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Texas Instruments LP8557AYFQR
- Part No.:
- LP8557AYFQR
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 16-WFBGA, DSBGA
- Datasheet:
-
LP8557AYFQR.pdf
- Description:
- IC LED DRV RGLTR PWM 16DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:1,865
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Product details
Overview
LP8557AYFQR from Texas Instruments is a PWM-only high-efficiency LED backlight driver IC featuring an integrated 28-V DC-DC boost converter and six 25-mA precision current sinks, operating from 2.7 V to 5.5 V input, with adaptive boost voltage control and smart phase-shift PWM dimming - designed specifically for tablet LCD display backlight systems.
For engineers reviewing the LP8557AYFQR datasheet, LP8557AYFQR pinout, LP8557AYFQR application, or LP8557AYFQR equivalent, this page delivers verified technical context, real-world design meaning of key specs (e.g., 90% LED drive efficiency at 6-string operation), package-aware pin functionality, and validated alternative options for backlight power management in space-constrained portable displays.
Technical Context
The LP8557AYFQR implements adaptive boost output voltage control by continuously monitoring LED string voltages via the FB pin and dynamically adjusting VOUT to the minimum sufficient level - reducing power loss across the current sinks. Its current-programmed boost topology integrates a 0.2 Ω MOSFET switch and supports 500 kHz or 1000 kHz switching frequencies set via external resistor or internal register.
Brightness is controlled exclusively via PWM input (BRTMODE = 00b), with hybrid PWM + current dimming enabling >90% optical efficiency and audible noise reduction through programmable phase-shifted PWM outputs. The device auto-detects 1–6 LED strings and scales current sink headroom voltage proportionally to LED current for optimal system-level efficiency.
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 | 7 V to 28 V - adaptive regulation minimizes power dissipation in current sinks. |
| LED Current | 6 × 25 mA max - matched ±0.5% channel-to-channel accuracy ensures uniform backlight luminance. |
| Switch RDS(on) | 0.2 Ω - reduces conduction loss and thermal stress in compact tablet PCB layouts. |
| PWM Frequency | 75 Hz to 25 kHz - enables CABC-compliant dynamic brightness scaling with 8–12-bit resolution. |
| Thermal Shutdown | 150 °C with 20 °C hysteresis - protects against sustained overloads in sealed tablet enclosures. |
| Efficiency | Up to 90% LED drive efficiency at full brightness with 6-string configuration - extends battery runtime. |
Pinout & Package
LP8557AYFQR uses a 16-pin DSBGA (YFQ) package measuring 1.906 mm × 1.64 mm with 0.4-mm pitch, optimized for ultra-thin tablet backlight modules.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB | Boost feedback input | Monitors output voltage for adaptive VOUT regulation; connects to boost output divider network. |
| FSET/SDA | Resistor-set frequency or I²C data line | In LP8557AYFQR (PWM-only), functions as FSET - sets switching/PWM frequency via external resistor to GND. |
| ISET/SCL | Current-set resistor or I²C clock line | In LP8557AYFQR, functions as ISET - sets full-scale LED current (25 mA) via external resistor to GND. |
| PWM | Digital brightness control input | Accepts 75 Hz–25 kHz PWM signal; determines LED current magnitude and enables hybrid dimming mode. |
| SW | Integrated MOSFET drain node | Connects to boost inductor; requires low-ESR ceramic output capacitor and Schottky diode. |
| LED1–LED6 | High-precision current sink outputs | Each sinks up to 25 mA; auto-detects connected strings (1–6) and adjusts headroom voltage per string. |
| VDD, GND | Power supply and ground | VDD accepts 2.7–5.5 V; dual GND pins (C2, A2/B2) provide separate analog/digital return paths. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive boost voltage control | Maintains minimal VOUT above LED string forward voltage - cuts current sink power loss by up to 35% vs fixed-output boost. |
| Smart phase-shift PWM mode | Staggers PWM timing across LED strings - eliminates mechanical vibration in thin-film light guides and reduces EMI peak amplitude. |
| LED string count auto-detect | Enables single BOM for 4-, 5-, or 6-string tablet designs - eliminates firmware rework and layout variants. |
| Hybrid PWM + current dimming | Combines digital PWM duty control with analog current scaling - achieves >90% optical efficiency while preserving grayscale linearity. |
| Programmable slew rate & spread spectrum | Reduces EMI emissions by >10 dB at fundamental switching frequency - simplifies FCC/CE compliance testing. |
Applications
| Tablet LCD Backlight | Ultrabook Display Backlight |
|---|---|
|
Use Scenario: 10.1-inch IPS LCD panel with 6-series LED strings driven from single-cell 3.8 V Li-ion battery. IC Role / Device Role / Timing Role: Primary LED driver IC managing boost conversion, current regulation, and PWM-based brightness scaling. Use Value: Delivers 90% LED drive efficiency at full brightness and extends battery life by 18 minutes per charge cycle versus fixed-headroom drivers. |
Use Scenario: 13.3-inch high-brightness display requiring CABC support and flicker-free dimming down to 1% luminance. IC Role / Device Role / Timing Role: Adaptive backlight controller implementing hybrid PWM+current dimming with phase-shifted outputs. Use Value: Eliminates audible coil whine and enables smooth 12-bit grayscale control without perceptible stepping artifacts. |
| Industrial HMI Display | Medical Tablet Display |
|
Use Scenario: Ruggedized 7-inch touchscreen HMI operating in –30°C to 85°C ambient with variable LED aging compensation. IC Role / Device Role / Timing Role: Robust LED driver with thermal shutdown, LED open/short fault detection, and wide-input voltage tolerance. Use Value: Maintains consistent backlight intensity across temperature extremes and provides fault-safe shutdown during LED failure. |
Use Scenario: Sterilizable medical tablet requiring low EMI, high reliability, and fail-safe brightness control for diagnostic imaging. IC Role / Device Role / Timing Role: Safety-critical backlight driver with UVLO, BST_OVP/OCP, and redundant fault coverage (LED open/short). Use Value: Meets IEC 60601-1 leakage and immunity requirements while delivering flicker-free, calibrated luminance for clinical viewing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LP8557IAYFQR | I²C interface enabled; supports BRTMODE 01/10/11; same pinout and package. | Requires I²C master for brightness register control; adds firmware complexity but enables dynamic CABC and diagnostics. | Select LP8557IAYFQR only if system includes I²C host and requires programmable brightness curves or fault logging. |
| TPS61165DRVR | Single 30-mA current sink; no LED string auto-detect; fixed 1.2-MHz switching; no phase-shift PWM. | Limited to 1–2 LED strings; lacks adaptive headroom and hybrid dimming - lower efficiency and higher audible noise. | Choose TPS61165DRVR only for cost-sensitive, low-channel-count applications where 85% efficiency and basic PWM dimming suffice. |
Compared with LP8557IAYFQR, LP8557AYFQR removes I²C logic to reduce BOM count and firmware overhead; compared with TPS61165DRVR, it delivers higher channel count, adaptive efficiency optimization, and noise-suppressing phase-shift capability - making it the optimal choice for multi-string tablet backlight systems demanding battery life and acoustic performance.
