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Texas Instruments LM3549SQX/NOPB
- Part No.:
- LM3549SQX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 24-WFQFN Exposed Pad
- Datasheet:
-
LM3549SQX/NOPB.pdf
- Description:
- IC LED DRV RGLTR I2C 24WQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,465
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Product details
Overview
LM3549SQX/NOPB from Texas Instruments is a high-power sequential RGB LED driver IC with integrated buck-boost DC-DC converter, three 700 mA constant-current low-side drivers (R_OUT/G_OUT/B_OUT), I²C interface, and non-volatile memory for standalone operation. It delivers ±6% current accuracy over temperature and supports PWM or register-based global brightness control in portable video projector light engines.
For engineers reviewing the LM3549SQX/NOPB datasheet, LM3549SQX/NOPB pinout, LM3549SQX/NOPB application, or LM3549SQX/NOPB equivalent, key selection considerations include sequential RGB timing control, integrated fault detection (LED open/short, thermal, UVLO), buck-boost output voltage up to 4.6 V, 24-pin WQFN package thermal performance (θJA = 35–50°C/W), and EEPROM-programmable current settings per color bank.
Technical Context
The LM3549SQX/NOPB implements sequential drive logic where only one of R_EN/G_EN/B_EN may be active at a time, enforcing strict time-multiplexed RGB illumination. Its buck-boost converter dynamically adjusts VOUT to match the forward voltage of the enabled LED, minimizing driver power dissipation and achieving up to 95% peak efficiency.
Fault detection is hardware-asserted via open-drain FAULT pin and readable through I²C register 17H, covering LED open/short, thermal shutdown (TJ = 150°C), under-voltage lockout (~2.5 V), and converter over-current. Current settings are stored in EEPROM across three independent banks (0–2), each with 10-bit resolution per channel, enabling white-point calibration and aging compensation without host intervention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Output Current | 705 mA per channel - enables high-brightness RGB LEDs in compact projector light engines |
| Current Accuracy | ±6% over −30°C to +85°C - ensures stable white balance without real-time recalibration |
| VIN Range | 2.7 V to 5.5 V - compatible with single-cell Li-ion or regulated 3.3 V/5 V rails |
| VOUT Max | 4.6 V - sufficient headroom for blue/white LED strings in boost mode |
| Switching Frequency | 2.25–2.55 MHz - allows use of small 2.2 µH inductors and low-ESR ceramic capacitors |
| Package | 24-pin WQFN (RTW0024A) - 4 mm × 4 mm footprint with exposed thermal pad for 35–50°C/W θJA |
| I²C Address | 0x36 (7-bit) - standard address avoids bus conflicts in multi-device systems |
| EEPROM Banks | 3 independent banks - supports factory calibration, field updates, and aging compensation |
Pinout & Package
LM3549SQX/NOPB uses a 24-pin WQFN package (package code RTW0024A) with 0.5 mm pitch and exposed thermal pad for enhanced power dissipation. Pin numbering follows standard top-view orientation with PIN 1 ID marker at top-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| L1 (Pins 2,3) | Inductor positive terminal | Connects to high-side switch node of buck-boost converter; requires low-ESR path to L1 inductor |
| L2 (Pins 5,6) | Inductor negative terminal | Completes buck-boost inductor loop; shared return for synchronous rectifier control |
| VOUT (Pins 7,9) | Buck-boost output | Delivers regulated voltage to LED anodes; dual pins reduce IR drop and improve current sharing |
| R_EN/G_EN/B_EN (Pins 10,12,13) | Enable inputs | Asynchronous, priority-ordered (R > G > B) digital controls for sequential LED activation |
| R_OUT/G_OUT/B_OUT (Pins 16–18) | Constant-current sinks | Low-side drivers with 0.2 Ω on-resistance; each capable of 705 mA continuous output |
| FAULT (Pin 19) | Fault interrupt output | Active-low open-drain signal asserting on any detected fault; requires external pull-up |
| SDA/SCL (Pins 20,21) | I²C interface | Standard bidirectional data/clock lines compliant with 400 kHz Fast Mode timing |
| EN (Pin 22) | Global enable | Hardware master enable; pulls device into shutdown (<1 µA) when low |
| VDDP/VDDS (Pins 23,11) | Power supplies | VDDP powers SMPS circuitry; VDDS powers logic and drivers - decoupling critical for stability |
