TPS3613 01
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SLVS340D − DECEMBER 2000 − REVISED JULY 2008
ADJUSTABLE BATTERY BACKUP SUPERVISOR
FOR RAM RETENTION
FEATURES
D
Supply Current of 40
µA
(Max)
D
Battery Supply Current of 100 nA (Max)
D
Supply Voltage Supervision Range:
D
D
Power-On Reset Generator With Fixed 100-ms
Reset Delay Time
− Adjustable
− Other Versions Available on Request
Backup-Battery Voltage Can Exceed V
DD
DESCRIPTION
The TPS3613-01 supervisory circuit monitors and controls
processor activity by providing backup-battery switchover
for data retention of CMOS RAM.
During power-on, reset (RESET and 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
at
the SENSE pin through external feedback resistors and
keeps reset active as long as SENSE remains below the
threshold voltage, V
IT
.
An internal timer delays the release of the reset state to
ensure proper system reset. The delay time starts after
SENSE rises above the threshold voltage, V
IT
.
When SENSE drops below V
IT
, reset becomes active
again.
The TPS3613-01 is available in a 10-pin MSOP package
and is characterized for operation over a temperature
range of −40
°
C to +85
°
C.
D
Active-High and Active-Low Reset Output
D
Chip-Enable Gating: 3 ns (at V
DD
= 5 V) Max
D
D
Propagation Delay
10-Pin MSOP Package
Temperature Range: −40°C to 85°C
APPLICATIONS
D
Fax Machines
D
Set-Top Boxes
D
Advanced Voice Mail Systems
D
Portable Battery-Powered Equipment
D
Computer Equipment
D
Advanced Modems
D
Automotive Systems
D
Portable Long-Time Monitoring Equipment
D
Point-of-Sale Equipment
Power
Supply
0.1
µF
CEIN
Rx
Ry
VDD
SENSE
RESET
TPS3613
MR
Manual
Reset
GND
VOUT
CEOUT
VBAT
Backup
Battery
Address
Decoder
Address Bus
uC
RESET
Data Bus
16
CE
CMOS
RAM
VCC
8
CE
CMOS
RAM
VCC
8
Real−
Time
Clock
VCC
Switchover
Capacitor
0.1
µF
VCC
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.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date. Products
conform to specifications per the terms of Texas Instruments standard warranty.
Production processing does not necessarily include testing of all parameters.
Copyright
2000−2008, Texas Instruments Incorporated
www.ti.com
TPS3613 01
www.ti.com
SLVS340D − DECEMBER 2000 − REVISED JULY 2008
detailed description
backup-battery switchover
In case of a brownout or power failure, it may be
necessary to preserve the contents of RAM. If a
backup battery is installed at V
BAT
, the device
automatically switches the connected RAM to
backup power when V
DD
fails. In order to allow the
backup battery (for example, 3.6-V lithium cells)
to have a higher voltage than V
DD
, these
VDD >VBAT
1
1
0
0
VDD >VIT
1
0
1
0
supervisors do not connect V
BAT
to V
OUT
when
V
BAT
is greater than V
DD
. V
BAT
only connects to
V
OUT
(through a 15-Ω switch) when V
DD
falls
below V
IT
and V
BAT
is greater than V
DD
. When
V
DD
recovers, switchover is deferred either until
V
DD
crosses V
BAT
, or when V
DD
rises above the
reset threshold V
IT
. V
OUT
connects to V
DD
through
a 1-Ω (max) PMOS switch when V
DD
crosses the
reset threshold.
VOUT
VDD
VDD
VDD
VBAT
VDD − Normal Supply Voltage
VDD − Mode
VIT Hysteresis
VBAT − Mode
VBSW Hysteresis
Undefined
VBAT − Backup-Battery Supply Voltage
Figure 1. V
DD
− V
BAT
Switchover
5
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