THS7001_16 Datasheet, PDF (24/41 Pages) Texas Instruments – 70-MHz PROGRAMMABLE-GAIN AMPLIFIERS

THS7001, THS7002
ą
70ĆMHz PROGRAMMABLEĆGAIN AMPLIFIERS
ą
SLOS214C − OCTOBER 1998 − REVISED MARCH 2007
APPLICATION INFORMATION
driving a capacitive load (continued)
499 Ω
Input
499 Ω
_
PREAMP
+
20 Ω
Output
CLOAD
Figure 61. Driving a Capacitive Load
offset voltage
The output offset voltage, (V_OO) is the sum of the input offset voltage (V_IO) and both input bias currents (I_IB) times
the corresponding gains. The following schematic and formula can be used to calculate the output offset
voltage:
RG
RF
IIB−
RS
IIB+
−
+
+−
VIO
VOS
ǒ Ǔ ǒ Ǔ VOS + " VIO " IIB₎ RS
1
)
RF
RG
" IIB_* RF
Figure 62. Output Offset Voltage Model
general configurations
When receiving low-level signals, limiting the bandwidth of the incoming signals into the system is often
required. The simplest way to accomplish this is to place an RC filter at the noninverting terminal of the THS7001
and THS7002 preamplifier (see Figure 63).
RG
RF
VI
R1
−
+
C1
f–3dB
+
1
2pR1C1
VO
ǒ Ǔǒ Ǔ ^VO
VI
+
1
)
RF
RG
1
1 ) sR1C1
Figure 63. Single-Pole Low-Pass Filter
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