19-2144; Rev 1; 7/04
+3.3V, 2.5Gbps Quad Limiting Amplifier
General Description
The MAX3822 quad limiting amplifier is ideal for multi-
channel systems with data rates up to 2.5Gbps. The
MAX3822 operates from a single +3.3V supply, over
temperatures ranging from 0°C to +85°C. A channel-
select (CS) pin is provided to program single-, dual-, or
quad-channel operation. The disabled channels are
shut down to reduce power consumption. The output
interface for all four channels is CML.
The input can be driven from 20mVp-p to 1000mVp-p
differentially. The threshold voltage control is common
for all four channels and is programmable by an exter-
nal resistor. Four separate power detectors are incorpo-
rated to monitor the received signal level for each
channel. Individual TTL-compatible loss-of-power (LOP)
indicators assert low if the channel signal input is below
the programmed threshold. Typically 4dB LOP hystere-
sis (2dB optical) is provided to prevent chattering when
the input signal level is close to the threshold. A general
LOP
indicator is also provided which asserts low if one
or more of the four inputs is in the LOP condition.
o
Single +3.3V Supply
o
Single-, Dual-, or Quad-Channel Operation at
2.5Gbps
o
700mW Total Power Dissipation (Quad-Channel
Operation)
o
120ps Maximum Output Edge Speed
o
Overall and Individual Channel Loss-of-Power
(LOP) Indicator
o
Differential CML Outputs with On-Chip Back
Termination Resistors
o
30ps Maximum Deterministic Jitter
o
2ps Random Jitter
o
Power-Down Feature Shuts Down Unused
Channels
o
Operating Temperature Range: 0°C to +85°C
Features
MAX3822
Ordering Information
PART
MAX3822UCM
MAX3822UCM+
MAX3822U/D
TEMP RANGE
0°C to +85°C
0°C to +85°C
0°C to +85°C
PIN-PACKAGE
48 TQFP-EP*
48 TQFP-EP*
Dice**
Applications
Optical System Interconnects
Multichannel Receiver Modules
Dense Digital Cross-Connects
ATM Switch Networks
High-Speed Parallel Links
*Exposed
pad.
**Contact
factory for availability. Dice are designed to operate
from T
A
= 0°C to T
A
= +85°C, but are tested and guaranteed
only at T
A
= +25°C.
+Denotes
lead-free package.
Pin Configuration
GND
CZ1+
CZ1-
GND
CZ2+
CZ2-
GND
CS
GND
GND
VTH
GND
48
47
46
45
44
43
42
41
40
39
38
37
TOP VIEW
Typical Operating Circuit appears at end of data sheet.
IN1+
IN1-
V
CC
IN2+
IN2-
V
CC
V
CC
IN3+
IN3-
V
CC
IN4+
IN4-
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
36
35
34
33
32
31
30
29
28
27
26
25
MAX3822
OUT1+
OUT1-
V
CC
OUT2+
OUT2-
V
CC
V
CC
OUT3+
OUT3-
V
CC
OUT4+
OUT4-
________________________________________________________________
Maxim Integrated Products
GND
CZ4-
CZ4+
GND
CZ3-
CZ3+
GND
LOP
LOP1
LOP2
LOP3
LOP4
TQFP-EP
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 Quad Limiting Amplifier
MAX3822
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V
CC
) ........................................... -0.5V to +6.0V
Differential Input Voltage Swing (IN1+ - IN1-), (IN2+ - IN2-),
(IN3+ - IN3-), (IN4+ - IN4-) ..............................................2Vp-p
Voltage at
LOP1, LOP2, LOP3,
LOP4, LOP,
CS........................................-0.5V to (V
CC
+ 0.5V)
Voltage at IN1+, IN1-, IN2+, IN2-, IN3+,
IN3-, IN4+, IN4- .............................(V
CC
- 1V) to (V
CC
+ 0.5V)
Voltage at VTH .....................................................+0.5V to +2.3V
Voltage at CZ1+, CZ1-, CZ2+, CZ2-,
CZ3+, CZ3-, CZ4+, CZ4- ........................-0.5V to (V
CC
+ 0.5V)
Current into OUT1+, OUT1-, OUT2+, OUT2-,
OUT3+, OUT3-, OUT4+, OUT4-, ..................................±22mA
Continuous Power Dissipation (T
A
= +85°C)
48-Pin TQFP-EP (derate 29.4mW/°C above +85°C) ......2.35W
Operating Junction Temperature Range(die) ...-55°C to +150°C
Processing Temperature (die) .........................................+400°C
Storage Temperature Range .............................-55°C to +150°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.
