STM1404A STMICROELECTRONICS [STMicroelectronics], STM1404A Datasheet - Page 5

• Manufacturer Part Number: STM1404A
• Description: Security Supervisor with Battery Switchover
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

TAMPER DETECTION
Physical
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. These inputs can
be connected externally to several types of actua-
tor 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
are connected externally through a closed switch
or a high-impedance resistor to V
of STM1404A or STM1404A) or V
of STM1404B/C), A tamper condition will be de-
tected when the input pin is pulled low. If not used,
tie the pin to V
TP
are connected externally through a high-imped-
ance resistor or a closed switch to V
condition will be detected when the input pin is
pulled high. If not used, tie the pin to V
1
2
and TP
and TP
3
4
are set Normally to High (NH). They
are set Normally to Low (NL). They
OUT
or V
TPU
.
OUT
TPU
SS
(in the case
(in the case
SS
. A tamper
.
Supply Voltage
The internally switched supply voltage, V
ther V
itored. If V
point, V
the under voltage trip point, V
cal). SAL will be driven active-low. Once the
tamper condition no longer exists, the SAL pin will
return to its normal High state.
Temperature
The STM1404 has a built-in, bandgap-based sen-
sor to monitor the temperature. If a preset (cus-
tomer-selectable,
temperature trip point (T
trip point (T
low.
When no tamper condition exists, SAL is normally
High.
When a tamper is detected, the SAL is activated
(driven low), independent of the part type. V
can be driven to one of three states, depending on
which variant of STM1404 is being used (see
vice Options, page
Note: The STM1404 must be initially powered
above V
alarms. For example, if the battery is on while V
= 0V, no alarm condition can be detected until V
rises above V
point on, alarms can be detected either on battery
or V
the device goes from no power to its operational
state.
ON;
High-Z; or
Ground (V
CC
CC
. This is done to avoid false alarms when
HV
input or V
RST
INT
(set at 4.2V, typical), or should go below
L
) is exceeded, the SAL is asserted
should exceed the over voltage trip
SS
to enable the tamper detection
RST
).
BAT
1):
(and t
factory-programmed)
input) is continuously mon-
H
rec
) or under-temperature
LV
expires). From this
(set at 2.0v, typi-
STM1404
INT
over-
OUT
De-
(ei-
5/9
CC
CC