TC1270A MICROCHIP [Microchip Technology], TC1270A Datasheet - Page 24

• Manufacturer Part Number: TC1270A
• Description: Voltage Supervisor with Manual Reset Input
• Manufacturer: MICROCHIP [Microchip Technology]

TC1270A/70AN/71A
5.4
Although the TC127XA device has a fixed voltage trip
point (V
custom adjustments. This can be accomplished by
connecting an external resistor divider to the TC127XA
V
higher voltage than when the TC127XA input equals
it’s V
To maintain detector accuracy, the bleeder current
through the divider should be significantly higher than
the 15 µA maximum operating current required by the
TC127XA. A reasonable value for this bleeder current
is 1 mA (67 times the 10 µA required by the TC127XA).
For example, if V
2.5V, the value of R
value of R
dard value and plugged into the equation of
to calculate values for R
tors are recommended.
FIGURE 5-5:
External Resistor Divider.
DS22035B-page 24
Where:
DD
Note:
V
pin. This causes the V
TRIP
R
R
V
SOURCE
SOURCE
2
1
V
TRIP
Modifying The Trip Point, V
voltage
TRIP
1
V
+ R
SOURCE
), it is sometimes necessary to make
In this example, V
greater than (V
V
2
= Voltage to be monitored
= Threshold Voltage setting
DD
TRIP
(Figure
can be rounded to the nearest stan-
1
= 2V and the desired trip point is
+ R
V
×
Modify Trip-Point using
TC127XA
SS
1
5-5).
------------------- -
R
2
and R
1
is 2.5 kΩ (2.5V/1 mA). The
SOURCE
R
TRIP
+
1
R
2
).
2
. 1% tolerance resis-
=
SOURCE
voltage to be at a
V
RST
or RST
TRIP
must be
Figure 5-5
TRIP
5.5
Low operating power and small physical size make the
TC1270AN series ideal for many voltage detector
applications.
protection circuit that prevents overheating of the
logic-level MOSFET due to insufficient gate voltage.
When the input signal is below the threshold of the
TC1270AN, its output grounds the gate of the
MOSFET.
FIGURE 5-6:
Protection.
Note 1:
TC1270AN
MOSFET Low-Drive Protection
This resistance needs to be properly
sized for the selected Trip point voltage
related to the V
Figure 5-6
V
TRIP
V
V
SS
DD
270Ω
MOSFET Low-Drive
© 2007 Microchip Technology Inc.
shows a low-voltage gate drive
RST
(1)
OL
operation.
V
DD
MTP3055EL
R
L