Datasheet

MAX9209/MAX9213
Programmable DC-Balanced
21-Bit Serializers
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Detailed Description
The MAX9209 operates at a parallel clock frequency of
8MHz to 34MHz in DC-balanced mode and 10MHz to
40MHz in non-DC-balanced mode. The MAX9213 oper-
ates at a parallel clock frequency of 16MHz to 66MHz
in DC-balanced mode and 20MHz to 85MHz in non-
DC-balanced mode.
DC-balanced or non-DC-balanced operation is con-
trolled by the DCB/NC pin (see Table 1). In non-DC-
balanced mode, each channel serializes 7 bits every
cycle of the parallel clock. In DC-balanced mode, 9 bits
are serialized every clock cycle (7 data bits + 2 DC-bal-
ance bits). The highest data rate in DC-balanced mode
for the MAX9213 is 66MHz x 9 = 594Mbps. In non-DC-
balanced mode, the maximum data rate is 85MHz x 7 =
595Mbps. A bit time is 1 divided by the data rate, for
example, 1 / 595Mbps = 1.68ns.
DC Balance
Through data coding, the DC-balance circuits limit the
imbalance of ones and zeros transmitted on each chan-
nel. If +1 is assigned to each binary one transmitted
and -1 is assigned to each binary zero transmitted, the
variation in the running sum of assigned values is
called the digital sum variation (DSV). The maximum
DSV for the MAX9209/MAX9213 data channels is 10. At
most, 10 more zeros than ones, or 10 more ones than
zeros, are transmitted. The maximum DSV for the clock
channel is 5. Limiting the DSV and choosing the correct
coupling capacitors maintain differential signal amplitude
and reduce jitter due to droop on AC-coupled links.
TxIN15 TxIN14 TxIN20 TxIN19 TxIN18 TxIN17 TxIN16 TxIN15 TxIN14
TxIN8 TxIN7 TxIN13 TxIN12 TxIN11 TxIN10 TxIN9 TxIN8 TxIN7
TxIN1 TxIN0 TxIN6 TxIN5 TxIN4 TxIN3 TxIN2 TxIN1 TxIN0
CYCLE N - 1 CYCLE N
TPPos0
TPPos1
TPPos2
TPPos3
TPPos4
TPPos5
TPPos6
TxCLK OUT
(DIFFERENTIAL)
TxOUT2
(SINGLE ENDED)
TxOUT1
(SINGLE ENDED)
TxOUT0
(SINGLE ENDED)
Figure 5. Non-DC-Balanced Mode LVDS Output Pulse Position Measurement
DEVICE DCB/NC
OPERATING
MODE
OPERATING
FREQUENCY
(MHz)
High or open DC balanced 8 to 34
MAX9209
Low
Non-DC
balanced
10 to 40
High or open DC balanced 16 to 66
MAX9213
Low
Non-DC
balanced
20 to 85
Table 1. DC-Balance Programming