STM1404ARMBQ6F STMICROELECTRONICS [STMicroelectronics], STM1404ARMBQ6F Datasheet - Page 13

• Manufacturer Part Number: STM1404ARMBQ6F
• Description: 3 V FIPS-140 security supervisor with battery switchover
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

STM1404
2.9
2.10
2.11
Note:
2.12
2.13
2.14
V
This is valid only when V
V
available on the STM1404A. On the STM1404B/C, this pin is V
or V
V
This is the supply voltage output. When V
voltage), V
V
(~2.4 V), or V
connected externally to a capacitor that will retain a charge for a period of time, in case an
intruder forces V
terminal of the battery to the V
capacitor. Three variations of parts will be offered with the following options:
1.
2.
3.
V
For STM1404B and STM1404C, this pin provides pull-up voltage for the physical tamper
pins (TP1-4). This pin is not to be used as voltage supply source for any other purpose.
V
V
This is the supply voltage (2.2 V to 3.6 V).
V
This is the secondary (backup battery) supply voltage. The pin is connected to the positive
terminal of the battery with a rectifying diode like the BAT54J from STMicroelectronics for
reverse charge protection. Voltage at this pin, after diode rectification, will be approximately
0.2 V less than the battery voltage, and will depend on the type of battery used as well as
the I
V
V
Ground, V
REF
CC
TPU
SS
OUT
REF
TPU
CC
BAT
SS
BAT
BAT
is required.) If no battery is used, connect the V
through a p-channel MOSFET switch. When V
STM1404A: V
operate in normal mode (see
STM1404B: V
high when this occurs; and
STM1404C: V
high when this occurs.
is pulled to ground with an internal 100 kΩ resistor. This is an optional feature
is the internally switched supply voltage from either the V
, reference voltage output (1.237, typ)
). If unused, this pin should float.
being drawn. (A capacitor of at least 1.0 µF connected between the V
SS
OUT
, is the reference for the power supply. It must be connected to system ground.
BAT
is supplied from V
, V
CC
OUT
OUT
OUT
OUT
or V
remains ON when SAL is active-low; Vccsw pin will continue to
is taken to High-Z when SAL is active-low; Vccsw pin will be set to
is driven to ground when SAL is active-low; Vccsw pin will be set to
is supplied from V
BAT
CC
to ground. The rectifying diode connected from the positive
is between 2.4 V and 3.6 V. When V
BAT
CC
pin of the STM1404 will prevent discharge of the
Section 2.3.1: Vccsw, V
. In this condition, V
CC
BAT
rises above V
. It is recommended that the V
CC
BAT
falls below the lower value of V
OUT
pin to the V
CC
SO
may be connected externally to
switch output on page
(battery backup switchover
TPU
CC
CC
pin or the V
(internally switched V
falls below 2.4 V (V
CC
pin.
Pin descriptions
OUT
BAT
BAT
pin be
pin.
pin and
11);
SW
13/36
SW
CC
),