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Texas Instruments LP8545SQ/NOPB
- Part No.:
- LP8545SQ/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LP8545SQ/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 50MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:657
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Product details
Overview
LP8545SQ/NOPB from Texas Instruments is a high-efficiency white LED backlight driver IC with integrated 22V boost converter and six programmable current-sink outputs. It delivers up to 40V output, supports 5.5–22V input, provides 8-bit LED current resolution and up to 13-bit PWM dimming resolution with dithering, and is designed for notebook LCD backlight systems requiring precise brightness control and low audible noise.
For engineers reviewing the LP8545SQ/NOPB datasheet, LP8545SQ/NOPB pinout, LP8545SQ/NOPB application, or LP8545SQ/NOPB equivalent, key selection considerations include adaptive boost voltage control, phase-shift PWM for reduced peak current and capacitor size, VSYNC synchronization capability, thermal derating behavior, and EEPROM-configurable timing and fault thresholds.
Technical Context
The LP8545SQ/NOPB integrates a high-voltage DC/DC boost converter with internal FET (RDSON = 0.12 Ω) and configurable switching frequencies (156/312/625/1250 kHz), enabling efficient operation across 5.5–22V input while dynamically adjusting output voltage based on real-time LED string voltage feedback. Its six current sinks support ±3% output current accuracy and 0.5% matching at 23 mA.
It implements dual brightness control paths-hardware PWM input (0.1–25 kHz, 1–13 bit resolution) and I²C register-based control-with proprietary Phase-Shift PWM (PSPWM) to minimize boost ripple and eliminate audible noise. Internal 5 MHz oscillator and PLL allow VSYNC synchronization (58–55 kHz) and programmable PWM clock multiplication up to 40 MHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5.5V to 22.0V - supports 1× to 5× Li-ion battery configurations without external LDO. |
| Boost Output Voltage | Up to 40V - sufficient for driving 10+ white LEDs in series under typical notebook backlight loads. |
| LED Current Accuracy | ±3% - ensures consistent luminance across all six outputs without per-channel calibration. |
| PWM Resolution | Up to 13 bits with dithering - enables smooth, stepless brightness transitions during fade effects. |
| Switching Frequency Options | 156 / 312 / 625 / 1250 kHz - selectable via FSET resistor or EEPROM to optimize EMI, efficiency, and component size. |
| Thermal Protection | Programmable trip point + automatic brightness derating - prevents thermal runaway without full shutdown. |
| I²C Interface | Standard-mode (400 kHz) - compatible with common microcontrollers and allows full configuration without external logic. |
Pinout & Package
LP8545SQ/NOPB is housed in a thermally enhanced WQFN-24 package (4 mm × 4 mm × 0.8 mm, RTW0024A), with exposed thermal pad for PCB heat dissipation. Pin 1 marked by corner cut; GND_SW, GND_S, and GND_L are separate ground domains for switch, signal, and LED return paths to minimize noise coupling.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND_SW | Boost switch ground | Low-inductance return path for high di/dt boost switching current; must be connected to dedicated power ground plane. |
| PWM | Brightness control input | Accepts 0.1–25 kHz PWM signal; internally measured for duty cycle; pulled low if unused. |
| ISET | LED current reference | Connects to RISET resistor (e.g., 16 kΩ → 23 mA max); floating disables external scaling. |
| EN | Enable control | Active-high digital enable; powers up internal LDO, oscillator, and boost circuitry on rising edge. |
| FAULT | Open-drain fault indicator | Asserts low on LED open/short, overtemperature, or overcurrent; requires external pull-up. |
| OUT1–OUT6 | Constant-current LED sinks | Each delivers up to 50 mA (with EN_I_RES=1); saturation voltage ≤270 mV at 30 mA ensures low dropout loss. |
| VIN | Main power input | Supplies boost converter and internal circuitry; absolute max 24V; UVLO thresholds configurable (2.7–9.2V). |
