LTC2931
Configurable Six Supply
Monitor with Adjustable Reset
and Watchdog Timers
DESCRIPTION
FEATURES
The LTC®2931 is a configurable supply monitor for
systemswithuptosixsupplyvoltages. Oneof16presetor
adjustable voltage monitor combinations can be selected
using an external resistive divider connected to the mode
select pin. The preset voltage thresholds are accurate
to 1.ꢀ5 over temperature. The LTC2931 also features
adjustable inputs with a 0.ꢀV nominal threshold. All six
open-drain voltage comparator outputs are connected to
separate pins for individual supply monitoring.
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Simultaneously Monitors Six Supplies
16 User Selectable Combinations of
■
5V, 3.3V, 3V, 2.5V, 1.8V, 1.5V and Adꢀustable
Voltage Thresholds
■
Guaranteed Threshold Accuracy: 1.5ꢁ
■
Adꢀustable Reset and Watchdog Timeout
■
Low Supply Current: 52μA
■
Comparator/Monitor Output for Each Supply
■
Power Supply Glitch Immunity
Guaranteed RST for V ≥ 1V
■
CC
The reset and watchdog timeout periods are adjustable
usingexternalcapacitors.Tightvoltagethresholdaccuracy
andglitchimmunityensurereliableresetoperationwithout
false triggering. The RST output is guaranteed to be in the
■
■
High Temperature Operation to 12ꢀ°C
20-Lead TSSOP Package
APPLICATIONS
correct state for V down to 1V. Each status output has
CC
a weak internal pull-up and may be externally pulled up
■
Desktop and Notebook Computers
to a user defined voltage.
■
Multivoltage Systems
■
The ꢀ2μA supply current makes the LTC2931 ideal for
power conscious systems and it may be configured to
monitor fewer than six inputs.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 6967591, 7239251, 7119714.
Telecom Equipment
Portable Battery-Powered Equipment
Network Servers
Automotive
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TYPICAL APPLICATION
Six Supply Monitor 12V (ADJ), 5V, 3.3V, 2.5V, 1.8V, 1.2V (ADJ)
Voltage Threshold Configuration Table
12V
V1 (V) V2 (V) V3 (V) V4 (V) V5 (V) V6 (V)
ꢀV
ꢀ.0
ꢀ.0
ꢀ.0
ꢀ.0
ꢀ.0
ꢀ.0
ꢀ.0
ꢀ.0
ꢀ.0
ꢀ.0
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.0
3.0
3.0
2.ꢀ
2.ꢀ
2.ꢀ
2.ꢀ
2.ꢀ
2.ꢀ
2.ꢀ
2.ꢀ
2.ꢀ
1.8
1.8
ADJ
ADJ
2.ꢀ
1.8
ADJ
1.8
1.8
1.8
1.ꢀ
ADJ
ADJ
1.8
1.ꢀ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
ADJ
3.3V
2.ꢀV
SYSTEM
LOGIC
1.8V
1.2V
ADJ
ADJ
–ADJ
ADJ
–ADJ
ADJ
ADJ
ADJ
1.ꢀ
ADJ
–ADJ
ADJ
ADJ
–ADJ
10k
POWER
GOOD
21ꢀ0k 124k
15
15
V1
V2
V3
WDI
0.1μF
V4
LTC2931
0.1μF
Vꢀ
WDO
RST
V6
100k
15
100k
15
ꢀ9k
15
VREF
R1
2931 TA01
VPG
t
t
= 94ms
= 940ms
RST
WD
CWT
CRT
GND
R2
40.2k
15
C
WT
47nF
C
RT
47nF
2931fb
1