DC ELECTRICAL CHARACTERISTICS
(V
CC
= +3.0V to +3.6V, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.) (Note 1)
PARAMETER
Power-Supply Current
Single-Ended Data Input
Voltage Range
Single-Ended Data Input
Resistance
Data Input Voltage for
LOP
Assert
R
TH
= 1kΩ
R
TH
= 649Ω
R
TH
= 400Ω
R
TH
= 1kΩ
LOP
Hysteresis
CML Differential Output
Single-Ended Data Output
Resistance
CML Output Common-Mode
Voltage
TTL Output High
TTL Output Low
V
OH
V
OL
Sourcing 200µA
Sinking 2mA
2.4
V
OD
R
TH
= 649Ω
R
TH
= 400Ω
R
L
= 50Ω to V
CC
640
40
3.0
3.4
740
50
V
CC
-
0.2
V
CC
0.4
1000
60
mVp-p
Ω
V
V
V
11.5
SYMBOL
I
CC
CONDITIONS
Single channel (Note 2)
Dual channel (Note 2)
Quad channel
V
IS
V
CC
-
0.5
40
50
14
18.5
34
4.5
6.0
dB
32.5
mVp-p
MIN
TYP
60
110
210
MAX
72
137
265
V
CC
+
0.25
60
V
Ω
mA
UNITS
2
_______________________________________________________________________________________
+3.3V, 2.5Gbps Quad Limiting Amplifier
AC ELECTRICAL CHARACTERISTICS
(V
CC
= +3.0V to +3.6V, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at V
CC
= +3.3V and T
A
= +25°C.) (Notes 1, 3)
PARAMETER
Data Input Voltage Range
Random Jitter
Deterministic Jitter
Data Output Edge Speed
LOP
Assert/Deassert Time
Input-Referred Noise
Offset Correction Low-
Frequency Cutoff
Channel-to-Channel Skew
(Note 7)
CZ1 = CZ2 = CZ3 = CZ4 = 0.033µF
(Note 8)
SYMBOL
V
IN
(Note 4)
V
IN
= 20mVp-p (Notes 5, 6)
V
IN
= 1000mVp-p to 1000mVp-p (Notes 5, 6)
(20% to 80%)
100
105
150
20
70
594
CONDITIONS
MIN
20
2
8
4
90
30
120
TYP
MAX
1000
9.5
UNITS
mVp-p
ps
RMS
psp-p
ps
ns
µV
RMS
kHz
ps
MAX3822
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
Note 7:
Note 8:
Characteristics at 0°C are guaranteed by design and characterization. Dice are tested at T
A
= +25°C.
When power is first applied, all four channels are briefly active.
AC characteristics are guaranteed by design and characterization.
Input data edge speed of 150ps (20% to 80%).
Data rate = 2.5Gbps. Measured with 2
13
-1 PRBS plus 100 consecutive identical digits.
Deterministic jitter (p-p) equals total jitter (p-p) minus random jitter (p-p).
Input-referred noise is specified (differential output noise)/(small-signal gain).
Measured by applying the same input signal to all channels. Skew measurements are made at 50% point of the transition.
_______________________________________________________________________________________
3
+3.3V, 2.5Gbps Quad Limiting Amplifier
MAX3822
Typical Operating Characteristics
(V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.)
