Three-channel boost LED driver for LCD backlighting
The LP8556TME-E11/NOPB: PWM dimming is supported directly, allowing brightness control via a PWM signal on the dimming input. The switching frequency is pin-selectable among 312 kHz, 625 kHz, and 1250 kHz, giving the designer flexibility to optimize inductor size versus switching losses and EMI profile. Output voltage range is 7 V to 21 V. Supply input range is 2.7 V to 20 V.
Switching frequency selection — inductor sizing trade-off
The three switching frequency options (312 kHz, 625 kHz, 1250 kHz) let the designer choose between a smaller inductor at higher frequency versus lower switching losses at lower frequency. At 1250 kHz the inductor can be physically smaller, which matters in space-constrained portable designs, but the higher gate-drive losses reduce efficiency slightly. At 312 kHz efficiency peaks, but the inductor value and footprint increase. The 625 kHz setting is a common middle ground for general-purpose backlight designs.
Package and assembly considerations
Operating temperature range is -30°C to 85°C ambient, which covers commercial and most industrial indoor environments but does not extend to automotive under-hood or extended outdoor enclosures where ambient may exceed 85°C.
Lifecycle and sourcing
It is ROHS3 compliant. For volume production or dual-source planning, the LM2703MF-ADJ/NOPB is a single-output boost regulator in the same functional class but with a 0.35 A output and a different package — it is not a pin-compatible drop-in but may serve as an alternative topology for single-string designs.