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Texas Instruments LP8557AYFQT
- Part No.:
- LP8557AYFQT
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 16-WFBGA, DSBGA
- Datasheet:
-
LP8557AYFQT.pdf
- Description:
- IC LED DRV RGLTR PWM 16DSBGA
- Quantity:
- Payment:
- Shipping:
Inventory:500
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Product details
Overview
LP8557AYFQT from Texas Instruments is a PWM-only high-efficiency LED backlight driver IC with integrated 28-V boost converter and six 25-mA precision current sinks, operating from 2.7 V to 5.5 V input, supporting 1–6 LED strings in tablet LCD displays.
For engineers reviewing the LP8557AYFQT datasheet, LP8557AYFQT pinout, LP8557AYFQT application, or LP8557AYFQT equivalent, key selection criteria include adaptive boost voltage control, hybrid PWM+current dimming, LED string auto-detect, programmable slew rate, and DSBGA-16 package compatibility with space-constrained portable designs.
Technical Context
The LP8557AYFQT implements adaptive boost output voltage control that dynamically adjusts VOUT to the minimum required level based on real-time monitoring of all six LED string headroom voltages - reducing power loss without compromising drive capability. Its current-programmed boost topology integrates a 0.2-Ω MOSFET switch and supports 500 kHz or 1 MHz switching frequency.
Brightness is controlled exclusively via external PWM input (BRTMODE = 00b), with 8–12-bit resolution depending on input frequency, and processed through curve shaping and hybrid PWM+current dimming to optimize optical efficiency and audible noise suppression. Fault protection includes UVLO, thermal shutdown, BST_OVP/OCP, and LED open/short detection.
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 LDO pre-regulation |
| Boost Output Range | 7 V to 28 V - sufficient for up to 6-series white LEDs at 2.85 V VF each |
| LED Sink Current | 25 mA per channel, ±3% accuracy - enables uniform brightness across multi-string backlight arrays |
| Switching Frequency | 500 kHz or 1 MHz - selectable via external resistor; balances EMI, efficiency, and component size |
| PWM Input Range | 75 Hz to 25 kHz - supports legacy and high-frequency dimming with 8–12-bit resolution |
| Thermal Shutdown | 150 °C threshold with 20 °C hysteresis - protects against sustained overload in sealed tablet enclosures |
| Package | DSBGA-16 (1.906 mm × 1.64 mm) - ultra-compact footprint for thin-profile display modules |
Pinout & Package
LP8557AYFQT uses a 16-pin DSBGA (YFQ) package with 0.4-mm pitch, optimized for low-inductance layout and minimal PCB area in portable backlight applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB | Boost feedback | Monitors output voltage for adaptive regulation; connects to boost output divider network |
| FSET/SDA | Frequency set / I²C data | In LP8557AYFQT (PWM-only), functions as FSET - sets switching frequency via resistor-to-GND |
| ISET/SCL | Current set / I²C clock | In LP8557AYFQT, functions as ISET - sets full-scale LED current via resistor-to-GND |
| PWM | Brightness control input | Digital PWM signal (0.4 V / 1.44 V logic thresholds) directly controls dimming level |
| SW | Power switch drain | Connects to boost inductor; carries peak currents up to 2.4 A |
| SW_GND | Switch source | Dedicated ground return for MOSFET source - critical for low-noise current sensing |
| LED1–LED6 | Current sink outputs | Individually configurable high-precision sinks; unused pins may float |
| VDD | Supply input | Primary power rail; decoupling capacitor required near pin for stability |
| GND | Ground reference | Four dedicated GND pins (C2, A2, B2, C3) minimize ground bounce in high-speed switching |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive boost voltage control | Maintains minimal VOUT headroom across all LED strings - improves system efficiency by up to 8% vs fixed-output boost |
| Hybrid PWM + current dimming | Combines digital PWM duty control with analog current scaling - preserves contrast ratio while reducing power at low brightness |
| LED string count auto-detect | Identifies active LED strings (1–6) at startup - eliminates firmware configuration and enables one-BOM flexibility |
| Smart phase-shift PWM mode | Staggered PWM timing across LED channels - suppresses mechanical resonance and audible coil whine |
| Programmable SW slew rate | Adjusts MOSFET turn-on/off speed via external resistor - optimizes EMI vs efficiency trade-off without layout changes |
Applications
| Tablet LCD Backlight | Ultrabook Display Module |
|---|---|
Use Scenario: Driving 6-series white LED strings in 10.1-inch IPS LCD panels with dynamic brightness control. IC Role / Device Role / Timing Role: Primary LED driver IC providing regulated current, adaptive boost voltage, and PWM-based dimming coordination. Use Value: Achieves >88% LED drive efficiency at 100% brightness and maintains >82% at 20% brightness via hybrid dimming and headroom optimization. | Use Scenario: Compact backlight solution for 13.3-inch FHD displays where board space and thermal envelope are constrained. IC Role / Device Role / Timing Role: Integrated boost + current sink driver eliminating discrete MOSFET, controller, and current sense resistors. Use Value: Reduces BOM count by ≥7 components and cuts PCB area by 35% versus discrete boost + TLC59xx solution. |
| Industrial HMI Panel | Medical Diagnostic Tablet |
Use Scenario: Reliable backlight for 7-inch resistive-touch HMIs operating in extended temperature ranges (–30°C to 85°C). IC Role / Device Role / Timing Role: Fault-resilient LED driver with UVLO, thermal shutdown, LED open/short detection, and robust ESD protection (±2 kV HBM). Use Value: Ensures uninterrupted operation under brown-out conditions and prevents LED damage during cable disconnect events. | Use Scenario: High-reliability backlight in FDA-cleared diagnostic tablets requiring consistent luminance and long-term calibration stability. IC Role / Device Role / Timing Role: Precision current sink driver with ±3% LED current accuracy and <0.5% channel-to-channel mismatch. Use Value: Maintains display uniformity over 5-year service life with <±0.3% drift in current accuracy across temperature and aging. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LP8557IAYFQT | I²C interface enabled; supports BRTMODE 01/10/11; same pinout and PWM capability | Required when system includes I²C master for dynamic brightness scheduling or diagnostics | Select LP8557IAYFQT only if firmware-level control or fault register readback is needed - adds software overhead but no hardware change |
| TPS61165DRVR | Single-channel 40-V boost + current sink; no LED string auto-detect or phase-shift PWM | Suitable for simpler 1–2 string designs; lacks multi-string efficiency optimization | Choose TPS61165DRVR for cost-sensitive, low-channel-count applications where adaptive headroom and hybrid dimming are not required |
Compared with LP8557IAYFQT, LP8557AYFQT removes I²C logic to reduce standby current (1 µA vs 2.2 µA) and simplify firmware; compared with TPS61165DRVR, it delivers higher integration (6 sinks + auto-detect), better efficiency at partial load, and lower audible noise in multi-string configurations.
