Datasheet
8 ______________________________________________________________________________________
MAX3946
1Gbps to 11.3Gbps, SFP+ Laser Driver
with Laser Impedance Mismatch Tolerance
Typical Operating Characteristics (continued)
(V
CC
= +3.3V, T
A
= +25°C, data pattern = 2
7
- 1 PRBS + 72 zeros + 2
7
- 1 PRBS (inverted) +72 ones, unless otherwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
(I
MOD
= 40mA
P-P
, I
BIAS
= 60mA)
MAX3946 toc09
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
9580655035205-10-25
60
70
80
90
100
50
-40
CURRENT INTO V
CC
, V
CCT
, AND V
CCD
PINS
TOTAL CURRENT vs. TEMPERATURE
(I
MOD
AT LOAD = 40mA
P-P
, I
BIAS
= 60mA)
MAX3946 toc10
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
9580-25 -10 5 35 5020 65
150
160
170
180
190
200
210
220
140
-40
CURRENT INTO V
CC
, V
CCT
, AND V
CCD
PINS
PLUS MODULATION AND BIAS CURRENT
25Ω LOAD
5Ω LOAD
EYE CROSSING PERCENT
vs. SET_PWCTRL
MAX3946 toc11
SET_PWCTRL[3:0]
CROSSING (%)
1001
1010
1011
1100
1101
1110
1111
0000
0001
0010
0011
0100
0101
0110
0111
30
35
40
45
50
55
60
65
70
75
25
BIAS CURRENT
vs. DAC SETTING
MAX3946 toc12
SET_IBIAS[8:0]
BIAS CURRENT (mA)
400200
20
40
60
80
100
120
0
0 600
MODULATION CURRENT (AT LOAD)
vs. DAC SETTING
MAX3946 toc13
SET_IMOD[8:0]
MODULATION CURRENT (mA
P-P
)
400200
10
20
30
40
50
60
70
80
90
0
0 600
R
LOAD
= 25Ω
DIFFERENTIAL
R
LOAD
= 50Ω
DIFFERENTIAL
MODULATION CURRENT DEEMPHASIS
vs. MANUAL DEEMPHASIS SETTING
MAX3946 toc14
SET_TXDE[5:0]
DEEMPHASIS (%)
3020
1
2
3
4
5
6
7
8
9
10
0
10 40
SET_IMOD[8:0] = 230d
TXDE_MD[1:0] = 2d
BIAS MONITOR CURRENT
vs. TEMPERATURE
MAX3946 toc15
TEMPERATURE (°C)
BMON CURRENT (µA)
9580655035205-25 -10
100
200
300
400
500
600
700
0
-40
I
BIAS
= 60mA
I
BIAS
= 30mA
I
BIAS
= 10mA
EDGE SPEED
vs. MODULATION CURRENT
MAX3946 toc16
I
MOD
(mA)
EDGE SPEED (ps)
80604020
15
20
25
30
35
40
10
0 100
FALL TIME
RISE TIME
25Ω LOAD, 20% TO 80%
10Gbps, 11111 00000 PATTERN
EDGE SPEED
vs. DEEMPHASIS SETTING
MAX3946 toc17
SET_TXDE[5:0]
EDGE SPEED (ps)
3020
15
20
25
30
35
40
10
10 40
FALL TIME
RISE TIME
SET_IMOD[8:0] = 230d
25Ω LOAD, 20% TO 80%
10Gbps, 1111 0000 PATTERN