Texas Instruments TPS61043DRBTG4

Overview

TPS61043DRBTG4 from Texas Instruments is a constant-current white LED driver IC with integrated 400 mA boost switch and 60 mA LED-series switch, operating from 1.8 V to 6 V input, regulating LED current via 252 mV feedback reference across external sense resistor RS, and featuring 18 V overvoltage protection - used in smartphone display backlighting with up to four series LEDs.

For engineers reviewing the TPS61043DRBTG4 datasheet, TPS61043DRBTG4 pinout, TPS61043DRBTG4 application, or TPS61043DRBTG4 equivalent, key selection criteria include PWM brightness control range (100 Hz–50 kHz), shutdown current (0.1 µA), 3-mm × 3-mm VSON-8 package thermal resistance (R_θJA = 48.6 °C/W), and OVP-triggered output voltage clamping at 17–19 V.

Technical Context

The TPS61043DRBTG4 implements pulse-frequency modulation (PFM) with peak-current control (400 mA typical limit) and fixed maximum on-time (4.5 µs) to regulate LED current by maintaining 252 mV across RS. Its dual-switch architecture separates power conversion (Q1) from LED current path (Q2), enabling LED disconnection during shutdown and independent OVP monitoring via dedicated OVP pin.

OVP activation disables Q1 when output exceeds 17–19 V, while CTRL pin combines enable/disable logic (500 µs high pulse to enable, ≥32 ms low to disable) and PWM dimming control - with brightness linearly proportional to duty cycle, independent of frequency or amplitude within 1%–100% range.

Key Specifications

Pinout & Package

TPS61043DRBTG4 uses an 8-pin VSON package (3.00 mm × 3.00 mm) with exposed thermal pad connected to GND for enhanced heat dissipation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar constant-current LED driver applications.

Compared with TPS61043DRBTG4, TPS61042DRBT lacks integrated OVP and requires external protection, while MAX16832ATA+T targets higher-voltage systems and omits the integrated LED switch - making TPS61043DRBTG4 uniquely suited for compact, battery-powered, 4-LED-series backlighting with built-in safety.

Availability

TPS61043DRBTG4 is available at Aetrix Electronics and suitable for smartphone display backlighting, handheld device sidelighting, and portable media player UI lighting requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for TPS61043DRBTG4 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 specializing in analog and embedded processing technologies, with leadership in power management ICs and precision analog solutions.

The TPS61043DRBTG4 belongs to TI's constant-current LED driver product line, engineered specifically for high-efficiency, low-voltage portable display backlighting with integrated protection and flexible dimming control.

FAQ

What is the minimum input voltage required for TPS61043DRBTG4 to start up and regulate LED current?

The TPS61043DRBTG4 features an undervoltage lockout (UVLO) threshold of 1.5 V (typical), but requires a minimum input voltage of 1.8 V to operate within its specified recommended conditions. Below 1.8 V, regulation is not guaranteed, and the device may not sustain stable LED current. The TPS61043DRBTG4 is designed for single-cell Li-ion (2.7–4.2 V), NiMH (1.2 V × 2), or alkaline (1.5 V × 2) battery inputs - ensuring reliable startup and regulation across the full 1.8 V to 6 V range.

How does the TPS61043DRBTG4 achieve LED current accuracy, and what is the tolerance of its feedback reference voltage?

The TPS61043DRBTG4 achieves LED current accuracy by regulating the voltage across the external sense resistor RS to a precise internal reference of 252 mV (typical), with a specified tolerance of 244 mV to 260 mV (±3.2%) over –40°C to +85°C. This feedback voltage sets LED current as I_LED = 0.252 V / R_S, so accuracy depends on both reference tolerance and RS resistor tolerance. For example, with a 1% RS resistor, total LED current error remains within ±4.2%, verified across temperature and line/load conditions per the datasheet's Electrical Characteristics table.

Can the TPS61043DRBTG4 drive more than four white LEDs in series, and what limits this capability?

The TPS61043DRBTG4 is rated to power up to four white LEDs in series when using the integrated OVP function, as its 17–19 V OVP threshold provides sufficient headroom for typical white LED forward voltages (~3.0–3.6 V each). Driving five or more LEDs would exceed the OVP clamp, causing repeated shutdown/restart cycles. However, if OVP is disabled (OVP pin tied to GND), the TPS61043DRBTG4 can generate up to 28 V output - enabling >5 LED strings, though external overvoltage protection becomes mandatory to avoid damaging the internal 30 V Q1 switch.

What is the purpose of the exposed thermal pad on the TPS61043DRBTG4 VSON-8 package, and how must it be implemented on the PCB?

The exposed thermal pad on the TPS61043DRBTG4 VSON-8 package is electrically connected to GND and serves as the primary thermal conduction path from the die to the PCB. It must be soldered to a solid copper GND plane using ≥4 thermal vias (0.3 mm diameter, spaced ≤1 mm apart) to achieve the specified R_θJA = 48.6 °C/W. Leaving the pad unconnected or floating degrades thermal performance by >30 °C/W, risking thermal shutdown under sustained 150 mW load - a critical requirement for reliable operation in compact handheld designs.

Does the TPS61043DRBTG4 support analog brightness control, and how is it implemented?

Yes, the TPS61043DRBTG4 supports analog brightness control via an external voltage divider network applied to the FB pin, as described in Section 9.1.3 of the datasheet. By injecting a controlled voltage (V_ADJ) into the FB node through resistors R1 and R2, the effective feedback reference is modulated, allowing linear LED current adjustment from 0 mA to full scale. This method replaces PWM dimming with smooth analog control - useful in noise-sensitive applications where PWM switching harmonics must be avoided. Implementation requires careful resistor selection to maintain FB bias current within 3–10 µA and avoid compromising regulation stability.