MAX4361EUA-T [MAXIM]
Line Driver, 2 Func, 2 Driver, BIPolar, PDSO8, MICRO MAX PACKAGE-8;
| 型号： | MAX4361EUA-T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Line Driver, 2 Func, 2 Driver, BIPolar, PDSO8, MICRO MAX PACKAGE-8 驱动 光电二极管 接口集成电路 驱动器 |
| 文件： | 总13页 (文件大小：302K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2299; Rev 0; 1/02
ADSL Drivers/Receivers for Customer Premise
Equipment
General Description
Features
The MAX4361/MAX4362/MAX4363 are a family of high-
performance ADSL drivers and drivers/receivers ideal
for the upstream transmit path and the downstream
receive path of customer premise equipment. These
devices operate from a single 5V supply and deliver up
to 12.5dBm average line power for DMT modulated sig-
nals, meeting the requirements of full-rate ADSL.
Spurious-free dynamic range (SFDR) at full output
power is typically -75dBC at 100kHz.
o Low-Noise Driver
4.8nV/√Hz Voltage-Noise Density
1.5pA/√Hz Current-Noise Density
o Full-Rate ADSL ATU-R Line Drivers and Receivers
o Single 5V Supply
o -75dBc SFDR at Full Output Power at 100kHz
o -95dB Driver-to-Receiver Crosstalk (MAX4363)
o +12.5dBm Average Line Power (DMT)
o 280mA (min) Peak Output Current
The MAX4361 is a differential IN/differential OUT driver
with a fixed gain of 3.1V/V. The MAX4362 is a dual
amplifier with shutdown intended for use as a differen-
tial IN/differential OUT driver with gain set with external
resistors. The MAX4363 is a quad amplifier with shut-
down intended for use as a differential IN/differential
OUT driver/receiver combination with gain set with
external resistors.
®
o Rail-to-Rail Output Swing
o Thermal and Short-Circuit Protection
Ordering Information
The MAX4361 is offered in a space-saving 8-pin µMAX
package.
PART
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 µMAX
8 SO
MAX4361EUA
MAX4361ESA
MAX4362EUB
MAX4362ESD
MAX4363EUP
MAX4363ESP
Applications
10 µMAX
14 SO
ADSL Line Interface
HDSL Line Driver
20 TSSOP
20 SO
Pin Configurations
TOP VIEW
N.C.
T1IN+
T1IN-
SHDN
T2IN-
T2IN+
N.C.
1
14 N.C.
13 GND
12 T1OUT
11 V+
T1IN+
T1IN-
SHDN
T2IN-
T2IN+
GND
1
2
3
4
5
6
7
8
9
20 GND (TX)
19 T1OUT
18 V+ (TX)
17 T2OUT
16 GND (TX)
15 N.C.
GND
IN+
1
2
3
4
8
7
6
5
OUT+ T1IN+
1
2
3
4
5
10 GND
2
3
4
5
6
7
T1IN-
V+
9
8
7
6
T1OUT
MAX4363
SHDN
V+
MAX4361
MAX4362
IN-
V+
MAX4362
T2IN-
T2OUT
GND
10 T2OUT
GND
OUT-
T2IN+
9
8
GND
N.C.
R1IN+
R1IN-
R2IN-
14
V+ (RX)
µMAX
µMAX/SO
13 GND (RX)
12 R1OUT
11 R2OUT
SO
R2IN+ 10
SO/TSSOP
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
________________________________________________________________ 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.
ADSL Drivers/Receivers for Customer Premise
Equipment
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V+ to GND) ....................................-0.3V to +6V
Analog Input Voltage .......................(GND - 0.3V) to (V+ + 0.3V)
SHDN Input Voltage.........................(GND - 0.3V) to (V+ + 0.3V)
Output Short-Circuit Duration .................................................10s
Driver Output Current...............................................................1A
Receiver Output Current...................................................150mA
8-Pin SO (derate 5.88mW/°C above +70°C).................471mW
14-Pin SO (derate 8.33mW/°C above +70°C)...............667mW
20-Pin SO (derate 10.0mW/°C above +70°C)...............800mW
20-Pin TSSOP (derate 10.9mW/°C above +70°C) ........879mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Continuous Power Dissipation (T = +70°C)
A
8-Pin µMAX (derate 4.5mW/°C above +70°C)..............362mW
10-Pin µMAX (derate 5.6mW/°C above +70°C)............444mW
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—Driver
(V+ = 5V, GND = 0, V
= 2.5V, R = 12.5Ω, SHDN = 0, T = T
to T
, unless otherwise noted. Typical values specified at
MAX
CM
L
A
MIN
T
= +25°C.)
