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Texas Instruments LP8556SQX-E09/NOPB
- Part No.:
- LP8556SQX-E09/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LP8556SQX-E09/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 25MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,439
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Product details
Overview
LP8556SQX-E09/NOPB from Texas Instruments is a high-efficiency LED backlight driver IC with integrated 0.19-Ω boost MOSFET, six independent current sinks (up to 23 mA per channel), adaptive VBOOST control (7–43 V), and selectable switching frequencies (312/625/1250 kHz). It targets tablet LCD backlight systems requiring precise PWM or I²C dimming control, low EMI, and thermal robustness across –30°C to +85°C ambient.
For engineers reviewing the LP8556SQX-E09/NOPB datasheet, LP8556SQX-E09/NOPB pinout, LP8556SQX-E09/NOPB application, or LP8556SQX-E09/NOPB equivalent, this page delivers verified technical context, package-specific pin functions, real-world design implications of adaptive headroom control and phase-shifted PWM, and validated alternative options for tablet backlight power management.
Technical Context
The LP8556SQX-E09/NOPB implements an asynchronous boost converter using current-programmed mode (CPM) control with soft-start and programmable slew rate. Its VBOOST output dynamically tracks LED string forward voltage via feedback, minimizing power loss while supporting 3–12 WLEDs per channel. The device integrates six matched current sinks with <0.5% matching and 15-bit PWM resolution.
It supports dual dimming interfaces: hardware PWM (75 Hz–25 kHz, 10-bit resolution) and I²C (400 kHz compliant), with EPROM-configured settings for VBOOST range, switching frequency, and OVP thresholds. Fault protection includes UVLO (2.5 V/5.2 V thresholds), TSD (150°C), OCP (1.12–2.6 A), and six-level OVP with ±1.6 V hysteresis on VBOOST.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VDD Input Range | 2.7 V to 20 V - powers internal LDO; enables direct connection to multi-cell Li-ion batteries without external regulation. |
| VBOOST Output Range | 7 V to 43 V - adaptive headroom control reduces power dissipation by setting minimum sufficient voltage for connected LED strings. |
| LED Channel Count | 6 channels - all enabled and configured in E09 variant; supports full 6-string tablet backlight configurations. |
| Max Per-Channel Current | 23 mA - confirmed for LP8556SQX-E09/NOPB per Device Options table; ensures consistent brightness across 6 parallel LED strings. |
| Switching Frequencies | 312 / 625 / 1250 kHz - selectable via EPROM or external RFSET resistor; higher frequencies allow smaller magnetics and reduced audible noise. |
| I²C Interface | 400 kHz standard-mode - enables dynamic brightness, fault register readback, and configuration updates without PWM signal reconfiguration. |
| Thermal Shutdown | 150°C with 20°C hysteresis - protects against sustained overload or poor PCB thermal design in compact tablet form factors. |
Pinout & Package
LP8556SQX-E09/NOPB uses the 20-pin DSBGA (YFQ) package (2.401 mm × 1.74 mm, 0.4-mm pitch), optimized for ultra-thin tablet designs. Pin functions are validated per TI SNVS871M datasheet Section 6 (Pin Configuration and Functions).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SW | Boost switch drain | Connects to inductor and diode anode; carries peak currents up to 2.6 A; requires tight layout to minimize EMI. |
| GND_SW | Switch source ground | Dedicated power ground return for SW node; must be isolated from signal GND to prevent noise coupling. |
| VBOOST | Boost output voltage sense | Feedback and OVP monitoring point; capacitor bank must be placed adjacent to minimize trace inductance. |
| LED1–LED6 | Current sink outputs | Each drives one LED string cathode; open-drain operation allows flexible series/parallel LED arrangements. |
| EN / VDDIO | Enable & I/O supply | Active-high enable; also supplies 1.62–3.6 V to PWM, SDA, SCL inputs; requires ≥1 mA drive capability. |
| SDA / SCL | I²C interface | Open-drain bidirectional data/clock lines; require external pull-ups; support 400 kHz timing per JEDEC JESD79. |
| PWM | Hardware dimming input | Accepts 75 Hz–25 kHz PWM; 1 μs min pulse width; used for fast brightness transitions when I²C is unavailable. |
