stm1404c STMicroelectronics, stm1404c Datasheet - Page 18

• Manufacturer Part Number: stm1404c
• Description: Security Supervisor With Battery Switchover
• Manufacturer: STMicroelectronics

Tamper detection
Physical
Supply voltage
Temperature
Note:
18/36
There are four (4) high-impedance physical tamper detect input pins, 2 normally set to High
(NH) and 2 normally set to Low (NL). Each input is designed with a glitch immunity (see
Table 7 on page
devices (e.g., switches, wire mesh). A tamper on any one of the four inputs that causes its
state to change will trigger the security alarm (SAL) and drive it to active-low. Once the
tamper condition no longer exists, the SAL will return to its normal High state.
TP
switch or a high-impedance resistor to V
V
is pulled low (see
V
TP
impedance resistor or a closed switch to V
input pin is pulled high (see
V
The internally switched supply voltage, V
monitored. If V
should go below the under voltage trip point, V
active-low. Once the tamper condition no longer exists, the SAL pin will return to its normal
High state.
The STM1404 has a built-in, bandgap-based sensor to monitor the temperature. If a preset
(customer-selectable, factory-programmed) over-temperature trip point (T
temperature trip point (T
When no tamper condition exists, SAL is normally High (see
page
When a tamper is detected, the SAL is activated (driven low), independent of the part type.
V
used (see
●
●
●
The STM1404 must be initially powered above V
For example, if the battery is on while V
V
on battery or V
its operational state.
OUT
TPU
TPU
SS
CC
1
2
.
and TP
and TP
ON;
High-Z; or
Ground (V
rises above V
.
12).
(in the case of STM1404B/C), A tamper condition will be detected when the input pin
can be driven to one of three states, depending on which variant of STM1404 is being
Table 1 on page
3
4
are set Normally to High (NH). They are connected externally through a closed
are set Normally to Low (NL). They are connected externally through a high-
INT
CC
SS
30). These inputs can be connected externally to several types of actuator
. This is done to avoid false alarms when the device goes from no power to
).
Figure 5
should exceed the over voltage trip point, V
RST
(and t
L
) is exceeded, the SAL is asserted low.
and
1):
Figure 7
rec
Figure 6 on page
expires). From this point on, alarms can be detected either
and
CC
OUT
INT
Figure 8 on page
SS
= 0V, no alarm condition can be detected until
(either V
(in the case of STM1404A or STM1404A) or
. A tamper condition will be detected when the
LV
RST
10). If not used, tie the pin to V
(set at 2.0v, typical). SAL will be driven
to enable the tamper detection alarms.
CC
input or V
11). If not used, tie the pin to
Section : Pin descriptions on
HV
(set at 4.2V, typical), or
BAT
input) is continuously
H
) or under-
OUT
or