| GND_SW/GND (Pins 4,15) | Ground terminals | GND_SW is SMPS power ground; GND is logic/analog ground - separate routing minimizes noise coupling |
Key Features
| Feature | Design Value |
|---|---|
| Sequential RGB drive logic | Hardware-enforced single-channel activation prevents simultaneous conduction and ensures precise frame timing |
| Integrated buck-boost converter | Eliminates need for external DC-DC stage; adapts VOUT dynamically to LED forward voltage for >95% efficiency |
| Non-volatile current calibration | Three 10-bit-per-channel EEPROM banks allow factory-set white balance and field recalibration without I²C bus |
| Comprehensive fault detection | Dedicated hardware monitors LED open/short, thermal shutdown, UVLO, and converter OCP - all reported via FAULT pin and register 17H |
| PWM + register brightness control | Supports both external PWM input (4–20 kHz) and I²C-accessible MASTER FADER register for seamless global dimming |
| Thermal-aware packaging | 24-pin WQFN with exposed pad achieves 35–50°C/W θJA - critical for sustained 700 mA per channel in portable enclosures |
Applications
| Portable Video Projectors | High-Brightness RGB Light Engines |
|---|---|
Use Scenario: Compact DLP or LCoS projectors requiring sequential RGB illumination with precise white-point stability across temperature and LED aging. IC Role / Device Role / Timing Role: Primary RGB LED driver managing time-multiplexed red/green/blue frames at 60 Hz, with dynamic VOUT adjustment per color and EEPROM-stored current calibration. Use Value: Enables 1.25–2.08 ms per-color timing (per Figure 15), ±6% current accuracy maintains color fidelity, and standalone EEPROM operation reduces system MCU overhead. | Use Scenario: Embedded laser/LED hybrid light sources in AR glasses or medical endoscopes needing high-efficiency, fault-resilient RGB drive in space-constrained PCB layouts. IC Role / Device Role / Timing Role: Integrated power management and current regulation IC delivering 705 mA per channel with buck-boost conversion and real-time fault reporting via FAULT pin. Use Value: Dual power domains (VDDP/VDDS), 2.25–2.55 MHz switching, and 4 mm × 4 mm WQFN minimize board area while sustaining >95% peak efficiency under load. |
| Automotive HUD Illumination | Industrial RGB Inspection Systems |
Use Scenario: Head-up displays requiring robust, thermally stable RGB illumination across −30°C to +85°C ambient with ESD-hardened interface. IC Role / Device Role / Timing Role: Fault-tolerant sequential LED driver with hardware-level thermal shutdown (TJ = 150°C), UVLO protection, and open-drain FAULT signaling for ASIL-B–aligned diagnostics. Use Value: Meets automotive-grade reliability requirements with 2 kV HBM ESD rating, −30°C to +125°C junction range, and EEPROM-based calibration retention over lifetime. | Use Scenario: Machine vision systems using pulsed RGB illumination for spectral analysis, requiring precise current matching and rapid enable/disable transitions. IC Role / Device Role / Timing Role: High-speed constant-current sink IC with 50 µs current rise/fall times, priority-encoded EN inputs, and I²C-configurable current banks for multi-spectral calibration. Use Value: 10-bit per-channel current resolution (0.64 mA step), 3-bank EEPROM storage, and 705 mA max output support repeatable, calibrated spectral response across inspection cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-power sequential RGB LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS61165DRVR | Single-channel 400 mA boost LED driver with I²C interface; no integrated buck-boost or sequential logic | Requires external sequencing logic and separate drivers for RGB; lacks EEPROM calibration and fault reporting granularity | Use only when RGB timing is handled externally and lower per-channel current suffices |
| MAX16826ATL+T | Triple-channel linear LED driver (no switching converter); max 150 mA/channel; analog/digital dimming only | No VOUT regulation or fault detection; unsuitable for high-efficiency portable projector applications | Select only for low-power, fixed-VF LED arrays where thermal dissipation is not constrained |
Compared with TPS61165DRVR and MAX16826ATL+T, LM3549SQX/NOPB uniquely integrates buck-boost conversion, hardware-enforced sequential drive, 705 mA per channel, and EEPROM-based calibration - making it the only option supporting standalone, high-efficiency RGB projection without external timing or power management ICs.
