THS6002_16 Datasheet, PDF (36/46 Pages) Texas Instruments – DUAL DIFFERENTIAL LINE DRIVERS AND RECEIVERS

THS6002
ą
DUAL DIFFERENTIAL LINE DRIVERS AND RECEIVERS
ą
SLOS202E− JANUARY 1998− REVISED MARCH 2007
APPLICATION INFORMATION
HDSL
Shown in Figure 60 is an example of the THS6002 being used for HDSL-2 applications. The receiver amplifiers
within the THS6002 have been configured as predrivers for the driver amplifiers. This dual composite amplifier
setup has the effect of raising the open loop gain for the combination of both amplifiers, thereby giving improved
distortion performance.
7.5 kΩ
1 kΩ
11 kΩ
Receiver 1
12 V
6
−
9
7 _{+ THS6002}
−12 V
Input
3 V(PP)
1 kΩ
U2
1 kΩ
12 V
2
−
6
1 _{+ THS4001}
1 kΩ
−12 V
Receiver 2
7.5 kΩ
11 kΩ
12 V
15
−
12
14 ₊
−12 V
12 V
4
+
2
5
−
Driver 1
−12 V
1 kΩ
30 Ω
511 Ω
Output
1:1.5 27.4 VO(PP)
135 Ω
12 V
17
+
16
−
19
Driver 2
−12 V
1 kΩ
30 Ω
511 Ω
Figure 60. HDSL-2 Line Driver
general configurations
A common error for the first-time CFB user is to create a unity gain buffer amplifier by shorting the output directly
to the inverting input. A CFB amplifier in this configuration is now commonly referred to as an oscillator. The
THS6002, like all CFB amplifiers, must have a feedback resistor for stable operation. Additionally, placing
capacitors directly from the output to the inverting input is not recommended. This is because, at high
frequencies, a capacitor has a very low impedance. This results in an unstable amplifier and should not be
considered when using a current-feedback amplifier. Because of this, integrators and simple low-pass filters,
which are easily implemented on a VFB amplifier, have to be designed slightly differently. If filtering is required,
simply place an RC-filter at the noninverting terminal of the operational-amplifier (see Figure 61).
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