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36
TS8388B
2144C–BDC–04/03
Figure 38.
Differential Output: 50
Terminated
VPLUSD = 2.4V
Figure 39.
Differential Output: Open Loaded
VPLUSD = 2.4V
Out of Range Bit
An Out of Range (OR, ORB) bit is provided that goes to logical high state when the input
exceeds the positive full scale or falls below the negative full scale.
When the analog input exceeds the positive full scale, the digital output datas remain at high
logical state, with (OR, ORB) at logical one.
When the analog input falls below the negative full scale, the digital outputs remain at logical
low state, with (OR, ORB) at logical one again.
Gray or Binary
Output Data
Format Select
The TS8388B internal regeneration latches indecision (for inputs very close to latches thresh-
old) may produce errors in the logic encoding circuitry and leading to large amplitude output
errors.
This is due to the fact that the latches are regenerating the internal analog residues into logical
states with a finite voltage gain value (Av) within a given positive amount of time
(t):
Av = exp(
(t)/
τ
), with
τ
the positive feedback regeneration time constant.
The TS8388B has been designed for reducing the probability of occurrence of such errors to
approximately 10
-13
(targeted for the TS8388B at 1 GSPS).
1.6V
75
75
-
+
11 mA
DVEE
50
50
impedance
Out
OutB
50
50
1.38V/1.05V
10 nF
Differential output:
+0.33V = 0.660V
1.05V/1.38V
Common mode level: -1.2V
(-1.2V below VPLUSD level)
1.6V
75
75
-
+
11 mA
DVEE
75
75
impedance
Out
OutB
1.6V/0.8V
Differential output:
+0.8V = 1.6V
0.8V/1.6V
Common mode level: -1.2V
(-1.2V below VPLUSD level)