Texas Instruments LM2754SQ

Overview

LM2754 from Texas Instruments is a switched-capacitor flash LED driver IC optimized for camera flash in mobile phones and digital cameras. It delivers up to 800mA total output current across four parallel regulated current sinks, operates from 2.8V–5.5V input, features adaptive 1x/1.5x/2x charge pump gain selection, and includes time-out protection limiting flash duration to 1 second.

For engineers reviewing the LM2754 datasheet, LM2754 pinout, LM2754 application, or LM2754 equivalent, key selection considerations include its WQFN-24 package thermal performance (θ_JA = 42°C/W), dual-current-set resistor interface (ISET1/ISET2), TX pin synchronization with RF power amplifier pulses, and absence of inductor requirement in flash LED power delivery.

Technical Context

The LM2754 implements an adaptive CMOS charge pump architecture that dynamically selects between 1x, 1.5x, and 2x voltage gain modes based on LED forward voltage and load demand-transitioning upward only (1x→1.5x→2x) in ≤2ms during Flash mode. Gain selection maintains VOUT regulation at ~4.7V (1x/1.5x) or ~5.1V (2x) under no-load conditions.

It integrates four independent, thermally monitored current sinks (D1–D4), each supporting up to 200mA in Flash mode or 100mA in Torch mode, with headroom voltage as low as 150mV at 50mA. Internal soft-start limits inrush current, and true shutdown disconnects VOUT while drawing <1µA quiescent current.

Key Specifications

Pinout & Package

LM2754 uses a thermally enhanced 24-pin WQFN package (4mm × 4mm × 0.8mm, package code RTW0024A) with an exposed die attach pad (DAP) centered on the bottom for PCB thermal conduction.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar switched-capacitor LED driver applications.

Compared with LM3644 and TPS68470, the LM2754 provides the most direct resistor-based analog control path, minimal external component count (5 capacitors only), and smallest footprint - making it ideal for cost-constrained, space-limited mobile flash applications where fixed-torch/flash current profiles suffice.

Availability

LM2754 is available at Aetrix Electronics and suitable for mobile phone camera flash, digital camera modules, and portable media player lighting requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for LM2754 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, specializing in analog, embedded processing, and power management technologies for industrial, automotive, and consumer markets.

The LM2754 belongs to TI's portable LED driver product line, engineered specifically for high-current, low-noise flash illumination in space-constrained battery-powered devices - emphasizing thermal robustness, RF coexistence, and minimal external component requirements.

FAQ

What is the maximum continuous output current supported by the LM2754?

The LM2754 supports up to 800mA total output current in Flash mode, distributed across four current sinks (D1–D4) at up to 200mA each. In Torch mode, maximum per-sink current is 100mA, yielding 400mA total. The LM2754 datasheet specifies these limits under thermal design guidelines - exceeding them risks junction temperature violation and automatic thermal shutdown.

How does the LM2754 synchronize flash timing with RF power amplifier pulses?

The LM2754 uses its dedicated TX pin to detect RF PA transmission pulses: when TX is driven high, the device immediately forces Torch-mode current (set by ISET1) regardless of T/F state. This prevents simultaneous high-current flash and RF transmit, avoiding battery droop and signal interference. Flash timeout is disabled during TX assertion, and current reverts to Flash level once TX returns low.

Can the LM2754 drive fewer than four LEDs, and how is this configured?

Yes - the LM2754 supports 1-, 2-, 3-, or 4-LED configurations. To disable D4 for 3-LED modules, assert SEL = High. For 1- or 2-LED operation, connect multiple Dx pins in parallel (e.g., D1+D2 for one LED), adjusting RSET so each sink delivers 25% or 50% of total desired current. All configurations retain full current regulation and thermal protection.

What capacitor types and values are required for stable LM2754 operation?

The LM2754 requires five MLCCs: CIN = 2.2µF, COUT = 4.7µF, and flying capacitors C1+/C1−/C2+/C2− = 2.2µF each. X5R or X7R dielectrics are mandatory; Y5V/Z5U are prohibited due to excessive capacitance drift. COUT must be rated ≥10V; all others ≥6.3V. Tantalum, aluminum electrolytic, and OS-CON capacitors are incompatible due to high ESR.

Does the LM2754 require an external inductor, and what is its impact on board layout?

No - the LM2754 is a switched-capacitor (inductorless) DC/DC converter. It eliminates inductors entirely, removing magnetic EMI concerns, reducing board area, and simplifying layout. Total solution size excluding LEDs is <28mm². Layout emphasis shifts to thermal management: the exposed DAP must be soldered to a large copper thermal pad with vias to inner ground planes to maintain junction temperature within −40°C to +125°C operating range.