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Texas Instruments LP8556SQX-E08/NOPB
- Part No.:
- LP8556SQX-E08/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LP8556SQX-E08/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 23MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,921
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Product details
Overview
LP8556SQX-E08/NOPB from Texas Instruments is a high-efficiency white LED backlight driver IC featuring an asynchronous boost converter and four precision current sinks for tablet LCD applications. It operates with 2.7–20 V input, delivers up to 43 V boost output, supports 312/625/1250 kHz switching frequencies, and provides PWM-only brightness control with up to 15-bit dimming resolution.
For engineers reviewing the LP8556SQX-E08/NOPB datasheet, LP8556SQX-E08/NOPB pinout, LP8556SQX-E08/NOPB application, or LP8556SQX-E08/NOPB equivalent, this device is selected for space-constrained tablet backlight designs requiring adaptive voltage control, phase-shifted PWM dimming, robust fault protection (OVP, OCP, open/short LED detection), and operation across –30°C to +85°C ambient.
Technical Context
The LP8556SQX-E08/NOPB integrates a CPM-mode boost controller with a 0.19-Ω internal MOSFET and adaptive output voltage regulation that dynamically adjusts VBOOST to the minimum required level-reducing power loss and heat generation. Its EPROM-configured variant E08 fixes channel count at four, disables I²C interface, and sets maximum LED current to 50 mA per sink.
It implements programmable slew-rate control and spread-spectrum modulation to suppress EMI, while phase-shifted PWM dimming across channels minimizes audible noise and allows smaller output capacitors. Fault protection includes UVLO (2.5 V falling threshold), thermal shutdown (150°C), six-level OVP, and LED open/short detection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7 V to 20 V - powers directly from multi-cell Li-ion battery packs without external LDO pre-regulation. |
| Boost Output Range | 7 V to 43 V - supports 3–12 series-connected WLEDs per channel with adaptive headroom control. |
| Switching Frequencies | 312 / 625 / 1250 kHz - selectable via EPROM; higher frequencies enable smaller inductors and reduced EMI filter size. |
| LED Channel Count | 4 channels - fixed by E08 EPROM configuration; each channel drives one independent LED string. |
| Max Sink Current | 50 mA per channel - sufficient for high-brightness tablet backlights; accuracy ±3% at 23 mA over temperature. |
| PWM Dimming Resolution | Up to 15 bits - enables ultra-fine brightness control down to 0.02% duty cycle at 100 Hz, critical for HDR display support. |
| Fault Protections | OVP (6 thresholds), OCP, UVLO, TSD, LED open/short detection - ensures system reliability without external monitoring circuitry. |
Pinout & Package
LP8556SQX-E08/NOPB is packaged in a 20-pin, 0.4-mm pitch DSBGA (YFQ) measuring 2.401 mm × 1.74 mm (max). This ultra-compact package targets thin-profile tablet PCBs with tight layout constraints and requires microvia routing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN / VDDIO | Dual-purpose enable & I/O supply | Must be driven ≥1.62 V to enable device; supplies logic threshold reference for PWM, SDA, SCL (not used in E08 variant). |
| PWM | Digital dimming input | Accepts 75 Hz–25 kHz PWM signal; unused pins must be tied to GND; controls all 4 channels synchronously or with phase shift. |
| VDD | Main power input | 2.7–20 V input to internal LDO; powers entire IC including boost gate driver and analog blocks. |
| VBOOST | Boost converter output | High-voltage node (7–43 V); connects to boost capacitor bank; monitored for OVP and feedback regulation. |
| SW | Power switch drain | Connects to inductor and diode; carries peak currents up to 2.07 A (E08 config); requires low-inductance layout. |
| GND_SW | Switch source ground | Separate ground return for high-current SW path; must be routed independently from signal GND to minimize noise coupling. |
| LED1–LED4 | Current sink outputs | Four dedicated high-precision sinks (50 mA max); each drives one WLED string cathode; open-drain with 200 mV saturation. |
| ISET | Current programming node | Connect RISET resistor to GND to set nominal LED current; floating if ISET_EN = 0 (E08 uses EPROM-programmed value). |
