© 2009 Microchip Technology Inc. DS21663D-page 9
TC2054/2055/2186
3.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3-1.
3.1 Unregulated Supply Input (V
IN
)
Connect the unregulated input supply to the V
IN
pin. If
there is a large distance between the input supply and
the LDO regulator, some input capacitance is
necessary for proper operation. A 1 µF capacitor,
connected from V
IN
to ground, is recommended for
most applications.
3.2 Ground Terminal (GND)
Connect the unregulated input supply ground return to
GND. Also connect one side of the 1 µF typical input
decoupling capacitor close to this pin and one side of
the output capacitor C
OUT
to this pin.
3.3 Shutdown Control Input (SHDN)
The regulator is fully enabled when a logic-high is
applied to SHDN. The regulator enters shutdown when
a logic-low is applied to this input. During shutdown, the
output voltage falls to zero and the supply current is
reduced to 0.5 µA (maximum).
3.4 Out-of-Regulation Flag (ERROR)
The open-drain ERROR flag provides indication that
the regulator output voltage is not in regulation. The
ERROR
pin will be low when the output is typically
below 5% of its specified value.
3.5 Regulated Voltage Output (V
OUT
)
Connect the output load to V
OUT
of the LDO. Also
connect one side of the LDO output decoupling
capacitor as close as possible to the V
OUT
pin.
TABLE 3-1: PIN FUNCTION TABLE
Pin Number Symbol Description
1V
IN
Unregulated supply input.
2 GND Ground terminal.
3SHDN
Shutdown control input. The regulator is fully enabled when a logic high is
applied to this input. The regulator enters shutdown when a logic low is applied
to this input. During shutdown, output voltage falls to zero, ERROR is open
circuited and supply current is reduced to 0.5 µA (maximum).
4 ERROR
Out-of-Regulation Flag. (Open-drain output). This output goes low when V
OUT
is
out-of-tolerance by approximately -5%.
5V
OUT
Regulated voltage output.
