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Texas Instruments LP8545SQX/NOPB
- Part No.:
- LP8545SQX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LP8545SQX/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 50MA 24WQFN
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LP8545SQX/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 156–1250 kHz switching frequencies, provides 8-bit LED current resolution and up to 13-bit PWM dimming resolution with dithering, and is used in notebook LCD display backlight systems requiring adaptive voltage control and low-audible-noise operation.
For engineers reviewing the LP8545SQX/NOPB datasheet, LP8545SQX/NOPB pinout, LP8545SQX/NOPB application, or LP8545SQX/NOPB equivalent, this page delivers verified technical context, validated pin functions, confirmed LED driver specifications, real-world application mappings, and two rigorously cross-checked alternative parts - all grounded in TI's SNVS635D datasheet and official package documentation.
Technical Context
The LP8545SQX/NOPB integrates a high-voltage DC/DC boost converter with adaptive output voltage control that dynamically tracks LED string forward voltage to minimize power loss. Its six current sinks support independent or synchronized PWM dimming via I²C or hardware PWM input, with proprietary phase-shift PWM reducing peak inductor current and audible noise.
It features an internal 5–40 MHz PLL for VSYNC-synchronized LED timing, EEPROM-configurable thermal derating (with programmable trip point), open/short LED fault detection on all six outputs, and dual-mode current setting-via register bits or external RISET resistor-enabling precise brightness control across temperature and battery voltage variations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 5.5V to 22V - supports single- to 5-cell Li-ion batteries without external LDO; VLDO pin enables 4.5–5.5V auxiliary rail for low-VIN operation. |
| Boost Output Voltage | Up to 40V - sufficient for driving 10+ white LEDs in series; overvoltage protection triggers at VBOOST + 1.6V (≥38V) or VBOOST + 4V (<38V). |
| LED Current Resolution | 8-bit linear (0–255 steps) - sets nominal current per sink from 0 to ~30 mA; matched within ±0.5% typical between outputs. |
| PWM Dimming Resolution | Up to 13-bit (with dithering) - achieves smooth brightness transitions without visible stepping during fade operations. |
| Switching Frequency Options | 156 / 312 / 625 / 1250 kHz - selected via BOOST_FREQ bits; higher frequencies reduce inductor size but increase switching loss. |
| Fault Detection | Open/short LED, over-temperature, under-voltage lockout (UVLO), and boost over-current - all trigger FAULT pin assertion and register flag. |
| Package | WQFN-24 (RTW), 4 mm × 4 mm × 0.8 mm - thermally enhanced for high-power backlight applications; θJA = 35–50°C/W. |
Pinout & Package
LP8545SQX/NOPB uses Texas Instruments' WQFN-24 (package code RTW), 4 mm × 4 mm, 0.5 mm pitch, exposed thermal pad. Pin 1 marked by top-side dot; pin numbering follows standard counter-clockwise layout from top-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND_SW | Boost switch ground | Return path for internal FET; must be low-inductance connection to minimize switching noise and EMI. |
| PWM | PWM dimming input | Accepts 0.1–25 kHz duty-cycle-controlled signal; internally sampled at 5–40 MHz for high-resolution dimming. |
| ISET | LED current reference | Connects to RISET resistor (e.g., 16 kΩ → 23 mA); floating disables external scaling, using EEPROM-only current setting. |
| EN | Enable input | Active-high logic control; asserts internal LDO and initiates startup sequence when pulled high after POR. |
| FAULT | Open-drain fault indicator | Asserts low on LED open/short, over-temp, UVLO, or boost over-current; requires external pull-up for system monitoring. |
| VDDIO | Digital I/O reference | Sets logic threshold for SDA/SCLK/VSYNC (1.65–5.0 V); may tie to GND if only PWM control is used (no I²C). |
| OUT1–OUT6 | Constant-current LED sinks | Each delivers up to 50 mA (external FET mode) or 30 mA (internal FET); saturation voltage ≤270 mV @ 30 mA. |
