MAX9249GCM/V+T Maxim Integrated Products, MAX9249GCM/V+T Datasheet - Page 23

• Manufacturer Part Number: MAX9249GCM/V+T
• Description: IC SERIALIZER GMSL LVDS 48TQFP
• Manufacturer: Maxim Integrated Products

Specifications of MAX9249GCM/V+T

• Function: Serializer
• Data Rate: 2.5Gbs
• Input Type: LVDS
• Output Type: Serial
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 105°C
• Mounting Type: Surface Mount
• Package / Case: 48-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Number Of Outputs: -
• Number Of Inputs: -

Table 4. CML Driver Strength (Default Level, CMLLVL = 11)
Table 5. Serial Output Spread
The serial line driver in the MAX9249 employs cur-
rent-mode logic (CML) signaling. The driver can be
programmed to generate a preemphasized waveform
according to the cable length and characteristics. There
are 13 preemphasis settings, as shown in Table 4.
Negative preemphasis levels are deemphasis levels in
which the swing is the same as normal, but the no-tran-
sition data is deemphasized. Program the preemphasis
levels through register 0x05 D[3:0] of the MAX9249. This
preemphasis function compensates the high-frequency
loss of the cable and enables reliable transmission over
longer link distances. Additionally, a lower power-drive
mode can be entered by programming CMLLVL bits
*Negative preemphasis levels denote deemphasis.
PREEMPHASIS LEVEL
000
001
010
011
100
101
110
111
SS
(dB)*
No spread spectrum.
Power-up default when SSEN = low.
Q0.5% spread spectrum.
Power-up default when SSEN = high.
Q1.5% spread spectrum
Q2% spread spectrum
No spread spectrum
Q1% spread spectrum
Q3% spread spectrum
Q4% spread spectrum
10.5
14.0
-6.0
-4.1
-2.5
-1.2
1.1
2.2
3.3
4.4
6.0
8.0
0
______________________________________________________________________________________
Serializer with LVDS System Interface
SPREAD (%)
PREEMPHASIS
(0x05, D[3:0])
SETTING
Preemphasis Driver
0100
0011
0010
0001
0000
1000
1001
1010
1011
1100
1101
1110
1111
Gigabit Multimedia Serial Link
(mA)
I
CML
12
13
14
15
16
16
16
16
16
15
14
13
12
(mA)
I
PRE
4
3
2
1
0
1
2
3
4
5
6
7
8
(0x05 D[5:4]) to reduce the driver strength down to
75% (CMLLVL = 10) or 50% (CMLLVL = 01) from 100%
(CMLLVL = 11, default).
To reduce the EMI generated by the transitions on the
serial link and outputs of the GMSL deserializer, both
the MAX9249 and GMSL deserializer support spread
spectrum. Turning on spread spectrum on the MAX9249
spreads the serial data and the GMSL deserializer out-
puts. Do not enable spread for both the MAX9249 and
GMSL deserializer. The six selectable spread-spectrum
rates at the MAX9249 serial output are
±
spectrum rates can only be used at lower RXCLKIN_
frequencies (Table 6). There is no RXCLKIN_ frequency
limit for the 0.5% spread rate.
Set the MAX9249 SSEN input high to select 0.5% spread
at power-up and SSEN input low to select no spread at
power-up. The state of SSEN is latched upon power-up
or when resuming from power-down mode. Whenever
the MAX9249 spread spectrum is turned on or off, the
serial link automatically restarts and remains unavailable
while the GMSL deserializer relocks to the serial data.
Turning on spread spectrum on the MAX9249 or GMSL
deserializer does not affect the audio data stream.
Changes in the MAX9249 spread settings only affect
the GMSL deserializer MCLK output if it is derived from
RXCLKIN_ (MCLKSRC = 0).
1.5%,
±
2%,
SINGLE-ENDED VOLTAGE SWING
MAX
(mV)
400
400
400
400
400
425
450
475
500
500
500
500
500
±
3%, and
±
4% (Table 5). Some spread-
Spread Spectrum
(mV)
MIN
200
250
300
350
400
375
350
325
300
250
200
150
100
±
0.5%,
±
1%,
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