LTC1728ES5-3.3#TRM Linear Technology, LTC1728ES5-3.3#TRM Datasheet - Page 12

• Manufacturer Part Number: LTC1728ES5-3.3#TRM
• Description: IC TRPL SUPPLY MONITOR TSOT23-5
• Manufacturer: Linear Technology
• Type: Multi-Voltage Supervisorr

Specifications of LTC1728ES5-3.3#TRM

• Number Of Voltages Monitored: 3
• Output: Open Drain or Open Collector
• Reset: Active Low
• Reset Timeout: 140 ms Minimum
• Voltage - Threshold: 1.683V, 3.086V, Adj
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: TSOT-23-5, TSOT-5, TSOP-5
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: LTC1728ES5-3.3#TRMTR

applicaTions inForMaTion
LTC1727/LTC1728
Typical applicaTions
Figure 4 contains a simple circuit for 5V systems that can’t
risk the RST output going high in the 3.1V to 4.15V range
(possibly due to very slow rise time on the 5V supply).
Diode D1 powers the LTC1728-5 while dropping ≈ 0.6V
from the V
internal override circuit from being activated. Without the
override circuit active, the RST pin stays low until V
reaches V
12
5V
0.1µF
Figure 4. LTC1728-5 Monitoring a Single 5V
Supply. D1 Used to Avoid RST High Near 3.1V
to 4V (See Figure 3).
RT5
CC5
≅ 4.675V. (See Figure 5.)
pin to the V
D1
5
4
3
2
D1: MMBD914 OR EQUIVALENT
V
V
V
GND
CC3
CC5
CCA
LTC1728-5
CC3
RST
pin. This prevents the part’s
ADJUSTABLE SUPPLY
OR DC/DC FEEDBACK
1
Triple Supply Monitor (3.3V, 5V and Adjustable)
R1
10k
DIVIDER
TO SYSTEM
RESET
1727/28 F04
R1*
*TO PRESERVE THRESHOLD ACCURACY, SET PARALLEL
COMBINATION OF R1 AND R2 ≤ 66.5k
3.3V
CC5
5V
R2*
5
4
3
2
LTC1727-2.5/LTC1728-2.5/LTC1728-1.8/LTC1728-3.3
Override Functions
The V
V
V
point for V
be tied to V
V
result in the continuous assertion of RST.
V
V
V
GND
CC18
CC3
CC25
CC3
CC5
CCA
LTC1728-5
and V
CCA
. This is an obvious solution since the trip points for
/V
RST
CC18
pin, if unused, can be tied to either V
CCA
CC25
CC3
Figure 5. RST Output Voltage
Characteristics of the Circuit in Figure 4
1727/28 TA03
5
4
3
2
1
0
1
and operating off of a 2.5V/1.8V supply will
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
. Likewise, the V
. V
V
10k PULL-UP FROM RST TO V
T
SYSTEM RESET
/V
CC5
A
= 25°C
CC3
CC18
= V
CCA
must always be used. Tying V
will always be greater than the trip
= 0V TO 5V
V
CC5
(V)
CC25
CC5
/V
CC18
1727/28 F05
, if unused, can
CC3
or V
CC3
CC25
17278fb
to
/