LTC6900_15 Datasheet, PDF (1/12 Pages) Linear Technology – Low Power, 1kHz to 20MHz Resistor Set SOT-23 Oscillator

FEATURES
n _{One External Resistor Sets the Frequency}
n _{1kHz to 20MHz Frequency Range}
n _{500μA Typical Supply Current, VS = 3V, 3MHz}
n _{Frequency Error ≤1.5% Max, 5kHz to 10MHz}
(T_A = 25°C)
n _{Frequency Error ≤ 2% Max, 5kHz to 10MHz}
(T_A = 0°C to 70°C)
n _{±40ppm/°C Temperature Stability}
n _{0.04%/V Supply Stability}
n _{50% ±1% Duty Cycle 1kHz to 2MHz}
n _{50% ± 5% Duty Cycle 2MHz to 10MHz}
n _{Fast Start-Up Time: 50μs to 1.5ms}
n _{100Ω CMOS Output Driver}
n _{Operates from a Single 2.7V to 5.5V Supply}
n _{Low Profile (1mm) ThinSOT™ Package}
APPLICATIONS
n _{Portable and Battery-Powered Equipment}
n _PDAs
n _{Cell Phones}
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}
LTC6900
Low Power, 1kHz to 20MHz
Resistor Set SOT-23 Oscillator
DESCRIPTION
The LTC^®6900 is a precision, low power 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 LTC6900 has been designed for high
accuracy operation (≤1.5% frequency error) without the
need for external trim components.
The LTC6900 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 10kΩ to 2MΩ to select a master
oscillator frequency between 100kHz and 20MHz (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 20MHz (5V supply). The LTC6900 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
•
⎛
⎝⎜
20k
N • R_SET
⎞
⎠⎟
,
N
=
⎧100,
⎨⎪^10,
⎩⎪^1,
DIV
DIV
DIV
Pin
Pin
Pin
=
=
=
V⁺
Open
GND
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Clock Generator
5V
10k ≤ R_SET ≤ 2M
0.1μF
1 _V+
1kHz ≤ f_OSC ≤ 20MHz
5
OUT
2 ^LTC6900
GND
5V, N = 100
3
4
SET DIV
6900 TA01a
( ) ^{fOSC = 10MHz •}
20k
N • R_SET
N=1
OPEN, N = 10
R_SET vs Desired Output Frequency
10000
1000
÷100 ÷10 ÷1
100
10
1
1k
10k 100k 1M 10M 100M
DESIRED OUTPUT FREQUENCY (Hz)
6900 TA01b
6900fa
1