MCP1603-0.8I/MC Microchip Technology, MCP1603-0.8I/MC Datasheet - Page 13

• Manufacturer Part Number: MCP1603-0.8I/MC
• Description: 2 MHZ 500MA BUCK REGULATOR
• Manufacturer: Microchip Technology

4.3
The output of the MCP1603 is controlled during start-
up. This control allows for a very minimal amount of
V
the UVLO voltage or SHDN being enabled.
4.4
Overtemperature protection circuitry is integrated in the
MCP1603. This circuitry monitors the device junction
temperature and shuts the device off, if the junction
temperature exceeds the typical 150°C threshold. If
this threshold is exceeded, the device will automatically
restart once the junction temperature drops by
approximately 10°C. The soft start is reset during an
overtemperture condition.
4.5
Cycle-by-cycle current limiting is used to protect the
MCP1603 from being damaged when an external short
circuit is applied. The typical peak current limit is
860 mA. If the sensed current reaches the 860 mA
limit, the P-Channel MOSFET is turned off, even if the
output voltage is not in regulation. The device will
attempt to start a new switching cycle when the internal
oscillator sets the internal RS latch.
© 2007 Microchip Technology Inc.
OUT
overshoot during start-up from V
Soft Start
Overtemperature Protection
Overcurrent Protection
IN
rising above
4.6
The SHDN pin is used to enable or disable the
MCP1603. When the SHDN pin is pulled low, the
device is disabled. When pulled high the device is
enabled and begins operation provided the input
voltage is not below the UVLO threshold or a fault
condition exists.
4.7
The UVLO feature uses a comparator to sense the
input voltage (V
than the voltage necessary to properly operate the
MCP1603, the UVLO feature will hold the converter off.
When V
UVLO is released and soft start begins. Hysteresis is
built into the UVLO circuit to compensate for input
impedance. For example, if there is any resistance
between the input voltage source and the device when
it is operating, there will be a voltage drop at the input
to the device equal to I
is 140 mV.
IN
Enable/Disable Control
Undervoltage Lockout (UVLO)
rises above the necessary input voltage, the
IN
) level. If the input voltage is lower
IN
x R
IN
MCP1603
. The typical hysteresis
DS22042A-page 13