| FSET | Frequency programming node | Connect RFSET resistor to GND to select boost/PWM frequency; floating in E08 since frequency is EPROM-configured. |
| VLDO | LDO output | 3.0 V ±5% regulated output; powers internal circuitry; requires 10 µF CVLDO capacitor to GND for stability. |
| GND | Signal and power ground | Multiple GND pads (A3/B3/D3/E3/DAP) provide low-impedance return paths; must be connected to solid ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive VBOOST Control | Maintains minimum sufficient 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 PWM edges across LED1–LED4 channels to cancel acoustic noise and lower RMS input current ripple, enabling smaller input capacitors. |
| Integrated 0.19-Ω MOSFET | Eliminates external high-side switch; reduces BOM count and PCB area; supports continuous 2.07 A SW current in DSBGA package. |
| Slew-Rate & Spread-Spectrum Control | Configurable edge rates (1.9–7.5 V/ns) and ±1% spread spectrum reduce peak EMI by >10 dB, easing CISPR-22 Class B compliance. |
| Full Fault Protection Suite | Single-chip solution for UVLO, OCP, OVP (6 thresholds), TSD, and LED open/short detection-no external comparators or sense resistors needed. |
Applications
| Tablet LCD Backlight | Industrial HMI Display |
|---|---|
Use Scenario: Driving 4 parallel WLED strings in a 10.1-inch tablet with 2000 cd/m² peak brightness and 10,000:1 contrast ratio. IC Role / Device Role / Timing Role: Primary LED driver IC providing adaptive boost voltage, synchronized 4-channel PWM dimming, and real-time fault monitoring. Use Value: Enables 30% longer battery life via adaptive VBOOST, eliminates audible coil whine through phase-shifted PWM, and ensures field reliability with integrated OVP/OCP. |
Use Scenario: Backlighting a ruggedized 7-inch industrial panel operating continuously at 70°C ambient in factory automation equipment. IC Role / Device Role / Timing Role: Constant-current LED driver with thermal shutdown (150°C) and wide input range (2.7–20 V) to tolerate unregulated 12 V DC bus fluctuations. Use Value: Maintains consistent brightness across temperature and input voltage variations; built-in LED open/short detection prevents display blackouts during field operation. |
| Medical Diagnostic Tablet | Automotive Infotainment Display |
Use Scenario: Powering high-color-fidelity backlight in portable ultrasound tablet requiring flicker-free dimming down to 0.1% brightness for low-light imaging. IC Role / Device Role / Timing Role: Precision current sink IC delivering 15-bit PWM resolution and <0.5% current matching across 4 channels for uniform luminance. Use Value: Supports clinical-grade grayscale rendering; adaptive dimming preserves optical efficiency at ultra-low brightness levels without color shift. |
Use Scenario: Backlighting a 12.3-inch digital instrument cluster with AEC-Q200-compliant thermal performance and EMI resilience in noisy vehicle environments. IC Role / Device Role / Timing Role: EMI-optimized LED driver using spread-spectrum switching and slew-rate control to meet automotive CISPR-25 Level 5 radiated emissions limits. Use Value: Passes stringent automotive EMC testing without added ferrites or shielding; robust UVLO and OVP protect against load-dump transients. |
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-E08/NOPB | Same DSBGA-20 package, identical E08 EPROM config, but adds I²C interface capability (unused in E08 mode). | Offers future firmware-upgrade path to I²C control; no change in pinout or electrical behavior for PWM-only use. | Select LP8557TME-E08/NOPB only if system design reserves option to add I²C-based dynamic brightness adjustment later. |
| TPS61165DRVR | Single-channel 40-V boost LED driver with 1.2-MHz fixed frequency; lacks multi-channel sync, phase shift, or adaptive VBOOST. | Requires four separate ICs to match LP8556SQX-E08/NOPB's 4-channel capability-increasing cost, board area, and thermal density. | Choose TPS61165DRVR only for simple single-string designs where channel count and EMI performance are secondary concerns. |
Compared with LP8556SQX-E08/NOPB, LP8557TME-E08/NOPB offers identical functionality with latent I²C readiness, while TPS61165DRVR requires quadrupling component count and sacrifices adaptive voltage control and phase-shifted dimming-making LP8556SQX-E08/NOPB optimal for compact, high-efficiency multi-string tablet backlighting.
