TC1268 MICROCHIP [Microchip Technology], TC1268 Datasheet - Page 5

• Manufacturer Part Number: TC1268
• Description: 500mA Fixed Output, Fast Response CMOS LDO with Shutdown
• Manufacturer: MICROCHIP [Microchip Technology]

3.2
A 10nF 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 this results in a longer time period to achieve
the rated output voltage, once power is initially applied.
3.3
A 1µF (min) capacitor from V
The output capacitor should have an effective series
resistance greater than 0.1Ω and less than 5Ω, and a
resonant frequency above 1MHz. A 1µF capacitor
should be connected from V
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,
response can be improved by increasing the value of
the input and output capacitors and employing passive
filtering techniques.
©
2002 Microchip Technology Inc.
Bypass Input
Output Capacitor
supply
noise
IN
rejection
OUT
to GND if there is more
to ground is required.
and
transient
3.4
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
regardless of the programmed output voltage value
(e.g., ERROR = V
regulator). ERROR output operation is shown in
Figure 3-3. Note that ERROR is active when V
or below V
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 C1). R1 x C1 should be
chosen to maintain ERROR below V
RESET input for at least 200msec to allow time for the
system to stabilize. Pull-up resistor R1 can be tied to
V
FIGURE 3-3:
ERROR
H
OUT
.
V
OUT
V
V
V
TH
OL
, V
IH
IN
ERROR Output
or any other voltage less than (V
TH
, and inactive when V
OL
ERROR OUTPUT
OPERATION
at 2.375V (typ.) for a 2.5V
TC1268
OUT
IH
OUT
DS21379B-page 5
of the processor
is above V
Hysteresis (V
falls out of
IN
+ 0.3V).
OUT
OUT
TH
is at
H
)
+
,