
Catalog
4A Sequencing LDO with Ramp Control and Tracking
Key Features
• * Stable with 10µF ceramic capacitor
• * Input voltage range: 1.65V to 5.5V
• * 0.5V reference
• * ±2.0% output tolerance over temperature
• * 4A maximum output current - peak start up
• * 3A continuous operating current
• * Tracking on turn-on and turn-off with pin strapping
• * Timing controlled sequencing on/off
• * Programmable Ramp Control™ for in-rush current limiting and slew rate control of the output voltage during Turn-On and Turn-Off
• * Power-on reset (POR) supervisor with programmable delay time
• * Single Master can control multiple Slave regulators with tracking output voltages
• * Maximum dropout (VIN - VOUT) of 500mV over temperature at 3A output current
• * Fixed and adjustable output voltages
• * Excellent line and load regulation specifications
• * Logic controlled shutdown
• * Thermal shutdown and current limit protection
Description
AI
The MIC68400 is a high peak current LDO regulator designed specifically for powering applications such as FPGA core voltages that require high start up current with lower nominal operating current. The MIC68400 can also implement a variety of power-up and power-down protocols such as sequencing, tracking, and ratiometric tracking.
The MIC68400 operates from a wide input range of 1.65V to 5.5V, which includes all of the main supply voltages commonly available today. It is designed to drive digital circuits requiring low voltage at high currents (i.e. PLDs, DSP, microcontroller, etc.). The MIC68400 incorporates a delay pin (Delay) for control of power on reset (POR) output at turn-on and power-down delay at turn-off. In addition there is a ramp control (RC) pin for either tracking applications or output voltage slew rate adjustment at turn-on and turn-off. This is important in applications where the load is highly capacitive and in-rush currents can cause supply voltages to fail and microprocessors or other complex logic chips to hang up.
Multiple MIC68400s can be daisy-chained in two modes. In tracking mode the output voltage of the Master drives the RC pin of a Slave so that the Slave tracks the main regulator during turn-on and turn-off. In sequencing mode the POR of the Master drives the enable (EN) of the Slave so that it turns on after the Master and turns off before (or after) the Master. This behavior is critical for power-up and power-down control in multi-output power supplies. The MIC68400 is fully protected offering both thermal, current limit protection, and reverse current protection. The MIC68400 has a junction temperature range of -40°C to +125°C and is available in fixed as well as an adjustable option.