Dual-rail generation from a single inductor set
The LT3472EDD#PBF integrates a boost converter and a Cuk (step-up/step-down) converter in one 10-DFN package, delivering a positive and a negative output rail from a single input. This topology generates a clean negative rail without a transformer or a separate inverting charge pump — useful when the board needs ±5V or ±15V for an op-amp front-end or a small ADC driver. Each output is rated for 50 mA continuous. The two channels share the same 1.1 MHz switching clock, so the inductor selection and output capacitor ripple current are calculated for that frequency. The 50 mA per channel limit means this part fits low-power analog rails — a dual op-amp drawing 10 mA total leaves headroom for the reference and the ADC supply. Input voltage range is 2.2 V to 16 V, and the adjustable outputs can be set from ±2.2 V up to ±34 V. The wide conversion ratio — 2.2 V in to 34 V out on the boost side — requires attention to the inductor saturation current and the output diode reverse voltage. The Cuk output inverts the input, so the negative rail magnitude is set by the same feedback divider as the positive rail.
Package, footprint, and storage
Housed in a 10-lead WFDFN with an exposed pad (3x3 mm body, supplier package 10-DFN). The 0.5 mm pitch DFN demands a solder-paste stencil aperture that matches the land pattern in the datasheet; a reflow profile with a peak temperature appropriate for the ROHS3-compliant finish is required. Shipped in a Tube (the listed package format). The DFN package is moisture-sensitive; store the tube in a dry cabinet or a moisture-barrier bag if the seal is broken. The commercial temperature grade (0°C to 70°C) limits the ambient operating range — this part is not specified for industrial enclosures or outdoor equipment where the ambient exceeds 70°C.