LTC1726_1 Datasheet, PDF (1/12 Pages) Linear Technology – Triple Supply Monitor and ® Supervisor with Adjustable Reset and Watchdog Timer

LTC1726
Triple Supply Monitor and
µP Supervisor with Adjustable
Reset and Watchdog Timer
FEATURES
■ _{Monitors Three Inputs Simultaneously}
LTC1726-5: 5V, 3.3V and ADJ
LTC1726-2.5: 2.5V, 3.3V and ADJ
■ _{±1.5% Threshold Accuracy Over Temperature}
■ _{Low Supply Current: 16µA Typ}
■ _{Adjustable Reset Timeout}
■ _{Adjustable Watchdog Timeout}
■ _{Active Low Open-Drain Reset Output}
■ _{Power Supply Glitch Immunity}
■ _{Guaranteed RESET for VCC3 ≥ 1V or VCC25/VCC5 ≥ 1V}
■ _{MS8 and SO-8 Packages}
U
APPLICATIO S
■ _{Desktop Computers}
■ _{Notebook Computers}
■ _{Intelligent Instruments}
■ _{Portable Battery-Powered Equipment}
■ _{Network Servers}
DESCRIPTIO
The LTC^®1726 is a triple supply monitor and microproces-
sor supervisory circuit with adjustable reset and watchdog
functions intended for systems with multiple supply volt-
ages. The part has a common open-drain reset output with
an adjustable delay. The reset and watchdog time-out
periods are both adjustable using external capacitors.
Tight 1.5% accuracy specifications and glitch immunity
ensure reliable reset operation without false triggering.
The RST output is guaranteed to be in the correct state for
V_CC5/V_CC25 or V_CC3 down to 1V. The LTC1726 may also be
configured to monitor any one or two V_CC inputs instead
of three, depending on system requirements.
The low (16µA typical) supply current makes the LTC1726
ideal for power-conscious systems.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIONS
A 3.3V, 5V and 1.8V Monitor
3.3V
0.1µF
5V
0.1µF
1.8V
(V_TRIP = 1.665V)
R1
66.5k
1%
C_RT
47nF
213
V_CC5 V_CC3 V_CCA
8
RT
6
RST
C_WT
47nF
LTC1726-5
7
WT
5
WDI
R2
100k
1%
RESET
µP
I/O
GND
t_RT = 155ms
4
t_WT= 1s
1726 TA01
A 3.3V, 2.5V and 1.8V Monitor
3.3V
0.1µF
2.5V
0.1µF
1.8V
(V_TRIP = 1.665V)
R1
66.5k
1%
C_RT
47nF
21 3
V_CC25 V_CC3 V_CCA
8
RT
6
RST
C_WT
47nF
LTC1726-2.5
7
WT
5
WDI
R2
100k
1%
RESET
µP
I/O
GND
t_RT = 155ms
4
t_WT= 1s
1726 TA02
1726fb
1