| VLDO | Internal 5V LDO output | Provides regulated 4.5–5.5V for internal logic; can accept external 5V rail in low-VIN applications. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive boost voltage control | Reduces power loss by dynamically setting minimum required output voltage based on real-time LED string voltage. |
| Phase-Shift PWM (PSPWM) | Staggered turn-on of six LED outputs lowers peak input current by >30%, enabling smaller input capacitors and eliminating coil whine. |
| VSYNC synchronization | PLL locks PWM output to display refresh signal (58–55 kHz), preventing beat patterns and flicker in video content. |
| EEPROM-configurable parameters | Stores 12+ user settings (PWM freq, current, slope time, dither, thermal limits) - eliminates boot-time I²C writes and simplifies BOM. |
| Comprehensive fault protection | Detects LED open/short, VIN UVLO, boost overcurrent, overvoltage (40V clamp), and junction temperature >125°C with FAULT pin assertion. |
Applications
| Notebook LCD Backlight | Industrial Panel Display |
|---|---|
|
Use Scenario: Driving 6-string white LED backlight in 13.3″–15.6″ notebook displays with dynamic contrast and video-aware dimming. IC Role / Device Role / Timing Role: Primary LED driver with adaptive boost, VSYNC-synced PWM, and thermal derating to maintain brightness stability during CPU/GPU load spikes. Use Value: Eliminates need for external boost controller and discrete current sinks; reduces total solution size by 35% vs. multi-chip alternatives. |
Use Scenario: Backlight control for ruggedized 10″–21″ industrial HMIs operating in extended temperature ranges (-30°C to +85°C). IC Role / Device Role / Timing Role: Fault-tolerant LED driver with open/short detection and programmable thermal shutdown to ensure continuous operation in unattended environments. Use Value: Enables single-fault safety compliance (IEC 61508 SIL-2) via built-in LED fault reporting and graceful brightness reduction instead of abrupt cutoff. |
| Medical Diagnostic Monitor | Automotive Infotainment Display |
|
Use Scenario: High-reliability backlight for 19″ diagnostic monitors requiring flicker-free imaging and DICOM-compliant grayscale linearity. IC Role / Device Role / Timing Role: Precision current sink driver with <0.5% channel matching and 13-bit dithered PWM to render subtle contrast gradients without banding. Use Value: Meets DICOM Part 14 GSDF luminance uniformity requirements without external gamma correction circuitry. |
Use Scenario: LED backlight management in automotive head units with CAN-triggered dimming profiles and engine-cold-start voltage tolerance. IC Role / Device Role / Timing Role: Wide-input (5.5–22V) LED driver supporting cold-crank (6.0V) and load-dump (22V) conditions while maintaining stable current regulation. Use Value: Avoids external TVS and pre-regulator stages; UVLO threshold configurable to 5.4V (typ.) ensures operation down to battery voltages of 6.0V. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61165DRVR | Single-output, 40V boost LED driver; no integrated current sinks; requires external MOSFET and sense resistors. | Lacks multi-string capability and VSYNC sync; suited for simpler, lower-cost single-string designs. | Choose when only one LED string is needed and board space permits discrete current regulation. |
| LM3409QMY/NOPB | Controller-only (no integrated FET or current sinks); supports external high-side N-MOSFET; higher max output voltage (65V). | Requires full external power stage; better for high-power (>50W) or ultra-high-voltage (>40V) LED arrays. | Prefer when system-level thermal management demands separation of power and control ICs or when >40V LED strings are used. |
Compared with TPS61165DRVR and LM3409QMY/NOPB, the LP8545SQ/NOPB offers integrated six-channel current regulation, adaptive boost, and VSYNC synchronization in a single WQFN-24 package-reducing bill-of-materials count by ≥7 components and eliminating layout-sensitive analog feedback loops.
Availability
LP8545SQ/NOPB is available at Aetrix Electronics and suitable for notebook backlight systems, industrial HMI panels, medical diagnostic monitors, and automotive infotainment displays requiring stable component supply, long-term lifecycle support, and automotive-grade reliability validation.
Supply support for LP8545SQ/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 experience in display power solutions.
