STW81101AT STMicroelectronics, STW81101AT Datasheet - Page 24

• 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

Circuit description
5.8.3
24/53
The SERCAL bit should be set to 1 at each division ratio change. The VCO calibration
procedure takes approximately 7 periods of the PFD frequency.
The maximum allowed F
higher F
1.
2.
VCO calibration auto-restart feature
The VCO calibration auto-restart feature, once activated, allows to restart the calibration
procedure when the Lock Detector reports that the PLL has moved to an unlock condition
(trigger on ‘1’ to ‘0’ transition of Lock Detector signal).
This situation could happen if the device experiences a significant temperature variation.
Once programmed at the initial temperature T
(-40 °C to +85 °C), the synthesizer is able to maintain the lock status only if the temperature
drift (in either direction) is within the limit specified by the ΔT
final temperature T
Each VCO featured by STW81102 has its specific ΔT
is typically lower than the maximum allowable drift (ΔT
vice versa).
By enabling the VCO Calibration Auto-Restart feature (through the CAL_AUTOSTART_EN
bit), the part will be able to select again the proper VCO frequency sub-range if the
temperature drift exceeds the ΔT
VCO voltage amplitude control
The voltage swing of the VCOs can be adjusted over four levels by means of two dedicated
programming bits (PLL_A1 and PLL_A0). This setting trades current consumption with
phase noise performances of the VCO. Higher amplitudes provide best phase noise,
whereas lower amplitudes save power.
Table 8
consumption, and the phase noise at 1 MHz.
Table 8.
PLL_A[1:0]
Calibrate the VCO at the desired frequency with an F
Set the A, B and R dividers ratio for the desired F
gives the voltage swing level expected on the resonator nodes, the current
00
01
10
11
PFD
, follow the steps below:
VCO A performances versus amplitude setting (Freq=3.6 GHz)
1
is still inside the nominal range.
voltage swing (Vp)
PFD
Differential
to perform the calibration process is 1 MHz. When using a
1.1
1.3
1.9
2.1
LK
limit, without any external user command.
0
inside the operating temperature range
consumption (mA)
LK
Current
PFD
MAX
15
16
24
27
parameter reported in Table 5, that
.
PFD
=125; from -40 °C to +85 °C and
LK
less than 1 MHz.
parameter, provided that the
PN @1 MHz (dBc/Hz)
-128.5
-124
-125
-129
STW81101