19-4695; Rev 0; 8/09
1Gbps to 14Gbps, SFP+ Multirate Limiting
Amplifier and VCSEL Driver
General Description
The MAX3799 is a highly integrated limiting amplifier
and VCSEL driver that operates up to 14Gbps, making
it suitable for Ethernet and Fibre Channel applications.
By providing a selectable data path with a noise-shap-
ing filter, the MAX3799 enables a module with 10G
optics to be fully compliant with both 1000BASE-SR
and 10GBASE-SR specifications. Operating from a sin-
gle +3.3V supply, this low-power integrated limiting
amplifier and VCSEL driver IC enables a platform
design for SFP MSA as well as for SFP+ MSA-based
optical transceivers. The high-sensitivity limiting ampli-
fier limits the differential input signal generated by a
transimpedance amplifier into a CML-level differential
output signal. The compact VCSEL driver provides a
modulation and a bias current for a VCSEL diode. The
optical average power is controlled by an average
power control (APC) loop implemented by a controller
that interfaces to the VCSEL driver through a 3-wire
digital interface. All differential I/Os are optimally back-
terminated for a 50Ω transmission line PCB design.
The use of a 3-wire digital interface reduces the pin
count while enabling advanced Rx (rate selection, LOS
threshold, LOS squelch, LOS polarity, CML output level,
signal path polarity, deemphasis, and fast mode-select
change time) and Tx settings (modulation current, bias
current, polarity, and eye safety control) without the
need for external components. The MAX3799 provides
multiple current and voltage DACs to allow the use of
low-cost controller ICs.
The MAX3799 is packaged in a lead-free, 5mm x 5mm,
32-pin TQFN package.
Features
♦
Enables Single-Module Design Compliance with
1000BASE-SR and 10GBASE-SR Specifications
♦
-21.5dBm Optical Sensitivity at 1.25Gbps Using a
10.32Gbps ROSA (-19.7dBm OMA)
♦
Low Power Dissipation of 320mW at 3.3V Power
Supply
♦
Typical Electrical Performance of 14.025Gbps on
Rx/Tx (Non-Retimed 16x Fibre Channel Solution)
♦
3mV
P-P
Receiver Sensitivity at 10.32Gbps
♦
4ps
P-P
DJ at Receiver Output at 8.5Gbps 8B/10B
♦
4ps
P-P
DJ at Receiver Output at 10.32Gbps
2
31
- 1 PRBS
♦
26ps Rise and Fall Time at Rx/Tx Output
♦
Rate Select for 1Gbps Mode or 10Gbps Mode
♦
CML Output Squelch
♦
Polarity Select for Rx and Tx
♦
LOS Assert Level Adjustment
♦
LOS Polarity Select
♦
Modulation Current Up to 12mA Into 100Ω
Differential Load
♦
Bias Current Up to 15mA
♦
Integrated Eye Safety Features
♦
3-Wire Digital Interface
♦
Programmable Deemphasis at Tx Output
MAX3799
Applications
1000BASE-SR/10GBASE-SR Multirate SFP+
Optical Transceiver
1x/2x/4x/8x/16x SFF/SFP/SFP+ MSA Fibre
Channel (FC) Optical Transceiver
Ordering Information
PART
MAX3799ETJ+
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
32 TQFN-EP*
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
Typical Application Circuit and Pin Configuration appear at
end of data sheet.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1Gbps to 14Gbps, SFP+ Multirate Limiting
Amplifier and VCSEL Driver
MAX3799
ABSOLUTE MAXIMUM RATINGS
V
CCR
, V
CCT
, V
CCD
.................................................-0.3V to +4.0V
Voltage Range at DISABLE, SDA, SCL, CSEL,
RSEL, FAULT, BMON, LOS, CAZ2.........-0.3V to (V
CC
+ 0.3V)
Voltage Range at ROUT+, ROUT- .....(V
CC
- 1V) to (V
CC
+ 0.3V)
Voltage at TIN+, TIN-........................(V
CC
- 2.5V) to (V
CC
- 0.5V)
Voltage Range at TOUT+, TOUT- ......(V
CC
- 2V) to (V
CC
+ 0.3V)
Voltage at BIAS ............................................................0V to V
CC
Voltage at RIN+, RIN- ..........................(V
CC
- 2V) to (V
CC
- 0.2V)
Current Range into FAULT, LOS...........................-1mA to +5mA
Current Range into SDA........................................-1mA to +1mA
Current into ROUT+, ROUT- ...............................................40mA
Current into TOUT+, TOUT- ................................................60mA
Continuous Power Dissipation (T
A
= +70°C)
32-Pin TQFN (derate 34.5W/°C above +70°C) ...........2759mW
Operating Junction Temperature Range ...........-55°C to +150°C
Storage Temperature Range .............................-65°C to +160°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
CC
= 2.85V to 3.63V, T
A
= -40°C to +85°C, CML receiver output load is AC-coupled to differential 100Ω, C
AZ
= 1nF, transmitter out-
put load is AC-coupled to differential 100Ω (see Figure 1), typical values are at +25°C, V
CC
= 3.3V, I
BIAS
= 6mA, I
MOD
= 6mA, unless
otherwise specified. Registers are set to default values unless otherwise noted, and the 3-wire interface is static during measure-
ments. For testing, the RATE_SEL bit was used and the RSEL pin was left open.)
