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Texas Instruments LM27966SQX
- Part No.:
- LM27966SQX
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LM27966SQX.pdf
- Description:
- IC LED DRV RGLTR I2C 30MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,505
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Product details
Overview
LM27966SQX from Texas Instruments is a highly integrated, I²C-compatible white LED driver with adaptive 1×/1.5× charge pump architecture. It delivers up to 180mA total output current across two independently controlled banks-five main display LEDs (D1–D5) and one auxiliary indicator LED (DAUX)-with 0.3% typical current matching and 91% peak efficiency. Designed for mobile phone display lighting, it operates from 2.7V to 5.5V input and supports resistor-programmable full-scale current via RSET.
For engineers reviewing the LM27966SQX datasheet, LM27966SQX pinout, LM27966SQX application, or LM27966SQX equivalent, key selection considerations include its dual-bank brightness control (32-level PWM for main display, 4-level analog for DAUX), VIN-to-POUT headroom management, thermal shutdown at 170°C, and WQFN-24 (4mm × 4mm) package compatibility with high-density portable PCB layouts.
Technical Context
The LM27966SQX implements an adaptive gain charge pump that dynamically switches between 1× (pass-through) and 1.5× modes based on real-time monitoring of VDX voltage across D1–D4 pins-ensuring optimal efficiency across the 2.7V–5.5V input range. Its internal current sinks use a precision 1.25V reference and 200× current gain from ISET to deliver tightly matched LED drive currents.
It integrates a full I²C-compatible interface (slave address 0x36) with dedicated registers for main display (0xA0) and auxiliary (0xC0) brightness control, plus a general-purpose register (0x10) for enabling/disabling banks and disabling D5 sensing. The RESET pin provides hardware-level disable independent of I²C communication.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7V to 5.5V - supports single-cell Li-ion battery operation without external regulation. |
| Total Output Current | 180mA max - distributed across six independently controllable current sinks (D1–D5 + DAUX). |
| LED Current Matching | 0.3% typical - ensures uniform brightness across main display LEDs under varying temperature and supply conditions. |
| Charge Pump Efficiency | 91% peak - achieved via adaptive 1×/1.5× gain selection and low ROUT (2.75Ω typical). |
| Brightness Control | Main: 32-step PWM (20kHz); AUX: 4-step analog - enables precise perceptual dimming without visible flicker. |
| I²C Address | 0x36 (7-bit) - allows multi-device bus configuration with standard I²C master controllers. |
| Thermal Shutdown | Engages at TJ = 170°C (typ.), releases at 165°C - protects against sustained overloads in compact handheld enclosures. |
Pinout & Package
LM27966SQX is housed in a 24-pin WQFN package (RTW0024A), 4.0mm × 4.0mm × 0.8mm, with exposed thermal pad (DAP) connected to GND for enhanced power dissipation. Pin pitch is 0.5mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (24) | Power Input | Supplies charge pump and internal circuitry; accepts 2.7V–5.5V Li-ion range with ±0.3V absolute max rating. |
| POUT (23) | Charge Pump Output | Regulated output node feeding all LED cathodes; voltage tracks VIN in 1× mode or steps to ~1.5×VIN in boost mode. |
| D1–D5 (12–16), DAUX (3) | LED Current Sink Outputs | Five main-display and one auxiliary constant-current sinks; each supports ≤30mA with programmable full-scale via RSET. |
| ISET (17) | Current Reference Input | Connects to GND via RSET; sets full-scale LED current as IDx = 200 × (1.25V / RSET). |
| SCL (1), SDIO (2), VIO (7) | I²C Interface | Standard open-drain I²C bus signals; VIO defines logic threshold (1.4V–VIN) and must match host controller voltage. |
| RESET (10) | Hardware Reset | Active-low asynchronous reset; forces all registers to default state and disables all outputs when pulled low. |
| GND (9, 18, DAP) | Ground Reference | Three dedicated ground pins plus thermal pad ensure low-impedance return path and stable current regulation. |
| NC (4, 5, 6, 8, 11) | No Connect | Unbonded pins; must remain unconnected per TI design guidelines to avoid parasitic coupling. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive Gain Charge Pump | Automatically selects 1× or 1.5× mode based on real-time VDX voltage to maximize efficiency across input and LED Vf variations. |
