LTC1799
U
TYPICAL APPLICATIO S
3V Digitally Controlled Oscillator with 5kHz to 85kHz Range (N = 100, Pin 4 = V+)
3V
LTC1659
C3
0.1µF
1
2
3
4
8
7
6
5
CLK
V
CC
CLK
3V
D
IN
V
OUT
D
IN
CS/LD
REF
CS/LD
C2
0.1µF
D
OUT
GND
R5
10k
4
3
2
+
1
R6
10k
1/4 LT1491
3V
–
R1
11
10k
10
9
+
5kHz TO 85kHz
OUT
R8
8
R2
10k
10k
1/4 LT1491
1
2
3
5
4
–
+
3V
R
V
OUT
S
R7
10k
C1
R4
10k
10k
LTC1799
0.1µF
C
4096
f
= 100kHz •
OSC
GND
SET
5
6
R3
10k
+
–
3V
1799 TA06
DIV
7
1/4 LT1491
+
(V – V
)
C
4096
SET
I =
•
C: DAC CODE 200 ≤ C ≤ 3480
10k
NOTES:
1. FOR N = 10 (PIN 4 OPEN) THE RANGE IS 50kHz TO 850kHz
2. FOR N = 1 (PIN 4 = GND) THE RANGE IS 500kHz TO 8.5MHz
3. DRIVING PIN 4 OF THE LTC1799 WITH A 3-STATE LOGIC DEVICE
GIVES A RANGE OF 5kHz TO 8.5MHz
Input Code vs Output Frequency
(N = 100, Pin 4 = V+)
100
75
50
25
0
0
1024
2048
3072
4096
DAC CODE
1799 TA07
10
Linear Systems [ Linear Systems ]
