19-1097; Rev 4; 8/08
KIT
ATION
EVALU
BLE
AVAILA
Low-Power, 622Mbps Limiting Amplifiers
with Chatter-Free Power Detect for LANs
____________________________Features
♦
Chatter-Free Power Detector with Programmable
Loss-of-Signal Outputs
♦
4mV Input Sensitivity
♦
PECL Data Outputs
♦
Single 5V Power Supply
♦
250ps Output Edge Speed
♦
Low 15ps Pulse-Width Distortion
♦
TTL Loss-of-Signal Interface Logic—MAX3761
♦
PECL Loss-of-Signal Interface Logic—MAX3762
_______________General Description
The MAX3761/MAX3762 limiting amplifiers, with 4mV
sensitivity and PECL data outputs, are optimized for
operation in low-cost, 622Mbps, LAN/ATM LAN fiber
optics applications.
An integrated power detector senses the input signal’s
amplitude. A received-signal-strength indicator (RSSI)
gives an analog indication of the power level, while the
complementary loss-of-signal (LOS) outputs indicate if
the input power level exceeds the programmed
threshold level. The LOS threshold can be adjusted to
detect signal amplitudes between 3mVp-p and
100mVp-p, providing a 15dB LOS adjustment in fiber
optic receivers. The LOS outputs have 3.5dB of
hysteresis, which prevents chatter when input signal
levels are small. The MAX3761’s LOS outputs are com-
patible with TTL-logic levels. The MAX3762 has PECL
LOS outputs.
DISABLE and LOS can be used to implement a squelch
function, which turns off the data outputs when the
input signal is below the programmed threshold.
MAX3761/MAX3762
Ordering Information
PART
MAX3761EEP+
MAX3761E/D
MAX3762EEP+
MAX3762E/D
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
20 QSOP
Dice*
20 QSOP
Dice*
________________________Applications
622Mbps LAN/ATM LAN Receivers
155Mbps LAN/ATM LAN Receivers
*Dice
are designed to operate from -40°C to +85°C, but are
tested and guaranteed only at T
A
= +25°C.
+Denotes
a lead-free/RoHS-compliant package.
__________________Pin Configuration
TOP VIEW
FILTER 1
RSSI 2
EN 3
V
CC
4
VIN+ 5
VIN- 6
GND 7
SUB 8
CZP 9
CZN 10
20 DISABLE
19 LOS+
18 LOS-
17 V
CC
_________Typical Operating Circuits
+5V
10nF
RSSI
VCCO
100pF
BYPASS
SUPPLY
C
IN
5.6nF
VIN+
C
IN
5.6nF
VIN-
V
CC
EN
CZP
CZN
DISABLE
LOS+
LOS-
OUT-
OUT+
50Ω
50Ω
GNDO
GND
VTH
SUB
V
CC
- 2V
C
AZ
150pF
MAX3761
MAX3762
16 VCCO
15 OUT+
14 OUT-
13 GNDO
12 VTH
11 INV
MAX3761
FILTER
100pF
+V
CC
R1
100kΩ
R2
22kΩ
C
FILTER
INV
QSOP
MAX3762 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.
Low-Power, 622Mbps Limiting Amplifiers
with Chatter-Free Power Detect for LANs
MAX3761/MAX3762
ABSOLUTE MAXIMUM RATINGS
V
CC
, VCCO............................................................-0.5V to +7.0V
FILTER, RSSI, EN, VIN+, VIN-, CZP, CZN,
DISABLE, LOS+, LOS-, INV, VTH...............-0.5V to (V
CC
+ 0.5V)
PECL Output Current (OUT+, OUT-, LOS+, LOS-) ............50mA
Continuous Power Dissipation (T
A
= +85°C)
QSOP (derate 9.1mW/°C above +85°C) .......................591mW
Operating Junction Temperature Range ...........-40°C to +150°C
Processing Temperature (die) .........................................+400°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+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.
DC ELECTRICAL CHARACTERISTICS
(V
CC
= +4.5V to +5.5V, DISABLE = low, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V
CC
= +5.0V, T
A
= +25°C.)
(Note 1)
PARAMETER
Power-Supply Current
LOS Output TTL High
LOS Output TTL Low
LOS Output PECL High
LOS Output PECL Low
DISABLE Input Current
DISABLE Input High
DISABLE Input Low
DISABLE Input PECL High
DISABLE Input PECL Low
PECL Data Output Voltage High (V
OH
)
PECL Data Output Voltage Low (V
OL
)
Disabled Differential Output
Disabled Common-Mode Output
MAX3761, I
VCC
MAX3762, I
VCC
MAX3761
MAX3761
(T
A
= +25°C to +85°C)
(T
A
= -40°C to +25°C)
-1150
-1830
2.65
0.8
-1160
-1470
-1150
-1830
-100
V
CC
- 0.7
-880
-1555
100
V
CC
-1.2
2.8
0.40
0.44
-880
-1555
100
CONDITIONS
MIN
TYP
25
30
MAX
37
46
UNITS
mA
V
V
mV
mV
μA
V
V
mV
mV
mV
mV
mV
V
MAX3762 (Notes 2, 3)
MAX3762 (Notes 2, 3)
Logic high
MAX3761
MAX3761
MAX3762 (Note 3)
MAX3762 (Note 3)
(Notes 2, 3)
(Notes 2, 3)
DISABLE = high
DISABLE = high
Note 1:
Dice are tested at T
A
= +25°C.
