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Texas Instruments LM27966SQ/NOPB
- Part No.:
- LM27966SQ/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LM27966SQ/NOPB.pdf
- Description:
- IC LED DRV RGLTR I2C 30MA 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:872
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Product details
Overview
LM27966SQ/NOPB from Texas Instruments is a highly integrated I²C-compatible white LED driver with adaptive 1×/1.5× charge pump, driving up to 6 LEDs (5 main + 1 auxiliary) at total 180mA output current, 0.3% current matching, and 91% peak efficiency - used in mobile phone display backlighting and indicator lighting.
For engineers reviewing the LM27966SQ/NOPB datasheet, LM27966SQ/NOPB pinout, LM27966SQ/NOPB application, or LM27966SQ/NOPB equivalent, key selection criteria include I²C register-addressable dual-bank brightness control (32-level main / 4-level aux), resistor-programmable full-scale current via RSET, 2.7V–5.5V input range, and WQFN-24 thermal performance with DAP ground pad.
Technical Context
The LM27966SQ/NOPB implements an adaptive gain charge-pump architecture that dynamically switches between 1× (pass-mode) and 1.5× based on real-time forward-voltage sensing across D1–D5 pins - maximizing efficiency by maintaining minimum headroom voltage (110 mV typical) while regulating current. It uses internal 20 kHz PWM for main-display dimming and analog scaling for DAUX.
Its dual-current-sink topology separates main display (D1–D5, configurable 4–5 LEDs) from auxiliary (DAUX) functions, each independently enabled and brightness-controlled via I²C registers (0xA0 and 0xC0) using slave address 0x36. The ISET pin sets full-scale current via external RSET (IDx = 200 × 1.25 V / RSET), with VIO pin enabling flexible logic-level interfacing (1.4 V to VIN).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.7 V to 5.5 V - supports single-cell Li-ion battery operation without external regulation. |
| Total Output Current | 180 mA max - distributed across two independent banks (≤30 mA per Dx/DAUX pin). |
| LED Current Matching | 0.3% typical - ensures uniform brightness across all 5 main-display LEDs under varying VLED and temperature. |
| Charge Pump Efficiency | 91% peak - achieved via adaptive 1×/1.5× gain selection and low-ROUT (2.75 Ω typical). |
| I²C Interface | Standard-mode compatible (36h slave address) - enables software-configurable brightness, enable/disable, and gain control without hardware changes. |
| Thermal Protection | Auto-shutdown at 170°C junction, recovery at 165°C - prevents permanent damage during sustained high-power operation. |
| Package | WQFN-24 (4 mm × 4 mm × 0.8 mm, RTW0024A) - includes exposed DAP for enhanced thermal dissipation (θJA = 41.3°C/W). |
Pinout & Package
LM27966SQ/NOPB is housed in a 24-pin Quad WQFN package (RTW0024A) with wettable flank leads and thermally enhanced exposed die attach pad (DAP) connected to GND. Pin 1 is SCL; pin 2 is SDIO; pins 9, 18, and DAP are GND; pin 10 is RESET; pin 24 is VIN; pin 23 is POUT; pins 12–16 are D1–D5; pin 3 is DAUX; pin 17 is ISET; pin 7 is VIO; pins 19, 20, 21, 22 are C1+/C1−/C2+/C2−; pins 4, 5, 6, 8, 11 are NC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SCL (Pin 1) | I²C serial clock input | Accepts standard-mode clock up to 400 kHz; referenced to VIO for level translation. |
| SDIO (Pin 2) | I²C bidirectional data line | Open-drain with external pull-up; acknowledges writes with 9th-bit low pulse. |
| DAUX (Pin 3) | Auxiliary LED current sink output | Independent 4-level analog dimming; no forward-voltage sensing - fixed gain operation. |
| D1–D5 (Pins 12–16) | Main display LED current sinks | Each drives one LED anode; forward-voltage sensing enables adaptive 1×/1.5× charge-pump gain switching. |
| ISET (Pin 17) | Current reference programming node | 1.25 V regulated reference; sets full-scale LED current via RSET (IDx = 200 × 1.25 V / RSET). |
| RESET (Pin 10) | Hardware reset input | Active-low asynchronous reset - forces all registers to power-on defaults and disables outputs. |
| VIO (Pin 7) | I²C logic-level reference | Defines SCL/SDIO voltage thresholds (VIH = 0.7×VIO); supports 1.4 V to VIN interface compatibility. |