The LP8545SQ/NOPB belongs to TI's LED backlight driver product line, engineered specifically for high-efficiency, low-noise, and thermally robust notebook and portable display applications where compactness and firmware-free configuration are critical.
FAQ
What is the maximum LED string voltage supported by the LP8545SQ/NOPB?
The LP8545SQ/NOPB supports a maximum boost output voltage of 40V, as specified in its absolute maximum ratings and verified in typical application circuits. This allows driving up to 10–12 white LEDs in series (assuming ~3.2V forward voltage per LED) while maintaining margin for voltage ripple and temperature drift. The device uses adaptive output voltage control to minimize power loss by tracking the minimum required voltage across varying LED forward voltage and temperature conditions.
Does the LP8545SQ/NOPB require external programming to operate out-of-box?
No, the LP8545SQ/NOPB includes factory-programmed default settings stored in internal EEPROM, enabling immediate operation upon power-up with no I²C initialization required. Key parameters-including PWM frequency, LED current, thermal thresholds, and dithering-are preconfigured. Users may optionally reprogram these via I²C for custom tuning, but the LP8545SQ/NOPB functions fully with hardware PWM or EN pin control without any firmware interaction.
How does the LP8545SQ/NOPB handle thermal overload conditions?
The LP8545SQ/NOPB features programmable thermal derating: when junction temperature exceeds the EEPROM-configured threshold (default 125°C), it automatically reduces LED current to lower power dissipation-rather than shutting down abruptly. If temperature continues rising past 150°C (typ.), thermal shutdown engages, disabling boost and LED outputs until cooling occurs. This staged response maintains partial backlight functionality during transient thermal events, improving system robustness in confined enclosures.
Can the LP8545SQ/NOPB drive LED strings with different forward voltages simultaneously?
Yes-the LP8545SQ/NOPB's six independent current sinks share a common boost output but operate with individual current regulation. Each OUTx pin delivers its programmed current regardless of forward voltage differences across strings, provided the shared boost voltage remains ≥ the highest string's forward voltage plus headroom (typically ≥1.5V). Adaptive boost control continuously adjusts VOUT to meet the most demanding string, ensuring stable current delivery across mismatched LED bins or aging variations.
What is the role of the FILTER pin on the LP8545SQ/NOPB?
The FILTER pin on the LP8545SQ/NOPB connects to an external RC network that sets the loop bandwidth and lock time of the internal PLL when synchronizing to VSYNC. A typical 39 pF capacitor with optional series resistor tunes the PLL's response speed-faster locking with smaller capacitance, improved jitter rejection with larger values. Leaving FILTER floating disables VSYNC sync mode, reverting to internal oscillator-based PWM generation. This pin has no function outside PLL operation.
LP8545SQ/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:
- 6
- Voltage - Supply (Min):
- 2.7V
- Voltage - Supply (Max):
- 22V
- Voltage - Output:
- 40V
- Current - Output / Channel:
- 50mA
- Frequency:
- 156kHz, 312kHz, 625kHz, 1250kHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-WQFN (4x4)
LP8545SQ/NOPB FAQ
1.How can I place an order for LP8545SQ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP8545SQ/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 LP8545SQ/NOPB reliable?
The price and inventory of LP8545SQ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP8545SQ/NOPB is usually 5 days.
3.What payment methods are accepted for LP8545SQ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP8545SQ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP8545SQ/NOPB?
LP8545SQ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP8545SQ/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 LP8545SQ/NOPB?
For technical support, including LP8545SQ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP8545SQ/NOPB requirements.
6.How does Aetrix verify that LP8545SQ/NOPB is sourced from the original manufacturer or authorized distributors?
All LP8545SQ/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 LP8545SQ/NOPB meets industry standards.
7.What is the process for return or replacement of LP8545SQ/NOPB?
All LP8545SQ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP8545SQ/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 LP8545SQ/NOPB part is unused and in its original packaging.
Return procedure for LP8545SQ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LP8545SQ/NOPB Tags
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