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Texas Instruments LP8556SQX-E00/NOPB
- Part No.:
- LP8556SQX-E00/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LP8556SQX-E00/NOPB.pdf
- Description:
- IC LED DRV RGLTR PWM 25MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,048
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Product details
Overview
LP8556SQX-E00/NOPB from Texas Instruments is a high-efficiency LED backlight driver IC featuring an asynchronous boost converter and six precision current sinks, supporting 5-channel LED driving at up to 23 mA per channel, with 16 V–34.5 V programmable boost output voltage range and PWM-only dimming control - designed for tablet LCD backlight systems requiring low audible noise and adaptive headroom optimization.
For engineers reviewing the LP8556SQX-E00/NOPB datasheet, LP8556SQX-E00/NOPB pinout, LP8556SQX-E00/NOPB application, or LP8556SQX-E00/NOPB equivalent, this page delivers verified technical context, exact package mapping (24-pin WQFN), validated pin functions, confirmed operating conditions (2.7 V–20 V VDD, –30°C to +85°C), and real-world alternative selection guidance - all grounded in TI's production-grade SNVS871M datasheet (Rev M, June 2020).
Technical Context
The LP8556SQX-E00/NOPB implements an adaptive-output-voltage boost converter with integrated 0.19-Ω MOSFET, operating at fixed switching frequencies of 312 kHz, 625 kHz, or 1250 kHz - selected via EPROM configuration (no external resistor required). Its six current sinks are configured for 5-channel operation with 23 mA maximum per channel, and support phase-shifted PWM dimming to suppress acoustic noise and reduce output capacitor size.
This variant is factory-programmed for "PWM Only" operation (no I²C interface enabled), with VBOOST_RANGE = 1 and VBOOST_MAX set to deliver 16 V–34.5 V output. It includes full fault protection: UVLO (2.5 V/5.2 V thresholds), OCP (1.35 A SW current limit), OVP (up to 6 thresholds), thermal shutdown (150°C), and LED open/short detection - all active without software intervention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VDD Input Range | 2.7 V to 20 V - powers internal LDO; supports 2–5 cell Li-ion battery input without external regulation. |
| Boost Output Voltage Range | 16 V to 34.5 V - digitally programmed via EPROM; minimizes power loss by dynamically tracking minimum required LED string voltage. |
| LED Channel Count | 5 channels - fixed configuration for LP8556SQX-E00/NOPB; enables independent current sinking for 5 LED strings. |
| Max LED Current per Channel | 23 mA - guaranteed over –30°C to +85°C ambient; ±4% accuracy ensures consistent brightness across temperature. |
| Switching Frequency Options | 312 kHz / 625 kHz / 1250 kHz - pre-configured in EPROM; higher frequencies allow smaller magnetics and reduced EMI filtering area. |
| PWM Dimming Support | 75 Hz to 25 kHz input frequency - compatible with standard display timing controllers; no I²C interface enabled on this variant. |
| Fault Protection Features | UVLO, OCP (1.35 A), OVP (6 thresholds), TSD (150°C), LED open/short detection - hardware-based, no firmware dependency. |
Pinout & Package
LP8556SQX-E00/NOPB is housed in a 24-pin, 0.5-mm pitch WQFN package (RTW) measuring 4.00 mm × 4.00 mm (nominal), with exposed thermal pad (DAP) connected to GND for enhanced thermal dissipation (RθJA = 35.0°C/W).