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
5.5
33
UNITS
V
Supply Voltage Range (Note 1)
Supply Current
V
4.5
CC
MAX4361, R = ∞
22
22
60
22
60
4
mA
mA
µA
L
SHDN = 0
33
MAX4362, R = ∞
L
SHDN = 5V
SHDN = 0
SHDN = 5V
SHDN = 0
SHDN = 5V
200
33
I
mA
µA
Q
MAX4363, measured at
V+ (TX), R = ∞
L
200
6.5
200
mA
µA
MAX4363, measured at
V+ (RX), R = ∞
L
70
DMT modulation
CAP modulation
MAX4361 (0.7V ≤ V
15.5
18
Maximum Average Output
Power (Notes 2, 3)
P
dBm
OUT
G
Gain
≤ (V+) - 0.7V)
3.0
68
3.1
81
3.2
V/V
dB
OUT
Open-Loop Gain
A
MAX4362/MAX4363 (0.7V ≤ V
≤ (V+) - 0.7V)
OUT
VOL
Second Harmonic Distortion
(Notes 3, 4)
G = 3.1, f = 100kHz, V
= 7.1V
-66
-76
-79
dBc
dBc
OUT(DIFF)
P-P
Third Harmonic Distortion
(Notes 3, 4)
G = 3.1, f = 100kHz, V
= 7.1V
-68
OUT(DIFF)
P-P
Peak Output Current
Input Offset Voltage
Input Bias Current
I
Inferred from Output Voltage Swing test
280
330
0.5
1.6
30
mA
mV
µA
OUT
V
10
4.5
OS
I
B
MAX4361
600
500
Input Offset Current
I
nA
OS
MAX4362/MAX4363
MAX4361
10
25
MΩ
kΩ
Differential Input Resistance
R
IN(DIFF)
MAX4362/MAX4363
40
2
_______________________________________________________________________________________
ADSL Drivers/Receivers for Customer Premise
Equipment
ELECTRICAL CHARACTERISTICS—Driver (continued)
(V+ = 5V, GND = 0, V
= 2.5V, R = 12.5Ω, SHDN = 0, T = T
to T
, unless otherwise noted. Typical values specified at
MAX
CM
L
A
MIN
T
A
= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
Inferred from CMRR test
MIN
TYP
MAX
UNITS
Input Common-Mode Voltage
Range
V
1.25
4.50
V
CM
MAX4361
60
70
60
60
73
85
89
74
63
49
Common-Mode Rejection
Ratio
CMRR
PSRR
1.25V ≤ V
≤ 4.5V
dB
dB
dB
CM
MAX4362/MAX4363
MAX4361
Power-Supply Rejection Ratio
V+ = 4.5V to 5.5V
f = 100kHz
MAX4362/MAX4363
MAX4361
AC Power-Supply Rejection
Ratio
PSRR
AC
MAX4362/MAX4363
Differential Output-Voltage
Swing (Note 4)
V
Inferred from Output Voltage Swing test
7.4
8.2
V
P-P
OUT(DIFF)
(V+) - V
215
230
400
430
400
430
650
0.3
550
550
600
650
600
650
OH
OH
OH
R = 100Ω
L
V
OL
(V+) - V
Output-Voltage Swing
(Note 4)
V
V
,
MAX4362/MAX4363
R = 12.5Ω
L
OH
mV
OL
V
OL
(V+) - V
MAX4361, R = 12.5Ω,
L
T
= -20°C to 85°C
A
V
OL
Output Short-Circuit Current
Output Resistance
I
mA
SC
MAX4361
R
Ω
OUT
MAX4362/MAX4363, G = 1
0.001
SHDN Logic Low
V
0.8
10
V
V
IL
SHDN Logic High
V
2.0
IH
SHDN Input Current
Shutdown Output Impedance
I
, I
IH IL
SHDN = 0 or SHDN = V+
f = 1MHz
µA
kΩ
Z
1.8
40
OUT(SD)
MAX4361
-3dB Bandwidth
Slew Rate
BW
MHz
V/µs
MAX4362/MAX4363, G = 1
60
SR
V
= 7.1V
step
30
OUT(DIFF)
P-P
MAX4361
115
V
step
= 7.1V
OUT(DIFF)
P-P
Settling Time (1%)
t
ns
S
MAX4362/MAX4363,
G = 3
165
Voltage-Noise Density
Current-Noise Density
Capacitive-Load Stability
Shutdown Delay Time
Enable Delay Time
e
f = 100kHz to 1.1MHz
f = 100kHz to 1.1MHz
4.8
1.5
10
nV/√Hz
pA/√Hz
nF
n
i
n
t
400
2.8
ns
SHDN
t
µs
ENABLE
_______________________________________________________________________________________
3
ADSL Drivers/Receivers for Customer Premise
Equipment
ELECTRICAL CHARACTERISTICS—Receiver (MAX4363 only)
(V+ = 5V, GND = 0, V
= 2.5V, R = ∞, SHDN = 0, T = T
to T
, unless otherwise noted. Typical values specified at
MAX
CM
L
A
MIN
T
A
= +25°C.)
