Twisted-Pair Driver.
Twisted-pair cables are used in many applications such
as telephony, video and data communications. The
CLC432's two matched channels make it well suited for
such applications and is illustrated in Fig. 5.
Rg
634Ω
Rf
634Ω
Ri
75Ω
½CLC431 13
½R
R
12
3
50Ω
Channel 1
SELECT
Rs
Vout
NC
75Ω
½Ro
10
Channel 2
½CLC432
Ri
RL
75Ω
5
9
½CLC431
75Ω
50Ω
Ro
634Ω
Optional
Vin
Rf
1kΩ
Rg
634Ω
½CLC432
½Ro
-15V
R
Fig. 3
R
The optional 1kΩ pull-down resistor connected from the
output of the 2:1 mux to the negative power supply (-VCC)
results in improved differential gain and phase perfor-
mance (0.02% and 0.01°) at PAL video levels.
Fig. 5
CCD Amplifier.
The CLC432 can easily be configured as 10MSPS CCD
amplifier with DC level shifting as illustrated in Fig 6.
Notice that one of the CLC432's channels buffers the
CCD output while the other channel is configured with
both an inverting DC gain and an AC gain in order to
achieve the overall transfer function shown in Fig. 6.
Switched Gain Amplifier (CLC431)
As seen from the front page, the CLC431 can also be
configured as a switched-gain amplifier that is similar to
the 2:1 mux. Configuring each of the two CLC431's
amplifiers with different non-inverting gains and tying the
twoinputstogether(eliminatingoneoftheinput-terminat-
ing resistors) allows the CLC431 to switch an input signal
between two different gains.
Vin
Vin
½CLC432
Vout
R
½CLC432
Inactive Channel Impedances (CLC431)
1kΩ
The impedance that is seen when looking into the output
of a disabled CLC431 is typically represented as
1MΩ||16pF. The inverting input impedance becomes
very high, essentially open. Therefore, the impedance
presented by a disabled channel is (Rf+Rg)||
(Ri+(1MΩ||16pF))asillustratedinFig. 4. Itshouldalsobe
noted that any trace capacitance that is associated with
the common output connection will add in parallel to that
presented by the CLC431's inactive channel.
Vref
Rx
Rf
Rg
0.1µF
−Vout
Vout
Rf
s
Vref
DC
= 1+
=
1
V
Rg
Rx
Rf
in
s +
RgCg
1
Rx >>
2πfinCg
for Rx >> Rg
Fig. 6
Rg
Rf
Ordering Information
Impedance
Presented
by
Disabled
CLC431
Ri
Model
Temperature Range Description
Impedance
Presented
by
Inactive
Channel
CLC431AJP
CLC431AJE
CLC431ALC
CLC431A8B
CLC431AMC
CLC432AJP
CLC432AJE
CLC432ALC
CLC432A8B
CLC432AMC
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
-55°C to +125°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-55°C to +125°C
-55°C to +125°C
14-pinPDIP
14-pin SOIC
dice
1MΩ
16pF
Vin
14-pinCerDIP,MIL-STD-883
dice,MIL-STD-883
8-pin PDIP
Rs
Vout
Ri
Active
Channel
RL
8-pin SOIC
dice
Rf
8-pinCerDIP,MIL-STD-883
dice,MIL-STD-883
Rg
DESCSMDnumbers:5962-94725.
Fig. 4
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