LTC2931 Datasheet, PDF (1/16 Pages) Linear Technology – Confi gurable Six Supply Monitor with Adjustable Reset and Watchdog Timers

LTC2931
FEATURES
Configurable Six Supply
Monitor with Adjustable Reset
and Watchdog Timers
DESCRIPTION
■ _{Simultaneously Monitors Six Supplies}
■ _{16 User Selectable Combinations of}
5V, 3.3V, 3V, 2.5V, 1.8V, 1.5V and ± Adjustable
Voltage Thresholds
■ _{Guaranteed Threshold Accuracy: ±1.5%}
■ _{Adjustable Reset and Watchdog Timeout}
■ _{Low Supply Current: 52μA}
■ _{Comparator/Monitor Output for Each Supply}
■ _{Power Supply Glitch Immunity}
■ _{Guaranteed RST for VCC ≥ 1V}
■ _{High Temperature Operation to 125°C}
■ _{20-Lead TSSOP Package}
APPLICATIONS
■ _{Desktop and Notebook Computers}
■ _{Multivoltage Systems}
■ _{Telecom Equipment}
■ _{Portable Battery-Powered Equipment}
■ _{Network Servers}
■ _Automotive
The LTC^®2931 is a configurable supply monitor for
systems with up to six supply voltages. One of 16 preset or
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 0.5V nominal threshold. All six
open-drain voltage comparator outputs are connected to
separate pins for individual supply monitoring.
The reset and watchdog timeout periods are adjustable
using external capacitors. Tight voltage threshold accuracy
and glitch immunity ensure reliable reset operation without
false triggering. The RST output is guaranteed to be in the
correct state for V_CC down to 1V. Each status output has
a weak internal pull-up and may be externally pulled up
to a user defined voltage.
The 52μA 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.
TYPICAL APPLICATION
Six Supply Monitor 12V (ADJ), 5V, 3.3V, 2.5V, 1.8V, 1.2V (ADJ)
12V
5V
3.3V
SYSTEM
2.5V
LOGIC
1.8V
1.2V
10k
2150k 124k
1% 1%
0.1μF
0.1μF
100k 100k
1% 1% _R1
59k
1%
R2
40.2k
1%
V1
V2
V3
V4
V5
V6
VREF
VPG
GND
POWER
GOOD
LTC2931
WDI
WDO
RST
2931 TA01
t_RST = 94ms
CWT
CRT t_WD = 940ms
C_WT
47nF
C_RT
47nF
Voltage Threshold Configuration Table
V1 (V) V2 (V) V3 (V) V4 (V) V5 (V) V6 (V)
5.0 3.3 2.5 1.8 ADJ ADJ
5.0 3.3 2.5 1.5 ADJ ADJ
5.0 3.3 2.5 ADJ ADJ ADJ
5.0 3.3 1.8 ADJ ADJ ADJ
5.0 3.3 1.8 –ADJ ADJ ADJ
5.0 3.3 ADJ ADJ ADJ ADJ
5.0 3.3 ADJ –ADJ ADJ ADJ
5.0 3.0 2.5 ADJ ADJ ADJ
5.0 3.0 1.8 ADJ ADJ ADJ
5.0 3.0 ADJ ADJ ADJ ADJ
3.3 2.5 1.8 1.5 ADJ ADJ
3.3 2.5 1.8 ADJ ADJ ADJ
3.3 2.5 1.8 –ADJ ADJ ADJ
3.3 2.5 1.5 ADJ ADJ ADJ
3.3 2.5 ADJ ADJ ADJ ADJ
3.3 2.5 ADJ –ADJ ADJ ADJ
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