General Description
The MAX3744/MAX3745 transimpedance amplifiers pro-
vide a compact, low-power solution for communication
up to 2.7Gbps. They feature 330nA input-referred noise
at 2.1GHz bandwidth (BW) with 0.85pF input capaci-
tance. The parts also have >2mA
P-P
AC input overload.
Both parts operate from a single +3.3V supply and con-
sume 93mW. The MAX3744/MAX3745 are in a compact
30-mil x 50-mil die and require no external compensa-
tion capacitor. A space-saving filter connection is pro-
vided for positive bias to the photodiode through an
on-chip 580
resistor to V
CC
. These features allow
easy assembly into a low-cost TO-46 or TO-56 header
with a photodiode.
The MAX3744 and MAX3748A receiver chip set pro-
vides an RSSI output using a Maxim-proprietary* inter-
face technique. The MAX3744 preamplifier, MAX3748A
postamplifier, and DS1858/DS1859 SFP controller meet
all the SFF-8472 digital diagnostic requirements.
Applications
Up to 2.7Gbps SFF/SFP Optical Receivers
Optimized for Small-Form-Factor Pluggable (SFP)
Optical Receivers
Features
o Up to 2.7Gbps (NRZ) Data Rates
o RSSI Implementation in 4-Pin TO46 Header
(MAX3744)
o 10ps
P-P
Deterministic Jitter for <100µA
P-P
Input
Current
o 330nA
RMS
Input-Referred Noise at 2.1GHz
Bandwidth
o 28mA Supply Current at +3.3V
o 2GHz Small-Signal Bandwidth
o 2.0mA
P-P
AC Overload
o Die Size: 30 mils x 50 mils
MAX3744/MAX3745
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
________________________________________________________________ Maxim Integrated Products
1
Ordering Information
V
CC
FILTER
4-PIN TO CAN
400pF
400pF
IN
OUT+
OUT-
GND
OUT+
0.1
µ
F
0.1
µ
F
3.3k
IN+
V
CC
IN-
RSSI
DISABLE
LOS
OUT-
MAX3748A
SFP OPTICAL RECEIVER
HOST
BOARD
MOD-DEF1
MOD-DEF2
4.7k
TO
10k
V
CC
= 3.3V
MAX3744
DS1858/
DS1859
Typical Application Circuit
19-2927; Rev 1; 8/03
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
**Dice are guaranteed to operate from -40°C to +85°C, but are
tested only at T
A
= +25°C.
PART
TEMP RANGE
PIN-PACKAGE
MAX3744E/D
-40
°C to +85°C
Dice**
MAX3745E/D
-40
°C to +85°C
Dice**
*Patent pending
MAX3744/MAX3745
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
CC
= +2.97V to +3.63V and T
A
= -40°C to +85°C. Typical values are at V
CC
= +3.3V, source capacitance (C
IN
) = 0.85pF, and T
A
=
+25°C, unless otherwise noted.) (Notes 1, 2)
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.