PARAMETER
SYMBOL
SFDR
CONDITIONS
G = 1, f = 1MHz, V = 1V
MIN
TYP
-75
190
77
MAX
UNITS
dBc
Spurious-Free Dynamic Range
Gain-Bandwidth Product
Open-Loop Gain
OUT
P-P
GBW
MHz
dB
A
1.5V ≤ V
≤ 3.5V
OUT
65
18
VOL
R = 50Ω, inferred from Output-Voltage
L
Peak Output Current
I
25
mA
OUT
Swing test
Input Offset Voltage
Input Bias Current
V
0.5
-0.75
20
10
-2
mV
µA
nA
pF
kΩ
OS
I
B
Input Offset Current
Input Capacitance
I
250
OS
C
1.6
IN
IN(DIFF)
Differential Input Resistance
R
76
Input Common-Mode Voltage
Range
V
Inferred from CMRR test
0.25
3.80
V
CM
Common-Mode Rejection Ratio
Power-Supply Rejection Ratio
C
0.25V ≤ V
≤ 3.8V
CM
70
60
87
75
dB
dB
MRR
PSRR
V+ = 4.5V to 5.5V
AC Power-Supply Rejection
Ratio
PSRR
f = 1MHz
47
dB
AC
(V+) - V
0.64
0.73
1.27
1.37
130
0.001
160
40
1
OH
OH
R = ∞
L
V
1
OL
Output-Voltage Swing
V
V
V
OH, OL
(V+) - V
1.5
1.6
R = 50Ω
L
V
OL
Output Short-Circuit Current
Output Resistance
I
mA
Ω
SC
R
G = 1
OUT
Slew Rate
SR
V
V
= 1V
step
V/µs
ns
OUT
OUT
P-P
Settling Time (1%)
t
= 100mV
step, G = 1
S
P-P
Voltage-Noise Density
Current-Noise Density
Driver-Receiver Crosstalk
e
f = 1MHz
f = 1MHz
f = 100kHz
8.5
nV/√Hz
pA/√Hz
dB
n
i
n
0.5
X
95
TALK
Note 1: Guaranteed by the Power-Supply Rejection Ratio (PSRR) test.
Note 2: Implied by worst-case output-voltage swing (V
), crest factor (C ) and load resistance (R ):
OUT(DIFF)
r L
✕
✕
P
Driver
= 10log((250 (V
)^2 / ((C )^2 R )) dBmW
OUT(DIFF)
r
L
Note 3: Guaranteed by design.
Note 4: May exceed absolute maximum ratings for power dissipation if unit is subject to full-scale sinusoids for long periods
(see Applications Information section).
4
_______________________________________________________________________________________
ADSL Drivers/Receivers for Customer Premise
Equipment
Typical Operating Characteristics
(V+ = 5V, GND = 0, V
= 2.5V, R = 12.5Ω, SHDN = 0, T = +25°C.)
CM
L
A
DRIVER DIFFERENTIAL DISTORTION
vs. FREQUENCY
DRIVER DIFFERENTIAL DISTORTION
vs. PEAK-TO-PEAK OUTPUT VOLTAGE
DRIVER DIFFERENTIAL DISTORTION
vs. LOAD RESISTANCE
-40
-50
-40
-50
-60
-70
V
= 7.2V
f = 100kHz
G = 3
R = 12.5
L
V
= 5V
OUT P-P
OUT
P-P
G = 3
R = 12.5Ω
f = 100kHz
G = 3
R = 12.5Ω
L
L
-60
-60
3RD HARMONIC
2ND HARMONIC
2ND HARMONIC
3RD HARMONIC
2ND HARMONIC
-70
-70
-80
3RD HARMONIC
-80
-80
-90
-90
-90
-100
-100
-100
10k
100k
1M
2
3
4
5
6
7
8
5
25
45
65
85
FREQUENCY (Hz)
PEAK-TO-PEAK OUTPUT VOLTAGE (V)
R
(Ω)
LOAD
DRIVER LINE POWER
vs. TURNS RATIO
DRIVER CURRENT AND VOLTAGE NOISE
DRIVER OUTPUT IMPEDANCE
vs. FREQUENCY
vs. FREQUENCY
MAX4361 toc05
16.0
15.5
15.0
14.5
14.0
13.5
13.0
12.5
12.0
11.5
11.0
10.5
10.0
100
10
1
100
10
1
100k
10k
1k
V+ = 5.5V
SHDN = V
CC
V+ = 5V
100
10
V+ = 4.5V
V
I
NOISE
1
SHDN = GND
10M
0.1
0.01
NOISE
3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0
TRANSFORMER TURNS RATIO
1k
10k
100k
1M
100k
1M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
