TS39103

1A Ultra Low Dropout Voltage Regulator

with Multi-Function

4/8

Version: A08

Functional Diagram

Application Information

The TS39103 are high performance with low dropout voltage regulator suitable for moderate to high current and

voltage regulator application. Its 630mV dropout voltage at full load and over temperature makes it especially valuable

in battery power systems and as high efficiency noise filters in post regulator applications. Unlike normal NPN

transistor design, where the base to emitter voltage drop and collector to emitter saturation voltage limit the minimum

The TS39103 is fully protected from damage due to fault conditions. Linear current limiting is provided. Output current

during overload conditions is constant. Thermal shutdown the device when the die temperature exceeds the maximum

safe operating temperature. Transient protection allows device survival even when the input voltage spikes above and

below nominal. The output structure of these regulators allows voltages in excess of the desired output voltage to be

applied without reverse current flow.

Output Capacitor Requirement

The TS39103 requires an output capacitor to maintain stability and improve transient response is necessary. The

value of this capacitor is dependent upon the output current, lower currents allow smaller capacitors. TS39103 output

capacitor selection is dependent upon the ESR of the output capacitor to maintain stability. When the output capacitor

is 10uF or greater, the output capacitor should have an ESR less than 2Ω. This will improve transient response as well

as promote stability. Ultra low ESR capacitors (<100mΩ), such as ceramic chip capacitors, may promote instability.

These very low ESR levels may cause an oscillation and/or under damped transient response. A low ESR solid

tantalum capacitor works extremely well and provides good transient response and stability over temperature

aluminum electrolytes can also be used, as long as the ESR of the capacitor is <2Ω. The value of the output capacitor

can be increased without limit. Higher capacitance values help to improve transient response and ripple rejection and

reduce output noise.

Input Capacitor Requirement

An input capacitor of 1uF or greater is recommended when the device is more than 4” away from the bulk AC supply

capacitance or when the supply is a battery. Small, surface mount, ceramic chip capacitors can be used for bypassing.

Larger values will help to improve ripple rejection by bypassing the input to the regulator, further improving the integrity

of the output voltage.

Minimum Load Current

The TS39103 is specified between finite loads. If the output current is too small leakage currents dominate and the

output voltage rises. A 10mA minimum load current is necessary for proper regulation.