| GND (Pins 9, 18, DAP) | Power and signal return path | DAP must be soldered to PCB ground plane for thermal and electrical integrity. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive 1×/1.5× charge pump | Switches gain automatically based on D1–D5 forward voltage to maintain >91% efficiency across 2.7–5.5 V input range. |
| Dual independent LED banks | Main display (D1–D5, 32-step PWM dimming) and auxiliary (DAUX, 4-step analog dimming) enable simultaneous but separate brightness control. |
| Resistor-programmable current | RSET between ISET and GND sets full-scale current from 15 mA to 30 mA per channel with ±9.5% regulation accuracy. |
| Integrated thermal shutdown | Protects against overtemperature failure with hysteresis (170°C trip / 165°C release) and no external components required. |
| Small leadless WQFN package | 4 mm × 4 mm footprint with exposed DAP reduces board area and improves thermal resistance (θJA = 41.3°C/W). |
Applications
| Mobile Phone Main Display Backlight | Smartphone Indicator LED |
|---|---|
Use Scenario: Driving 5 parallel white LEDs behind a 3.5-inch TFT-LCD panel in a GSM smartphone powered by a 3.7 V Li-ion battery. IC Role / Device Role / Timing Role: Constant-current charge-pump LED driver with adaptive gain and I²C brightness control - regulates current per LED while optimizing efficiency as battery discharges. Use Value: Delivers uniform brightness (0.3% matching) and extends battery life via 91% peak efficiency and pass-mode operation above 3.8 V input. | Use Scenario: Powering a status LED (e.g., charging indicator or notification light) on the front bezel of a compact Android handset. IC Role / Device Role / Timing Role: Auxiliary current sink with independent 4-level analog dimming - operates concurrently with main display bank without shared control registers. Use Value: Enables distinct visual feedback (e.g., pulsing amber for charging) without requiring additional driver ICs or firmware overhead. |
| PDA Display Lighting | Portable Media Player UI Lighting |
Use Scenario: Backlighting a QVGA resistive touchscreen in an industrial PDA operating from a 3.3 V regulated rail. IC Role / Device Role / Timing Role: Compact, inductorless LED driver supporting 4-LED main bank configuration with hardware RESET for system-level power sequencing. Use Value: Eliminates magnetic interference and board space penalty of inductors while meeting EMI requirements for handheld medical/data collection devices. | Use Scenario: Illuminating button icons and OLED status displays in a battery-powered MP3 player with variable ambient light conditions. IC Role / Device Role / Timing Role: Dual-bank driver allowing synchronized dimming of UI elements (main bank) and independent pulsing of playback status (DAUX). Use Value: Reduces BOM count by consolidating two lighting functions into one IC with minimal external components (4 caps + 1 RSET). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar white LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3530UMX/NOPB | 6-channel I²C LED driver with 12-bit linear dimming; requires external LDO for bias; no adaptive charge pump. | Designed for RGB backlighting with independent per-channel control - less efficient for monochrome white LED arrays. | Choose LM3530UMX/NOPB only when precise color mixing or >100 dimming steps are required; LM27966SQ/NOPB offers higher efficiency and simpler BOM for white-only use. |
| TPS61165DRVR | Single-output boost converter LED driver; 1.2 MHz fixed-frequency; no I²C interface; analog/dim pin control only. | Optimized for high-VF LEDs (up to 28 V) - lacks multi-bank capability and digital brightness control. | Use TPS61165DRVR for high-voltage single-LED applications where I²C control is unnecessary; LM27966SQ/NOPB is superior for dual-bank, software-configurable, low-input-voltage designs. |
Compared with LM3530UMX/NOPB and TPS61165DRVR, LM27966SQ/NOPB uniquely combines adaptive charge-pump efficiency, dual independent LED banks, and I²C register control in a thermally optimized 4 mm × 4 mm package - making it optimal for space-constrained mobile displays requiring both main backlight and auxiliary indicator functionality.
Availability
LM27966SQ/NOPB is available at Aetrix Electronics and suitable for mobile phone display lighting, PDA backlighting, and portable media player UI illumination requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM27966SQ/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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.