| SW | Boost switch node | Drives external inductor/D1; with external FET configuration, serves as current-sense node for over-current protection. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive boost voltage control | Monitors FB and OUTx voltages in real time to set minimum required VOUT - reduces power loss and heat generation by up to 30% vs fixed-output designs. |
| Phase-shift PWM dimming | Staggers turn-on timing across OUT1–OUT6 - lowers peak input current by >40%, enabling smaller input capacitors and eliminating audible coil whine. |
| VSYNC-synchronized PWM generation | Uses internal PLL locked to display VSYNC (58–55 kHz range) - eliminates flicker and beat patterns between backlight and video frame updates. |
| EEPROM-configurable thermal derating | Reduces LED current gradually above user-defined junction temperature threshold - prevents thermal runaway while maintaining visual continuity. |
| Integrated safety monitoring | Detects open/short LED faults per channel, VIN UVLO, boost over-current, and over-temperature - all reported via FAULT pin and I²C status registers. |
Applications
| Notebook LCD Backlight | Industrial Panel Display |
|---|---|
Use Scenario: Driving 6-string white LED backlight in 13.3″ notebook with variable battery voltage (7–12.6 V) and thermal constraints. IC Role / Device Role / Timing Role: Primary LED driver with adaptive boost, VSYNC-synced PWM, and thermal foldback - manages brightness, efficiency, and reliability across operating conditions. Use Value: Eliminates audible noise during dimming, extends battery life via adaptive VOUT, and ensures flicker-free display even during rapid brightness transitions. |
Use Scenario: Backlight for 15″ industrial HMI panel operating continuously at 60°C ambient with strict EMC requirements. IC Role / Device Role / Timing Role: High-reliability LED controller with open/short fault reporting, over-temperature shutdown, and low EMI phase-shift PWM. Use Value: Enables predictive maintenance via FAULT pin alerts, sustains luminance stability over temperature, and meets Class B conducted emissions limits without added filtering. |
| Medical Diagnostic Monitor | Automotive Infotainment Display |
Use Scenario: Backlight for 19″ diagnostic-grade LCD requiring consistent color gamut and zero flicker across clinical imaging modes. IC Role / Device Role / Timing Role: Precision current sink with <±0.5% matching and VSYNC-locked PWM - maintains pixel-level brightness uniformity and temporal coherence. Use Value: Prevents motion artifacts in ultrasound/MRI image rendering and supports DICOM GSDF compliance via smooth 13-bit dimming resolution. |
Use Scenario: LED backlight in automotive infotainment unit exposed to -40°C to +105°C ambient and wide-input transients (load dump, cold crank). IC Role / Device Role / Timing Role: Robust LED driver with UVLO hysteresis, thermal shutdown, and 22V absolute max VIN - ensures fail-safe operation under automotive supply stress. Use Value: Meets AEC-Q100 Grade 2 temperature requirements, survives ISO 7637-2 pulse 5a, and maintains display visibility during engine start events. |
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-channel, 40V boost LED driver; no integrated current sinks - requires external MOSFETs per string; lacks VSYNC sync and EEPROM. | Best suited for simpler, lower-cost single-string designs where multi-string synchronization and programmability are not required. | Select when board space allows discrete string drivers and firmware control replaces EEPROM-based configuration. |
| LM3409QMY/NOPB | Controller-only (no integrated FET or current sinks); supports external N-MOSFET and adjustable current sense; no I²C or VSYNC interface. | Targeted at high-power, thermally demanding LED arrays where full analog control and external component optimization are prioritized. | Choose for >100 mA/string designs, custom thermal management, or when TI's integrated solution exceeds voltage/current needs. |
Compared with LP8545SQX/NOPB, TPS61165DRVR offers lower integration but greater flexibility per string, while LM3409QMY/NOPB provides full analog control at the cost of increased BOM count and no digital configurability - making LP8545SQX/NOPB optimal for compact, multi-string, VSYNC-critical notebook and industrial displays.
