LTC2911
1
2911f
TYPICAL APPLICATION
DESCRIPTION
Precision Triple Supply
Monitor with Power-Fail
Comparator
The LTC2911 is a low power, high accuracy triple supply
monitor with a power-fail comparator. Reset timeout may
beselectedwithanexternalcapacitororsettoaninternally
generated 200ms.
The V1 pin monitors a 3.3V supply. The V2 pin monitors a
5V, 2.5V, 1.8V, 1.2V or adjustable supply. A third adjustable
input has a nominal 0.5V threshold allowing a resistive
divider to configure its threshold. All three comparators
feature a tight 1.5% threshold accuracy over the entire
operating temperature range while a glitch filter ensures
reliable reset operation.
A spare comparator can be configured to provide early
warningofalowvoltagecondition.ItcausesthePFOoutput
topulllowwhenthevoltageofthePFIinputfallsbelow0.5V,
allowing the power-fail threshold to be configured with
a resistive divider. A latch feature on the TMR pin allows
the RST output to be latched to prevent system resets,
simplifying margin testing.
FEATURES
APPLICATIONS
n
Ultralow Voltage Reset: VCC = 0.5V Guaranteed
n
Monitors Three Inputs Simultaneously:
3.3V, 5V, ADJ (LTC2911-1)
3.3V, 2.5V, ADJ (LTC2911-2)
3.3V, 1.8V, ADJ (LTC2911-3)
3.3V, 1.2V, ADJ (LTC2911-4)
3.3V, ADJ, ADJ (LTC2911-5)
n
±1.5% Threshold Accuracy
n
Power-Fail Monitor
n
RST State Can Be Held for Margining
n
Low Supply Current: 30A Typical
n
Input Glitch Immunity
n
Adjustable Reset Timeout Period
n
Selectable Internal Timeout Saves Components
n
Space Saving 8-Lead TSOT-23 and 3mm
× 2mm DFN
Packages
n
Network Servers
n
Desktop and Notebook Computers
n
Automotive and Industrial Electronics
RST Output Voltage With 10k Pull-Up to V1
+
LTC2911-2
76.8k
10k
3.3V
2.5V
1.0V
100k
576k
Li-Ion
BATTERY
STACK
100k
V1
TMR
V2
ADJ
RESET
LOBAT
RST
PFO
PFI
tRST = 200ms
2911 TA01a
GND
SYSTEM
LOGIC
DC/DC
CONVERTER
L
, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Protected by U.S. Patents, including 6949965, 7292076.
V1 (V)
0
V RST
(V)
2
4
6
1
3
5
0.5
1.5
2.5
3.5
2911 TA01b
5.5
0
1
2
3
4 4.5 5
V1 = V2