Buck controller with adjustable frequency
The LTC3822EDD#PBF is a step-down (buck) DC/DC controller from Analog Devices, designed for single-phase point-of-load regulation where a high-efficiency synchronous rectifier stage is needed. Switching frequency is pin-selectable among 300 kHz, 550 kHz, and 750 kHz — the 750 kHz setting shrinks the inductor and output capacitor but increases switching losses; the 300 kHz setting favours efficiency at the cost of larger magnetics.
Supply range and control features
Operates from a 2.75 V to 4.5 V bias supply (Vcc/Vdd) — this maps cleanly onto a 3.3 V intermediate bus or a 2.5 V rail, but the 2.75 V minimum means a 2.5 V rail with 5 % tolerance (2.375 V minimum) is too low; the controller needs a boosted supply or a different part. Control features include Enable and Frequency Control pins — the Enable pin allows a sequenced power-up, and the Frequency Control pin selects the switching frequency without external timing components. Maximum duty cycle is 99 %, so the controller can run near dropout — useful when the input rail is only a few hundred millivolts above the output target.
Package and thermal interface
Supplied in Tube (not tape-and-reel) — factor this into the pick-and-place feeder setup; the tube quantity is typically 121 pieces per tube, but confirm the exact count with the supplier at RFQ.