MAX3744E/D [MAXIM]
Telecom Circuit, 1-Func, Bipolar, 0.030 X 0.050 INCH, DIE-10;
| 型号： | MAX3744E/D |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Telecom Circuit, 1-Func, Bipolar, 0.030 X 0.050 INCH, DIE-10 放大器 |
| 文件： | 总10页 (文件大小：373K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2927; Rev 1; 8/03
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
General Description
Features
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-
ꢀ Up to 2.7Gbps (NRZ) Data Rates
ꢀ RSSI Implementation in 4-Pin TO46 Header
(MAX3744)
tance. The parts also have >2mA
AC input overload.
P-P
ꢀ 10ps
Deterministic Jitter for <100µA
Input
P-P
P-P
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
Current
ꢀ 330nA
Input-Referred Noise at 2.1GHz
RMS
Bandwidth
ꢀ 28mA Supply Current at +3.3V
ꢀ 2GHz Small-Signal Bandwidth
on-chip 580Ω resistor to V . These features allow
CC
easy assembly into a low-cost TO-46 or TO-56 header
with a photodiode.
ꢀ 2.0mA
AC Overload
P-P
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.
ꢀ Die Size: 30 mils x 50 mils
Applications
Ordering Information
Up to 2.7Gbps SFF/SFP Optical Receivers
PART
MAX3744E/D
MAX3745E/D
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
Dice**
Optimized for Small-Form-Factor Pluggable (SFP)
Optical Receivers
Dice**
**Dice are guaranteed to operate from -40°C to +85°C, but are
tested only at T = +25°C.
*Patent pending
A
Typical Application Circuit
SFP OPTICAL RECEIVER
400pF
V
CC
400pF
0.1µF
HOST
V
CC
BOARD
OUT+
OUT-
IN+
IN-
OUT+
FILTER
MAX3744
0.1µF
MAX3748A
V
= 3.3V
OUT-
IN
CC
GND
4.7kΩ
RSSI
DISABLE
LOS
TO
4-PIN TO CAN
10kΩ
3.3k
Ω
MOD-DEF1
MOD-DEF2
DS1858/
DS1859
________________________________________________________________ Maxim Integrated Products
1
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.
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
ABSOLUTE MAXIMUM RATINGS
Power-Supply Voltage (V ).................................-0.5V to +6.0V
Continuous Input Current (FILTER).......................-8mA to +8mA
Operating Junction Temperature Range (T )....-55°C to +150°C
CC
Continuous CML Output Current
J
(OUT+, OUT-) ............................................. -25mA to +25mA
Continuous Input Current (IN)...............................-4mA to +4mA
Storage Ambient Temperature Range (T
Die Attach Temperature...................................................+400°C
) ...-55°C to +150°C
STG
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
= +2.97V to +3.63V and T = -40°C to +85°C. Typical values are at V
= +3.3V, source capacitance (C ) = 0.85pF, and T =
CC IN A
CC
A
+25°C, unless otherwise noted.) (Notes 1, 2)
PARAMETER SYMBOL
Supply Current
CONDITIONS
MIN
TYP
MAX
41
UNITS
mA
I
Including CML output current (I = 0)
IN
28
CC
Input Bias Voltage
Input Overload
1.0
V
(Note 3)
2
mA
P-P
C
C
C
C
C
C
= 0.85pF, BW = 933MHz
= 0.85pF, BW = 2.1GHz
= 0.85pF, BW = 18GHz
= 0.85pF, BW = 933MHz
= 0.6pF, BW = 2.1GHz
= 0.6pF, BW = 18GHz
206
330
IN
IN
IN
IN
IN
IN
430
620
Input-Referred Noise
I
nA
RMS
N
206
300
380
550
4.5
Differential Transimpedance
Small-Signal Bandwidth (Note 3)
Low-Frequency Cutoff
Differential output, I = 40µA
2.8
1.8
1.6
3.5
2
kΩ
IN
AVE
-3dB, C = 0.6pF
IN
BW
DJ
GHz
kHz
-3dB, C = 0.85pF
IN
1.8
-3dB, input current = 20µA
(Note 3)
