Datasheet
Data Sheet ADF4351
Rev. 0 | Page 7 of 28
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
1
CLK
2
DATA
3
LE
4
CE
5
SW
6
7
24
V
REF
23
V
COM
22
21
20
19
18
17
8
SDV
DD
ADF4351
TOP VIEW
(Not to Scale)
9
AGND
10
AV
DD
11
REF
IN
12
DGND
13
DV
DD
14
15
16
32
31
30
29
28
SD
GND
27
26
25
PIN 1
INDICATOR
V
P
CP
OUT
CP
GND
MUXOUT
R
SET
RF
OUT
A+
RF
OUT
B+
RF
OUT
B−
RF
OUT
A−
V
VCO
V
TUNE
A
GNDVCO
A
GNDVCO
TEM
P
PDB
RF
LD
A
GNDVCO
V
VCO
NOTES
1. THE LFCSP HAS AN EXPOSED PAD THAT
MUST BE CONNECTED TO GND.
09800-003
Figure 3. Pin Configuration
Table 5. Pin Function Descriptions
Pin No. Mnemonic Description
1 CLK Serial Clock Input. Data is clocked into the 32-bit shift register on the CLK rising edge. This input is a high
impedance CMOS input.
2
DATA
Serial Data Input. The serial data is loaded MSB first with the three LSBs as the control bits. This input is a high
impedance CMOS input.
3 LE Load Enable. When LE goes high, the data stored in the 32-bit shift register is loaded into the register that is
selected by the three control bits. This input is a high impedance CMOS input.
4 CE Chip Enable. A logic low on this pin powers down the device and puts the charge pump into three-state mode.
A logic high on this pin powers up the device, depending on the status of the power-down bits.
5 SW Fast Lock Switch. A connection should be made from the loop filter to this pin when using the fast lock mode.
6 V
P
Charge Pump Power Supply. V
P
must have the same value as AV
DD
. Place decoupling capacitors to the ground
plane as close to this pin as possible.
7 CP
OUT
Charge Pump Output. When enabled, this output provides ±I
CP
to the external loop filter. The output of the
loop filter is connected to V
TUNE
to drive the internal VCO.
8 CP
GND
Charge Pump Ground. This output is the ground return pin for CP
OUT
.
9 AGND Analog Ground. Ground return pin for AV
DD
.
10 AV
DD
Analog Power Supply. This pin ranges from 3.0 V to 3.6 V. Place decoupling capacitors to the analog ground
plane as close to this pin as possible. AV
DD
must have the same value as DV
DD
.
11, 18, 21 A
GNDVCO
VCO Analog Ground. Ground return pins for the VCO.
12 RF
OUT
A+ VCO Output. The output level is programmable. The VCO fundamental output or a divided-down version is
available.
13 RF
OUT
A− Complementary VCO Output. The output level is programmable. The VCO fundamental output or a divided-
down version is available.
14 RF
OUT
B+ Auxiliary VCO Output. The output level is programmable. The VCO fundamental output or a divided-down
version is available.
15 RF
OUT
B− Complementary Auxiliary VCO Output. The output level is programmable. The VCO fundamental output or a
divided-down version is available.
16, 17 V
VCO
Power Supply for the VCO. This pin ranges from 3.0 V to 3.6 V. Place decoupling capacitors to the analog
ground plane as close to these pins as possible. V
VCO
must have the same value as AV
DD
.
19 TEMP Temperature Compensation Output. Place decoupling capacitors to the ground plane as close to this pin as
possible.
20
V
TUNE
Control Input to the VCO. This voltage determines the output frequency and is derived from filtering the CP
OUT
output voltage.