LX1734

Features:

* Fixed Frequency 1.0MHz Operation
* Very Low Noise: 1mVP-P Output Ripple Possible With Cuk Topology
* Stable Operation With Ceramic or Tantalum Capacitors
* -5V at 250mA from 5V Input
* Uses Small Surface Mount L/C Components
* Wide Input Range: 4.2V to 8V
* Low VCESAT Switch: 600mV at 600mA
* 6-Lead 3x3mm JEDEC MLPM Package
* Functionally Compatible with LT1611 or LT1931


Application

*Disk Drive MR Head Bias
* Digital Camera CCD Bias
*LCD Bias
* GaAs FET Bias
* Local -5V or -12V Supplies


Pinout




Specifications

Supply Voltage (VIN), Shutdown (SD).................................................... 0 to 10V
SW Voltage....................................................................................... -0.4V to 20V
NFB Voltage.................................................................................................... -2V
Current Into NFB Pin................................................................................... ±1mA
Operating Temperature Range............................................................0°C to 85°C
Maximum Junction Temperature ................................................................. 125°C
Storage Temperature......................................................................-65°C to 150°C
Peak Package Solder Reflow Temperature
(40 second maximum exposure) ..................................................... 260°C (+0, -5)


Description

The LX1734 is an inverting DC/DC current-mode controller. With a 750mA integrated switch, the LX 1734 can generate large output currents in a small footprint. The LX 1734 minimizes external component size and cost by implementing a high switching frequency of 1.0MHz, while generating -5V at 250mA.

When configured in the dual inductor inverting topology very low output voltage ripple approaching 1mVP-P can be achieved when used in conjunction with ceramic  output capacitors. The dual inductor can be implemented as a coupled or separate cores.LX1734 Fixed frequency operation ensures a clean output free from low frequency noise typically present with charge pump
solutions. The low impedance output remains within 1% of nominal during large load steps. The 18V switch allows high voltage outputs to be generated.

The LX1734 is available in the space saving 6-lead 3x3 Jedec MO-229 package, which has the same footprint and lead spacing as the SOT-23A. A complete inverter function utilizes less than 0.32 inches of PCB space.