LTC1799_15 Datasheet, PDF (1/14 Pages) Linear Technology – 1kHz to 33MHz Resistor Set SOT-23 Oscillator

LTC1799
1kHz to 33MHz
Resistor Set SOT-23 Oscillator
Features
n _{One External Resistor Sets the Frequency}
n _{Fast Start-Up Time: <1ms}
n _{1kHz to 33MHz Frequency Range}
n _{Frequency Error ≤1.5% 5kHz to 20MHz}
(T_A = 25°C)
n _{Frequency Error ≤2% 5kHz to 20MHz}
(T_A = 0°C to 70°C)
n _{±40ppm/°C Temperature Stability}
n _{0.05%/V Supply Stability}
n _{50% ±1% Duty Cycle 1kHz to 2MHz}
n _{50% ±5% Duty Cycle 2MHz to 20MHz}
n _{1mA Typical Supply Current}
n _{100Ω CMOS Output Driver}
n _{Operates from a Single 2.7V to 5.5V Supply}
n _{Low Profile (1mm) SOT-23 (ThinSOT™ Package)}
Applications
n _{Low Cost Precision Oscillator}
n _{Charge Pump Driver}
n _{Switching Power Supply Clock Reference}
n _{Clocking Switched Capacitor Filters}
n _{Fixed Crystal Oscillator Replacement}
n _{Ceramic Oscillator Replacement}
n _{Small Footprint Replacement for Econ Oscillators}
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and
ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property
of their respective owners. Protected by U.S. Patents including 6342817 and 6614313.
Description
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 oscil-
lator 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 out-
put, 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 programmed using
the simple formula outlined below:
f_OSC
=
10MHz
•


N
10k
• R_SET


,
N
=
_100,
^10,
^1,
DIV
DIV
DIV
Pin
Pin
Pin
=
=
=
V⁺
Open
GND
Typical Application
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
Typical Distribution of Frequency Error,
T_A = 25°C (5kHz ≤ f_OSC ≤ 20MHz, V⁺ = 5V)
25
20
15
10
5
TSOT-23 Actual Size
0
–1.25
–0.75 –0.25 0 0.25 0.75 1.25
FREQUENCY ERROR (%)
1799 TA02
1799fc
1