PARAMETER
POWER SUPPLY
Power-Supply Current
Power-Supply Voltage
GENERAL
Input Data Rate
Input/Output SNR
BER
POWER-ON RESET
High POR Threshold
Low POR Threshold
Rx INPUT SPECIFICATIONS
Differential Input Resistance
RIN+/RIN-
Input Sensitivity (Note 2)
Input Overload
Input Return Loss
Input Return Loss
Rx OUTPUT SPECIFICATIONS
Differential Output Resistance
R
OUTDIFF
75
100
125
R
IN_DIFF
V
INMIN
V
INMAX
SDD11
SCC11
DUT is powered on, f
DUT is powered on, f
5GHz
16GHz
5GHz
16GHz
RATE_SEL = 0 (1.25Gbps)
RATE_SEL = 1 (10.32Gbps)
1.2
14
7
8
8
75
100
1
3
125
3
8
mV
P-P
V
P-P
dB
dB
I
BIAS
= I
BIASOFF
and I
MOD
= I
MODOFF
2.3
2.55
2.45
2.75
V
V
1.0625
14.1
10E-12
10.32
Gbps
I
CC
V
CC
Includes the CML output current;
excludes I
BIAS
= 6mA, I
MOD
= 6mA,
V
DIFF_ROUT
= 400mV
P-P
(Note 1)
2.85
97
150
3.63
mA
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DUT is powered on, 1GHz < f
DUT is powered on, 1GHz < f
2
_______________________________________________________________________________________
1Gbps to 14Gbps, SFP+ Multirate Limiting
Amplifier and VCSEL Driver
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 2.85V to 3.63V, T
A
= -40°C to +85°C, CML receiver output load is AC-coupled to differential 100Ω, C
AZ
= 1nF, transmitter out-
put load is AC-coupled to differential 100Ω (see Figure 1), typical values are at +25°C, V
CC
= 3.3V, I
BIAS
= 6mA, I
MOD
= 6mA, unless
otherwise specified. Registers are set to default values unless otherwise noted, and the 3-wire interface is static during measure-
ments. For testing, the RATE_SEL bit was used and the RSEL pin was left open.)
PARAMETER
Output Return Loss
Output Return Loss
CML Differential Output Voltage
High
CML Differential Output Voltage
Medium
CML Differential Output DAC
Limit
Differential Output Signal When
Disabled
Data Output Transition Time
(20% to 80%)
(Notes 2, 3, 4)
Rx TRANSFER CHARACTERISTICS
60mV
P-P
V
IN
400mV
P-P
at 10.32Gbps,
RATE_SEL = 1, V
DIFF_ROUT
= 400mV
P-P
Deterministic Jitter
(Notes 2, 3, 5)
DJ
10mV
P-P
V
IN
1200mV
P-P
at 8.5Gbps,
RATE _SEL = 1, V
DIFF_ROUT
= 400mV
P-P
5mV
P-P
V
IN
1200mV
P-P
at 1.25Gbps,
RATE _SEL = 0, V
DIFF_ROUT
= 800mV
P-P
Input = 60mV
P-P
at 1.25Gbps
,
RATE_SEL = 0, V
DIFF_ROUT
= 800mV
P-P
Input = 60mV
P-P
at 8.5Gbps
,
RATE _SEL = 1, V
DIFF_ROUT
= 400mV
P-P
C
AZ
= 0.1μF
C
AZ
= open
14
10 x log (V
DEASSERT
/V
ASSERT
) (Note 6)
(Note 7)
SET_LOS[7] (Notes 2, 6)
SET_LOS[7] (Notes 2, 6)
SET_LOS[32] (Notes 2, 6)
SET_LOS[32] (Notes 2, 6)
SET_LOS[63] (Notes 2, 6)
SET_LOS[63] (Notes 2, 6)
1.25
2.3
8
14
39
65
77
127
11
18
48
81
94
158
2.1
80
14
21
58
95
112
182
4
4
20
1.8
0.32
2
500
77
2.5
ps
RMS
0.48
kHz
12
12
ps
P-P
SYMBOL
SDD22
SCC22
CONDITIONS
DUT is powered on, f
DUT is powered on, f
5GHz
16GHz
5GHz
16GHz
595
300
MIN
TYP
11
5
9
7
800
400
1005
515
215
MAX