30
31
AVE
2.1Gbps, K28.5 pattern
< input ≤
14
24
100µA
2mA
P-P
31
P-P
2.7Gbps, 2 -1 pattern
Deterministic Jitter
(Notes 3, 5)
ps
P-P
2.1Gbps, K28.5 pattern
10
16
10µA
< input ≤
P-P
31
100µA
2.7Gbps, 2 -1 pattern
20
P-P
Filter Resistance
510
85
580
690
115
Ω
Differential Output Resistance
(OUT+, OUT-)
100
280
Ω
Maximum Differential Output
Voltage
Input > 50µA
, output termination 50Ω to
AVE
V
220
400
mV
P-P
OD
V
(output in limited state)
CC
2
_______________________________________________________________________________________
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
ELECTRICAL CHARACTERISTICS (continued)
(V
= +2.97V to +3.63V and T = -40°C to +85°C. Typical values are at V
= +3.3V, source capacitance (C ) = 0.85pF, and T =
CC IN A
CC
A
+25°C, unless otherwise noted.) (Notes 1, 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Single-Ended Output Common-
Mode Minimum Level (MAX3744)
Relative to V , I = 1mA
540
490
mV
CC IN
AVE
Input > 200µA
(Note 3)
20% to 80% rise/fall time
P-P
Output Data Transition Time
Differential Output Return Loss
80
140
ps
Frequency ≤ 1GHz
17
10
46
34
21
dB
1GHz < frequency ≤ 2GHz
f < 1MHz
I
IN
= 0
Power-Supply Noise Rejection
RSSI Gain (MAX3744)
PSNR
dB
A/A
dB
(Note 6)
(Note 7)
10log(A
1MHz ≤ f < 10MHz
A
RSSI
/A
) where A
=
RSSI-NOM
RSSI RSSI-NOM
RSSI Gain Stability (MAX3744)
0.24
A
at 3.3V, +25°C (Note 3)
RSSI
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:
RMS output noise
Gain at f =100MHz
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 / ∆V ), where ∆V is the differential output voltage and ∆V is the
CC
OUT
CC
OUT
noise on V
.
CC
Note 7:
I
(I = 400µA)−I
(I = 0µA)
OUT_CM IN
OUT_CM IN
A
=
RSSI
400µA
+ I
I
OUT+
OUT−
where I
=
OUT_CM
2
RSSI range is from I = 6µA to 500µA
IN
_______________________________________________________________________________________
3
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
Typical Operating Characteristics
(V = +3.3V, C = 0.85pF, T = +25°C, unless otherwise noted.)
CC
IN
A
INPUT-REFERRED NOISE
vs. TEMPERATURE
INPUT-REFERRED NOISE
vs. TEMPERATURE
FREQUENCY RESPONSE
75
800
800
700
600
500
400
300
200
UNFILTER
BW = 2.1GHz
700
600
500
400
300
200
70
65
60
55
C
= 1.5pF
IN
C
IN
= 0.85pF
C
IN
= 1.5pF
C
= 0.5pF
IN
C
IN
= 0.85pF
C
IN
= 0.5pF
50
10M
100M
1G
10G
-40 -20
0
20
40
60
80 100
-40 -20
0
20
40
60
80 100
FREQUENCY (Hz)
TEMPERATURE (°C)
TEMPERATURE (°C)
EYE DIAGRAM
DETERMINISTIC JITTER
vs. INPUT AMPLITUDE
SMALL-SIGNAL TRANSIMPEDANCE
vs. TEMPERATURE
INPUT = 20µA , DATA RATE = 2.1Gbps
P-P
MAX3744 toc06
75
50
40
30
20
10
0
K28-5 PATTERN
70
65
2.7Gbp SONET
5mV/div
2.1Gbps FIBRE CHANNEL
60
60ps/div
0.01
0.1
1
10
-40 -20
0
20
40
60
80 100
INPUT AMPLITUDE (mA
)
P-P
TEMPERATURE (°C)
EYE DIAGRAM
EYE DIAGRAM
EYE DIAGRAM
INPUT = 20µA , DATA RATE = 2.7Gbps
INPUT = 2mA , DATA RATE = 2.7Gbps
INPUT = 2mA , DATA RATE = 2.1Gbps
P-P
P-P
P-P
MAX3744 toc07
23
MAX3744 toc09
23
MAX3744 toc08
2
-1 PATTERN
2
-1 PATTERN
K28-5 PATTERN
6mV/div
30mV/div
30mV/div
60ps/div
60ps/div
60ps/div
4
_______________________________________________________________________________________
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
Typical Operating Characteristics (continued)
(V = +3.3V, C = 0.85pF, T = +25°C, unless otherwise noted.)