Availability
LP8556SQX-E08/NOPB is available at Aetrix Electronics and suitable for tablet LCD backlighting, industrial HMI displays, medical diagnostic tablets, and automotive infotainment systems requiring stable component supply, long-term lifecycle support, and guaranteed traceability.
Supply support for LP8556SQX-E08/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 company specializing in analog and embedded processing technologies, with leadership in power management, signal chain, and high-reliability ICs.
The LP8556 product line is designed specifically for high-efficiency, low-EMI LED backlighting in portable consumer and industrial displays-emphasizing adaptive voltage control, multi-channel synchronization, and comprehensive fault protection.
FAQ
What is the maximum number of LED strings supported by LP8556SQX-E08/NOPB?
LP8556SQX-E08/NOPB supports exactly four LED strings, as defined by its E08 EPROM configuration. Unlike programmable variants, this version permanently fixes the channel count to four high-precision current sinks (LED1–LED4), with no software or hardware means to enable or disable additional channels. The IC does not support five or six strings in this variant.
Does LP8556SQX-E08/NOPB support I²C communication?
No, LP8556SQX-E08/NOPB is configured as a "PWM Only" variant per TI's Device Options table. Its EPROM disables the I²C interface-pins SDA and SCL are non-functional and must be left unconnected or tied to appropriate voltage levels per layout guidelines. Communication is limited to PWM signal input on the PWM pin.
What is the recommended inductor value for LP8556SQX-E08/NOPB at 625 kHz switching frequency?
For 625 kHz operation, TI recommends a 4.7 µH shielded power inductor with ≥2.5 A saturation current (e.g., Coilcraft XAL4020-472MEB). This value balances efficiency, size, and transient response per the Typical Application schematic in the LP8556 datasheet (Figure 9, page 47), and is validated for the E08 variant's 2.07 A SW current limit.
How does adaptive VBOOST control improve efficiency in LP8556SQX-E08/NOPB?
LP8556SQX-E08/NOPB continuously monitors LED string forward voltage and dynamically adjusts VBOOST to the lowest level sufficient to maintain regulation-typically 0.5–1.5 V above the highest string Vf. This reduces power dissipation in the current sinks and boost diode, improving system efficiency by up to 30% compared to fixed-output boost architectures under varying LED aging and temperature conditions.
What thermal derating applies to LP8556SQX-E08/NOPB in a 20-pin DSBGA package?
With RθJA = 66.2°C/W (DSBGA), LP8556SQX-E08/NOPB requires ambient temperature derating above 60°C when dissipating >300 mW. For example, at 85°C ambient, maximum allowable power dissipation drops to ~180 mW. Adequate PCB copper area (≥4 cm² thermal pad connected to internal ground plane) is mandatory to sustain full 50 mA/channel operation across –30°C to +85°C.
LP8556SQX-E08/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:
- 4
- 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-E08/NOPB FAQ
1.How can I place an order for LP8556SQX-E08/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP8556SQX-E08/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-E08/NOPB reliable?
The price and inventory of LP8556SQX-E08/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-E08/NOPB is usually 5 days.
3.What payment methods are accepted for LP8556SQX-E08/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP8556SQX-E08/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP8556SQX-E08/NOPB?
LP8556SQX-E08/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP8556SQX-E08/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-E08/NOPB?
For technical support, including LP8556SQX-E08/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP8556SQX-E08/NOPB requirements.
6.How does Aetrix verify that LP8556SQX-E08/NOPB is sourced from the original manufacturer or authorized distributors?
All LP8556SQX-E08/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-E08/NOPB meets industry standards.
7.What is the process for return or replacement of LP8556SQX-E08/NOPB?
All LP8556SQX-E08/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP8556SQX-E08/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-E08/NOPB part is unused and in its original packaging.
Return procedure for LP8556SQX-E08/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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