Description

The MIC37501/MIC37502 are 5A,low dropout linear voltage regulator that provide low voltage, high current outputs with a minimum of external components. They offer high precision,ultra-low dropout(500mV), and low ground current.

The MIC37501/MIC37502 operate from an input of 2.3V to 6.0V. They are designed to drive digital circuits requiring low voltage at high currents(i.e.,PLDs,DSPs, microcontrollers,etc.). They are available in fixed and adjustable output voltages. The adjustable version is capable of 1.24V to 5.5V.The MIC37501-1.8WR are available in fixed output voltages,the voltage is 1.8V

MIC37501/MIC37502 LDOs feature thermal and currentlimit protection and reverse current protection. Logic enable and error flag pins are available. Junction temperature range of the MIC37501/02 is from -40℃ to 125℃.

 

Features

5A minimum guaranteed output current

500mV maximum dropout voltage

-Ideal for 3.0V to 2.5V conversion

– Ideal for 2.5V to 1.8V, 1.65V,or 1.5V conversion

Stable with ceramic or tantalum capacitor

Wide input voltage range:

-VIN:2.3Vto 6.0V

±1.0% initial output tolerance

Fixed and adjustable output voltages:

-MIC37501-7 terminal fixed voltage

Excellent line and load regulation specifications

Logic controlled shutdown

Thermal shutdown and current-limit protection

Reverse-leakage protection

Low profile SPak packages

RoHS compliant with “high-melting solder” exemption.

 

Applications

LDO linear regulator for low-voltage digital IC

PC add-in cards

High efficiency linear power supplies

SMPS post regulator

Battery charger

 

Application Information

The MIC37501/02 is a high-performance, low dropout voltage regulator suitable for moderate to high-current regulator applications. lts 500mV dropout voltage at full load makes it especially valuable in battery- powered systems and as a high-efficiency noise filter in post-regulator applications. Unlike older NPN-pass transistor designs, where the minimum dropout voltage is limited by the based-to-emitter voltage drop and collector-to-emitter saturation voltage,dropout performance of the PNP output of these devices is limited only by the low Vce saturation voltage.

A trade-off for the low dropout voltage is a varying base drive requirement. Micrel’s Super Beta PNP process reduces this drive requirement to only 2% to 5% of the load current.

The MIC37501/02regulator is fully protected from damage due to fault conditions. Current limiting is provided. This limiting is linear; output current during overload conditions is constant. Thermal shutdown disables the device when the die temperature exceeds the maximum safe operating temperature. The output structure of these regulators allows voltages in excess of the desired output voltage to be applied without reverse current flow.

 

Output Capacitor

The MIC37501/02requires an output capacitor for stable operation. As a μCap LDO, the MIC37501/02 can operate with ceramic output capacitors as long as the amount of capacitance is 100μF or greater. For values of output capacitance lower than 100μF,the recommended ESR range is 200mΩto 2Ω. The minimum value of output capacitance recommended for the MIC37501/02 is 47μF.

For 100μF or greater, the ESR range recommended is less than 1Ω. Ultra-low ESR ceramic capacitors are recommended for output capacitance of 100μF or greater to help improve transient response and noise reduction at high frequency.X7R/X5Rdielectric-type ceramic capacitors are recommended because of their temperature performance.X7Rtype capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic capacitors.Z5U and Y5V dielectric capacitors change value by as much as 50% and 60%, respectively, over their operating temperature ranges. To use a ceramic chip capacitor withY5V dielectric, the value must be much higher than an X7R ceramic capacitor to ensure the same minimum capacitance over the equivalent operating temperature range.

 

Input Capacitor

An input capacitor of 1.0μF or greater is recommended when the device is more than 4 inches away from the bulk supply capacitance, or when the supply is a battery. Small, surfacemount chip capacitors can be used for the bypassing. The capacitor should be placed within 1″ of the device for optimal performance. Larger values will help to improve ripple rejection by bypassing the input to the regulator, further improving the integrity of the output voltage.