19-2269; Rev 3; 11/04
IT
TION K
VALUA
E
BLE
AVAILA
+3.3V, 2.5Gbps Low-Power
Limiting Amplifiers
General Description
Features
♦
Single +3.3V Power Supply
♦
33mA Supply Current
♦
5ps Deterministic Jitter
♦
90ps Edge Speed
♦
Output Squelch Function
♦
Programmable Loss-of-Signal Function
♦
CML Output Interface
♦
20-Pin 4mm
✕
4mm QFN or Thin QFN Package
♦
Selectable Output Polarity
MAX3272/MAX3272A
The MAX3272/MAX3272A 2.5Gbps limiting amplifiers
accept a wide range of input voltages and provide a
constant-level output voltage with controlled edge
speeds. Additional features include power detectors
with programmable loss-of-signal (LOS) indication, an
optional squelch function that mutes the data output sig-
nal when the input voltage falls below a programmable
threshold, and an output polarity selector. These parts
exhibit excellent jitter performance and have low power
dissipation.
The MAX3272/MAX3272A feature current-mode logic
(CML) data outputs that are tolerant of inductive con-
nectors, and are available in a 4mm
✕
4mm QFN pack-
age or in die form (MAX3272 only). Along with the
MAX3271, the MAX3272/MAX3272A are ideal for low-
power, compact optical receivers.
Ordering Information
PART
MAX3272EGP
MAX3272E/D
MAX3272AEGP
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
20 QFN
Dice*
20 QFN
PACKAGE
CODE
G2044-3
—
G2044-3
Applications
Gigabit Ethernet Optical Receivers
Fibre Channel Optical Receivers
System Interconnects
2.5Gbps Optical Receivers
SONET/SDH Receivers
MAX3272AETP+
-40°C to +85°C
20 Thin QFN T2044-3
+
Denotes Lead-Free Package.
*Dice are designed and guaranteed to operate from -40°C to
+85°C, but are tested only at T
A
= +25°C.
Pin Configuration appears at end of data sheet.
Typical Operating Circuit
C
AZ
+3.3V
+3.3V
CAZ1
OUTPOL
CAZ2
V
CC
MAX3272/
MAX3272A
SDI+
+3.3V
V
CC
IN+
0.1µF
0.1µF
IN-
100Ω
OUT+
SDO+
SDO-
MAX3873
OUT-
SDI-
CDR SCLKO+
SCLKO-
GND
MAX3271
CLOS
TH
C
CLOS
R
TH
LOSS
OF
SIGNAL
SQUELCH
GND LOS
LOS
LEVEL
Typical Operating Circuits continue at end of data sheet.
________________________________________________________________
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.
+3.3V, 2.5Gbps Low-Power
Limiting Amplifiers
MAX3272/MAX3272A
ABSOLUTE MAXIMUM RATINGS
Power-Supply Voltage (V
CC
) .................................-0.5V to +6.0V
Voltage at IN+, IN- ..........................(V
CC
- 2.4V) to (V
CC
+ 0.5V)
Voltage at SQUELCH, CAZ1, CAZ2,
TH, CLOS ...............................................-0.5V to (V
CC
+ 0.5V)
Voltage at LOS,
LOS
(MAX3272)...........................-0.5V to +6.0V
Voltage at LOS,
LOS
(MAX3272A) .............-0.5V to (V
CC
+ 0.5V)
Voltage at LEVEL...................................................-0.5V to +2.0V
Voltage at OUTPOL ...............................................-0.5V to +6.0V
Current into LOS,
LOS
..........................................-1mA to +9mA
Differential Input Voltage (IN+ - IN-).................................2.5V
P-P
Continuous Current at IN+, IN- ...........................................50mA
Continuous Current at
