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THS4150 Datasheet, PDF (18/27 Pages) Texas Instruments – HIGH-SPEED DIFFERENTIAL I/O AMPLIFIERS | |||
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THS4150, THS4151
HIGHÄSPEED DIFFERENTIAL I/O AMPLIFIERS
SLOS321D â MAY 2000 â REVISED JANUARY 2004
PRINCIPLES OF OPERATION
theory of operation
The THS415x is a fully differential amplifier. Differential amplifiers are typically differential in/single out, whereas
fully differential amplifiers are differential in/differential out.
Differential Amplifier
Rf
R(g)
_
R(g)
+
Rf
THS415x
Fully differential Amplifier
VCC+
VINâ
_
+
VIN+
_
+
VO+
VOâ
VOCM
VCCâ
Figure 36. Differential Amplifier Versus a Fully Differential Amplifier
To understand the THS415x fully differential amplifiers, the definition for the pinouts of the amplifier are
provided.
Ç Ç Ç Ç Input voltage definition VID + VI) â VIâ
VIC
+
ÇVI)Ç
)
2
ÇVIâÇ
Ç Ç Ç Ç Output voltage definition VOD + VO) â VOâ
VOC
+
ÇVO)Ç
)
2
ÇVOâÇ
Transfer function
VOD + VID x AÇfÇ
Output common mode voltage VOC + VOCM
Differential Structure Rejects
Coupled Noise at the Input
VCC+
VINâ
_
+
VIN+
_
+
Differential Structure Rejects
Coupled Noise at the Output
VO+
VOâ
Differential Structure Rejects
Coupled Noise at the Power Supply
VOCM
VCCâ
Figure 37. Definition of the Fully Differential Amplifier
18
⢠POST OFFICE BOX 655303 DALLAS, TEXAS 75265
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