CC
IN
A
SUPPLY CURRENT
vs. TEMPERATURE
DC TRANSFER FUNCTION
(V = 0V)
DIFFERENTIAL S22 vs. FREQUENCY
FILT
0
-5
70
60
50
40
30
20
10
0
200
150
100
50
MAX3744
-10
-15
-20
-25
-30
0
-50
-100
-150
-200
MAX3745
0
500 1000 1500 2000 2500 3000 3500 4000
FREQUENCY (MHz)
-40 -20
0
20
40
60
80 100
-100
-50
0
50
100
TEMPERATURE (°C)
INPUT CURRENT (mA
)
P-P
EYE DIAGRAM
TEMPERATURE = +100°C INPUT = 20µA
RSSI
P-P
DATA RATE = 2.7Gbps
BANDWIDTH vs. TEMPERATURE
MAX3744, MAX3748A
MAX3744 toc15
4.0
550
500
450
400
350
300
250
200
150
23
2
-1 PRBS
T
A
= -40°C
3.5
3.0
T
= +85°C
A
2.5
2.0
1.5
1.0
0.5
0
C
IN
= 0.6pF
6mV/div
60ps/div
-40 -20
0
20
40
60
80 100
0
500
1000
1500
2000
TEMPERATURE (°C)
AVERAGE INPUT CURRENT (µA)
_______________________________________________________________________________________
5
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
Pin Description
MAX3744/
MAX3745
NAME
FUNCTION
BOND PAD
1, 3
2, 7
4
V
Supply Voltage
No Connection
CC
N.C.
IN
TIA Input. Signal current from photodiode flows into this pin.
Provides bias voltage for the photodiode through a 580Ω resistor to V . When grounded, this
CC
pin disables the DC cancellation amplifier to allow a DC path from IN to OUT+ and OUT- for
testing.
5
6, 10
8
FILTER
GND
Supply Ground
Inverting Data Output. Current flowing into IN causes the voltage at OUT- to decrease. For the
MAX3744, the common mode between OUT+ and OUT- is proportional to the average input
current.
OUT-
Noninverting Data Output. Current flowing into IN causes the voltage at OUT+ to increase. For
the MAX3744, the common mode between OUT+ and OUT- is proportional to the average input
current.
9
OUT+
V
CC
MAX3744
R
F
R
F
TRANSIMPEDANCE
AMPLIFIER
TRANSIMPEDANCE
AMPLIFIER
50Ω
50Ω
OUT+
OUT-
OUT+
OUT-
IN
IN
50Ω
50Ω
V
V
CC
CC
DC CANCELLATION
CIRCUIT
DC CANCELLATION
CIRCUIT
RSSI
FILTER
MAX3745
FILTER
Figure 1. Functional Diagram
a standard 4-pin TO header, the RSSI level is added to
the common mode of the differential data output pins.
Detailed Description
The MAX3744/MAX3745 are transimpedance amplifiers
designed for up to 2.7Gbps SFF/SFP transceiver mod-
ules. A functional diagram of the MAX3744/MAX3745 is
shown in Figure 1. The MAX3744/MAX3745 comprise a
transimpedance amplifier stage, a voltage amplifier
stage, an output buffer, and a direct-current (DC) feed-
back cancellation circuit. The MAX3744 also includes a
signal strength indicator (RSSI). To provide this signal in
Transimpedance Amplifier Stage
The signal current at the input flows into the summing
node of a high-gain amplifier. Shunt feedback through
the resistor R converts this current to a voltage. In par-
F
allel with the feedback resistor are two back-to-back
Schottky diodes that clamp the output signal for large
input currents, as shown in Figure 2.
