The MAX5099 offers a dual-output, high-switching-fre-
quency DC-DC buck converter with an integrated high-
side switch. The MAX5099 integrates two low-side
MOSFET drivers to allow each converter to drive an
external synchronous-rectifier MOSFET. Converter 1
delivers up to 2A output current, and converter 2 can
deliver up to 1A of output current. The MAX5099 inte-
grates load-dump protection circuitry that is capable of
handling load-dump transients up to 80V for automotive
applications. The load-dump protection circuit utilizes
an internal charge pump to drive the gate of an external
n-channel MOSFET. When an overvoltage or load-
dump condition occurs, the series protection MOSFET
absorbs the high voltage transient to prevent damage
to lower voltage components.
The DC-DC converter operates over a wide 4.5V to 19V
operating voltage range. The MAX5099 operates 180°
out-of-phase with an adjustable switching frequency to
minimize external components while allowing the ability
to make trade-offs between the size, efficiency, and
cost. The high switching frequency also allows these
devices to operate outside the AM band for automotive
applications. These regulators can be protected
against high voltage transients such as a load-dump
condition by using the integrated overvoltage controller.
This device utilizes voltage-mode control for stable
operation and external compensation, so that the loop
gain is tailored to optimize component selection and
transient response. The MAX5099 has a maximum duty
cycle of 92.5% and is synchronized to an external clock
fed at the SYNC input.
Additional features include internal digital soft-start,
individual enable for each DC-DC regulator (EN1 and
EN2), open-drain power-good outputs (PGOOD1 and
PGOOD2), and shutdown input (ON/OFF).
Other features of the MAX5099 include overvoltage pro-
tection and short-circuit (hiccup current limit) and ther-
mal protection. The MAX5099 is available in a thermally
enhanced, exposed pad 5mm x 5mm, 32-pin TQFN
package and operates over the automotive -40°C to
+125°C temperature range.