STW81101AT STMicroelectronics, STW81101AT Datasheet - Page 40

• Manufacturer Part Number: STW81101AT
• Description: IC SYNTHESIZER MULTI RF 28VFQFPN
• Manufacturer: STMicroelectronics
• Type: Frequency Synthesizer (RF)r

Specifications of STW81101AT

• Pll: Yes
• Input: Clock, Crystal
• Output: Clock, Crystal
• Number Of Circuits: 1
• Ratio - Input:output: 3:2
• Differential - Input:output: No/No
• Frequency - Max: 4.4GHz
• Divider/multiplier: Yes/No
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-VFQFN, 28-VFQFPN
• Frequency-max: 4.4GHz
• Number Of Elements: 1
• Pll Input Freq (min): 10MHz
• Pll Input Freq (max): 200MHz
• Operating Supply Voltage (typ): 3.3V
• Operating Temp Range: -40C to 85C
• Package Type: VFQFPN
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 3.6V
• Operating Temperature Classification: Industrial
• Pin Count: 28
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

SPI digital interface
7.3.1
7.4
7.4.1
40/53
The LO output frequency is programmed by setting the proper values for A, B and R
according to the following formula:
where
and P is the selected prescaler modulus.
Default configuration
At power on, all the bits are set to '0'. Consequently the part starts in power down mode.
VCO calibration procedure
Calibration of the VCO center frequency is activated when the SERCAL bit (ST1 register
bit[6]) is set to 1.
To program the device properly while ensuring VCO calibration, perform the following steps
before every channel change:
1.
2.
The maximum allowed PFD frequency (F
higher than 1 MHz, perform the following additional steps:
●
●
VCO calibration auto-restart feature
The VCO calibration auto-restart feature can be enabled in two steps:
1.
2.
F
OUT
Program the ST2 register with the desired settings (functional mode, B and A
counters).
Program the ST1 register with the desired settings (R counter, VCO amplitude, charge
pump, prescaler modulus) and with the SERCAL bit set to 1.
Perform all the steps (step 1 and 2 above) of the calibration procedure, making sure to
program the desired VCO frequency with proper settings of the R, B and A counters so
that F
Program the device with the desired VCO and PFD frequency settings as per steps 1
and 2 above with SERCAL bit set to 0.
set the desired frequency ensuring VCO calibration as described above
program the ST2 register with the CAL_AUTOSTART_EN bit set to '1' while keeping
unchanged the others.
=
D
R
D
R
PFD
equals
×
(
is ≤ 1 MHz.
B
×
P
+
A
{
)
×
F
--------------------------- -
REF CLK
1
0.5
0.25 for output divided by 4
R
–
for direct output
for output divided by 2
PFD
) during calibration is 1 MHz; if you want a F
(Section
STW81101
7.4)
PFD