Availability
LP8557AYFQT is available at Aetrix Electronics and suitable for tablet LCD backlight, ultrabook display modules, industrial HMI panels, and medical diagnostic tablets requiring stable component supply and long-lifecycle support.
Supply support for LP8557AYFQT 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 delivering analog and embedded processing solutions, with deep expertise in power management and display interface technologies.
The LP8557 product line was designed specifically for high-efficiency, space-constrained LED backlighting in portable consumer and industrial displays - emphasizing adaptive power conversion, precision current matching, and robust fault coverage.
FAQ
What is the primary function of the LP8557AYFQT in a display system?
The LP8557AYFQT serves as a fully integrated LED backlight driver IC, combining a DC-DC boost converter and six precision current sinks to power and control LED strings in LCD displays. Its core function is to deliver stable, adjustable current to LEDs while maximizing power efficiency through adaptive voltage regulation and hybrid dimming - all within the LP8557AYFQT's compact DSBGA-16 package.
Does the LP8557AYFQT support I²C communication?
No, the LP8557AYFQT is the "PWM-only" variant and does not support I²C communication. Its FSET/SDA and ISET/SCL pins operate exclusively as analog programming inputs (resistor-set switching frequency and LED current). For I²C capability, the LP8557IAYFQT variant must be used - the LP8557AYFQT is functionally identical otherwise but omits I²C logic to reduce complexity and standby current.
How does the LP8557AYFQT achieve high LED drive efficiency across varying brightness levels?
The LP8557AYFQT achieves high efficiency via three coordinated mechanisms: (1) adaptive boost voltage control that minimizes VOUT headroom in real time, (2) hybrid PWM + current dimming that shifts from pure PWM at high brightness to mixed-mode at mid-low levels to preserve optical efficiency, and (3) smart phase-shift PWM that reduces ripple-induced losses and audible noise. These features collectively maintain >82% LED drive efficiency even at 20% brightness - confirmed in LP8557AYFQT typical characteristics graphs.
What fault protections are integrated into the LP8557AYFQT?
The LP8557AYFQT integrates comprehensive fault protection including undervoltage lockout (UVLO) at 2.5 V, thermal shutdown at 150 °C with 20 °C hysteresis, boost overvoltage protection (OVP) at VBOOST_MAX + 1.6 V, boost overcurrent protection (OCP), and LED open/short detection on all six channels. These protections operate autonomously without host intervention, ensuring safe operation in LP8557AYFQT-based backlight systems under abnormal conditions.
Can the LP8557AYFQT drive fewer than six LED strings?
Yes, the LP8557AYFQT supports 1 to 6 LED strings natively via its LED string auto-detect function. Unused LEDx pins (e.g., LED4–LED6 in a 3-string design) may be left floating - no external termination or configuration is required. The device automatically configures internal current sinks and adjusts boost voltage headroom based on detected string count, enabling flexible reuse of the same LP8557AYFQT across multiple display SKUs.
LP8557AYFQT 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
LP8557AYFQT FAQ
1.How can I place an order for LP8557AYFQT through Aetrix?
Please submit a Request for Quotation (RFQ) for LP8557AYFQT 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 LP8557AYFQT reliable?
The price and inventory of LP8557AYFQT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP8557AYFQT is usually 5 days.
3.What payment methods are accepted for LP8557AYFQT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP8557AYFQT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP8557AYFQT?
LP8557AYFQT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP8557AYFQT 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 LP8557AYFQT?
For technical support, including LP8557AYFQT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP8557AYFQT requirements.
6.How does Aetrix verify that LP8557AYFQT is sourced from the original manufacturer or authorized distributors?
All LP8557AYFQT 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 LP8557AYFQT meets industry standards.
7.What is the process for return or replacement of LP8557AYFQT?
All LP8557AYFQT units undergo pre-shipment inspection (PSI). If there is an issue with LP8557AYFQT, 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 LP8557AYFQT part is unused and in its original packaging.
Return procedure for LP8557AYFQT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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