MCP1725 データシートの表示（PDF） - Microchip Technology

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MCP1725

500 mA, Low Voltage, Low Quiescent Current LDO Regulator

Microchip Technology 

4.8 Dropout Voltage and

Undervoltage Lockout

Dropout voltage is defined as the input-to-output

voltage differential at which the output voltage drops

2% below the nominal value that was measured with a

VR + 0.6V differential applied. The MCP1725 LDO has

a very low dropout voltage specification of 210 mV

(typical) at 0.5A of output current. See Section 1.0

“Electrical Characteristics” for maximum dropout

voltage specifications.

The MCP1725 LDO operates across an input voltage

range of 2.3V to 6.0V and incorporates input Undervolt-

age Lockout (UVLO) circuitry that keeps the LDO

output voltage off until the input voltage reaches a

minimum of 2.18V (typical) on the rising edge of the

input voltage. As the input voltage falls, the LDO output

will remain on until the input voltage level reaches

2.04V (typical).

Since the MCP1725 LDO undervoltage lockout

activates at 2.04V as the input voltage is falling, the

dropout voltage specification does not apply for output

voltages that are less than 1.9V.

For high-current applications, voltage drops across the

PCB traces must be taken into account. The trace

resistances can cause significant voltage drops

between the input voltage source and the LDO. For

applications with input voltages near 2.3V, these PCB

trace voltage drops can sometimes lower the input

voltage enough to trigger a shutdown due to

undervoltage lockout.

MCP1725

4.9 Overtemperature Protection

The MCP1725 LDO has temperature-sensing circuitry

to prevent the junction temperature from exceeding

approximately 150°C. If the LDO junction temperature

does reach 150°C, the LDO output will be turned off

until the junction temperature cools to approximately

140°C, at which point the LDO output will automatically

resume normal operation. If the internal power

dissipation continues to be excessive, the device will

again shut off. The junction temperature of the die is a

function of power dissipation, ambient temperature and

package thermal resistance. See Section 5.0 “Appli-

cation Circuits/Issues” for more information on LDO

power dissipation and junction temperature.

© 2007 Microchip Technology Inc.

DS22026B-page 19

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