CML Outputs (OUT+, OUT-) .........................-25mA to +25mA
Continuous Power Dissipation at +85°C
20-Pin Thin QFN (derate 16.9mW/°C above +85°C) ......1.1W
20-Pin QFN (derate 20mW/°C above +85°C) .................1.3W
Storage Ambient Temperature
Range (T
STG
) .................................................-55°C to +150°C
Operating Junction Temperature
Range (T
J
) .....................................................-55°C to +150°C
Die Attach Temperature...................................................+400°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
= +3.0V to +3.6V, T
A
= -40°C to +85°C. Typical values are at V
CC
= +3.3V and T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Supply Current
Input Data Rate
Input Voltage Range
Output Deterministic Jitter
Random Jitter
Data Output Edge Speed
(20% to 80%)
Differential Input Resistance
Input-Referred Noise
CML Output Voltage
Output Signal when Squelched
Power-Supply Noise Rejection
Low Frequency Cutoff
Output Resistance
Single-Ended Output Return
Loss
Differential Input Return Loss
OUTPOL Input Limits
LOS Hysteresis
LOS Assert/Deassert Time
Low LOS Assert Level
Low LOS Deassert Level
Medium LOS Assert Level
Medium LOS Deassert Level
High LOS Assert Level
V
IL
V
IH
(Notes 3, 4, 8)
C
CLOS
= open (Notes 3, 9, 10)
C
CLOS
= 0.01µF (Notes 3, 9, 10)
R
TH
= 20kΩ (Notes 3, 10)
R
TH
= 20kΩ (Notes 3, 10)
R
TH
= 1kΩ (Notes 3, 10)
R
TH
= 1kΩ (Notes 3, 10)
R
TH
= 80Ω (Notes 3, 10)
24.3
7.8
2.3
4.5
2.4
2
3.3
1
50
6.5
9.5
12.9
17.4
48
22.4
12.7
100
PSNR
f
OC
R
OUT
V
OUT
LEVEL open, R
LOAD
= 50Ω
Outputs AC-coupled
f
≤
2MHz (Note 7)
C
AZ
= open
C
AZ
= 0.1µF
Single ended to V
CC
≤
2.5GHz
2.5GHz to 4.0GHz
4.0GHz
42.5
550
R
IN
V
IN
Differential
(Notes 3, 4, 5)
(Notes 4, 6)
(Notes 3, 4)
IN+ to IN-
15mV
P-P
< V
IN
≤
30mV
P-P
30mV
P-P
≤
V
IN
≤
1200mV
P-P
95
15
5
3
90
90
100
220
750
2.2
30
0.9
1.5
50
10
9
10
0.8
57.5
1200
130
115
105
SYMBOL
I
CC
(Note 2)
CONDITIONS
MIN
TYP
33
2.5
1200
27
MAX
44
UNITS
mA
Gbps
mV
P-P
ps
P-P
ps
RMS
ps
Ω
µV
RMS
mV
P-P
mV
P-P
dB
MHz
kHz
Ω
dB
dB
V
dB
µs
mV
P-P
mV
P-P
mV
P-P
mV
P-P
mV
P-P
2
_______________________________________________________________________________________
+3.3V, 2.5Gbps Low-Power
Limiting Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3.0V to +3.6V, T
A
= -40°C to +85°C. Typical values are at V
CC
= +3.3V and T
A
= +25°C, unless otherwise noted.)
PARAMETER
High LOS Deassert Level
LOS Output High Voltage
LOS Output Low Voltage
Squelch Input Current
SYMBOL
Sinking 30µA
Sourcing 1.2mA
CONDITIONS
R
TH
= 80Ω (Notes 3, 10)
2.4
0.4
400
MIN
TYP
73
MAX
124.7
UNITS
mV
P-P
V
V
µA
MAX3272/MAX3272A
Dice are designed and guaranteed from -40°C to +85°C but are tested only at T
A
= +25°C.
Supply current measurement excludes the current of the CML output stage (16mA typical). See Figure 1,
Power-Supply
Current Measurement.
Note 3:
Guaranteed by design and characterization.
Note 4:
Input edge speed is controlled using 4-pole, lowpass Bessel filters with bandwidth approximately 75% of the maximum
data rate.