UNITS
dB
dB
mV
P-P
mV
P-P
MAX3799
DUT is powered on, 1GHz < f
DUT is powered on, 1GHz < f
5mV
P-P
10mV
P-P
V
IN
V
IN
1200mV
P-P
, SET_CML[162]
1200mV
P-P
, SET_CML[80]
SET_CML[7:0]
Outputs AC-coupled, V
INMAX
applied to
input V
DIFF_ROUT
= 800mV
P-P
at 8.5Gbps
(Notes 2, 3)
10mV
P-P
V
IN
1200mV
P-P
,
RATE_SEL = 1, V
DIFF_ROUT
= 400mV
P-P
5mV
P-P
V
IN
1200mV
P-P
,
RATE_SEL = 0, V
DIFF_ROUT
= 800mV
P-P
6
15
mV
P-P
26
60
35
ps
100
t
R
/t
F
Random Jitter (Notes 2, 3)
RJ
Low-Frequency Cutoff
Rx LOS SPECIFICATIONS
LOS Assert Sensitivity Range
LOS Hysteresis
LOS Assert/Deassert Time
Low Assert Level
Low Deassert Level
Medium Assert Level
Medium Deassert Level
High Assert Level
High Deassert Level
mV
P-P
dB
μs
mV
P-P
mV
P-P
mV
P-P
mV
P-P
mV
P-P
mV
P-P
_______________________________________________________________________________________
3
1Gbps to 14Gbps, SFP+ Multirate Limiting
Amplifier and VCSEL Driver
MAX3799
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 2.85V to 3.63V, T
A
= -40°C to +85°C, CML receiver output load is AC-coupled to differential 100Ω, C
AZ
= 1nF, transmitter out-
put load is AC-coupled to differential 100Ω (see Figure 1), typical values are at +25°C, V
CC
= 3.3V, I
BIAS
= 6mA, I
MOD
= 6mA, unless
otherwise specified. Registers are set to default values unless otherwise noted, and the 3-wire interface is static during measure-
ments. For testing, the RATE_SEL bit was used and the RSEL pin was left open.)
PARAMETER
Tx INPUT SPECIFICATIONS
Differential Input Voltage
Common-Mode Input Voltage
Differential Input Resistance
Input Return Loss
Input Return Loss
Tx LASER MODULATOR
Maximum Modulation-On
Current into 100 Differential
Load
Minimum Modulation-On Current
into 100 Differential Load
Modulation Current DAC
Stability
Modulation Current Rise Time/
Fall Time
t
R
/t
F
I
MODMAX
Outputs AC-coupled, V
CCTO
2.95V
12
mA
V
IN
V
INCM
R
IN
SDD11
SCC11
DUT is powered on, f
DUT is powered on, f
5GHz
16GHz
5GHz
16GHz
75
Data rate = 1.0625Gbps
Data rate = 10.32Gbps
0.2
0.075
2.75
100
15
6
9
5
125
dB
dB
2.4
0.8
V
P-P
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DUT is powered on, 1GHz < f
DUT is powered on, 1GHz < f
I
MODMIN
Outputs AC-coupled
2mA
I
MOD
12mA (Note 8)
26
2
4
39
mA
%
ps
5mA I
MOD
10mA, 20% to 80%,
SET_TXDE[3:0] = 10 (Notes 2, 4)
5mA I
MOD
12mA, at 10.32Gbps,
250mV
P-P
V
IN
800mV
P-P
,
SET_TXDE[4:1] = 0
5mA I
MOD
12mA, at 10.32Gbps,
250mV
P-P
V
IN
800mV
P-P
,
SET_TXDE[4:1] = 10
6
12
6
13
Deterministic Jitter (Notes 2, 9)
DJ
5mA I
MOD
12mA, at 8.5Gbps,
250mV
P-P
V
IN
800mV
P-P
,
SET_TXDE[4:1] = 0
5mA I
MOD
12mA, at 8.5Gbps,
250mV
P-P
V
IN
800mV
P-P
,
SET_TXDE[4:1] = 10
2mA
2mA
I
MOD
I
MOD
12mA, at 4.25Gbps
12mA, at 1.0625Gbps
12mA, 250mV
P-P
5GHz
16GHz
15
V
IN
6
12
ps
6
5
5
0.17
12
5
12
Random Jitter
Output Return Loss
