RHF1201_11 STMICROELECTRONICS [STMicroelectronics], RHF1201_11 Datasheet - Page 23

• Manufacturer Part Number: RHF1201_11
• Description: Rad-hard 12-bit 50 Msps A/D converter
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

RHF1201
Figure 50. Differential implementation using a balun
Figure 51. Single-to-differential implementation with op-amps
With (Vout-diff) = (2R2/R1)
R1/(R1+R2) = R3/(R3+R4) and R4/(R6+R4) = (R5+R2)/R1 (refer to the RHF310-330-350
datasheet for the choice of R2).
Some applications may require a single-ended input, which can easily be achieved with the
configuration shown in
the rated performance of the RHF1201 may occur, compared to a differential configuration.
To avoid this, a sufficiently decoupled DC reference should be used to bias the RHF1201
inputs. One may also use an AC-coupled analog input and set the DC analog level with a
high value resistor R (10 kΩ to 100 kΩ) connected to a proper DC source.
Analog input signal
Vinpp
Vin - single
(50 Ω output)
0 V
50 Ω track
GND
GND
ADT1 -1
1:1
Figure
R6
R5
R1
R3
x
(Vin-single) and the following conditions on resistors:
52. However, with this type of configuration a degradation in
Doc ID 12585 Rev 5
470 nF* ceramic
(as close as possible
to the transformer)
*the use of a ceramic technology is
preferable for a large bandwidth
stability of the capacitor
R4
R4
Electrical characteristics (unchanged after 300 kRad)
+
+
RHF310
RHF330
RHF350
RHF310
RHF330
RHF350
_
_
100 pF
R2
R2
Short track
+Vinpp x R2/R1
50 Ω
-Vinpp x R2/R1
Riso
Riso
INCM
INCM
VINB
VIN
2 Vpp
RHF1201
INCM
REFM
VINB
REFP
VIN
100 nF* ceramic
(as close as
possible to
INCM pin)
RHF1201
REFP
INCM
1 V
REFM
Ground
External INCM
(optional)
External
INCM
(optional)
Ground
AM06134
AM04545
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