MIC68401 4A Sequencing LDO with Tracking and Ramp Control Features General Description Stable with 10F ceramic capacitor The MIC68401 is a high peak current LDO regulator Input voltage range: 1.65V to 5.5V designed specifically for powering applications such as FPGA core voltages that require high startup current with Low 0.5V reference voltage lower nominal operating current. Capable of sourcing 4A of 2.0% output tolerance over temperature current for start-up, the MIC68401 provides high power 4A output current from a small QFN package. The MIC68401 can also Timing-controlled sequencing on/off implement a variety of power-up and power-down Programmable Ramp Control for inrush current protocols such as sequencing, tracking, and ratiometric limiting and slew rate control of the output voltage during tracking. turn-on The MIC68401 operates from a wide input range of 1.65V Power-on-reset (POR) supervisor with programmable to 5.5V, which includes all of the main supply voltages delay time commonly available today. It is designed to drive digital Single master can control multiple slave regulators with circuits requiring low voltage at high currents (i.e., PLDs, tracking output voltages DSPs, microcontrollers, etc.). The MIC68401 incorporates a delay pin (DELAY) for control of power-on-reset (POR) Small 4mm 4mm QFN package output at turn-on. In addition, there is a ramp control (RC) Maximum dropout (V V ) of 500mV over IN OUT for either tracking applications or output voltage slew rate temperature at 3A output current control at turn-on. These features are important in Fixed and adjustable output voltages applications where the load is highly capacitive and inrush Excellent line and load regulation specifications currents can cause supply voltages to fail and microprocessors or other complex logic chips to hang up. Logic-controlled shutdown Thermal shutdown and current-limit protection Multiple MIC68401s can be daisy chained in two modes. In tracking mode the output voltage of the master drives Applications the RC pin of a slave so that the slave tracks the main regulator during turn-on and turn-off. In sequencing mode FPGA/PLD power supply the POR of the master drives the enable (EN) of the slave Networking/telecom equipment so that it turns on after the master. This behavior is critical Microprocessor core voltage for power-up control in multi-output power supplies. The High-efficiency linear post regulator MIC68401 is fully protected offering both thermal, current limit protection, and reverse current protection. Sequenced or tracked power supply The MIC68401 has an adjustable output voltage. The junction temperature range of part is rated from 40C to +125C. The MIC68401 is offered in the small 16-pin 4mm 4mm QFN package. Datasheets and support documentation are available on Micrels web site at: www.micrel.com. Ramp Control is a trademark of Micrel, Inc. Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC68401 Typical Application Revision 1.0 November 7, 2013 2