THS6012 Datasheet, PDF (31/35 Pages) Texas Instruments – 500-mA DUAL DIFFERENTIAL LINE DRIVER

THS6012
500-mA DUAL DIFFERENTIAL LINE DRIVER
SLOS226C– SEPTEMBER 1998 – REVISED FEBRUARY 2000
APPLICATION INFORMATION
general configurations (continued)
C1
VI
R1
+
R2
_
C2
RF
RG
R1 = R2 = R
C1 = C2 = C
Q = Peaking Factor
(Butterworth Q = 0.707)
+ f–3dB
1
2pRC
( ) ^{RG =}
RF
1
2– _Q
Figure 49. 2-Pole Low-Pass Sallen-Key Filter
There are two simple ways to create an integrator with a CFB amplifier. The first one shown in Figure 51 adds
a resistor in series with the capacitor. This is acceptable because at high frequencies, the resistor is dominant
and the feedback impedance never drops below the resistor value. The second one shown in Figure 52 uses
positive feedback to create the integration. Caution is advised because oscillations can occur because of the
positive feedback.
RG
VI
RF
C1
–
+
VO
THS6012
ǒ Ǔ_{ȧȡ ȧȣ} + ^{) VO}
RF
S
1
RFC1
Ȣ Ȥ ^VI
RG
S
Figure 50. Inverting CFB Integrator
RG
RF
–
THS6012
+
VO
R1
VI
RA
R2
C1
For Stable Operation:
R2
R1 || RA
≥
RF
RG
( ) ^{VO ≅ VI}
1+
RF
RG
sR1C1
Figure 51. Non-Inverting CFB Integrator
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