August 1996
N
Comlinear CLC418
Dual High-Speed, Low-Power Line Driver
General Description
Features
The Comlinear CLC418 dual high-speed current-feedback
operational amplifier is designed to drive low-impedance and
high capacitance loads while maintaining high signal fidelity.
Operating on ±5V power supplies, each of the CLC418’s
amplifiers produces a continuous 96mA output current. Into a
back-terminated 50Ω load, the devices produce -85/-64dBc
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130MHz bandwidth (A = +2)
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96mA output current
1.5mA supply current
-85/-75dBc HD2/HD3
15ns settling to 0.2%
-74dBc input-referred crosstalk (5MHz)
Single version available (CLC408)
second/third harmonic distortion (A = +2, V = 2V , f = 1MHz).
v
o
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The CLC418’s current-feedback architecture maintains consistent
performance over a wide range of gain and signal levels. DC gain
and bandwidth can be set independently. With proper resistor
selection, either maximally flat gain response or linear phase
response can be selected.
Applications
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ADSL/HDSL driver
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Coaxial cable driver
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UTP differential line driver
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Transformer/coil driver
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High capacitive-load driver
Video line driver
Portable/battery-powered line driver
Differential A/D driver
Requiring a mere 15mW quiescent power per amplifier, the
CLC418 offers superior performance-vs-power with a 130MHz
small-signal bandwidth, 350V/ms slew rate and quick 4.6ns
rise/fall times (2Vstep). The combination of low quiescent power,
high output current drive and high performance make the
CLC418 a great choice for many battery-powered personal
communication/computing systems.
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Non-Inverting Frequency Response
(Av = +2V/V, RL = 100Ω)
Combining the CLC418’s two amplifiers (shown below) results in
a powerful differential line driver for driving video signals over
unshielded twisted-pair (UTP). The CLC418 can also be used for
driving differential-input step-up transformers for applications
such as Asynchronous Digital Subscriber Lines (ADSL) or High-
Bit-Rate Digital Subscriber Lines (HDSL).
The CLC418’s amplifiers make excellent low-power high-
resolution A-to-D converter drivers with their very fast 15ns set-
tling time (to 0.2%) and ultra-low -85/-75dBc harmonic distortion
1M
10M
100M
(A = +2, V = 2V , f = 1MHz, R = 1kΩ).
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o
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L
Frequency (Hz)
Typical Application Diagram
Pinout
Differential Line Driver
DIP & SOIC
with Load Impedance Conversion
Rg2
Rf2
Vo1
Vinv1
VCC
Vd/2
Vin
Rt1
Vo2
+
1/2
CLC418
Rm/2
Io
-
I:n
-Vd/2
+
Vo
-
1/2
CLC418
Zo
Vnon-inv1
VEE
Vinv2
Vnon-inv2
-
Req
RL
Rf1
+
UTP
Rt2
Rm/2
Rg1
© 1996 National Semiconductor Corporation
Printed in the U.S.A.
http://www.national.com