TPS3610

• Supply Current of 40 µA (Max)
• Battery Supply Current of 100 nA (Max)
• Precision Supply-Voltage Monitor, 1.8 V, 5 V; Other Options on Request
• Watchdog Timer With 800-ms Time-Out
• Backup-Battery Voltage Can Exceed V_DD
• Power-On Reset Generator With Fixed 100-ms Reset Delay Time
• Battery-OK Output
• Voltage Monitor for Power-Fail or Low-Battery Monitoring
• Manual Switchover to Battery-Backup Mode
• Chip-Enable Gating ... 3 ns (at V_DD = 5 V) Max Propagation Delay
• Battery-Freshness Seal
• 14-pin TSSOP Package
• Temperature Range ... –40°C to 85°C
• typical 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

The TPS3610 family of supervisory circuits monitors and controls processor activity by providing backup-battery switchover for data retention of CMOS RAM. Other features include an additional power-fail comparator, low-line indication, watchdog function, battery-status indicator, manual switchover, and write protection for CMOS RAM.

The TPS3610 family allow usage of 3-V or 3.6-V lithium batteries as the backup supply in systems with, e.g., V_DD = 1.8 V. During power-on, RESET\ is asserted when the supply voltage (V_DD or V_BAT) becomes higher than 1.1 V. Thereafter, the supply-voltage supervisor monitors V_DD and keeps RESET\ output active as long as V_DD remains below the threshold voltage V_IT. An internal timer delays the return of the output to the inactive state (high) to ensure proper system reset. The delay time starts after V_DD has risen above the threshold voltage V_IT . When the supply voltage drops below the threshold voltage V_IT, the output becomes active (low) again.

The product spectrum is designed for supply voltages of 1.8 V and 5 V. The circuits are available in a 14-pin TSSOP package. TPS3610 devices are characterized for operation over a temperature range of –40°C to 85°C.