General Description

The MIC3808 and MIC3809 are a family of complementary output push-pull PWM control ICs that feature high speed and low power consumption. The MIC3808/9 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 dual-ended push-pull architecture of the MIC3808/9 allows more efficient utilization of the transformer than single ended 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.

Features

• Dual output drive stages in push-pull configuration

• Leading edge current-sense blanking

• 130µA typical start-up current

• 1mA typical run current

• Operation to 1MHz

• Internal soft start

• On-chip error amplifier with 4MHz gain bandwidth product

• On-chip VDD clamping

• Output drive stages capable of 500mA peak source current, 1A peak sink current

Applications

• High efficiency “brick” power supply modules

• Half bridge converters

• Full bridge converters

• Push-pull converters

• Voltage-fed push-pull converters

• Telecom equipment and power supplies

• Networking power supplies

• Industrial power supplies

• 42V automotive power supplies

• Base stations