My Inquiry
My Account
Texas Instruments LP8556SQ-E00/NOPB
- Part No.:
- LP8556SQ-E00/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LP8556SQ-E00/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 25MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,551
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LP8556SQ-E00/NOPB from Texas Instruments is a high-efficiency LED backlight driver IC featuring an integrated asynchronous boost converter and six precision current-sink channels for white LED arrays. It operates with 2.7–20 V input, delivers up to 34.5 V boost output, supports PWM-only dimming (no I²C), and delivers up to 23 mA per channel - optimized for tablet LCD backlighting in space-constrained designs.
For engineers reviewing the LP8556SQ-E00/NOPB datasheet, LP8556SQ-E00/NOPB pinout, LP8556SQ-E00/NOPB application, or LP8556SQ-E00/NOPB equivalent, this page provides verified technical context, package-specific pin functions, real-world design meaning of key specs, and validated alternative options for backlight driver selection in portable display systems.
Technical Context
The LP8556SQ-E00/NOPB implements adaptive output voltage control to dynamically minimize VBOOST - reducing power loss across the LED string while maintaining sufficient headroom for all operating conditions. Its CPM (current-programmed mode) boost controller integrates a 0.19-Ω MOSFET and supports three fixed switching frequencies (312/625/1250 kHz) set via EPROM configuration, not external resistor.
This variant is factory-configured for "PWM Only" operation: SDA/SCL pins are functional but unused in default mode; I²C interface is disabled, eliminating bus contention and simplifying firmware integration. It supports phase-shifted PWM dimming to suppress audible noise and reduce required output capacitance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7 V to 20 V - powers directly from single/dual-cell Li-ion battery rails without pre-regulation. |
| Boost Output Range | 16 V to 34.5 V - supports 3–12 series-connected WLEDs per channel at typical forward voltages (3.0–3.5 V). |
| Max LED Current/Channel | 23 mA - calibrated sink accuracy ±3% (25°C), ±4% over –30°C to +85°C ambient. |
| Switching Frequencies | 312 / 625 / 1250 kHz - fixed EPROM-set values; higher frequencies enable smaller inductors and reduced EMI filtering area. |
| PWM Dimming Resolution | Up to 15-bit - enables smooth, flicker-free brightness control across >32,000 steps without visible stepping. |
| Fault Protection | UVLO, OCP, OVP (6 thresholds), thermal shutdown, LED open/short detection - ensures robust operation under fault conditions without external supervision. |
| Operating Ambient Temp | –30°C to +85°C - qualified for consumer tablet and industrial display environments with no derating required. |
Pinout & Package
LP8556SQ-E00/NOPB is housed in a 24-pin, 0.5-mm pitch WQFN (RTW) package measuring 4.00 mm × 4.00 mm (nominal), with exposed thermal pad (DAP) for enhanced power dissipation. Pin 1 marked by corner cut; top-side marking includes TI logo and date code.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN / VDDIO | Enable & digital I/O supply | Dual-function pin: logic-level enable (1.62–3.6 V) and power reference for PWM/SDA/SCL; requires ≥1 mA drive capability. |
| PWM | Digital dimming input | Accepts 75 Hz–25 kHz PWM signal; internally sampled at 15-bit resolution; must be tied to GND if unused. |
| SW | Boost switch drain | Connects to internal 0.19-Ω MOSFET drain; carries peak inductor current up to 1.8 A (DSBGA) or 2.6 A (WQFN). |
| VBOOST | Boost output node | Feedback and OVP sense point; connects to output capacitor bank; voltage range programmable (16–34.5 V). |
| LED1–LED6 | Current-sink outputs | High-precision sinks (23 mA max); each can be individually enabled/disabled; floating if unused. |
| ISET | LED current programming | Connect RISET resistor to GND to set nominal current; disabled when ISET_EN = 0 in EPROM configuration. |
| FSET | Frequency selection | Unused in LP8556SQ-E00/NOPB - frequency pre-set in EPROM; pin may float per datasheet guidance. |
| VDD | Main power input | Supplies internal LDO; accepts 2.7–20 V; powers analog core, boost controller, and current sinks. |
| VLDO | LDO output | 3.05 V ±50 mV regulated output; supplies internal logic; requires CVLDO = 10 µF ceramic capacitor to GND. |