The LM27966SQ/NOPB belongs to TI's white LED driver product line, engineered specifically for high-efficiency, inductorless backlighting in battery-powered handheld devices with stringent size and thermal constraints.
FAQ
What is the maximum number of LEDs the LM27966SQ/NOPB can drive simultaneously?
The LM27966SQ/NOPB can drive up to six LEDs: five in the main display bank (D1–D5) and one auxiliary LED (DAUX). Each D1–D5 pin supports up to 30 mA, and DAUX supports up to 30 mA, for a total output current limit of 180 mA. Parallel connection of D1–D5 is supported for higher-current single-LED applications, but individual pin current must not exceed 30 mA. The LM27966SQ/NOPB datasheet specifies this configuration in the "Parallel Connected and Unused Outputs" section.
How does the LM27966SQ/NOPB achieve 91% peak efficiency without an inductor?
The LM27966SQ/NOPB achieves 91% peak efficiency using an adaptive switched-capacitor charge pump that operates in either 1× (pass-mode) or 1.5× gain mode. It selects the optimal gain based on real-time forward-voltage sensing across D1–D5 pins - staying in efficient 1× mode when input voltage is sufficient, and switching to 1.5× only when needed to maintain current regulation. This eliminates inductor losses while minimizing switching and conduction losses. The LM27966SQ/NOPB's low 2.75 Ω output resistance and 110 mV headroom requirement further contribute to its high efficiency.
What is the function of the RSET resistor in the LM27966SQ/NOPB circuit?
The RSET resistor connected between the ISET pin and GND sets the full-scale LED current for both the main display (D1–D5) and auxiliary (DAUX) banks using the formula IDx = 200 × 1.25 V / RSET. For example, a 16.9 kΩ RSET yields ~15 mA per channel. The LM27966SQ/NOPB's internal amplifier holds ISET at 1.25 V (typ.), making current setting predictable and stable across temperature and supply variations. RSET value directly determines maximum programmable brightness and impacts thermal design - undersized RSET risks exceeding 30 mA per pin or 180 mA total.
Can the LM27966SQ/NOPB operate with a 1.8 V I²C bus?
Yes, the LM27966SQ/NOPB supports 1.8 V I²C operation via the VIO pin, which defines logic thresholds for SCL and SDIO. When VIO = 1.8 V, VIH = 1.26 V (min) and VIL = 0.54 V (max), fully compatible with standard 1.8 V GPIO interfaces. The LM27966SQ/NOPB's I²C slave address is fixed at 0x36, and it responds to standard-mode (100 kHz) and fast-mode (400 kHz) clocks. Pull-up resistors on SCL/SDIO must be referenced to VIO, not VIN, to ensure correct logic levels.
Does the LM27966SQ/NOPB require external capacitors, and if so, what values are recommended?
Yes, the LM27966SQ/NOPB requires four external ceramic capacitors: two flying capacitors (C1, C2) and two bulk capacitors (CIN, COUT). TI recommends 1.0 µF, X5R, 0603-size MLCCs rated for ≥6.3 V (e.g., TDK C1608X5R1A105K or equivalent). C1/C2 provide charge transfer for the 1.5× pump; CIN filters input ripple; COUT stabilizes POUT. All capacitors must be placed close to their respective pins with short, low-inductance traces. The LM27966SQ/NOPB datasheet specifies ESR < 100 mΩ and Z < 1 Ω at 1 MHz for optimal performance.
LM27966SQ/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:
- 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)
LM27966SQ/NOPB FAQ
1.How can I place an order for LM27966SQ/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM27966SQ/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 LM27966SQ/NOPB reliable?
The price and inventory of LM27966SQ/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM27966SQ/NOPB is usually 5 days.
3.What payment methods are accepted for LM27966SQ/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM27966SQ/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM27966SQ/NOPB?
LM27966SQ/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM27966SQ/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 LM27966SQ/NOPB?
For technical support, including LM27966SQ/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM27966SQ/NOPB requirements.
6.How does Aetrix verify that LM27966SQ/NOPB is sourced from the original manufacturer or authorized distributors?
All LM27966SQ/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 LM27966SQ/NOPB meets industry standards.
7.What is the process for return or replacement of LM27966SQ/NOPB?
All LM27966SQ/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM27966SQ/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 LM27966SQ/NOPB part is unused and in its original packaging.
Return procedure for LM27966SQ/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM27966SQ/NOPB Tags
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