1

LTC1727/LTC1728

Micropower Precision

Triple Supply Monitors

in 8-Lead MSOP and

5-Lead SOT-23 Packages

s

Monitors Three Inputs Simultaneously

LTC1727-5: 5V, 3.3V and ADJ

LTC1727-2.5: 2.5V, 3.3V and ADJ

LTC1728-5: 5V, 3.3V and ADJ

LTC1728-2.5: 2.5V, 3.3V and ADJ

LTC1728-1.8: 3V, 1.8V and ADJ

s

±1.5% Threshold Accuracy Over Temperature

s

Very Low Supply Current: 10

µA Typ

s

200ms Reset Time Delay

s

Active Low RESET Output

s

Power Supply Glitch Immunity

s

s

LTC1727 Includes Monitor Output for Each Supply

s

LTC1727: 8-Lead MSOP and SO Packages

s

LTC1728: 5-Lead SOT-23 Package

The LTC

systems with multiple supply voltages. Each supply moni-

tor has its own open-drain output for individual supply

monitoring. A common open-drain reset output remains

low until all three supplies have been in compliance for

200ms. Tight 1.5% accuracy specifications and glitch

immunity ensure reliable reset operation without false

triggering.

The LTC1728 is functionally identical to the LTC1727

without the individual monitor outputs.

The RST output is guaranteed to be in the correct state for

LTC1728 may also be configured to monitor any one or

requirements.

Very low (10

µAtypical)supplycurrentmakestheLTC1727/

LTC1728 ideal for power conscious systems.

The LTC1727 is available in an 8-lead MSOP or SO

package and the LTC1728 is available in a 5-lead SOT-23

package.

, LTC and LT are registered trademarks of Linear Technology Corporation.

s

Desktop Computers

s

Notebook Computers

s

Intelligent Instruments

s

Portable Battery-Powered Equipment

s

Network Servers

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

RST

GND

LTC1728-5

1727/28 TA01

3.3V

5V

1.8V

0.1

µF

51

2

R1

61.9k

1%

R2

100k

1%

4

3

DC/DC

CONVERTER

SYSTEM

LOGIC

0.1

µF

1

2

3

4

8

7

6

5

LTC1727-2.5

R2

1727/28 TA08

R1

ADJUSTABLE

SUPPLY

3.3V

2.5V

R3

10k

POWER

GOOD

SYSTEM

RESET

R4

10k

GND

COMP3

COMP25

RST

COMPA

Triple Supply Monitor with Power Good Output

(3.3V, 2.5V and Adjustable)