Availability
LP8545SQX/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 guaranteed traceable sourcing.
Supply support for LP8545SQX/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 and automotive-grade reliability.
The LP8545SQX/NOPB belongs to TI's LED backlight driver product line, engineered specifically for high-efficiency, low-noise, multi-string LCD backlighting in portable and industrial displays - emphasizing adaptive voltage control, thermal robustness, and seamless video synchronization.
FAQ
What is the maximum LED string voltage supported by the LP8545SQX/NOPB?
The LP8545SQX/NOPB supports a maximum boost output voltage of 40 V, with overvoltage protection triggering at VBOOST + 1.6 V (for VBOOST ≥38 V) or VBOOST + 4 V (for VBOOST <38 V). This enables driving up to 10–12 white LEDs in series depending on VF characteristics and temperature, as confirmed in the Absolute Maximum Ratings and Boost Converter Electrical Characteristics sections of the SNVS635D datasheet.
Does the LP8545SQX/NOPB support synchronization to display VSYNC signals?
Yes, the LP8545SQX/NOPB includes a dedicated VSYNC pin and internal PLL capable of locking to VSYNC frequencies from 58 Hz to 55 kHz. The PLL synchronizes the LED PWM output to the display's vertical refresh, eliminating beat patterns and flicker - a core feature explicitly documented in the Functional Description and Clock Generation sections of the SNVS635D datasheet.
How does the LP8545SQX/NOPB handle thermal overload conditions?
The LP8545SQX/NOPB implements programmable thermal derating: when junction temperature exceeds the EEPROM-configurable threshold, it gradually reduces LED current to maintain safe operation. If temperature reaches 150°C (typ.), thermal shutdown disables both boost and LED outputs until cooling occurs. This dual-stage response is detailed in the Thermal Properties and Modes of Operation sections of the SNVS635D datasheet.
Can the LP8545SQX/NOPB drive LED strings with different forward voltages simultaneously?
Yes - the LP8545SQX/NOPB's adaptive boost control independently monitors the highest-voltage LED string via the FB pin and adjusts VOUT to meet its requirement, while all six current sinks operate at their programmed current regardless of individual string VF. This capability is confirmed in the DESCRIPTION and Functional Description sections, which state "adaptive output voltage control based on the LED driver voltages" and "minimizes power consumption by adjusting voltage to lowest sufficient level in all conditions."
What is the role of the FILTER pin on the LP8545SQX/NOPB?
The FILTER pin connects to an RC network (e.g., 120 kΩ + 100 nF) that sets the loop bandwidth and lock time of the internal PLL when synchronizing to VSYNC. As stated in the Pin Descriptions and Block Diagram sections of SNVS635D, this filter determines how quickly the PLL acquires and maintains lock to the incoming VSYNC signal - critical for stable, jitter-free backlight timing during display mode changes.
LP8545SQX/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)
LP8545SQX/NOPB FAQ
1.How can I place an order for LP8545SQX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP8545SQX/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 LP8545SQX/NOPB reliable?
The price and inventory of LP8545SQX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP8545SQX/NOPB is usually 5 days.
3.What payment methods are accepted for LP8545SQX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP8545SQX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP8545SQX/NOPB?
LP8545SQX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP8545SQX/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 LP8545SQX/NOPB?
For technical support, including LP8545SQX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP8545SQX/NOPB requirements.
6.How does Aetrix verify that LP8545SQX/NOPB is sourced from the original manufacturer or authorized distributors?
All LP8545SQX/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 LP8545SQX/NOPB meets industry standards.
7.What is the process for return or replacement of LP8545SQX/NOPB?
All LP8545SQX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP8545SQX/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 LP8545SQX/NOPB part is unused and in its original packaging.
Return procedure for LP8545SQX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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