LTC1799

1

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-

tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

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

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One External Resistor Sets the Frequency

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1kHz to 30MHz Frequency Range

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SOT-23 Miniature Package

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Frequency Error

≤1.5% 5kHz to 20MHz

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Frequency Error

≤2% 5kHz to 20MHz

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±40ppm/°C Temperature Stability

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0.05%/V Supply Stability

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50%

±1% Duty Cycle 1kHz to 2MHz

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50%

±5% Duty Cycle 2MHz to 20MHz

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1mA Typical Supply Current

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100

Ω CMOS Output Driver

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Operates from a Single 2.7V to 5.5V Supply

FEATURES

DESCRIPTIO

TYPICAL APPLICATIO

1kHz to 30MHz

Resistor Set SOT-23 Oscillator

January 2001

Final Electrical Specifications

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Low Cost Precision Oscillator

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Charge Pump Driver

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Switching Power Supply Clock Reference

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Clocking Switched Capacitor Filters

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Fixed Crystal Oscillator Replacement

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Ceramic Oscillator Replacement

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Small Footprint Replacement for Econ Oscillators

APPLICATIO S

The LTC

and occupies very little PC board space. The oscillator

frequency is programmed by a single external resistor

operation (

≤1.5% frequency error) without the need for

external trim components.

The LTC1799 operates with a single 2.7V to 5.5V power

supply and provides a rail-to-rail, 50% duty cycle square

wave output. The CMOS output driver ensures fast rise/fall

times and rail-to-rail switching. The frequency-setting

resistor can vary from 3.32k to 1M to select a master

oscillator frequency between 100kHz and 30MHz (5V

supply). The three-state DIV input determines whether the

master clock is divided by 1, 10 or 100 before driving the

output, providing three frequency ranges spanning 1kHz

to 30MHz (5V supply). The LTC1799 features a proprietary

feedback loop that linearizes the relationship between

calculate frequency. The oscillator can be easily pro-

grammed using the simple formula outlined below:

V+

1

2

3

5

5kHz

GND

5k

0.1

µF

1799 TA01

4

GND

LTC1799

SET

OUT

DIV

Hi-Z

÷10

÷100

÷10

25

20

15

10

5

0

–1.25

–0.75

–0.25 0 0.25

0.75

1.25

FREQUENCY ERROR (%)

1799 TA02

Basic Connection

f

MHz

k

NR

NHi Z

OSC

SET

=•

•









=











=

=

=

+

10

10

100

10

1

,

,

,

,

DIV PIN

V

DIV PIN

-

DIV PIN

GND

SOT-23 Actual Size