TSA1203 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'TSA1203' PDF : 21 Pages View PDF
Figure 5 : DC-coupled 2Vpp differential analog
input
analog
DC
analog
DC
VREFP-VREFM = 1 V
AC+DC
VREFP
VIN
TSA1203
VINB
VREFM
INCM
330pF 10nF 4.7uF
TSA1203
Single-ended input configuration
The single-ended input configuration of the
TSA1203 requires particular biasing and driving.
The structure being fully differential, care has to
be taken in order to properly bias the inputs in sin-
gle ended mode. Figure 6 summarizes the link
from the differential configuration to the sin-
gle-ended one; a wrong configuration is also pre-
sented.
- With differential driving, both inputs are centered
around the INCM voltage.
- The transition to single-ended configuration
implies to connect the unused input (VINB for
instance) to the DC component of the single input
(VIN) and also to the input common mode in order
to be well balanced. The mid-code is achieved at
the crossing between VIN and VINB, therefore
inputs are conveniently biased.
- Unlikely other structures of converters in which
the unused input can be grounded; in our case it
will end with unbalanced inputs and saturation of-
the internal amplifiers leading to a non respect of
the output codes.
Figure 6 : Input dynamic range for the various configurations
Differential configuration
+FS : code 1023
VIN - VINB
Single-ended configuration:
balanced inputs
+FS : code 1023
VIN - VINB
VINB
VIN
0 : code 511
INCM
0 : code 511
INCM
VIN
Single-ended configuration:
unbalanced inputs
+FS + offset : code > 1023
VIN - VINB
VIN
INCM
-FS : code 0
Ao + ac VIN
Ao + ac
VINB
INCM
Ao
Ao + ac VIN
-FS : code 0
-FS + offset : code > 0
Ao + ac VIN
VINB
INCM
Ao
VINB
INCM
Ao
Wrong configuration !
14/21
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