| Dual Independent Brightness Banks | Main display (D1–D5) uses 32-step PWM; DAUX uses 4-step analog scaling - eliminates need for separate drivers in dual-lighting systems. |
| Resistor-Programmable Full-Scale Current | RSET value directly determines LED current (e.g., 16.9kΩ → 15mA per Dx; 8.33kΩ → 30mA), enabling precise BOM optimization. |
| LED Forward Voltage Sensing | Monitors D1–D4 pins to trigger gain transition at ~175mV headroom - prevents current pinch-off and maintains regulation down to 2.0V LED Vf. |
| Hardware RESET with Asynchronous Disable | Independent of I²C state; allows system-level power sequencing and failsafe shutdown without firmware intervention. |
Applications
| Mobile Phone Main Display | Smartphone Indicator Lighting |
|---|---|
Use Scenario: Backlighting a 3.5-inch TFT-LCD panel with five parallel white LEDs in a compact handset. IC Role / Device Role / Timing Role: Constant-current sink driver with adaptive charge pump gain and I²C-controlled 32-level PWM dimming. Use Value: Delivers uniform brightness at 91% efficiency while extending battery life through dynamic gain selection and low quiescent current (3.32mA typ. in 1.5× no-load). | Use Scenario: Driving a status LED for notification, charging, or Bluetooth pairing in space-constrained smartphone bezel. IC Role / Device Role / Timing Role: Independently controlled auxiliary current sink with 4-level analog brightness scaling. Use Value: Enables discrete visual feedback without requiring additional driver ICs or GPIO resources-reducing BoM count and PCB area. |
| PDA Backlight System | Portable Media Player UI Lighting |
Use Scenario: Powering a 4.3-inch WVGA LCD backlight using four main-display LEDs and one spare channel for future expansion. IC Role / Device Role / Timing Role: Dual-bank LED driver with shared RSET programming and synchronized I²C register access. Use Value: Simplifies firmware by allowing simultaneous brightness updates across main and auxiliary banks using a single I²C transaction sequence. | Use Scenario: Illuminating button icons and status indicators on a handheld music/video player with variable ambient light conditions. IC Role / Device Role / Timing Role: Low-noise analog dimming source for non-flickering indicator illumination. Use Value: Provides smooth, stepless brightness transitions (20%/40%/70%/100%) without audible coil whine or EMI from PWM switching. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3530RSDX/NOPB | 6-channel I²C LED driver with 8-bit linear DAC per channel; no adaptive charge pump; requires external boost converter for >VIN LED loads. | Designed for higher-resolution dimming (256 steps) but lacks integrated charge pump - needs external power stage for 3.6V+ LEDs. | Select LM3530RSDX/NOPB only if fine-grained analog dimming is prioritized over integration and efficiency. |
| TPS61165DRVR | Single-output boost LED driver with 1.2MHz fixed-frequency PWM; supports up to 40mA; no I²C interface - uses analog/digital enable and PWM input for brightness control. | Targeted at single-LED applications with simple on/off or external PWM dimming; no multi-bank capability or I²C register control. | Choose TPS61165DRVR when system already uses discrete PWM generation and only one LED bank is required. |
Compared with LM27966SQX, LM3530RSDX/NOPB offers finer dimming resolution but demands external power conversion for typical white LED forward voltages, while TPS61165DRVR simplifies control at the cost of losing dual-bank independence and digital configurability-making LM27966SQX optimal for integrated dual-lighting subsystems in battery-powered handhelds.
Availability
LM27966SQX is available at Aetrix Electronics and suitable for mobile phone display lighting, PDA backlighting, and portable media player UI lighting requiring stable component supply and long-term production continuity.
Supply support for LM27966SQX 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 energy-efficient electronics.
The LM27966SQX belongs to TI's display power management product line, engineered specifically for high-efficiency, multi-bank white LED driving in space- and power-constrained portable devices.
FAQ
What is the maximum LED forward voltage supported by the LM27966SQX?
