (>125°C junction), and low-input-voltage shutdown. Fault status is available both via the open-drain FAULT pin (active-low) and through dedicated bits in the STATUS register, enabling real-time diagnostics and system-level error recovery.
LP8543SQ/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Regulator
- Topology:
- Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 7
- Voltage - Supply (Min):
- 5.5V
- Voltage - Supply (Max):
- 22V
- Voltage - Output:
- 40V
- Current - Output / Channel:
- 60mA
- Frequency:
- 625kHz ~ 1.25MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-WQFN (4x4)
LP8543SQ/NOPB FAQ
1.How can I place an order for LP8543SQ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP8543SQ/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 LP8543SQ/NOPB reliable?
The price and inventory of LP8543SQ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP8543SQ/NOPB is usually 5 days.
3.What payment methods are accepted for LP8543SQ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP8543SQ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP8543SQ/NOPB?
LP8543SQ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP8543SQ/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 LP8543SQ/NOPB?
For technical support, including LP8543SQ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP8543SQ/NOPB requirements.
6.How does Aetrix verify that LP8543SQ/NOPB is sourced from the original manufacturer or authorized distributors?
All LP8543SQ/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 LP8543SQ/NOPB meets industry standards.
7.What is the process for return or replacement of LP8543SQ/NOPB?
All LP8543SQ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP8543SQ/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 LP8543SQ/NOPB part is unused and in its original packaging.
Return procedure for LP8543SQ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LP8543SQ/NOPB Tags
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BCR402RE6327HTSA1
Infineon Technologies
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
Infineon Technologies
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BCR420UE6327HTSA1
Infineon Technologies
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BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
Diodes Incorporated
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
Diodes Incorporated
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