Datasheet

   
    
SLVS336B − DECEMBER 2000 − REVISED JANUARY 2007
6
Terminal Functions
TERMINAL
I/O
DESCRIPTION
NAME NO.
I/O
DESCRIPTION
BATTOK 9 O Battery status output
BATTON 6 O Logic output/external bypass switch driver output
CEIN 5 I Chip-enable input
CEOUT 10 O Chip-enable output
GND 3 I Ground
MR 11 I Manual reset input
MSWITCH 4 I Manual switch to force device into battery-backup mode (connect to GND if not used)
PFI 7 I Power-fail comparator input (connect to GND if not used)
PFO 8 O Power-fail comparator output
RESET 13 O Active-low reset output
V
BAT
14 I Backup-battery input
V
DD
2 I Input supply voltage
V
OUT
1 O Supply output
WDI 12 I Watchdog timer input
detailed description
battery freshness seal
The battery freshness seal of the TPS3600 family disconnects the backup battery from the internal circuitry until
it is needed. This ensures that the backup battery connected to V
BAT
should be fresh when the final product is
put to use. The following steps explain how to enable the freshness seal mode:
1. Connect V
BAT
(V
BAT
> V
BAT(min)
)
2. Ground PFO
3. Connect PFI to V
DD
or PFI > V
(PFI)
4. Connect V
DD
to power supply (V
DD
> V
IT
)
5. Ground MR
6. Power down V
DD
7. The freshness seal mode is entered and pins PFO and MR can be disconnected.
The battery freshness seal mode is disabled by the positive-going edge of RESET
when V
DD
is applied.
BATTOK output
This is a logic feedback of the device to indicate the status of the backup battery. The supervisor checks the
battery voltage every 200 ms with a voltage divider load of approximately 100 KΩ and a measure cycle on-time
of 25 µs. This measurement cycle starts after the reset is released. If the battery voltage V
BAT
is below the
negative-going threshold voltage V
(BOK)
, the indicator BATTOK does a high-to-low transition. Otherwise, its
status remains to the V
OUT
level.
Table 1. Typical Values for BATTOK Indication
SUPERVISOR TYPE V
IT
TYP V
BOK
MIN V
BOK
TYP V
BOK
MAX
TPS3600D20 1.78 V 1.84 V 1.91 V 1.97 V
TPS3600D25 2.22 V 2.3 V 2.38 V 2.46 V
TPS3600D33 2.93 V 3.04 V 3.14 V 3.24 V
TPS3600D50 4.40 V 4.56 V 4.71 V 4.86 V
www.ti.com