19-3026; Rev 1; 11/04
+2.97V to +5.5V, 125Mbps to 200Mbps Limiting
Amplifier with Loss-of-Signal Detector
General Description
The MAX3645 limiting amplifier functions as a data
quantizer and is pin compatible with the Mindspeed
MC2045-2 and MC2045-2Y postamplifiers. The amplifi-
er accepts a wide range of input voltages and provides
constant-level positive emitter-coupled logic (PECL)
output voltages with controlled edge speeds.
The MAX3645 features an integrated power detector
with complementary PECL loss-of-signal (LOS) outputs
that indicate when the input power level drops below a
programmable threshold. An optional squelch function
holds the data outputs at static levels during a
LOS condition.
The MAX3645 operates from a single +3.3V or +5.0V
power supply over a -40°C to +85°C temperature
range. It is available in 16-pin SO and 16-pin QSOP
packages.
Features
♦
Pin Compatible with the Mindspeed
MC2045-2/MC2045-2Y
♦
500µV Input Sensitivity (BER = 10
-12
)
♦
Compatible with 4B/5B Data Coding
♦
Programmable LOS Threshold
♦
Stable LOS Threshold Over Supply Range
♦
Output Disable Function and Automatic Squelch
♦
Single +3.3V or +5.0V Power Supply
♦
18mA Supply Current
MAX3645
Ordering Information
PART
MAX3645ESE
MAX3645EEE
MAX3645EEE+
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
16 SO
16 QSOP
16 QSOP
Applications
SONET 155Mbps Transceivers
Fast Ethernet Receivers
FDDI 125Mbps Receivers
FTTx Receivers
ESCON Receivers
+Denotes
lead-free package.
Pin Configuration
TOP VIEW
CAZ2 1
CAZ1 2
GNDA 3
DIN+ 4
DIN- 5
V
CCA
6
CSD 7
DIS 8
16 TH
15 N.C.
14 V
CCE
MAX3645
13 DOUT+
12 DOUT-
11 GNDE
10 LOS
9
LOS
SO/QSOP
Typical Application Circuit
V
CC
V
CC
V
CC
PIN K
OUT+
0.1µF
DIN+
C
SD
1nF
CSD V
CCA
CAZ1
CAZ2 V
CCE
N.C.
DOUT+
C
AZ
0.1µF
V
CC
MAX3644*
IN
GND
MAX3645
OUT-
0.1µF
DIN-
GNDA
TH
DOUT-
LOS
GNDE
50Ω
50Ω
50Ω
DIS
R
TH
100Ω
LOS
50Ω
V
CC
- 2V
*FUTURE PRODUCT
V
CC
- 2V
________________________________________________________________
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.
+2.97V to +5.5V, 125Mbps to 200Mbps Limiting
Amplifier with Loss-of-Signal Detector
MAX3645
ABSOLUTE MAXIMUM RATINGS
Power-Supply Voltage (V
CCA
, V
CCE
) ....................-0.5V to +7.0V
Voltage at CAZ1, CAZ2, DIN+,
DIN-, CSD, DIS, TH ................................-0.5V to (V
CC
+ 0.5V)
PECL Output Current (DOUT+, DOUT-, LOS,
LOS)
...........50mA
Differential Voltage between CAZ1 and CAZ2......-1.5V to +1.5V
Differential Voltage between DIN+ and DIN- ........-1.5V to +1.5V
Continuous Power Dissipation (T
A
= +85°C)
16-Pin SO (derate 8.7mW/°C above +85°C)................565mW
16-Pin QSOP (derate 8.3mW/°C above +85°C)...........540mW
Storage Ambient Temperature Range (T
S
)…….-65°C to +160°C
Lead Temperature (soldering, 10s)...........……………….+300°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
= +2.97V to +5.5V, PECL outputs are terminated with 50Ω to V
CC
- 2V, R
TH
= 100Ω, C
AZ
= 0.1µF, C
SD
= 1nF, T
A
= -40°C to
+85°C. Typical values are at V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.)
