TPS3617 Datasheet, PDF (1/14 Pages) Texas Instruments – BATTERY-BACKUP SUPERVISOR FOR RAM RETENTION

TPS3617
TPS3618
www.ti.com
SLVS339C – DECEMBER 2000 – REVISED NOVEMBER 2004
BATTERY-BACKUP SUPERVISOR FOR RAM RETENTION
FEATURES
• Supply Current of 40 µA (Max)
• Battery Supply Current of 100 nA (Max)
• Precision 5-V Supply Voltage Monitor, Other
Voltage Options on Request
• Backup-Battery Voltage Can Exceed V_DD
• 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°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
MSOP (DGK) Package
(TOP VIEW)
V_OUT
V_DD
GND
PFI
V_BAT
RESET
WDI
PFO
Power
Supply
0.1 µF
External
Source
ACTUAL SIZE
3,05 mm x 4,98 mm
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 V_DD drops below a
preset threshold (V_IT), the active low push-pull
RESET output asserts, and V_OUT switches from V_DD
to V_BAT. When V_DD rises above the trip threshold,
V_OUT switches immediately from V_BAT to V_DD.
The RESET output remains low until the delay time
(t_d) expires. During power on, RESET is asserted
when the supply voltage (V_DD or V_BAT) 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.
TPS3617
TPS3618
V_DD
V_BAT
Backup
Battery
Microcontroller
or
Microprocessor
R_x
PFI
RESET
WDI
PFO
R_y
V_OUT
GND
Switchover
Capacitor
0.1 µF
RESET
I/O
I/O
V_CC
GND
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2000–2004, Texas Instruments Incorporated