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.