Datasheet Linear Technology LT3688 — Datenblatt

LT3688
Dual 800mA Step-Down
Switching Regulator with
Power-On Reset and
Watchdog Timer
DESCRIPTION FEATURES Wide Input Range:
Operation from 3.8V to 36V
Low Ripple ( 125°C). As the switching frequency
is increased above fSW(MAX), the part is required to switch
for shorter periods to maintain the same duty cycle. Delays
associated with turning off the power switch dictate the
minimum on-time of the part. When the required on-time
decreases below the minimum on-time of 140ns, the switch
pulse width remains fixed at 140ns (instead of becoming
narrower) to accommodate the same duty cycle requirement. The inductor current ramps up to a value exceeding
the load current and the output ripple increases. The part
then remains off until the output voltage dips below the
programmed value before it begins switching again.
Maximum Operating Voltage Range
The maximum input voltage for LT3688 applications
depends on switching frequency, the absolute maximum
ratings of the VIN and BST pins, and by the minimum
duty cycle (DCMIN). The LT3688 can operate from input …