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SL6140
SL6140
Features
400MHz Bandwidth (R
L
=50
)
High voltage Gain 45dB (R
L
=1k
)
70dB Gain Control Range
High Output Level at Low Gain
Surface Mount Plastic Package
Low Cost
Applications
RF/IF Amplifier
High Gain Mixers
Video Amplifiers
Description
The SL6140 is an integrated broadband AGC amplifier,
designed on an advanced bipolar process. The
amplifier provides over 15dB of linear gain into 50
at
400MHz. Gain control is also provided with over 70dB
of dynamic range. The SL6140 offers over 45dB of
voltage gain with an R
L
of 1k
.
Figure 1 - Typical Application
10n
10n
10n
10n
1.0 F
+VCC
2
6
5
4
3
7
+VCC
OUTPUT
OUTPUT
RL
RL
RAGC
AGC
INPUT
INPUT
SL6140
8
1
The SL6140 (Figure 3) is a high gain amplifier with an
AGC control capable of reducing the gain of the amplifier
by over 70dB. The gain is adjustable by applying a
voltage to the AGC input via an external resistor (R
AGC
),
the value of which adjusts the curve of gain reduction
versus control voltage (see Figure 4). As the output
stage of the amplifier is an open collector the maximum
voltage gain is determined by R
L
. With load resistance
of 1k
the single ended voltage gain is 45dB and with
a load resistance of 50
the voltage gain is 15dB
(20log
10
V
OUT
/V
IN
). Another parameter that depends
on the load resistance is the bandwidth: 25MHz for R
L
= 1k
, as compared with 400MHz for R
L
= 50
. R
L
is
chosen to give either the required bandwidth or voltage
gain for the circuit.
Figure 7 through to 10 show the typical S parameters
for the device. Figures 11 and 12 show the typical
variation in 3rd order intercept performance with AGC.
In any application, the substrate should be connected
to the most negative point in the circuit, usually to the
same point as pin 3.
400MHz Wideband AGC Amplifier
DS2159
ISSUE 5.0
July 1999
Ordering Information
SL6140/NA/MP
Industrial temperature range miniature plastic package
SL6140/NA/MPTC
Tape and Reel