LTC6991



6991f

Typical applicaTion

FeaTures

DescripTion

TimerBlox: Resettable, Low

Frequency Oscillator

periodrangeof1.024msto9.54hours(29.1µHzto977Hz),

specifically intended for long duration timing events. The

LTC6991 is part of the TimerBlox™ family of versatile

silicon timing devices.

master oscillator frequency. The output clock period

is determined by this master oscillator and an internal

t

N

R

k

ms N

OUT

DIV

SET

DIV

=

=

•

• .

,

, , ,...,

50

1 024

Ω

In normal operation, the LTC6991 oscillates with a 50%

duty cycle. A reset function is provided to truncate the

pulse (reducing the duty cycle). The reset pin can also be

used to prevent the output from oscillating.

The RST and OUT pins can be configured for active-low

or active-high operation using a polarity function.

POL BIT

RST PIN

OUTPUT STATE

0

0

Oscillating

0

1

0 (reset)

1

0

1 (reset)

1

1

Oscillating

The LTC6991 is available in the 6-lead SOT-23 (ThinSOT)

package or a 6-lead 2mm

× 3mm DFN.

Art Titles Text for Graphics

applicaTions

n

Period Range: 1ms to 9.5 Hours

n

Configured with 1 to 3 Resistors

n

<1.5% Maximum Frequency Error

n

Output Reset Function

n

2.25V to 5.5V Single Supply Operation

n

55µA to 80µA Supply Current

(2ms to 9.5hr Clock Period)

n

500µs Start-Up Time

n

CMOS Output Driver Sources/Sinks 20mA

n

–40°C to 125°C Operating Temperature Range

n

Available in Low Profile (1mm) SOT-23 (ThinSOT™)

and 2mm

× 3mm DFN Packages

n

“Heartbeat” Timers

n

Watchdog Timers

n

Intervalometers

n

Periodic “Wake-Up” Call

n

High Vibration, High Acceleration Environments

n

Portable and Battery-Powered Equipment

L

, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and

ThinSOT and TimerBlox are trademarks of Linear Technology Corporation. All other trademarks

are the property of their respective owners.

LTC6991

2.25V TO 5.5V

0.1µF

OUT

R1

1M

R2

392k

715k

RST

GND

SET

OUT

DIV

470pF

2.26k

6991 TA01a

60 SECONDS

1µs PULSE WIDTH

Low Frequency Pulse Generator

Clock Period Range over Eight Divider Settings

0

10Sec

10Min

2.5

6991 TA01b

100ms

1ms

0.625

1.25

1.875

10Hr

1Sec

1Min

10ms

1Hr