STM690, STM704, STM795
STM802, STM804, STM805, STM806
3V Supervisor with Battery Switchover
FEATURES SUMMARY
■
■
■
■
■
■
■
■
■
■
■
■
RST OR RST OUTPUTS
NVRAM SUPERVISOR FOR EXTERNAL
LPSRAM
CHIP-ENABLE GATING (STM795 only) FOR
EXTERNAL LPSRAM (7ns max PROP
DELAY)
MANUAL (PUSH-BUTTON) RESET INPUT
200ms (TYP) t
rec
WATCHDOG TIMER - 1.6sec (TYP)
AUTOMATIC BATTERY SWITCHOVER
LOW BATTERY SUPPLY CURRENT - 0.4µA
(TYP)
POWER-FAIL COMPARATOR (PFI/PFO)
LOW SUPPLY CURRENT - 40µA (TYP)
GUARANTEED RST (RST) ASSERTION
DOWN TO V
CC
= 1.0V
OPERATING TEMPERATURE:
–40°C to 85°C (Industrial Grade)
Figure 1. Packages
8
1
SO8 (M)
TSSOP8 3x3 (DS)*
Table 1. Device Options
Watchdog
Input
STM690T/S/R
STM704T/S/R
STM795T/S/R
STM802T/S/R
STM804T/S/R
STM805T/S/R
STM806T/S/R
✔
✔
✔
✔
✔
Active-
Low RST
(1)
✔
✔
✔
(2)
✔
✔
(2)
✔
(2)
✔
✔
Active-
High
RST
Manual
Battery
Reset Input Switch-over
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
✔
Power-fail
Compar-
ator
✔
✔
✔
Chip-
Enable
Gating
Note: 1. All RST outputs push-pull (unless otherwise noted)
2. Open drain output.
* Contact local ST sales office for availability.
Rev 7
April 2006
1/32
STM690/704/795/802/804/805/806
TABLE OF CONTENTS
FEATURES SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Figure 1. Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Table 1. Device Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
SUMMARY DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 2. Logic Diagram (STM690/802/804/805) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 3. Logic Diagram (STM704/806) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 4. Logic Diagram (STM795). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Table 2. Signal Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Figure 5. STM690/802/804/805 Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 6. STM704/806 Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Figure 7. STM795 Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Table 3. Pin Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Figure 8. Block Diagram (STM690/802/804/805) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 9. Block Diagram (STM704/806) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Figure 10.Block Diagram (STM795) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 11.Hardware Hookup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Reset Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Push-button Reset Input (STM704/806). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Watchdog Input (NOT available on STM704/795/806) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Back-up Battery Switchover. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Table 4. I/O Status in Battery Back-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Chip-Enable Gating (STM795 only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Chip Enable Input (STM795 only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Chip Enable Output (STM795 only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 12.Chip-Enable Gating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 13.Chip Enable Waveform (STM795) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Power-fail Input/Output (NOT available on STM795) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Applications Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 14.Power-fail Comparator Waveform (STM690/704/802/804/805/806) . . . . . . . . . . . . . . . . 11
Using a SuperCap™ as a Backup Power Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 15.Using a SuperCap™ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Negative-Going V
CC
Transients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
TYPICAL OPERATING CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 16.V
CC
-to-V
OUT
On-Resistance vs. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 17.V
BAT
-to-V
OUT
On-Resistance vs. Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 18.Supply Current vs. Temperature (no load) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 19.Battery Current vs. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 20.V
PFI
Threshold vs. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2/32
STM690/704/795/802/804/805/806
Figure 21.Reset Comparator Propagation Delay vs. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . 15
Figure 22.Power-up t
rec
vs. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 23.Normalized Reset Threshold vs. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 24.Watchdog Time-out Period vs. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 25.E to E
CON
On-Resistance vs. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 26.PFI to PFO Propagation Delay vs. Temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 27.Output Voltage vs. Load Current (V
CC
= 5V; V
BAT
= 2.8V; T
A
= 25°C). . . . . . . . . . . . . . 18
Figure 28.Output Voltage vs. Load Current (V
CC
= 0V; V
BAT
= 2.8V; T
A
= 25°C). . . . . . . . . . . . . . 19
Figure 29.RST Output Voltage vs. Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Figure 30.RST Output Voltage vs. Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 31.Power-fail Comparator Response Time (Assertion) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Figure 32.Power-fail Comparator Response Time (De-Assertion) . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 33.Maximum Transient Duration vs. Reset Threshold Overdrive. . . . . . . . . . . . . . . . . . . . . 21
Figure 34.E to E
CON
Propagation Delay vs. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
MAXIMUM RATING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Table 5. Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
DC and AC PARAMETERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 6. Operating and AC Measurement Conditions . . . . . . . . . . . . . . . . . . . . . . . .
