SL2015
FUNCTIONAL DESCRIPTION
The SL2015 is a downconverter mixer oscillator with an
output AGC amplifier, when used with appropriate external
varactor tuned oscillator sustaining network performs the first
IF tuning function for a full band satellite receiver system. A
block diagram is contained in Fig. 2.
In application the RF input of the device is interfaced
through appropriate impedance matching to the first IF
signal, which is downlinked from the outdoor unit at typically
950-2150MHz. The RF input preamplifier of the device is
designed for low noise figure and for low distortion so
eliminating the requirement for RF AGC. The preamplifier
alsoprovidesgaintothemixersectionandbackisolationfrom
the local oscillator section.
The output of the preamplifier is fed to the mixer section
where the RF signal is mixed with the local oscillator
frequency, which is generated by an on-board oscillator. The
oscillator block uses an external tunable sustaining network
and is optimised for low phase noise. This section also
contains a buffer drive whose outputs can be used to
frequency lock the LO carrier to the required channel.
Signals from the mixer are fed to the AGC IF amplifier,
which gives an overall conversion gain programmable from
-10 to +30dB. The output of this stage can be switched to one
of two outputs to facilitate IF processing.
6.2nH
TO DEVICE
0.7pF
Fig. 3 RF input matching network
6mm STRIPLINE
2 x 1T379
10kΩ
TANK
0.75p
0.75p
TANKB
Vcnt
6mm STRIPLINE
Fig. 4 VCO application circuit
SL2015 phase noise
Lo frequency MHz
-62.00
1400
1600
1800
2000
2200
2400
2600
2800
-64.00
-66.00
-68.00
-70.00
-72.00
-74.00
-76.00
-78.00
LO frequency MHz
LO frequencyMHz
SL2015 phase noise
Fig. 5 LO phase noise variation with frequency (typical)
3
MITEL [ MITEL NETWORKS CORPORATION ]