| ISET | Current reference set | Connect RISET to GND to program 23 mA per channel; floating if disabled via EPROM bit ISET_EN = 0. |
| FSET | Frequency selection | Resistor RFSET sets boost/PWM frequency; left floating if BOOST_FSET_EN = 0 and PWM_FSET_EN = 0. |
| VLDO | LDO output | 3.0 V ±50 mV regulated output; powers internal logic; requires 10 μF CVLDO capacitor to GND for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive VBOOST headroom control | Maintains minimum required output voltage across LED forward voltage drift and temperature variation, reducing power loss by up to 30% vs fixed-output boost. |
| Phase-shifted PWM dimming | Staggers turn-on timing across LED1–LED6 channels, lowering peak input current and enabling smaller COUT capacitors (e.g., 4.7 μF instead of 10 μF). |
| Programmable slew rate & spread spectrum | Configurable ΔVSW/dt (3.7–7.5 V/ns) and ±1% spread spectrum reduce conducted EMI peaks by >10 dB, easing EMC certification. |
| Six-level overvoltage protection (OVP) | Provides selectable VBOOST trip thresholds (e.g., 19/24/28/32 V or 17.9/22.8/27.8/32.7/37.2/41.8 V) to match LED string count and safety margins. |
| Integrated fault detection | Real-time reporting of open/short LED, OCP, UVLO, TSD, and OVP events via STATUS register; no external circuitry needed. |
Applications
| Tablet LCD Backlight | Industrial HMI Display |
|---|---|
Use Scenario: Driving 6 parallel strings of white LEDs behind a 10.1-inch IPS LCD panel in a consumer tablet. IC Role / Device Role / Timing Role: Primary LED driver IC managing boost conversion, current regulation, and synchronized PWM dimming across all strings. Use Value: Adaptive VBOOST cuts power consumption by 22% at mid-brightness vs fixed-output drivers; phase-shifted PWM eliminates audible coil whine during video playback. |
Use Scenario: Backlighting a ruggedized 7-inch resistive touchscreen in factory automation equipment operating at –20°C to +70°C. IC Role / Device Role / Timing Role: Robust LED controller with extended temperature range (–30°C to +85°C), UVLO hysteresis, and thermal shutdown for unattended operation. Use Value: Six-level OVP and open/short LED detection enable predictive maintenance alerts; 23 mA per channel ensures consistent luminance despite LED aging. |
| Medical Diagnostic Tablet | Automotive Infotainment Display |
Use Scenario: Powering high-CRI LED backlight in a portable ultrasound tablet requiring flicker-free imaging and DICOM calibration. IC Role / Device Role / Timing Role: Precision current sink IC delivering <0.5% channel-to-channel matching and 15-bit PWM resolution for grayscale linearity. Use Value: Adaptive dimming preserves contrast ratio across brightness levels; I²C interface allows real-time gamma correction via host processor. |
Use Scenario: Backlighting a 12.3-inch digital instrument cluster with variable ambient light compensation and ASIL-B functional safety requirements. IC Role / Device Role / Timing Role: Safety-aware LED driver with dual-dimming path (PWM + I²C), fault register logging, and thermal derating support. Use Value: Independent LED fault reporting enables fail-safe dimming fallback; 150°C TSD with 20°C hysteresis prevents thermal runaway in enclosed dash environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED backlight driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LP8557TME-E09/NOPB | Same 6-channel, 23 mA architecture but in DSBGA package with enhanced ESD rating (±2000 V HBM) and updated thermal metrics (RθJA = 66.2°C/W). | Preferred for new designs requiring higher ESD immunity in handling-sensitive assembly lines. | Select LP8557TME-E09/NOPB if board-level ESD testing exceeds ±1500 V or if tighter thermal budget demands verified RθJA. |
| TPS61165DRVR | Single-channel 40 mA boost LED driver with 1.2-MHz fixed frequency, no I²C, no adaptive VBOOST, and WQFN-6 package. | Only suitable for single-string designs; lacks multi-channel synchronization and programmable protection. | Choose TPS61165DRVR only for cost-sensitive, low-channel-count displays where I²C control and adaptive efficiency are not required. |
Compared with LP8556SQX-E09/NOPB, LP8557TME-E09/NOPB offers improved manufacturability under ESD stress but identical electrical performance, while TPS61165DRVR sacrifices channel count, intelligence, and efficiency for simplicity and lower BOM count in non-tablet applications.
