Charge-pump LED driver for small-form-factor backlights
The MAX1574ETB+T is a switched-capacitor (charge-pump) LED driver from Analog Devices, designed to drive three strings at 60 mA each for backlight and camera flash applications. The 1 MHz switching frequency keeps the external flying capacitors small, which matters when board real estate is tight — the 10-TDFN (3x3 mm) package with an exposed pad pulls heat into the PCB ground plane rather than relying on airflow.
Supply headroom and dimming control
The multi-step dimming scheme switches between fixed current levels — no PWM input needed from the host processor, which simplifies the GPIO count on the system controller. Each of the three outputs sinks 60 mA, so total LED power is 180 mA × the forward voltage of the string. The charge-pump topology boosts the input voltage to match the LED forward-voltage stack without an inductor — the switching noise is higher in frequency (1 MHz fundamental) than a typical buck-boost, but the radiated field is smaller because the energy transfers through capacitors, not a magnetic core. Layout rule: keep the flying-capacitor traces short and the return path under the IC to the exposed pad.
It is ROHS3 compliant, so it passes the material-restriction check for EU and UK markets without a waiver.