adf7012 Analog Devices, Inc., adf7012 Datasheet - Page 7

• Manufacturer Part Number: adf7012
• Description: Multichannel Ism Band Fsk/gfsk/ook/gook/ask Transmitter
• Manufacturer: Analog Devices, Inc.

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
Table 4. Pin Functional Descriptions
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Mnemonic
DV
C
CP
TxDATA
TxCLK
MUXOUT
DGND
OSC1
OSC2
CLK
CLK
DATA
LE
CE
L1
L2
C
VCO
RF
RF
DV
AGND
R
C
SET
REG1
VCO
REG2
GND
OUT
OUT
DD
DD
OUT
IN
Description
Positive Supply for the Digital Circuitry. This must be between 2.3 V and 3.6 V. Decoupling capacitors to the analog
ground plane should be placed as close as possible to this pin.
A 2.2 µF capacitor should be added at C
improves regulator power-on time, but may cause higher spurious noise.
Charge Pump Output. This output generates current pulses that are integrated in the loop filter. The integrated
current changes the control voltage on the input to the VCO.
Digital Data to Be Transmitted is inputted on this pin.
GFSK and GOOK only. This clock output is used to synchronize microcontroller data to the TxDATA pin of the
ADF7012. The clock is provided at the same frequency as the data rate. The microcontroller updates TxDATA on
the falling edge of TxCLK. The rising edge of TxCLK is used to sample TxDATA at the midpoint of each bit.
Provides the Lock_Detect Signal. This determines if the PLL is locked to the correct frequency and also monitors
battery voltage. Other signals include Regulator_Ready, which indicates the status of the serial interface regulator.
Ground for Digital Section.
The reference crystal should be connected between this pin and OSC2.
The reference crystal should be connected between this pin and OSC1. A TCXO reference may be used, by driving
this pin with CMOS levels, and powering down the crystal oscillator bit in software.
A divided-down version of the crystal reference with output driver. The digital clock output may be used to drive
several other CMOS inputs, such as a microcontroller clock. The output has a 50:50 mark-space ratio.
Serial Clock Input. This serial clock is used to clock in the serial data to the registers. The data is latched into the
32-bit shift register on the CLK rising edge. This input is a high impedance CMOS input.
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.
Load Enable, CMOS Input. When LE goes high, the data stored in the shift registers is loaded into one of the four
latches, the latch being selected using the control bits.
Chip Enable. Bringing CE low puts the ADF7012 into complete power-down, drawing < 1uA. Register values are
lost when CE is low and the part must be reprogrammed once CE is brought high.
Connected to external printed or discrete inductor. See Choosing the External Inductor Value for advice on the
value of the inductor to be connected between L1 and L2.
Connected to external printed or discrete inductor.
A 220 nF capacitor should be tied between the C
This capacitor is necessary to ensure stable VCO operation.
The tuning voltage on this pin determines the output frequency of the voltage controlled oscillator (VCO). The
higher the tuning voltage, the higher the output frequency.
Ground for Output Stage of Transmitter.
The modulated signal is available at this pin. Output power levels are from –16 dBm to +12 dBm. The output
should be impedance matched using suitable components to the desired load. See the PA Matching section.
Voltage supply for VCO and PA section. This should have the same supply as DV
2.3 V and 3.6 V. Place decoupling capacitors to the analog ground plane as close as possible to this pin.
Ground Pin for the RF Analog Circuitry.
External Resistor to set charge pump current and some internal bias currents. Use 3.6 kV as default.
Add a 470 nF capacitor at C
regulator power-on time and phase noise, but may have stability issues over the supply and temperature.
REG
MUXOUT
to reduce regulator noise and improve stability. A reduced capacitor improves
TxDATA
CLK
TxCLK
CP
C
DGND
OSC1
OSC2
DATA
DV
REG1
CLK
OUT
OUT 10
DD
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11
12
1
2
3
4
5
6
7
8
9
(Not to Scale)
REG
ADF7012
TOP VIEW
Figure 3.
TSSOP
to reduce regulator noise and improve stability. A reduced capacitor
VCO
24
23
22
21
20
19
18
17
16
15
14
13
C
R
AGND
DV
RF
RF
VCO
C
L2
L1
CE
LE
and C
REG2
SET
VCO
DD
OUT
GND
IN
REG2
pins. This line should run underneath the ADF7012.
DD
Pin 1, and should be between
ADF7012