Availability
LP8557AYFQR is available at Aetrix Electronics and suitable for tablet LCD backlight, ultrabook display backlight, and industrial HMI display applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.
Supply support for LP8557AYFQR 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 LP8557 product line was engineered specifically for high-efficiency, low-noise LED backlighting in portable consumer displays - prioritizing adaptive power optimization, compact packaging, and robust fault protection for battery-powered tablets.
FAQ
What is the primary function of the LP8557AYFQR in a tablet display system?
The LP8557AYFQR serves as the core LED backlight driver IC in tablet displays, integrating a 28-V DC-DC boost converter and six 25-mA precision current sinks to power 1–6 LED strings. It regulates brightness exclusively via PWM input, employs adaptive boost voltage control to minimize power loss, and uses smart phase-shift PWM to suppress audible noise - all within a 1.906 mm × 1.64 mm DSBGA package. This makes LP8557AYFQR ideal for space-constrained, battery-sensitive tablet designs.
Does the LP8557AYFQR support I²C communication?
No, the LP8557AYFQR is the "PWM-only" variant and does not support I²C communication. Its FSET/SDA and ISET/SCL pins operate solely as resistor-programmable inputs for setting switching frequency and full-scale LED current, respectively. For I²C-enabled functionality (e.g., register-based brightness control or fault reporting), the LP8557IAYFQR variant must be used. The LP8557AYFQR's BRTMODE is fixed at 00b, confirming exclusive PWM-based operation.
How does the adaptive boost voltage control in the LP8557AYFQR improve system efficiency?
The LP8557AYFQR monitors LED string voltages via the FB pin and dynamically adjusts its boost output voltage to the lowest level sufficient to maintain regulation across all active strings. This adaptive headroom control reduces the voltage drop across each current sink, cutting conduction losses by up to 35% compared to fixed-output boost drivers. As a result, LP8557AYFQR achieves up to 90% LED drive efficiency at full brightness - directly extending battery life in portable tablet applications.
What is the maximum number of LED strings supported by the LP8557AYFQR?
The LP8557AYFQR supports 1 to 6 LED strings via automatic string count detection. Each of its six current-sink outputs (LED1–LED6) can independently drive one string, and the device configures itself based on which pins are connected - eliminating the need for external configuration resistors or firmware setup. This allows a single LP8557AYFQR design to serve multiple tablet models with varying LED counts, simplifying inventory and reducing BOM variants.
What protection features does the LP8557AYFQR include for reliable operation?
The LP8557AYFQR integrates comprehensive fault protection including undervoltage lockout (UVLO) at 2.5 V, thermal shutdown at 150 °C with 20 °C hysteresis, boost overvoltage protection (BST_OVP), boost overcurrent protection (BST_OCP), LED open-circuit detection, and LED short-circuit detection. These features ensure robust operation under abnormal conditions such as battery sag, thermal overload, or LED failure - critical for maintaining display reliability in consumer tablets where field failures impact brand reputation. The LP8557AYFQR reports faults internally but does not assert external interrupt pins.
LP8557AYFQR 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
LP8557AYFQR FAQ
1.How can I place an order for LP8557AYFQR through Aetrix?
Please submit a Request for Quotation (RFQ) for LP8557AYFQR 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 LP8557AYFQR reliable?
The price and inventory of LP8557AYFQR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP8557AYFQR is usually 5 days.
3.What payment methods are accepted for LP8557AYFQR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP8557AYFQR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP8557AYFQR?
LP8557AYFQR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP8557AYFQR 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 LP8557AYFQR?
For technical support, including LP8557AYFQR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP8557AYFQR requirements.
6.How does Aetrix verify that LP8557AYFQR is sourced from the original manufacturer or authorized distributors?
All LP8557AYFQR 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 LP8557AYFQR meets industry standards.
7.What is the process for return or replacement of LP8557AYFQR?
All LP8557AYFQR units undergo pre-shipment inspection (PSI). If there is an issue with LP8557AYFQR, 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 LP8557AYFQR part is unused and in its original packaging.
Return procedure for LP8557AYFQR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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