FEATURES
■ 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)
www■.Da1t.a5SVheteot45U..5cVomSupply Operation
■ Adjustable Watchdog Timeout
■ Windowed Watchdog Timeout for Higher Reliability
Applications (LTC2917-B, LTC2918-B)
■ 6.2V Shunt Regulator for High Voltage Operation
■ Guaranteed to 125˚C
■ Guaranteed Threshold Accuracy: ±1.5%
■ Low Quiescent Current: 30μA Typical
■ Power Supply Glitch Immunity
■ Guaranteed ⎯R⎯S⎯T for VCC ≥ 0.8V
■ 10-Lead MSOP Packages and (3mm × 2mm) DFN
Packages
APPLICATIONS
■ Handheld Devices
■ Cell Phone Base Stations
■ Automotive Control Systems
■ Network Servers
■ Optical Networking Systems
LTC2917/LTC2918
Low Voltage Supervisor
with 27 Selectable Thresh-
olds and Watchdog Timer
DESCRIPTION
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 fixed at –5%. Threshold accuracy is guaranteed
at ±1.5% over the entire operating temperature range.
Glitch filtering 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 ap-
plications.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
1.8V Supply Monitor with Manual
Reset and Internal Timers Selected
1.8V
0.1μF
10k
VCC
LTC2918-A
VM RST
RT WDI
WT SEL1
MR SEL2
GND
μP
RST
I/O
29178 TA01
tWDU = 1.6s
tRST = 200ms
Monitor Selection Table
NOMINAL VOLTAGE
12V
5V
3.3V
2.5V
1.8V
1.5V
1.2V
1V
ADJ (0.5V)
SEL1
VCC
VCC
VCC
Open
Open
Open
GND
GND
GND
SEL2
VCC
Open
GND
VCC
Open
GND
VCC
Open
GND
29178f
1
