LTC1799_01 Datasheet, PDF (1/12 Pages) –

LTC1799
1kHz to 33MHz
Resistor Set SOT-23 Oscillator
FEATURES
s _{One External Resistor Sets the Frequency}
s _{Fast Start-Up Time: < 1ms}
s _{1kHz to 33MHz Frequency Range}
s _{Low Profile (1mm) ThinSOT}^TM _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}
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
DESCRIPTIO
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 3k to 1M to select a master
oscillator frequency between 100kHz and 33MHz (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 33MHz (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
•


N
10k
• R_SET


,
N
=
^10,
^1,
DIV Pin = Open
DIV Pin = GND
TYPICAL APPLICATIO
Basic Connection
5V
3k ≤ R_SET ≤ 1M
0.1µF
1 _V+
1kHz ≤ f_OSC ≤ 33MHz
5
OUT
2 ^LTC1799
GND
3
4
SET DIV
5V
÷100
÷10
OPEN
1799 TA01
÷1
SOT-23 Actual Size
Typical Distribution of Frequency Error,
T_A = 25°C (5kHz ≤ f_OSC ≤ 20MHz, V⁺ = 5V)
25
20
15
10
5
0
–1.25
–0.75 –0.25 0 0.25 0.75 1.25
FREQUENCY ERROR (%)
1799 TA02
1