CLC5523 Datasheet, PDF (1/12 Pages) National Semiconductor (TI) – Low-Power, Variable Gain Amplifier

March 2000
CLC5523
Low-Power, Variable Gain Amplifier
General Descriptions
The CLC5523 is a low power, wideband, DC-coupled, voltage-
controlled gain amplifier. It provides a voltage-controlled gain
block coupled with a current feedback output amplifier. High
impedance inputs and minimum dependence of bandwidth on
gain make the CLC5523 easy to use in a wide range of
applications. This amplifier is suitable as a continuous gain
control element in a variety of electronic systems which benefit
from a wide bandwidth of 250MHz and high slew rate of
1800V/ms, with only 135mW of power dissipation.
Input impedances in the megaohm range on both the signal
and gain control inputs simplify driving the CLC5523 in any
application. The CLC5523 can be configured to use pin 3 as a
low impedance input making it an ideal interface for current
inputs. By using the CLC5523’s inverting configuration in which
R_G is driven directly, inputs which exceed the device’s input
voltage range may be used.
The gain control input (V_G), with a 0 to 2V input range, and a
linear-in-dB gain control, simplifies the implementation of AGC
circuits. The gain control circuit can adjust the gain as fast as
4dB/ns. Maximum gains from 2 to 100 are accurately and simply
set by two external resistors while attenuation of up to 80dB from
this gain can be achieved.
The extremely high slew rate of 1800V/ms and wide bandwidth
provides high speed rise and fall times of 2.0ns, with settling time
for a 2 volt step of only 22ns to 0.2%. In time domain applications
where linear phase is important with gain adjust, the internal cur-
rent mode circuitry maintains low deviation of delay over a wide
gain adjust range.
Features
s Low power: 135mW
s 250MHz, -3dB bandwidth
s Slew rate 1800V/ms
s Gain flatness 0.2dB @ 75MHz
s Rise & fall times 2.0ns
s Low input voltage noise 4nV/ÖHz
Applications
s Automatic gain control
s Voltage controlled filters
s Automatic signal leveling for A/D
s Amplitude modulation
s Variable gain transimpedance
Frequency Response with Changes in Vg
30
20
10
0
-10
-20
-30
-40
-50
1M
10M
100M
Frequency (Hz)
Typical Application
Variable Gain Amplifier
Circuit
V_in
R_g
V_G
+5V
2
1
+
8
CLC5523 ⁶
3_-
4
7
5 _Rf
25W _-5V
V_o
R_L
Pinout
DIP & SOIC
VG
VIN
Rg
GND
X1
-
+
+VCC
I-
V_O
-VCC
© 2000 National Semiconductor Corporation
Printed in the U.S.A.
http://www.national.com