PARAMETER
POWER SUPPLY
Supply Current
INPUT SPECIFICATIONS
Input Resistance
Input Sensitivity (Note 1)
Input Overload (Note 1)
Input-Referred Offset Voltage
Input Common-Mode Voltage
Input-Referred RMS Noise
DIS Input High
DIS Input Low
DIS Input Current
OUTPUT SPECIFICATIONS
PECL Output-Voltage High
PECL Output-Voltage Low
Data Output Transition Time
Pulse-Width Distortion
t
R
, t
F
PWD
(Notes 1, 2)
(Notes 1, 2)
20% to 80% (Notes 1, 2, 4)
(Notes 1, 2, 4, 5)
V
CC
-
1085
V
CC
-
1830
0.7
30
V
CC
-
880
V
CC
-
1555
1.4
200
mV
mV
ns
ps
V
CMM
V
IN-NOISE
V
IH
V
IL
I
IL
, I
IH
(Notes 2, 3)
PECL or CMOS logic
PECL or CMOS logic
0V
≤
V
DIS
≤
V
CC
V
CC
-
1160
0
-10
R
IN
V
IN-MIN
V
IN-MAX
Single ended; V
IN
= ±200mV
Single ended
Differential
Single ended
Differential
Unterminated input, output offset divided by
DC gain (Note 2)
750
1500
2
V
CC
-
0.87
36
50
V
CC
V
CC
-
1480
+10
40
3.3
4.8
6.4
0.5
1.0
kΩ
mV
P-P
mV
P-P
µV
V
µV
RMS
mV
mV
µA
I
CC
Excludes PECL termination currents
18
27
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
+2.97V to +5.5V, 125Mbps to 200Mbps Limiting
Amplifier with Loss-of-Signal Detector
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +2.97V to +5.5V, PECL outputs are terminated with 50Ω to V
CC
- 2V, R
TH
= 100Ω, C
AZ
= 0.1µF, C
SD
= 1nF, T
A
= -40°C to
+85°C. Typical values are at V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.)
PARAMETER
TRANSFER CHARACTERISTICS
Bandwidth
Low-Frequency Cutoff
Gain = 60dB
C
AZ
= open
C
AZ
= 0.1µF
0Ω
≤
R
TH
≤
2kΩ
10log (V
DEASSERT
/V
ASSERT
)
(Note 7)
R
TH
= 0Ω, low setting
LOS Assert Level
R
TH
= 1kΩ, medium setting
R
TH
= 2kΩ, high setting
R
TH
= 0Ω, low setting
LOS Deassert Level
Signal-Dectect Filter Resistance
R
SD
R
TH
= 1kΩ, medium setting
R
TH
= 2kΩ, high setting
Pin 7
2
1.4
2.3
0.5
4.8
12
1.1
8.0
20
14
0.9
6.6
17
1.5
10.8
28
20
2
80.0
1.3
8.3
22
1.9
13.5
36
26
kΩ
mV
P-P
mV
P-P
150
250
500
0.5
20
MHz
kHz
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX3645
LOSS-OF-SIGNAL SPECIFICATIONS
(Notes 2, 4, 6)
LOS Sensitivity Range
LOS Hysteresis
LOS Assert/Deassert Time
mV
P-P
dB
µs
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Between sensitivity and overload, the output amplitude is >95% of the fully limited amplitude and all AC specifications are met.
Guaranteed by design and characterization.
Noise is derived from BER measurement.
The data input transition time is controlled by a 4th-order Bessel filter with f
-3dB
= 0.75
×
data rate.
PWD = [(width of wider pulse) - (width of narrower pulse)] / 2, measured with 155Mbps 0011 pattern.
All LOS specifications are measured using a 155Mbps 2
23
- 1 PRBS pattern.
The signal at the input is switched between two amplitudes, SIGNAL_ON and SIGNAL_OFF, as shown in Figure 1.
V
IN
SIGNAL ON
1dB
MAXIMUM DEASSERT LEVEL
6dB
MAXIMUM POWER-DETECT WINDOW
MINIMUM ASSERT LEVEL
0V
SIGNAL OFF
TIME
Figure 1. Signal Levels for LOS Assert/Deassert Time
Measurement
_______________________________________________________________________________________
3
+2.97V to +5.5V, 125Mbps to 200Mbps Limiting
Amplifier with Loss-of-Signal Detector
MAX3645
Typical Operating Characteristics
(V
CC
= 3.3V, PECL outputs terminated with 50Ω to V
CC
- 2V, R
TH
= 100Ω, C
AZ
= 0.1µF, C
SD
= 1nF, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
(EXCLUDES PECL OUTPUT CURRENTS)
45
40
SUPPLY CURRENT (mA)
35
30
25
20
15
10
5
-40
-15
10
35
60
85
V
CC
= 3.3V
V
CC
= 5.0V
200mV/
div
MAX3645 toc01
OUTPUT EYE DIAGRAM
(V
IN
= 1mV
P-P
, 155Mbps, 2
23
- 1PRBS)
MAX3654 toc02
OUTPUT EYE DIAGRAM
(V
IN
= 1500mV
P-P
, 155Mbps, 2
23
- 1PRBS)
MAX3645 toc03
50
200mV/
div
1ns/div
1ns/div
TEMPERATURE (°C)
TRANSFER FUNCTION
MAX3654 toc04
BIT-ERROR RATIO vs.
