LT1799 Datasheet, PDF (1/4 Pages) Linear Technology – 1kHz to 30MHz Resistor Set SOT-23 Oscillator

FEATURES
s _{One External Resistor Sets the Frequency}
s _{1kHz to 30MHz Frequency Range}
s _{SOT-23 Miniature Package}
s _{Frequency Error ≤1.5% 5kHz to 20MHz}
(T_A = 25°C)
s _{Frequency Error ≤ 2% 5kHz to 20MHz}
(T_A = 0°C to 70°C)
s _{±40ppm/°C Temperature Stability}
s _{0.05%/V Supply Stability}
s _{50% ±1% Duty Cycle 1kHz to 2MHz}
s _{50% ±5% Duty Cycle 2MHz to 20MHz}
s _{1mA Typical Supply Current}
s _{100Ω CMOS Output Driver}
s _{Operates from a Single 2.7V to 5.5V Supply}
U
APPLICATIO S
s _{Low Cost Precision Oscillator}
s _{Charge Pump Driver}
s _{Switching Power Supply Clock Reference}
s _{Clocking Switched Capacitor Filters}
s _{Fixed Crystal Oscillator Replacement}
s _{Ceramic Oscillator Replacement}
s _{Small Footprint Replacement for Econ Oscillators}
Final Electrical Specifications
LTC1799
1kHz to 30MHz
Resistor Set SOT-23 Oscillator
DESCRIPTIO
January 2001
The LTC^®1799 is a precision oscillator that is easy to use
and occupies very little PC board space. The oscillator
frequency is programmed by a single external resistor
(R_SET). The LTC1799 has been designed for high accuracy
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
R_SET and frequency, eliminating the need for tables to
calculate frequency. The oscillator can be easily pro-
grammed using the simple formula outlined below:
100, DIV PIN = V ⁺
f_OSC
=
10MHz
•


10k
N • R_SET


,
N
=
^10,
^1,
DIV PIN = Hi - Z
DIV PIN = GND
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Basic Connection
V⁺
5k ≤ R_SET ≤ 200k
0.1µF
1
V+
5kHz ≤ f_OSC ≤ 20MHz
5
OUT
2 ^LTC1799
GND
3
4
SET DIV
V⁺
÷100
÷10
Hi-Z
1799 TA01
÷10
GND
SOT-23 Actual Size
Typical Distribution of Frequency Error, T_A = 25°C
25
20
15
10
5
0
–1.25
–0.75 –0.25 0 0.25 0.75 1.25
FREQUENCY ERROR (%)
1799 TA02
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.
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