TC1055 MICROCHIP [Microchip Technology], TC1055 Datasheet - Page 6

• Manufacturer Part Number: TC1055
• Description: 50mA, 100mA and 150mA CMOS LDOs with Shutdown and ERROR Output
• Manufacturer: MICROCHIP [Microchip Technology]

TC1054/TC1055/TC1186
3.0
The TC1054, TC1055 and TC1186 are precision fixed
output voltage regulators. (If an adjustable version is
desired, please see the TC1070/TC1071/TC1187 data
sheet.) Unlike bipolar regulators, the TC1054, TC1055
and TC1186 supply current does not increase with load
current. In addition, V
regulation over the entire 0mA to I
load current range, (an important consideration in RTC
and CMOS RAM battery back-up applications).
Figure 3-1 shows a typical application circuit. The
regulator is enabled any time the shutdown input
(SHDN) is at or above V
when SHDN is at or below V
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, supply current decreases to 0.05µA
(typical), V
circuited.
FIGURE 3-1:
DS21350B-page 6
(to CMOS Logic or Tie
Shutdown Control
to V
IN
if unused)
DETAILED DESCRIPTION
+
Battery
OUT
falls to zero volts, and ERROR is open-
+
1µF
Processor RESET Signal
if ERROR is used as a
GND
V
SHDN
C2 Required Only
IN
TYPICAL APPLICATION
CIRCUIT
OUT
TC1054
TC1055
TC1186
(See Text)
IH
, and shutdown (disabled)
remains stable and within
ERROR
V
OUT
IL
. SHDN may be
OUT
V+
+
R1
1M
0.2µF
C2
1µF
C1
MAX
V
operating
OUT
BATTLOW
or RESET
3.1
ERROR is driven low whenever V
regulation by more than – 5% (typical). This condition
may be caused by low input voltage, output current
limiting, or thermal limiting. The ERROR threshold is
5% below rated V
output voltage value (e.g. ERROR = V
for a 5.0V regulator and 2.85V (typ.) for a 3.0V
regulator). ERROR output operation is shown in
Figure 3-2.
Note that ERROR is active when V
inactive when V
As shown in Figure 3-1, ERROR can be used as a
battery low flag, or as a processor RESET signal (with
the addition of timing capacitor C2). R1 x C2 should be
chosen to maintain ERROR below V
RESET input for at least 200 msec to allow time for the
system to stabilize. Pull-up resistor R1 can be tied to
V
FIGURE 3-2:
3.2
A 1µF (min) capacitor from V
recommended. The output capacitor should have an
effective series resistance greater than 0.1Ω and less
than 5.0Ω, and a resonant frequency above 1MHz. A
1µF capacitor should be connected from V
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 approxi-
mately -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.
OUT
ERROR
V
OUT
V
V
, V
V
TH
OL
IH
IN
ERROR Open Drain Output
Output Capacitor
or any other voltage less than (V
OUT
OUT
rises above V
OPERATION
ERROR OUTPUT
regardless of the programmed
©
2002 Microchip Technology Inc.
TH
OUT
OUT
IH
by V
OUT
OL
HYSTERESIS (V
of the processor
falls to V
to ground is
at 4.75V (typ.)
HYS
falls out of
IN
IN
to GND if
+ 0.3V).
.
TH
, and
H
)