Figure 35.E to ECON Propagation Delay Test Circuit. . . . . . . . . . . . . . . . . . . . . . . . .
Figure 36.AC Testing Input/Output Waveforms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 37.MR Timing Waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figure 38.Watchdog Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table 7. DC and AC Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
......
......
......
......
......
......
. . . . 23
. . . . 23
. . . . 23
. . . . 24
. . . . 24
. . . . 24
PACKAGE MECHANICAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 39.SO8 – 8-lead Plastic Small Outline, 150 mils body width, Package Mech. Drawing. . . . 27
Table 8. SO8 – 8-lead Plastic Small Outline, 150 mils body width, Package Mechanical Data . . 27
Figure 40.TSSOP8 – 8-lead, Thin Shrink Small Outline, 3x3mm body size, Outline . . . . . . . . . . . 28
Table 9. TSSOP8 – 8-lead, Thin Shrink Small Outline, 3x3mm body size, Mechanical Data . . . . 28
PART NUMBERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Table 10. Ordering Information Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Table 11. Marking Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
REVISION HISTORY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 12. Document Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3/32
STM690/704/795/802/804/805/806
SUMMARY DESCRIPTION
The STM690/704/795/802/804/805/806 Supervi-
sors are self-contained devices which provide mi-
croprocessor supervisory functions with the ability
to non-volatize and write-protect external
LPSRAM. A precision voltage reference and com-
parator monitors the V
CC
input for an out-of-toler-
ance condition. When an invalid V
CC
condition
occurs, the reset output (RST) is forced low (or
high in the case of RST). These devices also offer
Figure 2. Logic Diagram (STM690/802/804/805)
V
CC
V
BAT
a watchdog timer (except for STM704/795/806) as
well as a power-fail comparator (except for
STM795) to provide the system with an early
warning of impending power failure.
These devices are available in a standard 8-pin
SOIC package or a space-saving 8-pin TSSOP
package.
Figure 4. Logic Diagram (STM795)
V
CC
V
BAT
V
OUT
WDI
PFI
STM690/
802/804/
805
RST(RST)
(1)
PFO
V
CCSW
STM795
E
V
OUT
RST
E
CON
V
SS
AI08846
V
SS
AI08848
Note: 1. For STM804/805, reset output is active-high and open
drain.
Table 2. Signal Names
MR
WDI
Push-button Reset Input
Watchdog Input
Active-Low Reset Output
Active-High Reset Output
Chip Enable Input
Conditioned Chip Enable Output
V
CC
Switch Output
Supply Voltage Output
Supply Voltage
Back-up Supply Voltage
Power-fail Input
Power-fail Output
Ground
Figure 3. Logic Diagram (STM704/806)
V
CC
V
BAT
RST
RST
(1)
V
OUT
MR
PFI
STM704
STM806
RST
PFO
E
(2)
E
CON(2)
Vccsw
(2)
V
OUT
V
SS
AI08847
V
CC
V
BAT
PFI
PFO
V
SS
Note: 1. Open drain for STM804/805 only.
2. STM795
4/32
STM690/704/795/802/804/805/806
Figure 5. STM690/802/804/805 Connections
SO8/TSSOP8
V
OUT
V
CC
V
SS
PFI
1
2
3
4
8
7
6
5
V
BAT
RST(RST)
(1)
WDI
PFO
AI08849
Figure 6. STM704/806 Connections
SO8/TSSOP8
V
OUT
V
CC
V
SS
PFI
1
2
3
4
8
7
6
5
V
BAT
RST
MR
PFO
AI08850
Note: 1. For STM804/805, reset output is active-high and open
drain.
Figure 7. STM795 Connections
SO8/TSSOP8
V
OUT
V
CC
V
CCSW
V
SS
1
2
3
4
8
7
6
5
V
BAT
RST
E
CON
E
AI08851
5/32
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