SL2009 Zarlink Semiconductor Inc, SL2009 Datasheet - Page 2

• Manufacturer Part Number: SL2009
• Description: Dual stage IF amplifier for cable tuners
• Manufacturer: Zarlink Semiconductor Inc

SL2009
2
Functional Description
The SL2009 is an IF amplifier intended primarily for
application in cable tuners, and requiring a minimum
external component count to integrate the IF gain,
AGC facility and level detect.
The pin allocation is contained in figure (1) and the
block diagram in figure (2)
SAWF driver stage
In normal application the IF output of the tuner,
which is typically in the region of 30-50 MHz, is
interfaced to input preamplifier of the SAWF driver
stage, which is optimised for both signal handling
and NF referred to 2 k .
The input preamplifier interfaces with the variable
gain stage, which is under control of the first AGC
sender and provides for 14 dB of gain control. The
typical gain characteristic is contained in figure (3).
The AGC stage then interfaces with the output buffer
amplifier, which presents a balanced 50
the IF SAW filter and offers high signal handling to
minimise intermodulation distortions.
The SAWF amplifier also incorporates a level detect
block whose output AGCOUT, can be used to control
the gain of the SAWF amplifier or other gain stages
in front of the SL2009. This AGC characteristic can
be set up by a "current set" resistor connected
between the AGCBIAS input and Vee. The typical
characteristic curve for AGC set, output level under
SAWF driver stage
Input operating range
Input NF, referred to 2k
OPIP3
Gain
IF Amplifier stage
Input operating range
Input NF, referred to 2 k
OPIP3
Gain
Characteristics
Table 1 - Quick reference data
drive to
different AGCBIAS conditions is contained in figure
(4).
See figures (5) and (6) for SAW amplifier input and
output impedances respectively.
IF amplifier section
In normal application the output of the SAW filter is
coupled differentially to the input preamplifier of the
IF amplifier, which presents a differential 2 k
load to the SAW filter and is optimised for both signal
handling and NF. See figure (8) for IF amplifier input
impedance.
The input preamplifier, then interfaces with the
variable gain stage which is under control of the
second AGC sender and this provides for 20 dB of
gain control. The typical AGC characteristic is
contained in figure (7)
The AGC output is then connected to the output
driver stage, which presents a low differential output
impedance, see figure (9) and is optimised for output
signal handling.
The typical key performance data at 5V Vcc and 25
deg C ambient are shown in the table entitled
'QUICK REFERENCE DATA'.
30 - 50
4
4
14 - 28
30 - 50
6
8
20 - 40
MHz
dB
dBV
dB
MHz
dB
dBV
dB
Units
3 pF