The LM27966SQX supports LED forward voltages from 2.0V to 4.0V per diode. Its adaptive charge pump automatically transitions between 1× and 1.5× gain modes to maintain regulation-enabling reliable operation even as LED Vf varies with temperature or aging. For example, at VIN = 3.6V and Vf = 3.6V, the device operates in 1× mode; below ~3.2V input, it shifts to 1.5× to sustain 180mA total output. This range is validated across the full –30°C to +85°C ambient operating temperature.
How do I configure the LM27966SQX for 30mA per LED in the main display bank?
To set 30mA per LED on the LM27966SQX main display bank (D1–D5), connect a 8.33kΩ resistor between ISET (Pin 17) and GND. This yields IDx = 200 × (1.25V / 8.33kΩ) ≈ 30mA. Confirm operation using the Electrical Characteristics table: at RSET = 8.33kΩ and VIN = 3.6V, the LM27966SQX delivers 30mA (±7.7%) across all enabled Dx pins. Ensure D5 sensing is disabled via EN-D5 = 0 in the General Purpose Register (0x10) if D5 is unused.
Does the LM27966SQX require external capacitors, and what values are recommended?
Yes, the LM27966SQX requires four external ceramic capacitors: two flying capacitors (C1, C2) and two bulk capacitors (CIN, COUT). TI specifies 1.0µF, X5R, 0603-size MLCCs rated for ≥6.3V (e.g., TDK C1608X5R1A105K). C1/C2 handle charge transfer between VIN and POUT; CIN filters input ripple; COUT stabilizes POUT. All must be low-ESR surface-mount types-failure to meet these specs risks instability, reduced efficiency, or startup failure.
Can the LM27966SQX drive more than six LEDs?
The LM27966SQX has six dedicated current sinks (D1–D5 + DAUX), but outputs can be paralleled: D1–D5 may be shorted to drive one high-current LED up to 150mA (5 × 30mA), provided RSET is recalculated so each sink contributes 20% of total target current (e.g., 60mA total → 12mA/sink → RSET = 20.8kΩ). DAUX remains independent. Parallel operation preserves all electrical specs-including matching and thermal limits-but disables D1–D4 forward-voltage sensing, forcing permanent 1.5× mode unless D5 is grounded and EN-D5 = 0.
What I²C timing parameters must be met for reliable communication with the LM27966SQX?
The LM27966SQX requires SCL clock period ≥2.5µs (max 400kHz), data setup time ≥100ns before SCL high, and data hold time ≥100ns after SCL high for START/STOP conditions. SDIO must remain stable during SCL high periods. TI validates operation with VIO = 1.8V–3.3V and pull-up resistors sized per VOL spec: RPU > (VIO – 0.4V)/3mA (e.g., ≥567Ω at VIO = 2.2V). Violating these causes register write failures or intermittent brightness control-especially during rapid dimming transitions.
LM27966SQX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 24-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- DC DC Regulator
- Topology:
- Switched Capacitor (Charge Pump)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 6
- Voltage - Supply (Min):
- 2.7V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 2V ~ 4V
- Current - Output / Channel:
- 30mA
- Frequency:
- 1.27MHz
- Dimming:
- I2C
- Applications:
- Backlight
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-WQFN (4x4)
LM27966SQX FAQ
1.How can I place an order for LM27966SQX through Aetrix?
Please submit a Request for Quotation (RFQ) for LM27966SQX 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 LM27966SQX reliable?
The price and inventory of LM27966SQX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM27966SQX is usually 5 days.
3.What payment methods are accepted for LM27966SQX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM27966SQX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM27966SQX?
LM27966SQX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM27966SQX 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 LM27966SQX?
For technical support, including LM27966SQX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM27966SQX requirements.
6.How does Aetrix verify that LM27966SQX is sourced from the original manufacturer or authorized distributors?
All LM27966SQX 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 LM27966SQX meets industry standards.
7.What is the process for return or replacement of LM27966SQX?
All LM27966SQX units undergo pre-shipment inspection (PSI). If there is an issue with LM27966SQX, 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 LM27966SQX part is unused and in its original packaging.
Return procedure for LM27966SQX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM27966SQX Tags
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BCR402RE6327HTSA1
Infineon Technologies
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
Infineon Technologies
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BCR420UE6327HTSA1
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BCR421UE6327HTSA1
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LYT1604D-TL
Power Integrations
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HV9910CLG-G
Microchip Technology
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CL2N8-G
Microchip Technology
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
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