Note 2:
Outputs terminated with 50Ω to V
CC
- 2V.
Note 3:
Voltage measurements are relative to V
CC
.
2
_______________________________________________________________________________________
Low-Power, 622Mbps Limiting Amplifiers
with Chatter-Free Power Detect for LANs
AC ELECTRICAL CHARACTERISTICS
(V
CC
= +4.5V to +5.5V, PECL outputs terminated with 50Ω to V
CC
- 2V, input 4mV to 2Vp-p, T
A
= -40°C to +85°C, unless otherwise
noted. Typical values are at V
CC
= +5.0V, T
A
= +25°C.) (Note 5)
PARAMETER
Minimum LOS Assert Input
Data-Output Edge Speed
Data-Output Overshoot
Pulse-Width Distortion
Input Resistance
LOS Hysteresis
20% to 80%
(Note 6)
(Notes 6, 7)
Differential
2
23
- 1 PRBS, VTH = 1.8V
15
3900
3.5
CONDITIONS
T
A
= -40°C, 2
23
- 1 PRBS
MIN
TYP
MAX
3.2
250
20
80
UNITS
mV
ps
%
ps
Ω
dB
MAX3761/MAX3762
Note 5:
AC parameters are guaranteed by design and characterization.
Note 6:
Input signal is a 1-0 pattern, 622Mbps.
Note 7:
PWD = [(width of wider pulse) - (width of narrower pulse)] / 2.
__________________________________________Typical Operating Characteristics
(MAX3761/MAX3762 EV kit, V
CC
= +5.0V, PECL outputs terminated with 50Ω to V
CC
- 2V, input is a 1-0 pattern, 622Mbps, T
A
= +25°C,
unless otherwise noted.)
MAX3762
SUPPLY CURRENT vs. TEMPERATURE
MAX3761/62-01
RSSI vs. INPUT AMPLITUDE
AND DATA PATTERN
MAX3761/62-02
RSSI vs.
INPUT POWER AND FREQUENCY
2.28
2.16
RSSI VOLTAGE (V)
2.04
1.92
1.80
1.68
1.56
1.44
1.32
1.20
500MHz
MAX3761/62-03
50
45
V
CC
= 5.5V
40
35
30
25
V
CC
= 5.0V
20
V
CC
= 4.5V
15
10
-40
-15
10
35
60
2.40
2.28
2.16
RSSI VOLTAGE (V)
2.04
1.92
1.80
1.68
1.56
1.44
1.32
1.20
1-0 PATTERN
2
23
- 1
PRBS PATTERN
2.40
10MHz
CURRENT (mA)
85
1
AMBIENT TEMPERATURE (°C)
10
100
INPUT SIGNAL (mVp-p)
1000
-50 -45 -40 -35 -30 -25 -20 -15 -10 -5
INPUT POWER (dBm)
0
_______________________________________________________________________________________
3
Low-Power, 622Mbps Limiting Amplifiers
with Chatter-Free Power Detect for LANs
MAX3761/MAX3762
____________________________Typical Operating Characteristics (continued)
(MAX3761/MAX3762 EV kit, V
CC
= +5.0V, PECL outputs terminated with 50Ω to V
CC
- 2V, input is a 1-0 pattern, 622Mbps, T
A
= +25°C,
unless otherwise noted.)