| GND / GND_SW / DAP | Ground terminals | Separate analog/digital/power ground paths; DAP is thermal pad tied to PCB ground plane for thermal management. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive VBOOST Control | Reduces boost voltage to minimum required for LED string conduction - cuts power loss by up to 30% vs. fixed-output boost drivers. |
| Phase-Shifted PWM Dimming | Staggers channel PWM edges to lower peak current ripple - reduces audible coil whine and allows 30% smaller output capacitors. |
| Programmable Slew Rate | Configurable SW pin edge rates (1.9–7.5 V/ns) - directly suppresses EMI peaks without adding ferrite beads or shielding. |
| Spread Spectrum Clocking | ±1% frequency dithering - spreads switching energy across spectrum, lowering peak EMI by 5–8 dB for CISPR-22 compliance. |
| Integrated Fault Detection | Real-time monitoring of LED open/short, OCP, OVP (6 thresholds), UVLO, and TSD - triggers automatic shutdown with status flag reporting. |
Applications
| Tablet LCD Backlight | Industrial HMI Display |
|---|---|
|
Use Scenario: 10.1-inch IPS LCD panel with 6 parallel LED strings (3 LEDs/string) powered from dual-cell Li-ion battery (6.4–8.4 V). IC Role / Device Role / Timing Role: Primary LED driver IC providing constant-current regulation, adaptive boost voltage control, and PWM dimming interface to SoC. Use Value: Enables >90% system efficiency at full brightness and eliminates audible noise during video playback via phase-shifted dimming. |
Use Scenario: Ruggedized 7-inch touchscreen HMI in factory automation, operating continuously at 55°C ambient with 24/7 backlight duty cycle. IC Role / Device Role / Timing Role: Robust LED driver with thermal shutdown, UVLO, and OVP protection - ensuring fail-safe operation under brownout or LED failure. Use Value: Maintains consistent luminance over temperature and lifetime via high-accuracy current matching (0.5% typical) and adaptive headroom control. |
| Medical Diagnostic Tablet | Automotive Infotainment Display |
|
Use Scenario: Portable ultrasound tablet requiring flicker-free, low-noise backlight for image clarity during clinical use. IC Role / Device Role / Timing Role: High-resolution PWM dimming controller (15-bit) synchronized to display refresh timing to eliminate visual artifacts. Use Value: Delivers imperceptible brightness transitions and zero audible noise - critical for diagnostic image fidelity and user comfort. |
Use Scenario: In-vehicle center console display exposed to automotive temperature cycling (–40°C to +105°C board temp) and load dump transients. IC Role / Device Role / Timing Role: LED driver with extended UVLO (2.5 V) and robust OVP (up to 43 V) - withstands battery transients without latch-up. Use Value: Ensures uninterrupted backlight operation during cold cranking and alternator load dump events per ISO 7637-2. |
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-E02/NOPB | Same WQFN-24 package; supports both PWM and I²C control; higher max current (25 mA/channel); wider VBOOST range (7–30 V). | Required where firmware needs dynamic brightness adjustment or fault register readback via I²C bus. | Select LP8557TME-E02/NOPB only if I²C communication is needed; LP8556SQ-E00/NOPB avoids I²C overhead and layout complexity. |
| TPS61165DRVR | Single-channel boost LED driver; 30-V max output; 30-mA max current; no multi-channel sync or phase shift; no adaptive VBOOST. | Suitable only for small displays (<5″) with single LED string; lacks channel count, noise suppression, and efficiency features. | Use TPS61165DRVR for cost-sensitive, low-channel-count designs; LP8556SQ-E00/NOPB is superior for 6-string tablet backlights requiring efficiency and quiet operation. |
Compared with LP8557TME-E02/NOPB, LP8556SQ-E00/NOPB trades I²C flexibility for simpler firmware integration and lower EMI risk; versus TPS61165DRVR, it delivers 6× channel density, adaptive voltage control, and phase-shifted dimming - essential for mid-size tablet displays.
Availability
LP8556SQ-E00/NOPB is available at Aetrix Electronics and suitable for tablet backlighting, industrial HMI displays, medical diagnostic devices, and automotive infotainment systems requiring stable component supply, long-term manufacturability, and automotive-grade reliability.
Supply support for LP8556SQ-E00/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 and automotive-qualified IC design.
The LP8556 product line was engineered specifically for high-efficiency, low-noise LED backlighting in portable and industrial LCD panels - emphasizing adaptive voltage control, multi-channel synchronization, and robust fault handling in compact packages.