Tx BIAS GENERATOR
Maximum Bias-On Current
Minimum Bias-On Current
I
BIASMAX
I
BIASMIN
SDD22
5mA I
MOD
800mV
P-P
0.5
ps
RMS
dB
DUT is powered on, f
DUT is powered on, f
Current into BIAS pin
Current into BIAS pin
mA
2
mA
4
_______________________________________________________________________________________
1Gbps to 14Gbps, SFP+ Multirate Limiting
Amplifier and VCSEL Driver
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= 2.85V to 3.63V, T
A
= -40°C to +85°C, CML receiver output load is AC-coupled to differential 100Ω, C
AZ
= 1nF, transmitter out-
put load is AC-coupled to differential 100Ω (see Figure 1), typical values are at +25°C, V
CC
= 3.3V, I
BIAS
= 6mA, I
MOD
= 6mA, unless
otherwise specified. Registers are set to default values unless otherwise noted, and the 3-wire interface is static during measure-
ments. For testing, the RATE_SEL bit was used and the RSEL pin was left open.)
PARAMETER
BIAS Current DAC Stability
Compliance Voltage at BIAS
BIAS Current Monitor Current
Gain
Compliance Voltage at BMON
BIAS Current Monitor Current
Gain Stability
Tx SAFETY FEATURES
Average voltage, FAULT warning always
occurs for V
BMON
V
CC
- 0.55V, FAULT
warning never occurs for V
BMON
V
CC
-
0.65V
Average voltage, FAULT always occurs for
V
BIAS
0.44V, FAULT never occurs for
V
BIAS
0.65V
FAULT or DISABLE, V
BIAS
= V
CC
V
CC
-
0.65V
V
CC
-
0.6V
V
CC
-
0.55V
V
BIAS
I
BMON
V
BMON
I
BMON
2mA
I
BIAS
15mA (Note 10)
External resistor to GND defines the
voltage gain
0
SYMBOL
2mA
I
BIAS
CONDITIONS
15mA (Notes 2, 10)
0.9
16
1.8
5
MIN
TYP
MAX
4
2.1
UNITS
%
V
mA/A
V
%
MAX3799
Excessive Voltage at BMON
V
BMON
V
Excessive Voltage at BIAS
Maximum VCSEL Current in Off
State
SFP TIMING REQUIREMENTS
DISABLE Assert Time
V
BIAS
I
OFF
0.44
0.48
0.65
V
25
μA
t_
OFF
Time from rising edge of DISABLE input
signal to I
BIAS
= I
BIASOFF
and I
MOD
=
I
MODOFF
Time from falling edge of DISABLE to I
BIAS
and I
MOD
at 90% of steady state when
FAULT = 0 before reset
Time from power-on or negation of FAULT
using DISABLE
Time from fault to FAULT on,
C
FAULT
20pF, R
FAULT
= 4.7k
Time DISABLE must be held high to reset
FAULT
5
1
μs
DISABLE Negate Time
FAULT Reset Time of Power-On
Time
FAULT Reset Time
DISABLE to Reset
t_
ON
t_
INIT
t_
FAULT
500
μs
100
10
ms
μs
μs
OUTPUT_LEVEL VOLTAGE DAC (SET_CML)
Full-Scale Voltage
Resolution
Integral Nonlinearity
Full-Scale Voltage
Resolution
Integral Nonlinearity
BIAS CURRENT DAC (SET_IBIAS)
Full-Scale Current
I
FS
21
mA
INL
11mV
P-P
V
TH_LOS
94mV
P-P
INL
V
FS
5mA
I
CML_LEVEL
20mA
LOS THRESHOLD VOLTAGE DAC (SET_LOS)
94
1.5
±0.7
mV
P-P
mV
P-P
LSB
V
FS
100
differential resistive load
1200
5
±0.9
mV
P-P
mV
P-P
LSB
_______________________________________________________________________________________
5
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