LTC1726IS8-5 Linear Technology, LTC1726IS8-5 Datasheet - Page 10

• Manufacturer Part Number: LTC1726IS8-5
• Description: IC MON TRPL SPPLY SUPERVSR 8SOIC
• Manufacturer: Linear Technology
• Type: Multi-Voltage Supervisorr

Specifications of LTC1726IS8-5

• Number Of Voltages Monitored: 3
• Output: Open Drain or Open Collector
• Reset: Active Low
• Reset Timeout: Adjustable/Selectable
• Voltage - Threshold: 3.085V, 4.675V, Adj
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

LTC1726
applicaTions inForMaTion
Selecting the Reset and Watchdog
Time-Out Capacitors
The reset time-out period is adjustable in order to accom-
modate a variety of µP applications. The reset time-out
period, t
between the RT pin and ground. The value of this capacitor
is determined as follows:
with C
The capacitor should be a low leakage type. A ceramic
capacitor is recommended.
Typical applicaTions
ADJUSTABLE SUPPLY
10
OR DC/DC FEEDBACK
C
RT
RT
= t
Triple Supply Monitor (3.3V, 5V and Adjustable)
RT
DIVIDER
RT
in pF and t
, is adjusted by connecting a capacitor, C
/3.30
R1*
*TO PRESERVE THRESHOLD ACCURACY, SET PARALLEL
COMBINATION OF R1 AND R2 ≤ 66.5k
RT
3.3V
5V
R2*
in µs (i.e., 1500pF ⇒ 4.95ms).
1
2
3
4
V
V
V
GND
CC3
CC5
CCA
LTC1726-5
ADJUSTABLE
SUPPLY
WDI
RST
WT
RT
8
7
6
5
SYSTEM RESET
WDI
C
R1*
RT
Disabling the Watchdog Timer
*TO PRESERVE THRESHOLD ACCURACY, SET PARALLEL
THE WATCHDOG TIMER CAN BE DISABLED BY CONNECTING
THE WDI AND WT PINS TO GROUND. THE PART WILL ACT
STRICTLY AS A TRIPLE SUPPLY MONITOR WITH AN
ADJUSTABLE RESET TIME-OUT PERIOD
COMBINATION OF R1 AND R2 ≤ 66.5k
5V/2.5V
R2*
3.3V
C
WT
1726 TA04
RT
1
2
3
4
LTC1726-5/LTC1726-2.5
,
V
V
V
GND
CC3
CC5
CCA
/V
The watchdog period is also adjustable so that the watchdog
time-out period can be optimized for software execution.
The watchdog time-out period, t
ing a capacitor, C
the optimum watchdog time-out period (t
the value of the capacitor is calculated as follows:
with C
The capacitor should be a low leakage type. A ceramic
capacitor is recommended.
CC25
C
WT
RST
WDI
Dual Supply Monitor (3.3V and 5V, Defeat V
WT
RT
WT
= t
8
7
6
5
in pF and t
WT
3.3V
5V
SYSTEM
RESET
C
/21.8
1726 TA03
RT
WT
1
2
3
4
, between the WT pin and ground. Once
V
V
V
GND
WT
CC3
CC5
CCA
LTC1726-5
in µs (i.e., 1500pF ⇒ 32.7ms).
WDI
RST
WT
RT
WT
8
7
6
5
, is adjusted by connect-
SYSTEM RESET
WDI
C
RT
WT
C
) is determined,
WT
CCA
1726 TA05
Input)
1726fc