STM1403 STMicroelectronics, STM1403 Datasheet - Page 12

• Manufacturer Part Number: STM1403
• Description: 3 V FIPS-140 security supervisor with battery switchover
• Manufacturer: STMicroelectronics

Pin descriptions
2.1.4
2.1.5
2.1.6
2.1.7
2.1.8
2.1.9
12/34
1.
2.
3.
BLD, V
This is an internally loaded test of the battery, activated only during a power-up sequence to
insure that the battery is good either prior to or after encapsulation of the module. There are
three customer options for V
●
●
●
This output pin will go active-low when it detects a voltage on the V
will be released when V
Active-low RST output (open drain)
Goes low and stays low when V
customer), or when MR is logic low. It remains low for t
above V
MR, manual reset input
A logic low on MR asserts the RST output. The RST output remains asserted as long as MR
is low and for t
(typical) pull-up resistor. It can be driven from a TTL or CMOS logic line or shorted to ground
with a switch. Leave it open if unused.
PFO, power-fail output (open drain)
When PFI is less than V
(battery switchover threshold ~ 2.4 V), PFO goes low, otherwise, PFO remains high. Leave
this pin open if unused.
PFI, power-fail input
When PFI is less than V
active-low. If this function is unused, connect this pin to V
V
This is valid only when V
V
available on the STM1403A. On the STM1403B/C, this pin is V
or V
REF
REF
BAT
STM1403A (V
operate in normal mode;
STM1403B (V
high when this occurs; and
STM1403C (V
high when this occurs.
2.3 V (2.5 V – external diode drop of about 0.2 V) for a 3 V lithium cell
2.5 V (2.7 V – 0.2 V) for a 3 V lithium cell or
3.2 V (3.4 V – 0.2 V) for a 3.68 V lithium “AA” battery
is pulled to ground with an internal 100 kΩ resistor. This is an optional feature
, reference voltage output (1.237, typ)
). If unused, this pin should float.
RST
BAT
and MR goes from low to high.
low voltage detect output (open drain)
rec
after MR returns to high. This active low input has an internal 40 kΩ
OUT
OUT
OUT
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
CC
PFI
PFI
CC
, or when V
drops below V
(power-fail input threshold voltage) or V
is between 2.4 V and 3.6 V. When V
DET
Doc ID 13232 Rev 6
CC
:
drops below V
CC
RST
falls below V
.
RST
(reset threshold selected by the
rec
SW
(200ms, typical) AFTER V
SS
(see PFO, above), PFO goes
.
TPU
CC
BAT
(internally switched V
CC
falls below 2.4 V (V
falls below V
pin below V
STM1403
DET
SW
CC
. BLD
rises
SW
CC
),