Note 5:
Deterministic jitter is measured with a K28.5 pattern (0011 1110 1011 0000 0101). Deterministic jitter is the peak-to-peak
deviation from ideal time crossings, measured at the zero-level crossings of the differential output per ANSI X3.230, Annex A.
Note 6:
Random jitter is measured with the minimum input signal. For Fibre Channel and Gigabit Ethernet applications, the peak-
to-peak random jitter is 14.1 times the RMS random jitter.
Note 7:
Power-supply noise rejection (PSNR) is calculated by the equation PSNR = 20log (∆V
CC
/(∆V
OUT
)), where
∆V
OUT
is the
change in differential output voltage due to the power-supply noise,
∆V
CC
. See Power-Supply Noise Rejection vs.
Frequency in the
Typical Operating Characteristics.
Note 8:
Hysteresis is defined as: 20
✕
log(V
LOS-DEASSERT
/V
LOS-ASSERT
).
Note 9:
Response time to a 10dB change in input power. For the specification guaranteed, the power is assumed to switch back
and forth between two levels (separated by 10dB and equidistant from assert and deassert levels) outside of the two
hysteresis thresholds.
Note 10:
All power-detect AC parameters are guaranteed with a 2
23
- 1 PRBS, 2.5Gbps input, with the longest possible run of 80CID.
Note 1:
Note 2:
Typical Operating Characteristics
(V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.)
OUTPUT AMPLITUDE
vs. INPUT AMPLITUDE
MAX3272 toc01
SUPPLY CURRENT
vs. AMBIENT TEMPERATURE
MAX3272 toc02
DETERMINISTIC JITTER
vs. INPUT AMPLITUDE
18
DETERMINISTIC JITTER (ps
P-P
)
16
14
12
10
8
6
4
2
0
MAX3272 toc03
1000
950
900
V
OUT
(mV
P-P
)
850
800
LEVEL = OPEN
750
700
650
600
0
10
20
30
40
LEVEL = GND
70
65
60
SUPPLY CURRENT (mA)
55
50
45
40
35
30
25
20
20
50
-40
-15
10
35
60
85
1
10
100
1000
10,000
V
IN
(mV
P-P
)
AMBIENT TEMPERATURE (°C)
INPUT AMPLITUDE (mV
P-P
)
_______________________________________________________________________________________
3
+3.3V, 2.5Gbps Low-Power
Limiting Amplifiers
MAX3272/MAX3272A
Typical Operating Characteristics (continued)
(V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.)
RANDOM JITTER vs. INPUT AMPLITUDE
MAX3272 toc04
LOS HYSTERESIS
vs. AMBIENT TEMPERATURE
MAX3272 toc05
LOSS-OF-SIGNAL WITH SQUELCH
V
IN
MAX3272 toc06
10
9
8
RANDOM JITTER (ps
RMS
)
7
6
5
4
3
2
1
0
1
10
100
1000
5.0
4.5
HYSTERESIS (dB)
4.0
R
TH
= 80Ω
3.5
3.0
2.5
2.0
V
OUT
R
TH
= 20kΩ
R
TH
= 1kΩ
V
LOS
C
CLOS
= 0.01µF
10,000
-40
-15
10
35
60
85
20µs/div
INPUT AMPLITUDE (mV
p-p
)
AMBIENT TEMPERATURE (°C)
LOSS OF SIGNAL TRESHOLD vs. R
TH
XXXXXXXX
DATA OUTPUT EYE DIAGRAM
(MINIMUM INPUT)
MAX3272 toc08
DATA OUTPUT EYE DIAGRAM
(MAXIMUM INPUT)
2.5Gbps
2
23
-1 PRBS
1200mV
P-P
INPUT
MAX3272 toc09
50
45
40
LOS ASSERT (mV)
35
30
25
20
15
10
5
0
10
100
1k
10k
100k
2.5Gbps
2
23
-1 PRBS
15mV
P-P
INPUT
150mV/
div
150mV/
div
1M
100ps/div
100ps/div
R
TH
(Ω)
POWER-SUPPLY NOISE REJECTION
vs. FREQUENCY
MAX3272 toc10
INPUT RETURN LOSS vs. FREQUENCY
MAX3272 toc11
OUTPUT RETURN LOSS vs. FREQUENCY
40
OUTPUT RETURN LOSS (dB)
35
30
25
20
15
10
5
0
MAX3272 toc12
60
POWER-SUPPLY NOISE REJECTION (dB)
50
40
30
20
10
0
1k
10k
100k
FREQUENCY (Hz)
1M
45
40
INPUT RETURN LOSS (dB)
35
30
25
20
15
10
5
0
45
10M
10M
100M
1G
10G
10M
100M
1G
10G
FREQUENCY (Hz)
FREQUENCY (Hz)
4
_______________________________________________________________________________________
+3.3V, 2.5Gbps Low-Power
Limiting Amplifiers
MAX3272/MAX3272A
Typical Operating Characteristics (continued)
(V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.)
