FEATURES
· Supply Current of 40 mA (Max)
· Battery Supply Current of 100 nA (Max)
· Precision 5-V Supply Voltage Monitor, Other
Voltage Options on Request
· Backup-Battery Voltage Can Exceed VDD
· Watchdog Timer With 800-ms Time-Out
· Power-On Reset Generator With Fixed 100-ms
Reset Delay Time
· Voltage Monitor for Power-Fail or Low-Battery
Monitoring
· Battery Freshness Seal (TPS3617 Only)
· 8-Pin MSOP Package
· Temperature Range: –40° to +85°C

APPLICATIONS
· Fax Machines
· Set-Top Boxes
· Advanced Voice Mail Systems
· Portable Battery Powered Equipment
· Computer Equipment
· Advanced Modems
· Automotive Systems
· Portable Long-Time Monitoring Equipment
· Point-of-Sale Equipment

DESCRIPTION
The TPS3617 and TPS3618 are battery-backup
supervisors that monitor 5 V supplies. They provide
a battery-backup function ideal for applications that
require data retention of CMOS RAM during fault conditions. When the voltage at VDD drops below a
preset threshold (VIT), the active low push-pull
RESET output asserts, and VOUT switches from VDD
to VBAT. When VDD rises above the trip threshold,
VOUT switches immediately from VBAT to VDD. The RESET output remains low until the delay time
(td) expires. During power on, RESET is asserted
when the supply voltage (VDD or VBAT) goes higher
than 1.1 V.
The PFI and PFO pins are provided if additional
voltage monitoring is needed. If the voltage at PFI is
less than 1.15 V, the push-pull PFO pin will assert
low. When the voltage at PFI exceeds the threshold
voltage, PFO will go high.
These devices also feature a watchdog timer pin
(WDI) that monitors processor activity and asserts
RESET if the the processor is inactive longer than
the watchdog timeout period. If the watchdog timer is
not used, the WDI pin should be left floating.
The TPS3617 and TPS3618 are available in an 8-pin
MSOP package and are characterized for operation
over a temperature range of –40°C to +85°C.