RSSI vs. TEMPERATURE
(622Mbps 2
23
- 1 PRBS)
MAX3761/62-04
LOS HYSTERESIS vs. TEMPERATURE
(622Mbps 2
23
- 1 PRBS PATTERN)
MAX3761/62-05
LOS HYSTERESIS vs. TEMPERATURE
(622Mbps 1-0 PATTERN)
ASSERT LEVEL SET
TO APPROXIMATELY
2mVp-p
MAX3761/62-06
2.00
1.92
1.84
RSSI VOLTAGE (V)
1.76
1.68
1.60
1.52
1.44
1.36
1.28
1.20
-40
-20
0
20
40
60
V
IN
= 4mVp-p
V
IN
= 16mVp-p
V
IN
= 50mVp-p
4.00
3.75
HYSTERESIS (dB)
3.50
3.25
3.00
2.75
2.50
ASSERT LEVEL SET
TO APPROXIMATELY
2mVp-p
8
7
HYSTERESIS (dB)
6
5
ASSERT LEVEL SET
TO APPROXIMATELY
30mVp-p
ASSERT LEVEL SET
TO APPROXIMATELY 30mVp-p
-40
-20
0
20
40
60
80
100
4
3
-40
-20
0
20
40
60
80
100
AMBIENT TEMPERATURE (°C)
AMBIENT TEMPERATURE (°C)
80
AMBIENT TEMPERATURE (°C)
DATA OUTPUT LEVELS
(REFERENCE TO V
CC
)
MAX3761/62-07
DIFFERENTIAL OUTPUT
vs. INPUT AMPLITUDE
1280
DIFFERENTIAL OUTPUT (mV)
1160
1040
920
800
680
560
440
320
200
60
80
0.1m
1m
0.01
0.1
INPUT SIGNAL (Vp-p)
1
10
0
0.001
MAX3761/62-08
PULSE-WIDTH DISTORTION
(622Mbps DATA RATE)
MAX3761/62-09
-0.8
VOH
-1.0
VOLTAGE (V)
1400
50
PULSE-WIDTH DISTORTION (PS)
40
-40°C
30
-1.2
-1.4
20
-1.6
VOL
10
+85°C
0.01
0.1
1
INPUT SIGNAL (Vp-p)
10
-1.8
-40
-20
0
20
40
AMBIENT TEMPERATURE (°C)
LOS OPERATION
WITH SQUELCHING
MAX3761/62-10
LOS OPERATION
WITHOUT SQUELCHING
MAX3761/62-11
DATA OUTPUT SINGLE-ENDED
(2
23
- 1 PRBS PATTERN)
INPUT = 4mVp-p
T
A
= +85°C
MAX3761/62-12
OUT+
OUT+
100mV/
div
LOS+
100mV/
div
DATA IN
LOS+
50mV/
div
DATA IN
5μs/div
5μs/div
500ps/div
4
_______________________________________________________________________________________
Low-Power, 622Mbps Limiting Amplifiers
with Chatter-Free Power Detect for LANs
____________________________Typical Operating Characteristics (continued)
(MAX3761/MAX3762 EV kit, V
CC
= +5.0V, PECL outputs terminated with 50Ω to V
CC
- 2V, input is a 1-0 pattern, 622Mbps, T
A
= +25°C,
unless otherwise noted.)
DATA OUTPUT SINGLE-ENDED
(2
23
-1 PRBS PATTERN)
MAX3761/62-13
MAX3761/MAX3762
RANDOM JITTER
MAX3761/62-14
RANDOM JITTER vs.
POWER-SUPPLY NOISE FREQUENCY
DIFFERENTIAL OUTPUT RANDOM JITTER
DATA INPUT AMPLITUDE = 16mVp-p
INPUT AMPLITUDE
POWER SUPPLY = 100mVp-p
MAX3761/62-15
INPUT = 2Vp-p
T
A
= +85°C
50mV/
div
200mV/
div
RANDOM JITTER (ps rms)
DIFFERENTIAL OUTPUT
(OUT+ - OUT-)
INPUT = 16mVp-p
T
A
= +27°C
1-0 PATTERN 622Mbps
10
8
6
4
2
500ps/div
200ps/div
10
3
10
4
10
5
FREQUENCY ON POWER SUPPLY (Hz)
10
6
______________________________________________________________Pin Description
PIN
1
2
3
4, 17
5
6
7
8
9
10
11
12
13
14
15
16
18
19
20
NAME
FILTER
RSSI
EN
V
CC
VIN+
VIN-
GND
SUB
CZP
CZN
INV
VTH
GNDO
OUT-
OUT+
VCCO
LOS-
LOS+
DISABLE
FUNCTION
Sets the integration frequency of the power detector. Impedance at this node is approximately 500Ω.
Received-Signal-Strength Indicator. An analog DC voltage representing the input power.
Connect to V
CC
.
+5V Power Supply
Positive Input Data
Negative Input Data
Supply Ground
Substrate. Connect to ground.
Sets input offset correction, low-frequency cutoff.
Sets input offset correction, low-frequency cutoff.
Negative Input to Op Amp. Used for programming the loss-of-signal threshold.
Loss-of-Signal Threshold Voltage
Ground Power Supply for Output Buffers
Negative PECL Data Output
Positive PECL Data Output
+5V Power Supply for Output Buffers
Negative Loss-of-Power Flag, TTL (MAX3761) or PECL (MAX3762)
Positive Loss-of-Power Flag, TTL (MAX3761) or PECL (MAX3762)
Disables the data outputs when high. TTL (MAX3761) or PECL (MAX3762).
_______________________________________________________________________________________
5
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