Datasheet

 2002-2012 Microchip Technology Inc. DS21357C-page 3
TC1108
2.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 2-1.
TABLE 2-1: PIN FUNCTION TABLE
3.0 DETAILED DESCRIPTION
The TC1108 is a precision, fixed output LDO. Unlike
bipolar regulators, the TC1108’s supply current does
not increase with load current. In addition, V
OUT
remains stable and within regulation over the entire
0mA to I
OUTMAX
operating load current range, (an
important consideration in RTC and CMOS RAM
battery back-up applications).
Figure 3-1 shows a typical application circuit.
FIGURE 3-1: TYPICAL APPLICATION
CIRCUIT
3.1 Output Capacitor
A 1F (min) capacitor from V
OUT
to ground is required.
The output capacitor should have an effective series
resistance greater than 0.1 and less than 5.0. A 1F
capacitor should be connected from V
IN
to GND if there
is more than 10 inches of wire between the regulator
and the AC filter capacitor, or if a battery is used as the
power source. Aluminum electrolytic or tantalum
capacitor types can be used. (Since many aluminum
electrolytic capacitors freeze at approximately -30°C,
solid tantalums are recommended for applications
operating below -25°C.) When operating from sources
other than batteries, supply-noise rejection and
transient response can be improved by increasing the
value of the input and output capacitors and employing
passive filtering techniques.
Pin No.
(3-Pin SOT-223)
Symbol Description
1V
IN
Unregulated supply input.
2 GND Ground terminal.
3V
OUT
Regulated voltage output.
C1
1μF
Battery
TC1108
1
2
3
V
IN
V
OUT
C2
1μF
GND
V
OUT
+
–
+
+