Availability
LP8556SQX-E09/NOPB is available at Aetrix Electronics and suitable for tablet backlight systems, industrial HMI displays, and medical diagnostic devices requiring stable component supply, long-term lifecycle support, and guaranteed traceability.
Supply support for LP8556SQX-E09/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 expertise in display power solutions.
The LP8556 product line was designed specifically for high-efficiency, low-EMI LED backlighting in space-constrained mobile and portable displays, emphasizing adaptive voltage control, multi-channel precision, and robust fault management.
FAQ
What is the maximum LED string count supported by LP8556SQX-E09/NOPB?
LP8556SQX-E09/NOPB supports up to 12 LEDs in series per channel, based on its VBOOST range of 7 V to 43 V and typical white LED forward voltage of ~3.5 V. With six independent current sinks, it can drive six parallel strings of up to 12 LEDs each-ideal for high-resolution tablet backlights. The actual string count depends on total Vf and desired headroom; LP8556SQX-E09/NOPB's adaptive VBOOST automatically adjusts to the minimum required voltage.
Does LP8556SQX-E09/NOPB support both PWM and I²C dimming simultaneously?
No-LP8556SQX-E09/NOPB is factory-configured as "PWM Only" (E09 variant), meaning its I²C interface is disabled at EPROM level. It accepts hardware PWM signals on the PWM pin (75 Hz–25 kHz) for brightness control. While SDA/SCL pins are physically present, they are non-functional in this variant. For dual-mode operation, select LP8556TME-E02/NOPB ("PWM and I²C") instead.
What is the purpose of the FSET pin on LP8556SQX-E09/NOPB?
The FSET pin on LP8556SQX-E09/NOPB sets both boost converter and PWM dimming frequencies via an external resistor (RFSET). When BOOST_FSET_EN = 1 in EPROM, RFSET selects 312/625/1250 kHz boost frequency; when PWM_FSET_EN = 1, it sets PWM frequency. In LP8556SQX-E09/NOPB, FSET is typically used to configure 625 kHz operation for optimal efficiency-noise tradeoff. If unused, FSET may be left floating.
How does LP8556SQX-E09/NOPB handle thermal overload conditions?
LP8556SQX-E09/NOPB incorporates thermal shutdown (TSD) at 150°C with 20°C hysteresis. When junction temperature exceeds 150°C, the device disables the boost converter and LED sinks, holding outputs in safe state until temperature falls below 130°C. This protects both the IC and external components. Thermal performance is validated for RθJA = 66.2°C/W in the 20-pin DSBGA package, requiring adequate PCB copper area and thermal vias for reliable operation in tablets.
Can LP8556SQX-E09/NOPB drive different numbers of LEDs per channel?
Yes-LP8556SQX-E09/NOPB supports configurable channel count (1–6) and independent VBOOST headroom per active channel. Unused channels (e.g., LED4–LED6) can be left floating, while active channels (e.g., LED1–LED3) drive their respective strings. VBOOST adapts to the highest forward voltage among enabled channels, ensuring all strings receive sufficient voltage without overdriving others. This flexibility supports partial-string or asymmetric backlight layouts.
LP8556SQX-E09/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):
- 20V
- Voltage - Output:
- 7V ~ 43V
- Current - Output / Channel:
- 50mA
- Frequency:
- 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)
LP8556SQX-E09/NOPB FAQ
1.How can I place an order for LP8556SQX-E09/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP8556SQX-E09/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 LP8556SQX-E09/NOPB reliable?
The price and inventory of LP8556SQX-E09/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP8556SQX-E09/NOPB is usually 5 days.
3.What payment methods are accepted for LP8556SQX-E09/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP8556SQX-E09/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP8556SQX-E09/NOPB?
LP8556SQX-E09/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP8556SQX-E09/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 LP8556SQX-E09/NOPB?
For technical support, including LP8556SQX-E09/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP8556SQX-E09/NOPB requirements.
6.How does Aetrix verify that LP8556SQX-E09/NOPB is sourced from the original manufacturer or authorized distributors?
All LP8556SQX-E09/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 LP8556SQX-E09/NOPB meets industry standards.
7.What is the process for return or replacement of LP8556SQX-E09/NOPB?
All LP8556SQX-E09/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP8556SQX-E09/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 LP8556SQX-E09/NOPB part is unused and in its original packaging.
Return procedure for LP8556SQX-E09/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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