6
_______________________________________________________________________________________
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
AMPLITUDE
AMPLITUDE
INPUT FROM PHOTODIODE
TIME
TIME
OUTPUT (SMALL SIGNALS)
OUTPUT (LARGE SIGNALS)
INPUT AFTER DC CANCELLATION
Figure 2. MAX3744/MAX3745 Limited Output
Figure 3. DC Cancellation Effect on Input
Voltage Amplifier Stage
The voltage amplifier stage provides gain and converts
the single-ended input to differential outputs.
V
CC
100Ω
DC Cancellation Circuit
The DC cancellation circuit uses low-frequency feed-
back to remove the DC component of the input signal
(Figure 3). This feature centers the input signal within
the transimpedance amplifier’s linear range, thereby
reducing pulse-width distortion caused by large input
signals. The DC cancellation circuit is internally com-
pensated and therefore does not require external
capacitors.
OUT+
OUT-
Output Buffer
The output buffer provides a reverse-terminated voltage
output. The buffer is designed to drive a 100Ω differential
load between OUT+ and OUT-. The MAX3744 must be
DC-coupled to the MAX3748A. See Figures 4 and 5.
Figure 4. Equivalent Output MAX3744
For optimum supply-noise rejection, the MAX3745
should be terminated with a matched load. If a single-
ended output is required, the unused output should be
V
CC
terminated to a 50Ω resistor to V . The MAX3745
CC
does not drive a DC-coupled, 50Ω grounded load;
however, it does drive a compatible 50Ω CML input.
50Ω
50Ω
Signal-Strength Indicator
The MAX3744 produces a signal proportional to the
average photodiode current. This is added to the com-
mon mode of the data outputs OUT+ and OUT-. This
signal is intended for use with the MAX3748A to pro-
vide a ground-referenced RSSI voltage.
OUT+
OUT-
Applications Information
Signal-Strength Indicator
The SFF-8472 digital diagnostic specification requires
monitoring of input receive power. The MAX3748A and
MAX3744 receiver chipset allows for the monitoring of
the average receive power by measuring the average
DC current of the photodiode.
Figure 5. Equivalent Output MAX3745
_______________________________________________________________________________________
7
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
The MAX3744 preamp measures the average photodi-
Optical Sensitivity Calculation
ode current and provides the information to the output
common mode. The MAX3748A RSSI detect block
senses the common-mode DC level of input signals IN+
and IN- and provides a ground-level-referenced output
signal of the photodiode current. The advantage of this
implementation is that it allows the TIA to be packaged
in a low-cost conventional 4-pin TO-46 header.
The input-referred RMS noise current (I ) of the
N
MAX3744/MAX3745 generally determines the receiver
sensitivity. To obtain a system bit-error rate (BER) of
1E-12, the signal-to-noise ratio must always exceed
14.1. The input sensitivity, expressed in average power,
can be estimated as:
The MAX3748A RSSI output is connected to an analog
input channel of the DS1858/DS1859 SFP controller to
convert the analog information into a 16-bit word. The
DS1858/DS1859 provide the received power informa-
tion to the host board of the optical receiver through a
2-wire interface. The DS1859 allows for internal calibra-
tion of the receive power monitor.
14.1 × I (r + 1)
N e
Sensitivity = 10log
1000 dBm
2ρ(r − 1)
e
where ρ is the photodiode responsivity in A/W and I is
N
RMS current in amps.
Input Optical Overload
The overload is the largest input that the MAX3744/
MAX3745 can accept while meeting deterministic jitter
specifications. The optical overload can be estimated
in terms of average power with the following equation:
The MAX3744 and the MAX3748A have been optimized
to achieve RSSI stability of better than 2.5dB within the
6µA to 500µA range of average input photodiode cur-
rent. To achieve the best accuracy, Maxim recom-
mends receive power calibration at the low end (6µA)
and the high end (500µA) of the required range.
2mA
(r + 1)
RMS e
Overload = 10log
1000 dBm
2ρ(r − 1)
e
Optical Power Relations
Many of the MAX3744/MAX3745 specifications relate to
the input signal amplitude. When working with optical
receivers, the input is sometimes expressed in terms of
average optical power and extinction ratio. Figure 6
and Table 1 show relations that are helpful for convert-
ing optical power to input signal when designing with
the MAX3744/MAX3745. (Refer to Application Note
HFAN–3.0.0: Accurately Estimating Optical Receiver
Sensitivity.)
