Data Sheet

ADF4252

Rev. E | Page 7 of 30

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

NOTES

1. THE EXPOSED PAD MUST BE CONNECTED TO AGND.

MUXOUT 6

ADF4252

TOP VIEW

Figure 3. Pin Configuration

Table 4. Pin Function Descriptions

Pin No.

Mnemonic

Function

1

RF Charge Pump Output. This pin is normally connected to a loop filter that drives the input to an external VCO.

2

RF Charge Pump Ground.

3

Input to the RF Prescaler. This small signal input is normally taken from the VCO.

4

Complementary Input to the RF Prescaler.

5

Analog Ground for the RF Synthesizer.

6

MUXOUT

This multiplexer output allows either the RF or IF lock detect, the scaled RF or IF, or the scaled reference frequency

to be accessed externally.

7

100 kΩ. This input can be driven from a TTL or CMOS crystal oscillator.

8

Reference Output.

9

Digital Ground for the Fractional Interpolator.

10

CLK

Serial Clock Input. This serial clock is used to clock in the serial data to the registers. The data is latched into the shift

register on the CLK rising edge. This input is a high impedance CMOS input.

11

DATA

Serial Data Input. The serial data is loaded MSB first with the three LSBs being the control bits. This input is a high

impedance CMOS input.

12

LE

Load Enable, CMOS Input. When LE goes high, the data stored in the shift registers is loaded into one of the seven

latches, the latch being selected using the control bits.

13

Connecting a resistor between this pin and ground sets the minimum charge pump output current. The

14

Ground for the IF Synthesizer.

15

Complementary Input to the IF Prescaler.

16

Input to the IF Prescaler. This small signal input is normally taken from the IF VCO.

17

Positive Power Supply for the Fractional Interpolator Section. Decoupling capacitors to the ground plane must be

18

IF Charge Pump Ground.

19

IF Charge Pump Output. This pin is normally connected to a loop filter that drives the input to an external VCO.

20

IF Charge Pump Power Supply. Decoupling capacitors to the ground plane must be placed as close as possible to

21

Positive Power Supply for the IF Section. Decoupling capacitors to the ground plane must be placed as close as

22

Positive Power Supply for the RF Digital Section. Decoupling capacitors to the ground plane must be placed as

23

Positive Power Supply for the RF Analog Section. Decoupling capacitors to the ground plane must be placed as

24

RF Charge Pump Power Supply. Decoupling capacitors to the ground plane must be placed as close as possible to

EPAD