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

23

22

21

20

19

18

17

8

ADF4351

TOP VIEW

(Not to Scale)

PIN 1

INDICATOR

TEMP

NOTES

1. THE LFCSP HAS AN EXPOSED PAD THAT

MUST BE CONNECTED TO GND.

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

plane as close to this pin as possible.

7

CP

OUT

Charge Pump Output. When enabled, this output provides ±I

loop filter is connected to V

8

CP

GND

Charge Pump Ground. This output is the ground return pin for CP

9

AGND

Analog Ground. Ground return pin for AV

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

11, 18, 21

A

GNDVCO

VCO Analog Ground. Ground return pins for the VCO.

12

RF

VCO Output. The output level is programmable. The VCO fundamental output or a divided-down version is

available.

13

RF

Complementary VCO Output. The output level is programmable. The VCO fundamental output or a divided-

down version is available.

14

RF

Auxiliary VCO Output. The output level is programmable. The VCO fundamental output or a divided-down

version is available.

15

RF

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

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.