DETERMINISTIC JITTER
vs. DIFFERENTIAL INPUT VOLTAGE
PEAK-TO-PEAK DETERMINISTIC JITTER (psp-p)
MAX3822 toc01
RANDOM JITTER
vs. DIFFERENTIAL INPUT VOLTAGE
MAX3822 toc02
8
7
6
5
4
3
2
1
0
9
8
RANDOM JITTER (ps
RMS
)
7
6
5
4
3
2
1
0
100mV/div
0 100 200 300 400 500 600 700 800 900 1000
DIFFERENTIAL INPUT VOLTAGE (mV)
0 100 200 300 400 500 600 700 800 900 1000
DIFFERENTIAL INPUT VOLTAGE (mVp-p)
75ps/div
ELECTRICAL EYE DIAGRAM
(V
IN
= 20mV DIFFERENTIAL)
MAX3822 toc04
ELECTRICAL EYE DIAGRAM
(V
IN
= 100mV DIFFERENTIAL)
MAX3822 toc05
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
POWER-SUPPLY REJECTION RATIO (dB)
-10
-20
-30
-40
-50
-60
-70
-80
-90
1
10
100
1000
MAX3822 toc06
0
100mV/div
100mV/div
75ps/div
75ps/div
FREQUENCY (MHz)
COMMON-MODE REJECTION RATIO
vs. FREQUENCY
MAX3822 toc07
LOSS-OF-POWER THRESHOLD LEVEL
vs. THRESHOLD RESISTANCE
DIFFERENTIAL INPUT VOLTAGE (mVp-p)
MAX3822 toc08
15
COMMON-MODE REJECTION RATIO (dB)
10
5
0
-5
-10
-15
-20
-25
1
10
FREQUENCY (MHz)
70
60
50
40
DEASSERT THRESHOLD
30
20
10
0
ASSERT
THRESHOLD
100
0
400
800
1200
1600
2000
R
TH
(Ω)
4
_______________________________________________________________________________________
MAX3822 toc03
9
10
ELECTRICAL EYE DIAGRAM
(V
IN
= 1V DIFFERENTIAL)
+3.3V, 2.5Gbps Quad Limiting Amplifier
Pin Description
PIN
1
2
3, 6, 7, 10,
27, 30, 31, 34
4
5
8
9
11
12
13, 16, 19,
37, 39, 40,
42, 45, 48
14
15
17
18
20
21
22
23
24
25
NAME
IN1+
IN1-
V
CC
IN2+
IN2-
IN3+
IN3-
IN4+
IN4-
GND
Noninverted Data Input for Channel 1
Inverted Data Input for Channel 1
+3.3V Supply Voltage
Noninverted Data Input for Channel 2
Inverted Data Input for Channel 2
Noninverted Data Input for Channel 3
Inverted Data Input for Channel 3
Noninverted Data Input for Channel 4
Inverted Data Input for Channel 4
Supply Ground
A capacitor connected between this pin and CZ4+ extends the time constant for the offset-
correction loop associated with channel 4. Maxim recommends a capacitor value of 0.033µF.
A capacitor connected between this pin and CZ4- extends the time constant for the offset-
correction loop associated with channel 4. Maxim recommends a capacitor value of 0.033µF.
A capacitor connected between this pin and CZ3+ extends the time constant for the offset-
correction loop associated with channel 3. Maxim recommends a capacitor value of 0.033µF.
A capacitor connected between this pin and CZ3- extends the time constant for the offset-
correction loop associated with channel 3. Maxim recommends a capacitor value of 0.033µF.
LOP is low when any of the individual power detectors (LOP1,
LOP2, LOP3, LOP4)
are low.
LOP1
asserts low when the data input signal level to channel 1 drops below the programmed
threshold.
LOP2
asserts low when the data input signal level to channel 2 drops below the programmed
threshold.
LOP3
asserts low when the data input signal level to channel 3 drops below the programmed
threshold.
LOP4
asserts low when the data input signal level to channel 4 drops below the programmed
threshold.
Inverted Data Output for Channel 4
DESCRIPTION
MAX3822
CZ4-
CZ4+
CZ3-
CZ3+
LOP
LOP1
LOP2
LOP3
LOP4
OUT4-
_______________________________________________________________________________________
5
嵌入式系统