Power-Supply Voltage (V
CC
) .................................-0.5V to +6.0V
Continuous CML Output Current
(OUT+, OUT-) ............................................. -25mA to +25mA
Continuous Input Current (IN)...............................-4mA to +4mA
Continuous Input Current (FILTER).......................-8mA to +8mA
Operating Junction Temperature Range (T
J
) ....-55°C to +150°C
Storage Ambient Temperature Range (T
STG
) ...-55°C to +150°C
Die Attach Temperature...................................................+400°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Supply Current
I
CC
Including CML output current (I
IN
= 0)
28
41
mA
Input Bias Voltage
1.0
V
Input Overload
(Note 3)
2
mA
P-P
C
IN
= 0.85pF, BW = 933MHz
206
C
IN
= 0.85pF, BW = 2.1GHz
330
430
C
IN
= 0.85pF, BW = 18GHz
620
C
IN
= 0.85pF, BW = 933MHz
206
C
IN
= 0.6pF, BW = 2.1GHz
300
380
Input-Referred Noise
I
N
C
IN
= 0.6pF, BW = 18GHz
550
nA
RMS
Differential Transimpedance
Differential output, I
IN
= 40µA
AVE
2.8
3.5
4.5
k
-3dB, C
IN
= 0.6pF
1.8
2
Small-Signal Bandwidth (Note 3)
BW
-3dB, C
IN
= 0.85pF
1.6
1.8
GHz
Low-Frequency Cutoff
-3dB, input current = 20µA
AVE
(Note 3)
30
kHz
2.1Gbps, K28.5 pattern
14
31
100µA
P-P
< input
2mA
P-P
2.7Gbps, 2
31
-1 pattern
24
2.1Gbps, K28.5 pattern
10
16
Deterministic Jitter
(Notes 3, 5)
DJ
10µA
P-P
< input
100µA
P-P
2.7Gbps, 2
31
-1 pattern
20
ps
P-P
Filter Resistance
510
580
690
Differential Output Resistance
(OUT+, OUT-)
85
100
115
Maximum Differential Output
Voltage
V
OD
Input > 50µA
AVE
, output termination 50
to
V
CC
(output in limited state)
220
280
400
mV
P-P
MAX3744/MAX3745
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +2.97V to +3.63V and T
A
= -40°C to +85°C. Typical values are at V
CC
= +3.3V, source capacitance (C
IN
) = 0.85pF, and T
A
=
+25°C, unless otherwise noted.) (Notes 1, 2)
Note 1: Die parameters are production tested at room temperature only, but are guaranteed by design and characterization from
-40
°C to +85°C.
Note 2: Source capacitance represents the total capacitance at the IN pad during characterization of the noise and bandwidth para-
meters.
Note 3: Guaranteed by design and characterization.
Note 4: Input-referred noise is:
Note 5: Deterministic jitter is the sum of pulse-width distortion (PWD) and pattern-dependent jitter (PDJ).
Note 6: Power-supply noise rejection PSNR = -20log(
V
OUT
/
V
CC
), where
V
OUT
is the differential output voltage and
V
CC
is the
noise on V
CC
.
Note 7:
A
I
I
A
I
I
A
A
where I
I
I
RSSI range is from I
A to
A
RSSI
OUT CM IN
OUT CM IN
OUT CM
OUT
OUT
IN
=
=
-
=
=
+
=
+
-
_
_
_
(
)
(
)
400
0
400
2
6
500
µ
µ
µ
µ
µ
RMS output noise
Gain at f
MHz
=
100
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Single-Ended Output Common-
Mode Minimum Level (MAX3744)
Relative to V
CC
, I
IN
= 1mA
AVE
540
490
mV
Output Data Transition Time
Input > 200µA
P-P
20% to 80% rise/fall time
(Note 3)
80
140
ps
Frequency
1GHz
17
Differential Output Return Loss
1GHz < frequency
2GHz
10
dB
f < 1MHz
46
Power-Supply Noise Rejection
PSNR
I
IN
= 0
(Note 6)
1MHz
f < 10MHz
34
dB
RSSI Gain (MAX3744)
A
RSSI
(Note 7)
21
A/A
RSSI Gain Stability (MAX3744)
10log(A
RSSI
/A
RSSI-NOM
) where A
RSSI-NOM
=
A
RSSI
at 3.3V, +25°C (Note 3)
0.24
dB
MAX3744/MAX3745
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
4
_______________________________________________________________________________________
Typical Operating Characteristics
(V
CC
= +3.3V, C
IN
= 0.85pF, T
A
= +25
°C, unless otherwise noted.)
