MIC3839

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 MIC3839 has a lower turn-on threshold of 4.3V. Both devices are available in a small size MSOP-10 package with an operating range of 40°C to +85°C.

Data sheets and support documentation can be found on Micrel's web site at www.micrel.com.