MCP1700 Microchip Technology, MCP1700 Datasheet - Page 11

• Manufacturer Part Number: MCP1700
• Description: Low Quiescent Current LDO
• Manufacturer: Microchip Technology

4.0
4.1
A portion of the LDO output voltage is fed back to the
internal error amplifier and compared with the precision
internal bandgap reference. The error amplifier output
will adjust the amount of current that flows through the
P-Channel pass transistor, thus regulating the output
voltage to the desired value. Any changes in input
voltage or output current will cause the error amplifier
to respond and adjust the output voltage to the target
voltage (refer to
4.2
The MCP1700 internal circuitry monitors the amount of
current flowing through the P-Channel pass transistor.
In the event of a short-circuit or excessive output
current, the MCP1700 will turn off the P-Channel
device for a short period, after which the LDO will
attempt to restart. If the excessive current remains, the
cycle will repeat itself.
FIGURE 4-1:
© 2007 Microchip Technology Inc.
DETAILED DESCRIPTION
Output Regulation
Overcurrent
Figure
V
IN
Block Diagram.
4-1).
Overcurrent
Overtemperature
Voltage
Reference
GND
MCP1700
Error Amplifier
-
+
+V
4.3
The internal power dissipation within the LDO is a
function of input-to-output voltage differential and load
current. If the power dissipation within the LDO is
excessive, the internal junction temperature will rise
above the typical shutdown threshold of 140°C. At that
point, the LDO will shut down and begin to cool to the
typical turn-on junction temperature of 130°C. If the
power dissipation is low enough, the device will
continue to cool and operate normally. If the power
dissipation remains high, the thermal shutdown
protection circuitry will again turn off the LDO,
protecting it from catastrophic failure.
IN
Overtemperature
MCP1700
V
OUT
DS21826B-page 11