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Texas Instruments LP8557IAYFQT
- Part No.:
- LP8557IAYFQT
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 16-WFBGA, DSBGA
- Datasheet:
-
LP8557IAYFQT.pdf
- Description:
- IC LED DRV RGLTR PWM 16DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:500
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Product details
Overview
LP8557IAYFQT from Texas Instruments is a high-efficiency LED backlight driver IC featuring an integrated 28-V DC-DC boost converter and six 25-mA precision current sinks, designed for tablet LCD display backlighting with adaptive headroom control, hybrid PWM+current dimming, and I²C programmability. It operates from 2.7 V to 5.5 V input and supports 1–6 LED strings.
For engineers reviewing the LP8557IAYFQT datasheet, LP8557IAYFQT pinout, LP8557IAYFQT application, or LP8557IAYFQT equivalent, key selection criteria include its I²C-enabled brightness control, adaptive boost voltage regulation, 6-channel current matching (±0.5%), smart phase-shift PWM mode, and DSBGA-16 package compatibility with space-constrained portable designs.
Technical Context
The LP8557IAYFQT implements a current-mode controlled inductive boost converter with adaptive output voltage regulation-monitoring all six LED string voltages via FB to dynamically adjust VOUT between 7 V and 28 V, minimizing power loss. Its dual-function pins (FSET/SDA, ISET/SCL) support either resistor-based configuration or full I²C register access depending on BRTMODE setting.
Brightness control combines hardware PWM input and software-programmable registers, enabling hybrid dimming where low-duty cycles use current reduction and high-duty cycles use PWM switching-reducing audible noise and improving optical efficiency. Fault protection includes LED open/short detection, BST_OVP/OCP, UVLO, and thermal shutdown at 150°C with 20°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VDD Range | 2.7 V to 5.5 V - supports single-cell Li-ion battery operation without external LDO. |
| Boost Output Range | 7 V to 28 V - adaptive regulation ensures minimal headroom across 1–6 LED strings. |
| LED Sink Current | 25 mA per channel - precise current delivery enables uniform backlight luminance. |
| Current Matching | ±0.5% - tight channel-to-channel matching eliminates visible brightness gradients. |
| Switching Frequency | 500 kHz or 1000 kHz - selectable via resistor or I²C to optimize EMI and efficiency trade-offs. |
| I²C Interface | 400 kHz standard mode - enables dynamic brightness scaling, fault logging, and CABC implementation. |
| Thermal Shutdown | 150°C with 20°C hysteresis - protects against sustained overloads in sealed tablet enclosures. |
Pinout & Package
LP8557IAYFQT uses a 16-pin DSBGA (YFQ) package measuring 1.906 mm × 1.64 mm with 0.4-mm pitch, optimized for ultra-thin tablet PCBs. The package features bottom-side thermal pads and requires controlled-impedance routing for SW and FB traces.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB | Boost feedback input | Monitors combined LED string voltage to regulate adaptive VOUT; connects to boost output node via resistive divider. |
| FSET/SDA | I²C data / frequency set | Configures switching frequency when used as FSET; serves as I²C SDA when BRTMODE ≠ 00b. |
| ISET/SCL | I²C clock / current set | Sets full-scale LED current via resistor; functions as I²C SCL in I²C-enabled modes. |
| PWM | Digital brightness input | Accepts 75 Hz–25 kHz PWM signal; determines brightness level in BRTMODE = 00b or hybrid modes. |
| LED1–LED6 | Current sink outputs | Each drives one LED string with 25-mA max sink capability and <200 mV saturation voltage. |
| SW | Boost switch drain | Connects to external inductor and diode; carries peak currents up to 2.4 A during switching. |
| VDD | Power supply input | Supplies internal circuitry and gate drive; requires local 4.7-µF ceramic decoupling. |
| GND | Ground reference | Multiple GND pins (C2, A2, B2) provide low-inductance return paths for power and analog sections. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive Boost Voltage Control | Maintains minimum required VOUT by monitoring all six LED string voltages, reducing power loss by up to 15% vs fixed-output boosters. |
