TC1270ATVRCTR Microchip Technology, TC1270ATVRCTR Datasheet - Page 21

• Manufacturer Part Number: TC1270ATVRCTR
• Description: IC,Power Supply Supervisor,TO-253,4PIN,PLASTIC
• Manufacturer: Microchip Technology
• Type: Simple Reset/Power-On Resetr

Specifications of TC1270ATVRCTR

• Number Of Voltages Monitored: 1
• Output: Push-Pull, Totem Pole
• Reset: Active Low
• Reset Timeout: 140 ms Minimum
• Voltage - Threshold: 3.08V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SOT-143, SOT-143B, TO-253AA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table 4-2
and their V
ative percentage change from common regulated
voltages is also shown.
If the V
crosses the V
active. Then, the desired circuitry is forced into Reset,
or the circuitry has the indication that the V
the selected V
If the V
RST/RST pin is driven inactive after the Reset Delay
Timer elapses. Then, the desired circuitry is released
from Reset and will start to operate in its Normal mode,
or the circuitry has the indication that the V
the selected V
TABLE 4-2:
The
optimized to reject fast transient glitches on the V
line. If the low input signal (which is below V
rejected, the Reset output is driven active within 50 µs
of V
After the device exits the Reset condition, the delay
circuitry will hold the RST/RST pin active until the
appropriate Reset delay time (t
During device power-up, the input voltage is below the
trip point voltage. The device must enter the valid oper-
ating range for the device to start operation.
 2010 Microchip Technology Inc.
Note 1:
Selection
Voltage
DD
Trip
M
R
T
S
L
TC1270A/TC1270AN/TC1271A
2:
DD
falling through the Reset voltage threshold.
DD
shows the various device trip point options
is rising as it crosses the V
TRIP(MAX)
is falling from the regulated voltage as it
Voltage regulator circuit must have tighter
tolerance (%) than V
regulated voltage.
Circuitry being reset must have a wider
tolerance (%) than V
regulated voltage.
V
TRIP
V
TRIP
TRIP
TRIP(MAX)
TRIP(MIN)
4.75V
4.50V
4.50V
4.25V
3.15V
3.00V
3.00V
2.85V
2.70V
2.55V
.
.
SELECTING THE TRIP POINT
voltage, the RST/RST pin is driven
/
and V
(2)
(1)
TRIP(MIN)
10.0%
10.0%
15.0%
5.0%
5.0V
—
—
—
—
—
—
RST
Regulated Voltage
TRIP(MAX)
TRIP(MIN)
) has elapsed.
voltages. The neg-
- % From
TRIP
13.7%
4.5%
9.2%
9.2%
3.3V
—
—
—
—
—
—
devices
% from
% from
voltage, the
DD
DD
TRIP
is above
is below
10.0%
15.0%
3.0V
) is not
—
—
—
—
—
—
—
—
are
DD
4.2.1
There is also a minimal hysteresis (V
point. This is so that small noise signals on the device
voltage (V
“jitter” (oscillate between active and inactive levels).
The characterization graphs shown in Figures
through
percentage of the voltage trip point (V
The Reset Delay Timer (t
hysteresis for the system.
4.2.2
As the device V
remain active until the voltage rises above the “actual”
trip point (V
Figure 4-7
waveform of the RST and RST pins. As the device
powers up, the voltage will start below the valid
operating voltage of the device. At this voltage, the
RST/RST output is not valid. Once the voltage is above
the minimum operating voltage (1V) and below the
selected V
Once the device voltage rises above the V
the Reset Delay Timer (t
Delay Timer times out, the Reset output (RST/RST) is
driven inactive.
FIGURE 4-7:
Power-up.
Note 1: Additional system current is consumed
TC1270A/70AN/71A
V
RST
RST
DD
2-15
2: The TC1270AN requires an external
DD
TRIP
(2)
TRIP
HYSTERESIS
POWER-UP/RISING V
shows a power-up sequence and the
during the t
pull-up resistor.
) do not cause the Reset pin (RST/RST) to
, the Reset output will be active.
show the device hysteresis as a
).
1V
DD
rises, the device’s Reset circuit will
RST/RST Pin Operation
RST
V
RST
TRIP
time.
RST
) starts. When the Reset
) gives a time-based
DS22035C-page 21
DD
TRIP
HYS
t
RST
).
TRIP
) on the trip
(1)
voltage,
2-13