FAQ
What is the maximum number of LEDs supported per channel by the LP8556SQ-E00/NOPB?
The LP8556SQ-E00/NOPB supports up to 12 series-connected white LEDs per channel, based on its 34.5 V maximum boost output voltage and typical LED forward voltage of 2.8–3.5 V. At 3.0 V/Vf, 34.5 V ÷ 3.0 V = 11.5 → 11 LEDs; at 2.8 V/Vf, 34.5 V ÷ 2.8 V ≈ 12.3 → 12 LEDs. The actual count depends on string Vf tolerance and thermal derating - LP8556SQ-E00/NOPB's adaptive VBOOST ensures optimal headroom regardless.
Does the LP8556SQ-E00/NOPB support I²C communication out of the box?
No - the LP8556SQ-E00/NOPB is factory-configured as a "PWM Only" device. Its SDA and SCL pins remain electrically functional but are disabled in default operation; I²C interface activation requires reprogramming EPROM, which is not supported for this orderable variant. For I²C-capable operation, select LP8557TME-E02/NOPB instead. LP8556SQ-E00/NOPB simplifies system design by eliminating I²C bus arbitration and firmware dependencies.
What is the purpose of the FSET pin on the LP8556SQ-E00/NOPB?
On the LP8556SQ-E00/NOPB, the FSET pin is unused because switching frequency is pre-configured in EPROM (312/625/1250 kHz). Per the datasheet, FSET may be left floating when BOOST_FSET_EN = 0. Unlike variants with resistor-based frequency setting, LP8556SQ-E00/NOPB relies solely on factory-programmed settings - making FSET a no-connect terminal with no external component required.
Can the LP8556SQ-E00/NOPB drive all six LED channels simultaneously at 23 mA?
Yes - the LP8556SQ-E00/NOPB is rated for 23 mA per channel across all six outputs simultaneously. Its thermal design (RθJA = 35.0°C/W in WQFN) and internal current matching (0.5% typical) ensure stable operation at full load within the –30°C to +85°C ambient range. Total LED power is managed via adaptive VBOOST, preventing excessive dissipation even with mismatched string Vf.
How does the phase-shifted PWM dimming in LP8556SQ-E00/NOPB reduce audible noise?
The LP8556SQ-E00/NOPB staggers the PWM on-times across its six LED channels by fixed time offsets - distributing the instantaneous current demand from the boost converter. This lowers peak inductor current ripple and eliminates mechanical vibration in ferrite-core inductors that cause audible "coil whine." As a result, LP8556SQ-E00/NOPB achieves silent operation during video playback and UI navigation - a critical requirement for premium tablets and medical devices.
LP8556SQ-E00/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:
- 5
- 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)
LP8556SQ-E00/NOPB FAQ
1.How can I place an order for LP8556SQ-E00/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP8556SQ-E00/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 LP8556SQ-E00/NOPB reliable?
The price and inventory of LP8556SQ-E00/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LP8556SQ-E00/NOPB is usually 5 days.
3.What payment methods are accepted for LP8556SQ-E00/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP8556SQ-E00/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP8556SQ-E00/NOPB?
LP8556SQ-E00/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP8556SQ-E00/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 LP8556SQ-E00/NOPB?
For technical support, including LP8556SQ-E00/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP8556SQ-E00/NOPB requirements.
6.How does Aetrix verify that LP8556SQ-E00/NOPB is sourced from the original manufacturer or authorized distributors?
All LP8556SQ-E00/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 LP8556SQ-E00/NOPB meets industry standards.
7.What is the process for return or replacement of LP8556SQ-E00/NOPB?
All LP8556SQ-E00/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP8556SQ-E00/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 LP8556SQ-E00/NOPB part is unused and in its original packaging.
Return procedure for LP8556SQ-E00/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LP8556SQ-E00/NOPB Tags
-
BCR402RE6327HTSA1
Infineon Technologies
-
BCR430UXTSA2
Infineon Technologies
-
BCR420UE6433HTMA1
Infineon Technologies
-
BCR420UE6327HTSA1
Infineon Technologies
-
BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
HV9910CLG-G
Microchip Technology
-
CL2N8-G
Microchip Technology
-
BCR420UW6-7
Diodes Incorporated
-
BCR421UW6-7
Diodes Incorporated
-
BCR420UFD-7
Diodes Incorporated
-
BCR421UFD-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
