DC/DC Controllers convert telecom line voltages to logic levels.

Micrel Semiconductor, Inc. Dec 13, 2001

Press Release Summary:

MIC9130 and MIC9131 can convert 48V input to 3.3V output at 20A with up to 92% efficiency. They have built-in high-voltage start-up circuitry that allows devices to be connected directly to telecom lines, which are subject to large voltage transients. Both devices have soft-start functions to reduce in-rush current during start-up, powerful output driver that allows them to drive large external MOSFET, and narrow-body SO-16 packages.

Original Press Release:

Micrel Releases High Speed, High Input Voltage Telecom DC/DC Controllers

-can convert a 48V input to 3.3V output at 20A with up to 92% efficiency

SAN JOSE, Calif. -- (July 19, 2001) -Micrel has released two new dc/dc controllers that convert telecom line voltages to logic levels. The MIC9130 and MIC9131, were designed and developed by Micrel Semiconductor (NASDAQ: MCRL), an industry leader in analog and power management integrated circuits.

The M1C9130/1 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 saves valuable board space by integrating up to five external components. Typically the MIC9130/1 are used to step down the telecom line voltage to a logic-level voltage like 3.3V.

The MIC9130/1 allow the design of very high-speed forward or flyback dc/dc power supplies. The MIC9130, for example, can switch an external MOSFET at 1.5MHz, allowing the smallest possible external components to be used. The delay from sensing a current limit to shutting off the output driver is only 34ns, a three-fold improvement over competing devices. This short delay time allows the MIC9130/1 to operate at higher frequencies than other available devices. Besides saving space, the high- speed capability of the MIC9130/1 is an advantage in DSL systems. To minimize noise in these systems, the converter's switching frequency must be above the 1.2MHz DSL transmit/receive band.

"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 3.3V output at 20A, with up to 92% efficiency, this performance can be achieved in a small 1/4 brick footprint." says Tony Grizelj, Micrel's marketing manager for power products. The MIC9130 features a 50% maximum duty cycle while the MIC9131 has a 75% maximum duty cycle. The MIC9130/1 are constant frequency current-mode PWM controllers. These devices can easily be synchronized, making them ideal for noise- sensitive telecommunications applications. Both devices have soft-start functions to reduce in-rush current during start-up. Low quiescent current of 1.3mA and a resistor- programmable current sense threshold allows high efficiency designs for low output power converters.

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; meaning the MIC9130/1 can be designed into a footprint half the size of a standard narrow-body SO-16 package. Micrel Boosts Output Current of World's Simplest Page 3 Buck Regulator to 2A, Retains SO-8 Package

Summary of Features & Applications: MIC9130 and MIC9131
* Built-in start-up circuitry allows input voltages up to 1 80V
* Constant-frequency PWM current-mode control
* Internal oscillator up to 2MHz operation, sync to 3MHz
* 40ns delay from current limit to output
* 1.3mA quiescent current
* lÂµA shutdown mode
* Undervoltage lockout
* Resistor programmable current sense threshold
* Soft start
* 16-pin narrow-body SOIC package Applications
* Telecom and datacom dc/dc power supplies
* Distributed power systems * DSL cards
* Line cards
* Base stations