Availability
LM3549SQX/NOPB is available at Aetrix Electronics and suitable for portable video projectors, high-brightness RGB light engines, and automotive HUD systems requiring stable component supply, long-term lifecycle support, and traceable sourcing for production programs.
Supply support for LM3549SQX/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 headquartered in Dallas, Texas, designing and manufacturing analog, embedded processing, and logic ICs for industrial, automotive, and consumer applications.
The LM3549SQX/NOPB belongs to TI's high-efficiency LED driver product line, engineered specifically for sequential RGB illumination in portable projection systems where thermal density, power efficiency, and calibration stability are critical design constraints.
FAQ
What is the maximum continuous output current per channel for the LM3549SQX/NOPB?
The LM3549SQX/NOPB supports a maximum continuous output current of 705 mA per channel (R_OUT, G_OUT, B_OUT) under full operating conditions (−30°C to +85°C ambient). This rating assumes proper thermal management using the 24-pin WQFN package's exposed pad and adherence to recommended PCB layout guidelines for heat dissipation. The device also features over-current protection that triggers at programmable thresholds to safeguard against transient faults.
Does the LM3549SQX/NOPB require an I²C interface to operate?
No, the LM3549SQX/NOPB does not require an I²C interface to operate. Its integrated non-volatile memory stores current settings, fault masks, and fader values, enabling fully standalone operation after initial calibration. Once programmed, the LM3549SQX/NOPB can be controlled solely via R_EN/G_EN/B_EN and PWM inputs. I²C remains available for dynamic reconfiguration, diagnostics, and EEPROM updates during service or recalibration.
How does the LM3549SQX/NOPB handle thermal protection?
The LM3549SQX/NOPB incorporates thermal shutdown (TSD) protection that activates at a typical junction temperature of 150°C and releases at 140°C. When triggered, TSD forces the device into Standby mode, disabling the buck-boost converter and LED drivers while preserving register contents. The fault condition is latched in register 17H and asserted on the open-drain FAULT pin. Reading the FAULT register clears the latch and returns FAULT to high-impedance state.
What is the purpose of the BANK_SEL register in the LM3549SQX/NOPB?
The BANK_SEL register (address 00H) selects one of three independent current-setting banks (Bank 0, Bank 1, Bank 2) used to store 10-bit per-channel LED current values. Each bank contains registers for red, green, and blue channels (e.g., IR0_LSB/IR0_MSB for Bank 0 red). This architecture enables factory calibration, field updates, and aging compensation - for example, Bank 0 may hold initial white-point settings, while Bank 1 stores updated values after 10,000 hours of LED operation. The LM3549SQX/NOPB applies the selected bank's values at startup.
Can the LM3549SQX/NOPB drive multiple LEDs simultaneously?
No, the LM3549SQX/NOPB is designed exclusively for sequential RGB drive: only one of R_EN, G_EN, or B_EN may be active at any time. If a second enable signal is asserted while the first is still high, the corresponding output will not activate until the prior enable goes low - with fixed priority order (R > G > B). This hardware-enforced behavior ensures precise time-multiplexed illumination required for portable video projectors and eliminates risk of cross-conduction or excessive power dissipation.
LM3549SQX/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-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 3
- Voltage - Supply (Min):
- 2.7V
- Voltage - Supply (Max):
- 5.5V
- Voltage - Output:
- 4.6V
- Current - Output / Channel:
- 705mA
- Frequency:
- 2.4MHz
- Dimming:
- I2C
- Applications:
- -
- Operating Temperature:
- -30°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-WQFN (4x4)
LM3549SQX/NOPB FAQ
1.How can I place an order for LM3549SQX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3549SQX/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 LM3549SQX/NOPB reliable?
The price and inventory of LM3549SQX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3549SQX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3549SQX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3549SQX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3549SQX/NOPB?
LM3549SQX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3549SQX/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 LM3549SQX/NOPB?
For technical support, including LM3549SQX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3549SQX/NOPB requirements.
6.How does Aetrix verify that LM3549SQX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3549SQX/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 LM3549SQX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3549SQX/NOPB?
All LM3549SQX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3549SQX/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 LM3549SQX/NOPB part is unused and in its original packaging.
Return procedure for LM3549SQX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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