Optical Linear Range
The MAX3744/MAX3745 have high gain, which limits
the output when the input signal exceeds 50µA . The
P-P
MAX3744/MAX3745 operate in a linear range (10% lin-
earity) for inputs not exceeding:
50µA
(r + 1)
RMS e
Linear Range = 10log
1000 dBm
2ρ(r − 1)
e
Table 1. Optical Power Relations
PARAMETER
Average power
SYMBOL
RELATION
P
P
= (P + P ) / 2
AVG
AVG
0
1
Extinction ratio
r
r = P / P
e 1
e
0
Optical power of a 1
Optical power of a zero
Signal amplitude
P
P
P = 2P
(r ) / (r + 1)
e e
1
0
1
AVG
P = 2P
/ (r + 1)
e
0
AVG
P
P
= P - P ; P = 2P
(r - 1) / (r + 1)
IN
IN
1
0
IN
AVG e e
Note: Assuming 50% average duty cycle and mark density.
8
_______________________________________________________________________________________
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
Current generated by supply noise voltage is divided
between C and C . The input noise current due
to supply noise is (assuming the filter capacitor is much
larger than the photodiode capacitance):
Layout Considerations
Noise performance and bandwidth are adversely affect-
ed by capacitance at the IN pad. Minimize capacitance
on this pad and select a low-capacitance photodiode.
Assembling the MAX3744/MAX3745 in die form using
chip and wire technology provides the best possible
performance. Figure 7 shows a suggested layout for a
TO header for the MAX3744/MAX3745. The placement
of the filter cap to minimize the ground loop of the pho-
todiode is required to achieve the specified bandwidth.
The OUT+ and OUT- bond wire lengths should also be
minimized to meet the bandwidth specification. Special
care should be taken to ensure that ESD at IN does not
exceed 500V.
FILTER
PD
I
= (V
)(C ) / (R
)(C
FILTER
)
FILTER
NOISE
NOISE
PD
If the amount of tolerable noise is known, the filter
capacitor can be easily selected:
C
FILTER
= (V
)(C ) / (R
)(I
)
NOISE
PD
FILTER NOISE
For example, with maximum noise voltage = 100mV
,
P-P
selected to
C
= 0.85pF, R
= 600Ω, and I
PD
FILTER
NOISE
be 350nA:
C
FILTER
= (100mV)(0.85pF) / (600Ω)(350nA) = 405pF
Wire Bonding
Photodiode Filter
For high-current density and reliable operation, the
MAX3744/MAX3745 use gold metalization. Connections
to the die should be made with gold wire only, using ball-
bonding techniques. Die thickness is typically 14 mils
(0.4mm).
Supply voltage noise at the cathode of the photodiode
produces a current I = C
∆V/∆t, which reduces the
is the photodiode capaci-
tance.) The filter resistor of the MAX3744/MAX3745,
combined with an external capacitor, can be used to
reduce this noise (see the Typical Application Circuit).
PD
receiver sensitivity (C
PD
TOP VIEW OF TO-46 HEADER
CASE
GROUND
400pF TO
1000pF
PI
400pF TO
1000pF
V
CC
PHOTODIODE
OUT-
P
AVG
PO
OUT+
TIME
MAX3744
MAX3745
Figure 7. Suggested Layout for TO-46 Header
Figure 6. Optical Power Relations
_______________________________________________________________________________________
9
2.7Gbps SFP Transimpedance
Amplifiers with RSSI
Chip Topography
GND
MAX3744
MAX3745
10
V
1
9
OUT+
CC
N.C.
2
3
0.03in
(0.76mm)
V
CC
IN
4
5
FILTER
7
6
8
OUT-
GND
N.C.
0.05in
(1.26mm)
Pad Coordinates
Chip Information
TRANSISTOR COUNT: 301
PROCESS: SiGe Bipolar
SUBSTRATE: ISOLATED
COORDINATES (µm)
COORDINATES (µm)
PAD
X
Y
1
2
1.4
0
495.6
336
224
112
0
DIE THICKNESS: 0.014in 0.001in
3
0
4
0
5
0
6
494.2
865.2
1005.2
1005.2
490
-1.4
-1.4
-1.4
495.6
495.6
7
8
9
10
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2003 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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