Texas Instruments LP8550TLX-A/NOPB

Overview

LP8550TLX-A/NOPB from Texas Instruments is a high-efficiency, six-channel white-LED backlight driver IC with integrated 40-V boost converter, I²C/PWM dual brightness control, and adaptive output voltage regulation. It delivers up to 210 mA per channel with ±4% current accuracy, supports 156–1250 kHz switching frequencies, and targets notebook LCD backlight systems requiring precise luminance control and thermal safety.

For engineers reviewing the LP8550TLX-A/NOPB datasheet, LP8550TLX-A/NOPB pinout, LP8550TLX-A/NOPB application, or LP8550TLX-A/NOPB equivalent, key selection considerations include its phase-shift PWM architecture for ripple/noise reduction, VSYNC-synchronized dimming capability, EEPROM-programmable thermal de-rating thresholds, and DSBGA-25 (2.49 × 2.49 mm) package compatibility with space-constrained display power designs.

Technical Context

The LP8550TLX-A/NOPB integrates a high-voltage DC/DC boost converter with adaptive feedback (FB pin) that dynamically adjusts output voltage to match LED string forward voltage-minimizing power loss. Its six current-sink outputs (OUT1–OUT6) support independent 8-bit current programming and up to 13-bit PWM resolution via dithering.

A dedicated PLL synchronizes LED PWM output to external VSYNC signals (58–55 kHz), while internal EEPROM stores configuration for PWM frequency, phase-shift mode, current setpoints, temperature trip points, and fade slope timing-enabling full system calibration without runtime host intervention.

Key Specifications

Pinout & Package

LP8550TLX-A/NOPB uses a 25-pin DSBGA (YZR) package measuring 2.49 × 2.49 mm with 0.4-mm pitch. The package features dedicated ground domains (GND_SW, GND_S, GND_L) for noise isolation between boost, logic, and LED return paths.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LED backlight driver applications.

Compared with TPS61165DRVR and LM3409QMY/NOPB, the LP8550TLX-A/NOPB uniquely combines six-channel integration, VSYNC synchronization, EEPROM-configurable thermal response, and phase-shift PWM in a 2.49 × 2.49 mm DSBGA-making it optimal for space-constrained, high-fidelity display backlight systems requiring robustness and precision.

Availability

LP8550TLX-A/NOPB is available at Aetrix Electronics and suitable for notebook backlight systems, industrial HMIs, medical imaging monitors, and automotive infotainment displays requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for LP8550TLX-A/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 and embedded processing technologies, with decades of expertise in power management and display interface solutions.

The LP8550TLX-A/NOPB belongs to TI's high-efficiency LED backlight driver product line, designed specifically for medium-format LCD displays where thermal management, optical fidelity, and PCB area minimization are critical engineering constraints.

FAQ

What is the maximum LED string voltage supported by the LP8550TLX-A/NOPB?

The LP8550TLX-A/NOPB boost converter supports up to 40 V output, enabling drive of white LED strings with combined forward voltage up to ~35 V (e.g., 10× 3.2 V LEDs). Absolute maximum rating is 44 V on OUTx pins, but recommended operating limit is 40 V to ensure reliability and thermal margin. This makes LP8550TLX-A/NOPB suitable for 13–15 inch notebook panels with multi-string topologies.

How does the LP8550TLX-A/NOPB achieve VSYNC synchronization without external clock sources?

The LP8550TLX-A/NOPB uses an internal PLL that locks to the incoming VSYNC signal (58–55 kHz) on pin D2. Its 13-bit counter (PLL[12:0]) dynamically adjusts multiplication ratio to generate precise PWM output frequencies aligned to display refresh rate. The FILTER pin capacitor sets loop bandwidth, allowing stable lock even with intermittent VSYNC pulses. This hardware-based sync is implemented entirely within LP8550TLX-A/NOPB-no external clock generator or MCU intervention is needed.

Can the LP8550TLX-A/NOPB operate without an external microcontroller?

Yes. The LP8550TLX-A/NOPB supports fully autonomous operation using its internal EEPROM and analog control inputs. Brightness can be set via the PWM pin (A4), current via RISET (B3), and PWM frequency via RFSET (B4). All safety functions-including thermal de-rating, LED fault detection, and UVLO-operate independently. The LP8550TLX-A/NOPB only requires an MCU for advanced configuration updates or real-time fault logging via I²C.

What is the role of the three separate ground pins (GND_SW, GND_S, GND_L) on the LP8550TLX-A/NOPB?

GND_SW (A1/A2/B1/B2) carries high-frequency boost switch return current; GND_S (B5) serves digital/analog logic including I²C and PWM detector; GND_L (E4) is the dedicated return path for all six LED sink currents. Separating these grounds prevents coupling of switching noise into sensitive analog references and digital interfaces-critical for achieving <0.5% current matching and clean I²C communication. Layout best practice requires individual ground traces converging at a single point near the IC.

Does the LP8550TLX-A/NOPB support both analog and PWM dimming simultaneously?

No-the LP8550TLX-A/NOPB implements automatic hybrid dimming, not simultaneous analog+PWM. At high brightness levels (>50%), it uses current dimming (adjusting ISET-derived sink current) for efficiency; at lower levels, it switches to PWM dimming for precision. This transition is seamless and configurable via EEPROM registers (MODE_25/50%_SEL). The LP8550TLX-A/NOPB does not support concurrent analog current scaling and PWM duty cycle modulation on the same channel.