Datasheet Microchip MIC3839 — Datenblatt

MIC3838/3839 Micrel MIC3838/3839
Flexible Push-Pull PWM Controller General Description Features The MIC3838 and MIC3839 are a family of complementary
output push-pull PWM control ICs that feature high speed and
low power consumption. The MIC3838/9 are ideal for telecom
level (36V to 75V) isolated step down dc/dc conversion
applications where high output current, small size, and high
efficiency are required
The MIC3838/9 are designed for high flexibility with minimum
pin-count. The devices are easily configurable for either
voltage-mode or current-mode control. Additionally, the
MIC3838/9 can easily implement a volt-second clamp that
automatically limits the duty cycle during input transients,
allowing designers to use the smallest possible transformers
and power components. A 3V reference output is also available that eliminates the need for an external reference.
The dual-ended push-pull architecture of the MIC3838/9
allows more efficient utilization of the transformer than singleended topologies, allowing smaller size dc/dc solutions.
Additionally, the out-of-phase push-pull topology allows a
higher effective duty cycle, reducing input and output ripple
as well as stress on the external components. The dead-time
between the two outputs is adjustable between 60ns to
200ns, limiting the duty cycle of each output stage to less than
50%.
The MIC3838 has a turn-on threshold of 12.5V whereas the …