TC1014/TC1015/TC1185
4.0
DETAILED DESCRIPTION
4.1
Bypass Input
The TC1014, TC1015 and TC1185 are precision fixed
output voltage regulators (if an adjustable version is
needed, see the TC1070, TC1071 and TC1187 data
sheet (DS21353). Unlike bipolar regulators, the
TC1014, TC1015 and TC1185 supply current does not
increase with load current. In addition, the LDOs’ out-
put voltage is stable using 1 µF of capacitance over the
entire specified input voltage range and output current
range.
shows a typical application circuit. The
regulator is enabled anytime the shutdown input
(SHDN) is at or above V
IH
, and disabled when SHDN is
at or below V
IL
. SHDN may be controlled by a CMOS
logic gate or I/O port of a microcontroller. If the SHDN
input is not required, it should be connected directly to
the input supply. While in shutdown, the supply current
decreases to 0.05 µA (typical) and V
OUT
falls to zero
volts.
A 470 pF capacitor connected from the Bypass input to
ground reduces noise present on the internal
reference, which in turn, significantly reduces output
noise. If output noise is not a concern, this input may be
left unconnected. Larger capacitor values may be
used, but results in a longer time period to rated output
voltage when power is initially applied.
4.2
Output Capacitor
+
+
1 µF
V
IN
V
OUT
+
1 µF
V
OUT
Battery
TC1014
TC1015
TC1185
GND
A 1 µF (min) capacitor from V
OUT
to ground is required.
The output capacitor should have an effective series
resistance greater than 0.1Ω and less than 5Ω. A 1 µF
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.
4.3
Input Capacitor
SHDN
Bypass
470 pF
Reference
Bypass Cap
(Optional)
Shutdown Control
(to CMOS Logic or Tie
to V
IN
if unused)
FIGURE 4-1:
Typical Application Circuit.
A 1 µF capacitor should be connected from V
IN
to GND
if there is more than 10 inches of wire between the
regulator and this AC filter capacitor, or if a battery is
used as the power source. Aluminum electrolytic or
tantalum capacitors can be used (since many
aluminum
electrolytic
capacitors
freeze
at
approximately -30°C, solid tantalum is 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.
DS21335E-page 12
©
2007 Microchip Technology Inc.
MICROCHIP [ MICROCHIP TECHNOLOGY ]
