Texas Instruments TPS61042DRBTG4

Overview

TPS61042DRBTG4 from Texas Instruments is a constant-current white LED driver IC with integrated 30 V/500 mA boost switch and 60 mA LED switch, operating from 1.8 V to 6 V input, regulating LED current via 252 mV FB reference, and featuring overvoltage protection (OVP) up to 30 V - used in backlighting for handheld displays requiring precise PWM or analog brightness control.

For engineers reviewing the TPS61042DRBTG4 datasheet, TPS61042DRBTG4 pinout, TPS61042DRBTG4 application, or TPS61042DRBTG4 equivalent, key selection considerations include its 1 MHz max switching frequency, 38 µA no-load quiescent current, 0.1 µA shutdown current, 252 mV feedback reference accuracy, and dual-switch architecture enabling series-LED drive with leakage-free shutdown.

Technical Context

The TPS61042DRBTG4 implements pulse-frequency modulation (PFM) with peak-current control, using internal 500 mA main switch (Q1) and 60 mA LED switch (Q2) to regulate LED current by maintaining 252 mV across external sense resistor RS. It operates in discontinuous conduction mode (DCM), where switching frequency varies with load, input voltage, and inductor value - enabling high efficiency across wide LED current ranges.

Its CTRL pin integrates enable functionality and PWM dimming control (100 Hz–50 kHz), while OVP circuitry disables Q1 when output exceeds 27.5–30 V, and undervoltage lockout (UVLO) prevents operation below 1.5 V. Thermal shutdown activates at ~160°C junction temperature, and softstart limits inrush current via stepped current-limit ramp over 512 cycles.

Key Specifications

Pinout & Package

TPS61042DRBTG4 is housed in an 8-pin SON (DRB) package, 3.00 mm × 3.00 mm, with exposed thermal die pad electrically connected to GND for enhanced thermal dissipation in space-constrained handheld PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS61042DRBTG4, TPS61040DRBT offers cost reduction at the expense of OVP margin and switch robustness, while MAX16832ATA+T trades integration for scalability - making TPS61042DRBTG4 optimal for compact, battery-efficient 20–60 mA LED strings with integrated safety.

Availability

TPS61042DRBTG4 is available at Aetrix Electronics and suitable for smartphone backlighting, PDA sidelighting, handheld medical UIs, industrial scanner indicators, and battery-powered display modules requiring stable component supply and long-term manufacturability.

Supply support for TPS61042DRBTG4 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 ICs, with decades of expertise in high-efficiency DC/DC conversion and precision analog design.

The TPS61042DRBTG4 belongs to TI's constant-current LED driver product line, engineered specifically for low-voltage, space-constrained portable displays requiring high efficiency, ultra-low quiescent current, and integrated protection - not general-purpose boost converters.

FAQ

What is the maximum number of white LEDs the TPS61042DRBTG4 can drive in series?

The TPS61042DRBTG4 supports up to 8 white LEDs in series, based on its 30 V internal switch rating and 27.5 V typical OVP threshold. With typical white LED forward voltage of 3.0–3.5 V per device, 8 LEDs require ≈24–28 V - staying within safe operating limits when using conservative layout and thermal design. Always verify actual string voltage under worst-case temperature and aging conditions before finalizing.

How does the TPS61042DRBTG4 achieve LED current accuracy across temperature and input voltage variations?

The TPS61042DRBTG4 achieves LED current accuracy by regulating the voltage across the external sense resistor RS to a tightly controlled 252 mV (±3%) reference at the FB pin - independent of VIN or LED forward voltage. Its PFM control scheme maintains regulation stability across temperature (−40°C to +85°C ambient), and the 252 mV reference exhibits only ±8 mV drift over that range, ensuring <1% LED current variation in typical applications.

Can the TPS61042DRBTG4 operate with a 1.8 V input and still deliver full LED brightness?

Yes, the TPS61042DRBTG4 is fully specified down to 1.8 V input and maintains regulation across its entire 1.8–6 V range. At 1.8 V, it delivers full rated LED current (e.g., 20 mA with 12.6 Ω RS) while stepping up to required output voltage - demonstrated in TI's Figure 22 (82.7% efficiency at 3.0 V/19 mA) and validated in recommended operating conditions (VI min = 1.8 V). UVLO ensures clean startup above 1.5 V.

What is the minimum PWM frequency supported on the CTRL pin for reliable brightness control?

The TPS61042DRBTG4 supports PWM dimming from 100 Hz to 50 kHz on the CTRL pin. At 100 Hz, the device requires ≥32 ms low-time to enter shutdown - allowing full dimming range without unintended disable events. For stable operation, ensure converter switching frequency remains >2× PWM frequency; with typical 500–800 kHz operation, even 100 Hz PWM yields smooth, ripple-free dimming.

Does the TPS61042DRBTG4 require an external Schottky diode, and what are the key selection criteria?

Yes, the TPS61042DRBTG4 requires an external Schottky diode (e.g., ZHCS400) connected between SW and output capacitor. Key selection criteria include: 30 V+ reverse voltage rating (to match OVP), low forward voltage (<0.4 V at peak LED current) to minimize loss, fast recovery (<10 ns) to reduce switching losses, and thermal capability matching PCB copper area. TI recommends ZHCS400 or equivalent 40 V/1 A Schottky diodes.