DIFFERENTIAL INPUT VOLTAGE
10
-4
10
-5
BIT-ERROR RATIO
10
-6
10
-7
10
-8
10
-9
10
-10
10
-11
10
-12
155Mbps, 2
23
- 1 PRBS
MAX3645 toc05
INPUT-REFERRED RMS NOISE
vs. TEMPERATURE
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
-40
MAX3645 toc06
2000
DIFFERENTIAL OUTPUT VOLTAGE (mV
P-P
)
1800
1600
1400
1200
1000
800
600
400
0.01
0.1
1
10
R
TH
= 1kΩ
R
TH
= 2kΩ
R
TH
= 0Ω
R
TH
= 100Ω
10
-3
INPUT-REFERRED NOISE (µV
RMS
)
V
CC
= +5.0V
V
CC
= +3.3V
100
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
-15
10
35
60
85
DIFFERENTIAL INPUT VOLTAGE (mV
P-P
)
DIFFERENTIAL INPUT VOLTAGE (mV
P-P
)
TEMPERATURE (°C)
SMALL-SIGNAL GAIN vs. R
TH
MAX3645 toc07
LOSS-OF-SIGNAL THRESHOLD
vs. R
TH
(V
CC
= +3.3V AND +5.0V)
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
0
MAX3645 toc08
LOSS-OF-SIGNAL HYSTERESIS
vs. TEMPERATURE
3.0
10log (DEASSERT/ASSERT) (dB)
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
R
TH
= 100Ω
R
TH
= 1kΩ
R
TH
= 2kΩ
155Mbps, 2
23
- 1 PRBS
MAX3645 toc09
100
90
80
20log (V
OUT
/V
IN
) (dB)
70
60
50
40
30
20
10
0
0
0.2
0.5
0.7
1.0
R
TH
(kΩ)
1.2
1.5
1.7
V
IN
= 0.1mV
P-P
3.2
155Mbps, 2
23
- 1 PRBS
DIFFERENTIAL INPUT VOLTAGE (mV
P-P
)
LOS DEASSERT
LOS ASSERT
2.0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
R
TH
(kΩ)
-40
-15
10
35
60
85
TEMPERATURE (°C)
4
_______________________________________________________________________________________
+2.97V to +5.5V, 125Mbps to 200Mbps Limiting
Amplifier with Loss-of-Signal Detector
MAX3645
Typical Operating Characteristics (continued)
(V
CC
= 3.3V, PECL outputs terminated with 50Ω to V
CC
- 2V, R
TH
= 100Ω, C
AZ
= 0.1µF, C
SD
= 1nF, T
A
= +25°C, unless otherwise noted.)
LOSS-OF-SIGNAL WITH SQUELCH
(155Mbps, 2
23
- 1PRBS)
MAX3654 toc10
PULSE-WIDTH DISTORTION
vs. DIFFERENTIAL INPUT VOLTAGE
155Mbps 0011 PATTERN
90
PULSE-WIDTH DISTORTION (ps)
MAX3645 toc11
100
V
IN
80
70
60
50
40
30
20
10
0
V
OUT
LOS
10µs/div
0.1
1
10
100
1000
10,000
DIFFERENTIAL INPUT VOLTAGE (mV
P-P
)
DATA OUTPUT TRANSITION TIME
vs. DIFFERENTIAL INPUT VOLTAGE
MAX3645 toc12
3.0
2.5
TRANSITION TIME (ns)
2.0
1.5
1.0
0.5
0
0.1
1
10
100
1000
10,000
DIFFERENTIAL INPUT VOLTAGE (mV
P-P
)
_______________________________________________________________________________________
5
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