COMMON-MODE REJECTION RATIO
vs. FREQUENCY
MAX3272 toc13
LOS ASSERT AND DEASSERT LEVELS
vs. DATA RATE
MAX3272 toc14
19.0
COMMON-MODE REJECTION RATIO (dB)
18.5
18.0
12
10
8
V
IN
(mV
P-P
)
6
ASSERT
4
DEASSERT
17.5
17.0
16.5
16.0
15.5
15.0
100k
1M
10M
100M
FREQUENCY (Hz)
2
0
0
2
23
- 1 PRBS PATTERN
R
TH
= 20kΩ
C
IN
= 0.1µF
500
1000
1500
2000
2500
DATA RATE (Mbps)
Pin Description
PIN
1, 4, 17
2
3
5
6, 12, 15, 20
7
8
NAME
GND
IN+
IN-
TH
V
CC
CLOS
SQUELCH
Supply Ground
Noninverted Input Signal
Inverted Input Signal
Loss-of-Signal Threshold Pin. Resistor to ground sets the LOS threshold.
Power Supply
LOS Time-Constant Capacitor Connection. For SONET applications, C
CLOS
= 0.01µF is recommended.
Squelch Input. The squelch function is disabled when SQUELCH is not connected or set to TTL low
level. When SQUELCH is set to TTL high level and LOS is asserted, the data outputs (OUT+, OUT-)
are forced to static levels.
Noninverted Loss-of-Signal Output. LOS is asserted TTL high when the signal drops below the assert
threshold set by the TH input. The MAX3272 does not have ESD protection on this pin. The
MAX3272A has ESD protection on this pin.
Inverted Loss-of-Signal Output. LOS is asserted TTL low when the signal drops below the assert
threshold set by the TH input. The MAX3272 does not have ESD protection on this pin. The
MAX3272A has ESD protection on this pin.
Output Current Level. When this pin is not connected, the CML output current is approximately
16mA. When this pin is connected to ground, the output current increases to about 20mA.
Inverted Data Output
Noninverted Data Output
Output Polarity Control Input. Connect to GND for an inversion of polarity through the limiting
amplifier and connect to V
CC
for normal operation.
Offset-Correction-Loop Capacitor Connection. A capacitor connected between this pin and CAZ1
extends the time constant of the offset correction loop. Typical value of C
AZ
is 0.1µF.
Offset-Correction-Loop Capacitor Connection. A capacitor connected between this pin and CAZ2
extends the time constant of the offset correction loop. Typical value of C
AZ
is 0.1µF.
Connect the exposed paddle to board ground for optimal electrical and thermal performance.
FUNCTION
9
LOS
10
LOS
11
13
14
16
18
19
EP
LEVEL
OUT-
OUT+
OUTPOL
CAZ2
CAZ1
EXPOSED
PAD
_______________________________________________________________________________________
5
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