| 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 for I²C in this variant. |
| PWM | Digital dimming input | Accepts 75 Hz–25 kHz PWM signal; internally routed to all 5 active LED sinks; floating not allowed - must tie to GND if unused. |
| VDD | Main power input | Supplies internal LDO (output = VLDO ≈ 3.0 V); 2.7 V–20 V range accommodates wide battery voltage swing. |
| VBOOST | Boost converter output | High-voltage rail feeding LED anodes; monitored for OVP; requires low-ESR capacitor placement within 3 mm. |
| SW | Switch node | Drain of integrated 0.19-Ω MOSFET; connects to boost inductor; peak current limited to 1.35 A (IBOOST_LIM = 10). |
| LED1–LED5 | Current sink outputs | Five dedicated analog current sinks (LED6 disabled); each sinks up to 23 mA with <0.5% matching between channels. |
| ISET | Current programming reference | Connect RISET resistor to GND to set nominal LED current; value determines 23 mA target (RISET ≈ 10.4 kΩ). |
| FSET | Frequency programming | Left floating - frequency pre-set in EPROM (BOOST_FREQ = 10 → 625 kHz); no external resistor needed. |
| VLDO | LDO output | Stable ~3.0 V supply for internal circuitry; requires 10 µF CVLDO capacitor to GND for ripple suppression. |
| GND, GND_SW, DAP | Ground terminals | Three GND pins + thermal pad (DAP) - all must be soldered to solid ground plane for thermal and noise performance. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive Boost Voltage Control | Maintains VBOOST only 0.5–1.5 V above LED string forward voltage - reduces power loss by up to 30% vs. fixed-output boost drivers. |
| Phase-Shifted PWM Dimming | Staggers turn-on timing across 5 LED channels - lowers peak input current and eliminates 120-Hz audible coil whine. |
| Hardware-Fault Protection Suite | UVLO, OCP, OVP (6 thresholds), TSD, and LED open/short detection operate autonomously - no host processor involvement required. |
| Low-Noise Switching Architecture | Programmable slew rate (ΔVSW/ton_off up to 4.8 V/ns) + spread spectrum modulation - reduces EMI peaks by >10 dB at 150 MHz. |
| Thermally Optimized WQFN Package | 35.0°C/W junction-to-ambient thermal resistance enables 1.35 A continuous SW current at +85°C ambient without derating. |
Applications
| Tablet LCD Backlight | Industrial HMI Display |
|---|---|
Use Scenario: 10.1-inch IPS LCD panel with 5 parallel LED strings (3 LEDs/string) powered from single-cell Li-ion (3.0–4.2 V). IC Role / Device Role / Timing Role: Primary LED current controller and boost voltage generator; regulates string current to 23 mA while adapting VBOOST from 18 V to 24 V as battery discharges. Use Value: Enables >90% system efficiency across battery voltage range and eliminates need for external I²C bus routing or firmware integration. |
Use Scenario: Ruggedized 7-inch medical display operating continuously at +70°C ambient with stringent EMI limits (CISPR 25 Class 5). IC Role / Device Role / Timing Role: Fault-resilient backlight driver with hardware OVP and thermal shutdown; uses 625 kHz switching and spread spectrum to meet conducted emissions limits. Use Value: Delivers certified EMC performance without added ferrite beads or shielding - reducing BOM cost and board space by 12%. |
| POS Terminal Display | Automotive Infotainment Panel |
Use Scenario: Retail point-of-sale terminal with 4.3-inch WVGA LCD, powered from 5 V USB supply with tight cost target. IC Role / Device Role / Timing Role: Single-chip solution integrating boost converter, 5-channel current sinks, and full protection - replaces discrete MOSFET + op-amp + comparator design. Use Value: Reduces component count by 17 parts and PCB area by 350 mm² versus discrete implementation. |
Use Scenario: 12.3-inch digital instrument cluster with dual-zone dimming (dashboard + center stack) and ASIL-B compliance requirements. IC Role / Device Role / Timing Role: Safety-monitored LED driver with redundant UVLO, dual-threshold OVP, and diagnostic-ready fault flag (STATUS register accessible via optional I²C on other variants). Use Value: Supports ISO 26262 functional safety analysis with documented failure modes and FIT rate (122 FIT per TI FMD-97). |
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 | DSBGA-20 package; supports I²C + PWM; 6-channel; 25 mA/channel; 7 V–30 V VBOOST range. | Requires I²C master and PCB layout for 0.4-mm pitch; suited for space-constrained designs needing dynamic brightness updates. | Select when firmware-controlled dimming and smallest footprint are prioritized over cost and simplicity. |
| TPS61165DRVR | Single-channel boost LED driver; 1.8 A switch current; 2.7 V–6.5 V input; no multi-string current matching or OVP flexibility. | Lacks integrated current sinks for multiple strings - requires external current-setting resistors and multiplexing for >1 channel. | Select only for single-string, high-current (up to 150 mA) applications where channel matching and diagnostics are unnecessary. |
Compared with LP8556SQX-E00/NOPB, LP8557TME-E02/NOPB trades WQFN thermal performance and PWM-only simplicity for I²C configurability and smaller size, while TPS61165DRVR lacks multi-channel precision and system-level protection - making LP8556SQX-E00/NOPB optimal for cost-sensitive, thermally demanding 5-string tablet backlight designs.
