ADF4116 Analog Devices, ADF4116 Datasheet - Page 9

• Manufacturer Part Number: ADF4116
• Description: Single, Integer-n 550 MHZ PLL
• Manufacturer: Analog Devices

CIRCUIT DESCRIPTION
REFERENCE INPUT SECTION
The reference input stage is shown below in Figure 2. SW1
and SW2 are normally closed switches; SW3 is normally open.
When power-down is initiated, SW3 is closed and SW1 and SW2
are opened. This ensures that there is no loading of the REF
pin on power-down.
–100
–60
–70
–80
–90
0
REF
IN
NC
POWER-DOWN
20
SW1
CONTROL
NO
NC
TEMPERATURE – C
SW3
SW2
40
100k
BUFFER
60
–0.2
–0.4
–0.6
–0.8
–1.0
–1.2
1.2
1.0
0.8
0.6
0.4
0.2
0
TO R COUNTER
0
80
V
V
DD
P
0.5
= 5V
= 3V
1.0
100
1.5
IN
2.0
V
CP
2.5
– Volts
RF INPUT STAGE
The RF input stage is shown in Figure 3. It is followed by a
2-stage limiting amplifier to generate the CML clock levels
needed for the prescaler.
3.0
V
I
CP
3.0
2.5
2.0
1.5
1.0
0.5
0.0
P
3.5
= 5V
SETTING : 1mA
0
RF
RF
4.0
IN
IN
ADF4116/ADF4117/ADF4118
A
B
GENERATOR
4.5
PRESCALER OUTPUT FREQUENCY – MHz
BIAS
50
5.0
500
1.6V
100
500
AGND
AV
150
DD
200