MAX3841
12.5Gbps CML 2
×
2 Crosspoint Switch
4 _______________________________________________________________________________________
Pin Description
PIN NAME FUNCTION
1, 12 V
CC
+3.3V Core Supply Voltage
2, 5 VCC1IN Supply Voltage for CML Input IN1. Connect to 1.8V, 2.5V, or 3.3V.
3 IN1+ Positive Serial Data Input 1, CML
4 IN1- Negative Serial Data Input 1, CML
6 SEL1 Output 1 Select, LVCMOS Input. See Table 1.
7 SEL2 Output 2 Select, LVCMOS Input. See Table 1.
8, 11 VCC2IN Supply Voltage for CML Input IN2. Connect to 1.8V, 2.5V, or 3.3V.
9 IN2+ Positive Serial Data Input 2, CML
10 IN2- Negative Serial Data Input 2, CML
13, 24 GND Supply Ground
14, 17 VCC1OUT Supply Voltage for CML Output OUT1. Connect to 1.8V, 2.5V, or 3.3V.
15 OUT1- Negative Serial Data Output 1, CML
16 OUT1+ Positive Serial Data Output 1, CML
18 ENO1 Output 1 Enable, LVCMOS Input. See Table 1.
19 ENO2 Output 2 Enable, LVCMOS Input. See Table 1.
20, 23 VCC2OUT Supply Voltage for CML Output OUT2. Connect to 1.8V, 2.5V, or 3.3V.
21 OUT2- Negative Serial Data Output 2, CML
22 OUT2+ Positive Serial Data Output 2, CML
— EP
Exposed Pad. The exposed pad must be soldered to the circuit board ground for proper thermal and
electrical performance.
Detailed Description
The MAX3841 contains a pair of CML inputs that drive
two 2:1 multiplexers, with separate select inputs SEL1
and SEL2, providing a 2 × 2 crosspoint data path. The
outputs of the multiplexers each drive a high-perfor-
mance CML output that can be disabled (powered
down) using the ENO1/ENO2 inputs. All of the data
paths are fully differential to minimize jitter, crosstalk,
and signal skew. See Figure 1 for the functional diagram.
CML Input and Output Buffers
The MAX3841 input and output buffers are terminated
with 50Ω to independent supply lines, and are also com-
patible with 100Ω differential terminations. (See Figures 3
and 4.) Separate power-supply connections are provided
for the core, input buffers, and output buffers to allow DC-
coupling to 1.8V, 2.5V, or 3.3V CML ICs. If desired, the
CML inputs and outputs can be AC-coupled.
The CML inputs accept serial NRZ data with differential
amplitude from 150mV
P-P
to 1200mV
P-P
(see Figure 2).
The CML outputs provide 500mV
P-P
nominal differential
swing, resulting in low power consumption.
MAX3841
CML
CML
CML
CML
1
0
1
0
OUT1
ENO1
SEL1
OUT2
ENO2
SEL2
IN1
IN2
2
2
2
2
Figure 1. Functional Diagram
