LTC2917/LTC2918

1

29178f

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

Low Voltage Supervisor

with 27 Selectable Thresh-

olds and Watchdog Timer

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.

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 to 125˚C

■

Guaranteed Threshold Accuracy: ±1.5%

■

Low Quiescent Current: 30μA Typical

■

Power Supply Glitch Immunity

■

■

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

5V

Open

3.3V

GND

2.5V

Open

1.8V

Open

Open

1.5V

Open

GND

1.2V

GND

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.

1.8V

10k

29178 TA01

VM

WDI

RT

WT

SEL1

SEL2

MR

GND

LTC2918-A

μP

RST

RST

I/O

0.1

μF

Monitor Selection Table