60ps/div
EYE DIAGRAM
INPUT = 2mA
P-P
, DATA RATE = 2.7Gbps
30mV/div
MAX3744 toc09
2
23
-1 PATTERN
60ps/div
EYE DIAGRAM
INPUT = 2mA
P-P
, DATA RATE = 2.1Gbps
30mV/div
MAX3744 toc08
K28-5 PATTERN
60ps/div
EYE DIAGRAM
INPUT = 20
µA
P-P
, DATA RATE = 2.1Gbps
5mV/div
MAX3744 toc06
K28-5 PATTERN
50
10M
10G
1G
100M
FREQUENCY RESPONSE
75
60
55
70
65
MAX3744 toc03
FREQUENCY (Hz)
GAIN (dB)
60ps/div
EYE DIAGRAM
INPUT = 20
µA
P-P
, DATA RATE = 2.7Gbps
6mV/div
MAX3744 toc07
2
23
-1 PATTERN
200
400
300
600
500
700
800
-40
20
40
-20
0
60
80
100
INPUT-REFERRED NOISE
vs. TEMPERATURE
MAX3744 toc01
TEMPERATURE (
°C)
INPUT-REFERRED NOISE (nA
RMS
)
UNFILTER
C
IN
= 1.5pF
C
IN
= 0.85pF
C
IN
= 0.5pF
200
400
300
600
500
700
800
-40
20
40
-20
0
60
80
100
INPUT-REFERRED NOISE
vs. TEMPERATURE
MAX3744 toc02
TEMPERATURE (
°C)
INPUT-REFERRED NOISE (nA
RMS
)
BW = 2.1GHz
C
IN
= 1.5pF
C
IN
= 0.85pF
C
IN
= 0.5pF
DETERMINISTIC JITTER
vs. INPUT AMPLITUDE
MAX3744 toc04
INPUT AMPLITUDE (mA
P-P
)
DETERMINISTIC JITTER (ps
P-P
)
1
0.1
10
20
30
40
50
0
0.01
10
2.7Gbp SONET
2.1Gbps FIBRE CHANNEL
60
65
70
75
-40
0
20
-20
40
60
80
100
SMALL-SIGNAL TRANSIMPEDANCE
vs. TEMPERATURE
MAX3744 toc05
TEMPERATURE (
°C)
TRANSIMPEDANCE (dB
)
MAX3744/MAX3745
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
_______________________________________________________________________________________
5
Typical Operating Characteristics (continued)
(V
CC
= +3.3V, C
IN
= 0.85pF, T
A
= +25
°C, unless otherwise noted.)
0
1.0
0.5
2.5
1.5
3.5
4.0
-40
20
-20
40
60
100
BANDWIDTH vs. TEMPERATURE
MAX3744 toc14
TEMPERATURE (
°C)
3dB BANDWIDTH (GHz)
3.0
2.0
0
80
C
IN
= 0.6pF
DIFFERENTIAL S22 vs. FREQUENCY
MAX3744 toc10
FREQUENCY (MHz)
S22 (dB)
3500
3000
2500
2000
1500
1000
500
-25
-20
-15
-10
-5
0
-30
0
4000
MAX3744
MAX3745
0
20
10
40
30
60
50
70
-40
0
20
-20
40
60
80
100
SUPPLY CURRENT
vs. TEMPERATURE
MAX3744 toc11
TEMPERATURE (
°C)
SUPPLY CURRENT (mA)
-200
-150
-100
-50
0
50
100
150
200
-100
-50
0
50
100
DC TRANSFER FUNCTION
(V
FILT
= 0V)
MAX3744 toc12
INPUT CURRENT (mA
P-P
)
OUTPUT VOLTAGE (mV
P-P
)
150
200
250
300
350
400
450
500
550
0
500
1000
1500
2000
RSSI
MAX3744, MAX3748A
MAX3744 toc13
AVERAGE INPUT CURRENT (
µA)
MAX3748 RSSI OUTPUT (
µ
A)
T
A
= -40
°C
T
A
= +85
°C
60ps/div
EYE DIAGRAM
TEMPERATURE = +100
°C INPUT = 20µA
P-P
DATA RATE = 2.7Gbps
6mV/div
MAX3744 toc15
2
23
-1 PRBS
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