| Hybrid PWM + Current Dimming | Automatically blends PWM duty-cycle control and analog current scaling to maximize optical efficiency while suppressing audible coil whine. |
| Smart Phase-Shift PWM Mode | Staggers PWM timing across LED channels to lower RMS input current ripple and reduce EMI filter size by 30%. |
| LED String Auto-Detect | Identifies connected LED count (1–6 strings) at startup, eliminating manual configuration and enabling single-BOM flexibility across product variants. |
| Programmable Slew Rate & Spread Spectrum | Reduces EMI peaks by >10 dB through adjustable SW edge rate and frequency dithering-critical for FCC/CE compliance in tablets. |
Applications
| Tablet LCD Backlight | Ultrabook Display Driver |
|---|---|
Use Scenario: Driving 6-series LED strings in a 10.1-inch IPS LCD panel powered by a single 3.7-V Li-ion cell. IC Role / Device Role / Timing Role: Primary LED backlight controller providing regulated current, adaptive boost voltage, and I²C-configurable CABC profiles. Use Value: Achieves >88% LED drive efficiency at 100% brightness and maintains ±0.5% channel matching across temperature, ensuring uniform screen luminance. | Use Scenario: Backlight solution for a 13.3-inch high-resolution display requiring dynamic dimming based on ambient light and content metadata. IC Role / Device Role / Timing Role: I²C-managed backlight driver executing real-time brightness adjustments via host processor commands and PWM synchronization. Use Value: Enables seamless transition between sRGB and HDR modes using programmable gamma correction and hybrid dimming curves stored in internal EPROM. |
| Industrial HMI Panel | Medical Diagnostic Display |
Use Scenario: Ruggedized 7-inch touchscreen display operating in extended temperature range (–30°C to 85°C) with high reliability requirements. IC Role / Device Role / Timing Role: Fault-tolerant LED driver with comprehensive protection (LED open/short, OVP, TSD) and diagnostic register readback via I²C. Use Value: Delivers continuous operation under thermal stress with automatic recovery from transient faults-no firmware intervention required. | Use Scenario: DICOM-compliant 15-inch grayscale monitor requiring precise luminance stability (<±2% drift) over 8-hour clinical shifts. IC Role / Device Role / Timing Role: Precision current source with <0.5% channel matching and factory-trimmed current references for calibration-critical imaging. Use Value: Maintains grayscale linearity and eliminates banding artifacts through adaptive headroom control that compensates for LED forward-voltage drift with temperature. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LP8557AYFQT | No I²C interface; FSET/ISET pins dedicated to resistor programming only; BRTMODE fixed at 00b. | Suitable only for PWM-only systems without host microcontroller I²C capability. | Select LP8557AYFQT when system lacks I²C master and brightness control is exclusively PWM-driven. |
| TPS61165DRVR | Single-channel 40-mA sink; no adaptive boost or I²C; fixed 1.2-MHz switching frequency; no LED auto-detect. | Limited to simpler displays with ≤2 LED strings and no dynamic dimming requirements. | Choose TPS61165DRVR only for cost-sensitive, low-channel-count applications where programmability and efficiency optimization are secondary. |
Compared with LP8557AYFQT, the LP8557IAYFQT adds full I²C configurability and flexible BRTMODE selection-enabling advanced CABC, fault logging, and multi-source brightness control. Against TPS61165DRVR, it delivers six independent channels, adaptive regulation, and superior thermal management for high-reliability portable displays.
Availability
LP8557IAYFQT is available at Aetrix Electronics and suitable for tablet backlighting, ultrabook display drivers, industrial HMI panels, and medical diagnostic displays requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LP8557IAYFQT 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 display power solutions.
The LP8557I product line was developed specifically for high-efficiency, space-constrained LED backlighting in portable consumer electronics-emphasizing adaptive power conversion, precision current regulation, and intelligent dimming for battery-powered displays.
