Texas Instruments LM3630ATMX

Overview

LM3630ATMX from Texas Instruments is a high-efficiency dual-string white LED driver IC implementing a current-mode boost converter with I²C-compatible digital control and independent PWM dimming. It delivers up to 28.5 mA per string across two LED strings (up to 10 LEDs/chain), supports 2.3–5.5 V input, provides programmable overvoltage protection up to 40 V, and operates in –40°C to +85°C ambient for smartphone LCD backlighting.

For engineers reviewing the LM3630ATMX datasheet, LM3630ATMX pinout, LM3630ATMX application, or LM3630ATMX equivalent, key selection considerations include dual-string current matching (±2.5% at 10 mA), selectable 500 kHz / 1 MHz switching frequency, 8-bit I²C brightness control, true shutdown isolation, and adaptive headroom regulation for optimal efficiency across varying LED forward voltages.

Technical Context

The LM3630ATMX integrates a synchronous boost controller with two matched current sinks (ILED1/ILED2), each capable of regulating output current from 5 mA to 28.5 mA with 256-step exponential or linear dimming via I²C. Its adaptive headroom control dynamically adjusts the output voltage to minimize power loss while maintaining sufficient margin above the LED string V_F.

It features dual fault detection paths: overvoltage protection (OVP) triggered at user-selectable thresholds (16 V / 24 V / 32 V / 40 V) sensed at the OVP pin, and thermal shutdown activation at 140°C (typical) with 15°C hysteresis. The device supports both hardware enable (HWEN) and software-controlled shutdown via I²C register.

Key Specifications

Pinout & Package

LM3630ATMX is housed in a 12-pin DSBGA package (1.94 mm × 1.42 mm, 0.4 mm pitch), optimized for ultra-thin mobile applications. The package uses bottom-side solder bumps for direct PCB mounting and thermal conduction.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-string LED driver applications.

Compared with LM3630ATMX, LM3630AYFQR offers identical performance in a standard production reel format, while TPS61165DRVR sacrifices dual-string precision and digital control for lower BOM count in simpler lighting systems.

Availability

LM3630ATMX is available at Aetrix Electronics and suitable for smartphone backlighting, tablet keypad illumination, automotive infotainment displays, and portable medical device UIs requiring stable component supply, consistent parametric performance, and long-term lifecycle support.

Supply support for LM3630ATMX 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 90 years of innovation in high-reliability IC design.

The LM3630A product line was engineered specifically for space-constrained, battery-powered LCD and OLED display backlighting, emphasizing high efficiency, minimal solution size (<32 mm²), and robust thermal performance in portable consumer electronics.

FAQ

What is the maximum LED string voltage supported by the LM3630ATMX?

The LM3630ATMX supports up to 40 V output voltage, programmable via its OVP pin configuration. This allows safe operation with LED strings totaling up to ~12 white LEDs (assuming typical V_F ≈ 3.3 V) while maintaining 1–2 V headroom. The 40-V OVP threshold is selected using I²C register settings and verified in the Electrical Characteristics table (VOVP = 39–44 V for 40-V option).

Does the LM3630ATMX support independent brightness control for each LED string?

Yes, the LM3630ATMX provides fully independent current regulation and dimming control for ILED1 and ILED2 strings. Each sink is programmable from 5 mA to 28.5 mA with 256-step exponential or linear mapping via separate I²C registers (BRT1/BRT2), enabling asymmetric backlight tuning essential for bezel-less smartphone displays.

What is the purpose of the SEL pin on the LM3630ATMX?

The SEL pin on the LM3630ATMX selects the 7-bit I²C slave address: grounded → 0x36; connected to VIN → 0x38. This allows two LM3630ATMX devices to coexist on the same I²C bus without address conflict, supporting dual-display or multi-zone backlight systems in a single controller design.

How does the adaptive headroom feature improve efficiency in the LM3630ATMX?

The LM3630ATMX's adaptive headroom feature continuously monitors LED string voltage and dynamically adjusts the boost output to maintain just enough margin (typically 160–240 mV) above the required V_F sum. This reduces power dissipation in the current sinks and improves overall efficiency-especially critical during low-brightness states or at elevated temperatures where V_F drifts.

Can the LM3630ATMX operate with a 1-MHz switching frequency, and what are the trade-offs?

Yes, the LM3630ATMX supports 1-MHz switching (selected via I²C register). This enables use of smaller, lower-profile inductors (e.g., 10 µH vs. 22 µH at 500 kHz), reducing solution footprint. Trade-offs include slightly lower peak efficiency (~2–3% reduction per Figure 22–24) and higher switching losses, but it remains >80% efficient across most operating conditions.