Micrel Semiconductor Releases the MIC9130 and MIC9131 DC/DC Controllers
Micrel Semiconductor (San Jose, CA) has released two new dc/dc controllers that convert telecommunications line voltages to logic levels. The MIC9130 and MIC9131 feature built-in, high-voltage start-up circuitry that allows the devices to be connected directly to telecom line voltages. The 48V nominal telecom line voltage is subject to large voltage transients; therefore, the MIC9130 can operate to 180V to ensure safe operation. The built-in start-up circuitry integrates up to five external components. Typically, the MIC9130 and MIC9131 are used to step-down the telecom line voltage to a logic-level voltage like 3.3V.
"The high-speed operation of the MIC9130 and MIC9131, coupled with their built-in start-up circuitry, allows the design of high-performance telecom dc/dc converters in the smallest possible area. The dc/dc controllers both feature a powerful output driver that allows them to drive a large external MOSFET. The MIC9130 and MIC9131 can convert a 48V input to a 3.3V output at 20A, with up to 92 percent efficiency; this performance can be achieved in a small quarter-brick footprint." says Tony Grizelj, Micrel’s marketing manager for power products.
The MIC9130 features a 50-percent maximum duty cycle while the MIC9131 has a 75-percent maximum duty cycle. The MIC9130 and MIC9131 are constant-frequency current-mode PWM controllers. These devices can easily be synchronized, making them suitable for noise-sensitive telecommunications applications. Both devices have soft-start functions to reduce in-rush current during start-up. They also feature quiescent current of 1.3mA and a resistor-programmable current-sense threshold.
The MIC9130BM and MIC9131BM are housed in narrow-body SO-16 packages, and are priced at $3.50 when purchased in 1,000-piece quantities. Samples are available from stock, and production quantities are stock to 12 weeks ARO. In addition, a QSOP-16 package option will be available September 2001.