FAQ
What is the primary function of the LP8557IAYFQT in a tablet display system?
The LP8557IAYFQT serves as the core LED backlight driver IC in tablet displays, integrating a 28-V adaptive boost converter and six 25-mA precision current sinks to power 1–6 LED strings. Its role includes regulating LED current uniformly, minimizing power loss via dynamic headroom control, and enabling I²C- or PWM-based brightness adjustment-making LP8557IAYFQT essential for energy-efficient, high-uniformity LCD backlighting.
How does the adaptive boost voltage control in LP8557IAYFQT improve system efficiency?
The LP8557IAYFQT monitors voltage at all six LED sink terminals via the FB pin and adjusts its boost output voltage in real time to maintain only the minimum headroom required-typically 7 V to 28 V. This prevents excessive voltage overhead across the current sinks, reducing conduction losses and improving overall LED drive efficiency by up to 15% compared to fixed-output boost architectures. That adaptive behavior is intrinsic to LP8557IAYFQT's design and verified across operating conditions.
Can LP8557IAYFQT operate without an I²C master controller?
Yes, LP8557IAYFQT can operate without an I²C master by configuring BRTMODE = 00b, which disables I²C functionality and reverts FSET/SDA and ISET/SCL pins to resistor-based programming for switching frequency and LED current. In this mode, brightness is controlled solely via the PWM input pin-retaining full boost regulation, adaptive headroom, and fault protection. So LP8557IAYFQT remains fully functional even in PWM-only systems.
What protection features are integrated into LP8557IAYFQT?
LP8557IAYFQT integrates UVLO (2.5 V threshold), thermal shutdown (150°C with 20°C hysteresis), boost overvoltage protection (VBOOST_MAX + 1.6 V), boost overcurrent protection (2.4 A limit), and LED-specific fault detection-including open-circuit and short-circuit sensing on all six LED channels. These protections operate autonomously without host intervention, ensuring robust operation in LP8557IAYFQT-based designs across environmental and load variations.
Is LP8557IAYFQT pin-compatible with LP8557AYFQT?
Yes, LP8557IAYFQT is pin-compatible with LP8557AYFQT-they share identical 16-pin DSBGA (YFQ) packaging, pinout, and footprint. Both devices use the same physical layout, allowing direct PCB reuse. However, LP8557IAYFQT enables I²C communication on FSET/SDA and ISET/SCL pins when BRTMODE is configured accordingly, whereas LP8557AYFQT dedicates those pins exclusively to resistor programming. So LP8557IAYFQT offers enhanced functionality without layout changes.
LP8557IAYFQT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-WFBGA, DSBGA
- 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):
- 5.5V
- Voltage - Output:
- 28V
- Current - Output / Channel:
- 25mA
- Frequency:
- 500kHz, 1MHz
- Dimming:
- PWM
- Applications:
- Backlight
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-DSBGA
LP8557IAYFQT FAQ
1.How can I place an order for LP8557IAYFQT through Aetrix?
Please submit a Request for Quotation (RFQ) for LP8557IAYFQT 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 LP8557IAYFQT reliable?
The price and inventory of LP8557IAYFQT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP8557IAYFQT is usually 5 days.
3.What payment methods are accepted for LP8557IAYFQT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP8557IAYFQT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP8557IAYFQT?
LP8557IAYFQT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP8557IAYFQT 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 LP8557IAYFQT?
For technical support, including LP8557IAYFQT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP8557IAYFQT requirements.
6.How does Aetrix verify that LP8557IAYFQT is sourced from the original manufacturer or authorized distributors?
All LP8557IAYFQT 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 LP8557IAYFQT meets industry standards.
7.What is the process for return or replacement of LP8557IAYFQT?
All LP8557IAYFQT units undergo pre-shipment inspection (PSI). If there is an issue with LP8557IAYFQT, 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 LP8557IAYFQT part is unused and in its original packaging.
Return procedure for LP8557IAYFQT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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