Datasheet

ADF41020 Data Sheet
Rev. A | Page 6 of 16
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Figure 3. Pin Configuration
Table 4. Pin Function Descriptions
Pin No. Mnemonic Description
1, 2, 3, 5, 9, 10 GND Ground Pins.
4 RF
IN
Input to the RF Prescaler. This input is ac-coupled internally.
6, 7 AV
DD
Analog Power Supply. This may range from 2.85 V to 3.15 V. Decoupling capacitors to the ground plane
should be placed as close as possible to this pin. Pin 6 is the supply for the fixed divide-by-4 prescaler.
8 REF
IN
Reference Input. This is a CMOS input with a nominal threshold of DV
DD
/2 and a dc equivalent input
resistance of 100 kΩ (see Figure 9). This input can be driven from a TTL or CMOS crystal oscillator or it
can be ac-coupled.
11 CE
Chip Enable. A logic low on this pin powers down the device and puts the charge pump output into three-
state mode. Taking the pin high powers up the device, depending on the status of the power-down bit, PD1.
12 CLK
Serial Clock Input. This serial clock is used to clock in the serial data to the registers. The data is latched into
the 24-bit shift register on the CLK rising edge. This is a high impedance CMOS input.
13 DATA
Serial Data Input. The serial data is loaded MSB first with the two LSBs being the control bits. This is a high
impedance CMOS input.
14 LE
Load Enable, CMOS Input. When LE goes high, the data stored in the shift registers is loaded into one of the
four latches with the latch being selected using the control bits.
15 MUXOUT
This multiplexer output allows either the lock detect, the scaled RF, or the scaled reference frequency to be
accessed externally.
16, 17 DV
DD
Digital Power Supply. This may range from 2.85 V to 3.15 V. Decoupling capacitors to the ground plane
should be placed as close as possible to this pin. DV
DD
must be the same value as AV
DD
.
18 V
P
Charge Pump Power Supply.
19 R
SET
Connecting a resistor between this pin and GND sets the maximum charge pump output current.
The nominal voltage potential at the R
SET
pin is 0.66 V. The relationship between I
CP
and R
SET
is
SET
MAXCP
R
I
5
.25
=
So, with R
SET
= 5.1 kΩ, I
CP MAX
= 5.0 mA.
20 CP
Charge Pump Output. When enabled, this provides ±I
CP
to the external loop filter, which in turn drives the
external VCO.
EP Exposed Pad. The exposed pad must be connected to GND.
14
13
12
1
3
4
LE
15
MUXOUT
DATA
CLK
11
CE
GND
GND
2
GND
RF
IN
5
GND
7
AV
DD
6
AV
DD
8
REF
IN
9
GND
10
GND
19
R
SET
20
CP
18
V
P
17
DV
DD
16
DV
DD
TOP
VIEW
NOTES
1. THE EXPOSED PAD MUST BE
CONNECTED TO GND.
ADF41020
10304-003