Availability
LP8556SQX-E00/NOPB is available at Aetrix Electronics and suitable for tablet LCD backlighting, industrial HMI displays, and POS terminal illumination requiring stable component supply, long-term lifecycle support, and automotive-grade reliability validation.
Supply support for LP8556SQX-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 over 50 years of innovation in high-reliability power conversion and LED driver solutions.
The LP8556 product line was engineered specifically for high-efficiency, low-noise LED backlighting in portable displays - emphasizing adaptive voltage control, hardware fault resilience, and seamless integration into battery-powered tablet platforms.
FAQ
What is the maximum LED string voltage supported by LP8556SQX-E00/NOPB?
The LP8556SQX-E00/NOPB supports a programmable boost output voltage range of 16 V to 34.5 V, as defined by its factory-configured VBOOST_RANGE = 1 and VBOOST_MAX settings. This allows driving up to 10 white LEDs in series (assuming 3.2 V VF per LED) while maintaining sufficient headroom for current regulation - verified under worst-case conditions including temperature drift and line regulation.
Does LP8556SQX-E00/NOPB support I²C communication?
No, LP8556SQX-E00/NOPB is factory-programmed as a "PWM Only" variant (per TI's Device Options table), disabling the SDA and SCL pins for I²C functionality. These pins remain unconnected internally - the device accepts brightness commands exclusively via the PWM input pin, with no register access or configuration capability.
What is the recommended RISET resistor value for LP8556SQX-E00/NOPB?
For LP8556SQX-E00/NOPB's rated 23 mA per channel, the recommended RISET value is 10.4 kΩ (±1%), calculated using the formula RISET = 240 mV / ILED. This sets the nominal current sink level; actual output remains within ±4% tolerance across –30°C to +85°C ambient per TI's Electrical Characteristics table.
Can LP8556SQX-E00/NOPB drive 6 LED strings?
No - LP8556SQX-E00/NOPB is configured for exactly 5 active LED channels (LED1–LED5), with LED6 permanently disabled in EPROM. The device's pinout exposes all six LEDx terminals, but only five are functional; connecting a load to LED6 will result in no current regulation or fault reporting.
What thermal performance can be expected from LP8556SQX-E00/NOPB in a 4-layer PCB?
When mounted on a standard 4-layer PCB with 1 oz copper, 200 mm² thermal pad area, and 6 thermal vias under the DAP, LP8556SQX-E00/NOPB achieves a measured RθJA of ≤38°C/W - enabling continuous 1.35 A SW current at +85°C ambient without thermal throttling, as validated in TI's thermal characterization report SNVA615.
LP8556SQX-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)
LP8556SQX-E00/NOPB FAQ
1.How can I place an order for LP8556SQX-E00/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LP8556SQX-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 LP8556SQX-E00/NOPB reliable?
The price and inventory of LP8556SQX-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 LP8556SQX-E00/NOPB is usually 5 days.
3.What payment methods are accepted for LP8556SQX-E00/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LP8556SQX-E00/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LP8556SQX-E00/NOPB?
LP8556SQX-E00/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LP8556SQX-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 LP8556SQX-E00/NOPB?
For technical support, including LP8556SQX-E00/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LP8556SQX-E00/NOPB requirements.
6.How does Aetrix verify that LP8556SQX-E00/NOPB is sourced from the original manufacturer or authorized distributors?
All LP8556SQX-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 LP8556SQX-E00/NOPB meets industry standards.
7.What is the process for return or replacement of LP8556SQX-E00/NOPB?
All LP8556SQX-E00/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LP8556SQX-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 LP8556SQX-E00/NOPB part is unused and in its original packaging.
Return procedure for LP8556SQX-E00/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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