MIC3838YMM [Microchip]

The MIC3838/39 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 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%. 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.

• Dual output drive stages in push-pull configuration
• Configurable for current-mode or voltage-mode control
• Easily implements volt-second clamp
• Leading edge current-sense blanking
• 3V reference output available
• 130µA typical start-up current
• 1mA typical run current
• Operation to 1MHz
• On-chip error amplifier with 4MHz gain bandwidth product
• Internal soft start
• On-chip VDD clamping
• Output drive stages capable of 500mA peak source current, 1A peak sink current