LTC2917/LTC2918
1
29178fb
TYPICAL APPLICATION
FEATURES
APPLICATIONS
DESCRIPTION
Voltage Supervisor with
27 Selectable Thresholds
and Watchdog Timer
The LTC
®
2917-A/LTC2917-B and LTC2918-A/LTC2918-B
are low voltage single-supply monitors with selectable
thresholds and an adjustable watchdog timer. The parts
operate from 1.5V to 5.5V and consume a quiescent cur-
rent of only 30μA.
Two three state inputs select one of nine internally pro-
grammed thresholds without the need for external resistors.
For the LTC2917, an additional three state input determines
the tolerance (–5%, –10%, –15%). The tolerance for the
LTC2918 is fi xed at –5%. Threshold accuracy is guaranteed
at ±1.5% over the entire operating temperature range.
Glitch fi ltering ensures reliable reset operation without
false triggering.
The reset timeout and the watchdog timeout may be set
with no external components, or adjusted using an exter-
nal capacitor. A windowed watchdog feature is available
for high-reliability applications (B1 versions). A separate
manual reset input on the LTC2918-A/LTC2918-B allows
a simple push button interface.
Operation to 125°C makes the LTC2917-A/LTC2917-B
and LTC2918-A/LTC2918-B suitable for automotive
applications.
1.8V Supply Monitor with Manual
Reset and Internal Timers Selected
■
9 Selectable Supply Voltages
12V, 5V, 3.3V, 2.5V, 1.8V
1.5V, 1.2V, 1V, +ADJ (0.5V)
■
3 Selectable Tolerances
–5%, –10%, –15% (LTC2917)
■
Manual Reset Input (LTC2918)
■
1.5V to 5.5V Supply Operation
■
Adjustable Watchdog Timeout
■
Windowed Watchdog Timeout for Higher Reliability
Applications (LTC2917-B, LTC2918-B)
■
6.2V Shunt Regulator for High Voltage Operation
■
Guaranteed Operation to 125°C
■
Guaranteed Threshold Accuracy: ±1.5%
■
Low Quiescent Current: 30μA Typical
■
Power Supply Glitch Immunity
■
Guaranteed RST for V
CC
≥ 0.8V
■
10-Lead MSOP Packages and (3mm × 2mm) DFN
Packages
■
Handheld Devices
■
Cell Phone Base Stations
■
Automotive Control Systems
■
Network Servers
■
Optical Networking Systems
NOMINAL VOLTAGE SEL1 SEL2
12V V
CC
V
CC
5V V
CC
Open
3.3V V
CC
GND
2.5V Open V
CC
1.8V Open Open
1.5V Open GND
1.2V GND V
CC
1V GND Open
ADJ (0.5V) GND GND
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
29178 TA01
VM
WDIRT
WT
SEL1
SEL2
MR
GND
V
CC
LTC2918-A μP
RST
RST
I/O
10k
0.1μF
1.8V
t
WDU
= 1.6s
t
RST
= 200ms
Monitor Selection Table
