DAC38RF80_017 Datasheet, PDF (58/155 Pages) Texas Instruments – Dual- or Single-Channel, Single-Ended or Differential Output, 14-Bit, 9-GSPS, RF-Sampling DAC With JESD204B Interface and On-Chip PLL

DAC38RF80, DAC38RF83, DAC38RF84
DAC38RF85, DAC38RF90, DAC38RF93
SLASEA3C – DECEMBER 2016 – REVISED JULY 2017
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ES[3:0]
1x11
Table 29. Eye Scan Mode Selection (continued)
EFFECT
Timed Compare. As ES = 001x, but analyses over the time interval specified by ESLEN. Analyses zeroes when ES[2] =
0, and ones when ES[2] = 1.
When ES[3] = 0, the selected analysis runs continuously. However, when ES[3] = 1, only the number of qualified
samples specified by ESLed, as shown in Table 30. In this case, analysis is started by writing a 1 to ESRUN (it is
not necessary to set it back to 0). When analysis completes, ESDONE is set to 1.
ESLen
00
01
10
11
Table 30. Eye Scan Run Length
NUMBER OF SAMPLES ANALYZED
127
1023
8095
65535
When ESVO OVR = 1, the ESVO field determines the amount of offset voltage that is applied to the eye scan
data samplers associated with rxpi and rxni. The amount of offset is variable between 0 and 300 mV in
increments of ~10 mV, as shown Table 31. When ES[3] = 1, ESVO OVR must be 0 to allow the optimized
voltage offset to be read back via ESVO.
ESVO
100000
…
111110
111111
000000
000001
000010
…
011111
Table 31. Eye Scan Voltage Offset
OFFSET (mV)
-310
…
-20
-10
0
10
20
…
300
The phase position of the samplers associated with rxpi and rxni, is controlled to a precision of 1/32UI. When ES
is not 00, the phase position can be adjusted forwards or backwards by more than one UI using the ESPO field,
as shown in Table 32. In normal use, the range should be limited to ±0.5 UI (+15 to –16 phase steps).
ESPO
011111
…
000001
000000
111111
…
100000
Table 32. Eye Scan Phase Offset
OFFSET (1/32 UI)
+63
…
+1
0
-1
…
-64
58
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