鈮?/div>
2% Max, 5kHz to 10MHz
(T
A
= 0擄C to 70擄C)
鹵40ppm/擄C
Temperature Stability
Fast Start-Up Time: 50碌s to 1.5ms
100鈩?CMOS Output Driver
Operates from a Single 2.7V to 5.5V Supply
Available in 10-Lead MS Package
The LTC
廬
6902 is a precision, low power and easy-to-use
oscillator that provides multiphase outputs in a small
package. The oscillator frequency is set by a single exter-
nal resistor (R
SET
). The LTC6902 also provides an optional
spread spectrum frequency modulation (SSFM) capability
that can be activated and controlled by an additional
external resistor (R
MOD
).
The LTC6902鈥檚 master oscillator is controlled by the R
SET
resistor and has a range of 100kHz and 20MHz. In order
to accommodate a wider output frequency range, a pro-
grammable divider (divide by 1, 10 or 100) is included.
The integrated programmable multiphase circuit pro-
vides either 2-, 3- or 4-phase waveforms.
The LTC6902鈥檚 SSFM capability modulates the oscillator鈥檚
frequency by a pseudorandom noise (PRN) signal to
spread the oscillator鈥檚 energy over a wide frequency band.
This spreading decreases the peak electromagnetic radia-
tion level and improves electromagnetic compatibility
(EMC) performance. The amount of frequency spreading
is programmable by a single additional external resistor
(R
MOD
) and is disabled by grounding the MOD pin.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
s
s
s
s
s
Switching Power Supply Clock Reference
Portable and Battery-Powered Equipment
PDAs
Cell Phones
Clocking Switched Capacitor Filters
TYPICAL APPLICATIO
5V
0.1碌F
R
MOD
10k
R
SET
10k
LTC6902
V
+
OPEN
DIV
PH
SET
MOD
GND
Output Frequency Spectrum With and Without SSFM
0
OUTPUT
SPECTRUM
WITH SSFM
DISABLED
OUTPUT
SPECTRUM
WITH 20%
SPREADING
500kHz, 4-Phase Clock with 20% Frequency Spreading
RELATIVE AMPLITUDE (dBm)
鈥?0
鈥?0
鈥?0
OUT1 OUT4
OUT2 OUT3
OUT4
OUT3
OUT2
6902 TA01
鈥?0
鈥?00
OUT1
400
U
550
450
500
FREQUENCY (kHz)
600
6902 TA02
U
U
6902f
1