TPS3619-33

TPS3619-33, TPS3619-50 TPS3620-33, TPS3620-50 www.ti.com SLVS387H – APRIL 2001 – REVISED DECEMBER 2007 BACKUP-BATTERY SUPERVISORS FOR RAM RETENTION FEATURES 1 2 Supply Current of 40 µA (Max) Battery-Supply Current of 100 nA (Max) Precision Supply Voltage Monitor 3.3 V, 5 V, Other Options on Request Backup-Battery Voltage Can Exceed VDD Power On Reset Generator With Fixed 100-ms Reset Delay Time Voltage Monitor For Power-Fail or Low-Battery Monitoring Battery Freshness Seal (TPS3619) Pin-For-Pin Compatible With MAX819, MAX703, and MAX704 8-Pin MSOP Package Temperature Range –40°C 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 TPS3619 and TPS3620 families of supervisory circuits monitor and control processor activity by providing backup-battery switchover for data retention of CMOS RAM. During power on, RESET is asserted when the supply voltage (VDD or VBAT) becomes higher than 1.1 V. Thereafter, the supply voltage supervisor monitors VDD and keeps RESET output active as long as VDD remains below the threshold voltage (VIT). An internal timer delays the return of the output to the inactive state (high) to ensure proper system reset. The delay time starts after VDD has risen above VIT. When the supply voltage drops below VIT, the output becom...