DRIVER OUTPUT SWING
vs. LOAD RESISTANCE
DRIVER GAIN AND PHASE
DRIVER POWER-SUPPLY REJECTION
RATIO vs. FREQUENCY
vs. FREQUENCY
MAX4361 toc07
2.5
2.4
2.3
2.2
2.1
2.0
1.9
1.8
1.7
20
15
120
90
10
0
G = 3
G = 1
R = 12.5Ω
L
+SWING
10
60
-10
-20
-30
-40
-50
-60
-70
-80
GAIN
5
30
-SWING
0
0
-5
-30
-60
-90
-120
-150
-180
PHASE
-10
-15
-20
-25
-30
1.6
1.5
1.4
1.3
1.2
1.1
1.0
1
10
100
1k
10k
10k
100k
1M
10M
100M
1G
1k
10k
100k
1M
10M
1G
LOAD RESISTANCE (Ω)
FREQUENCY (Hz)
FREQUENCY (Hz)
_______________________________________________________________________________________
5
ADSL Drivers/Receivers for Customer Premise
Equipment
Typical Operating Characteristics (continued)
(V+ = 5V, GND = 0, V
= 2.5V, R = 12.5Ω, SHDN = 0, T = +25°C.)
CM
L
A
RECEIVER DIFFERENTIAL DISTORTION
vs. FREQUENCY
RECEIVER GAIN AND PHASE
vs. FREQUENCY
RECEIVER CURRENT AND VOLTAGE
NOISE vs. FREQUENCY
MAX4361 toc12
MAX4361 toc11
120
90
-40
-50
70
60
50
40
30
20
10
0
100
10
1
100
10
1
G = 1000
R = 500Ω
V
= 1V
P-P
OUT
L
G = 1
R = 150Ω
60
L
V
NOISE
GAIN
30
-60
0
2ND HARMONIC
-30
-60
-90
-120
-150
-180
-70
3RD HARMONIC
-80
I
NOISE
PHASE
1M
-10
-20
-30
-90
-100
0.1
0.1
10k
100k
1M
10k
100k
10M
100M
1G
1k
10k
100k
1M
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
RECEIVER POWER-SUPPLY REJECTION
RATIO vs. FREQUENCY
DRIVER-TO-RECEIVER CROSSTALK
vs. FREQUENCY
RECEIVER-TO-RECEIVER CROSSTALK
vs. FREQUENCY
10
0
0
-20
0
G = 1
-20
-10
-20
-30
-40
-50
-60
-70
-80
-40
-40
-60
R = 150Ω
L
-60
NO LOAD
R = 12.5Ω
L
-80
-80
-100
-120
-100
-120
NO LOAD
100M
1k
10k
100k
1M
10M
100M
10k
100k
1M
10M
1G
10k
100k
1M
10M
100M
1G
FREQUENCY (Hz)
FREQUENCY (Hz)
FREQUENCY (Hz)
RECEIVER OUTPUT AMPLITUDE
vs. FREQUENCY
4
2
R = 1kΩ
F
R = 500Ω
F
0
-2
-4
-6
-8
-10
R = 100Ω
F
G = -1
R = 150Ω
P-P
L
V
= 100mV
10k
100k
1M
10M
100M
1G
FREQUENCY (Hz)
6
_______________________________________________________________________________________
ADSL Drivers/Receivers for Customer Premise
Equipment
Pin Descriptions
MAX4361
PIN
NAME
GND
IN+
FUNCTION
1, 4
2
Ground
First Driver Input
Second Driver Input
Second Driver Output
3
IN-
5
OUT-
V+
6, 7
8
Positive Power-Supply Voltage. Bypass V+ to GND with a 0.1µF capacitor.
First Driver Output
OUT+
MAX4362
PIN
NAME
FUNCTION
µMAX
SO
1
2
2
T1IN+
T1IN-
SHDN
T2IN-
T2IN+
GND
First Driver Noninverting Input
3
First Driver Inverting Input
3
4
Shutdown. Connect to GND for normal operation.
Second Driver Inverting Input
4
5
5
6
9, 13
10
Second Driver Noninverting Input
Ground
6, 10
7
T2OUT
V+
Second Driver Output
8
11
Positive Power-Supply Voltage. Bypass V+ to GND with a 0.1µF capacitor.
First Driver Output
9
12
T1OUT
N.C.
—
1, 7, 8, 14
No Connection. Not internally connected.
_______________________________________________________________________________________
7
ADSL Drivers/Receivers for Customer Premise
Equipment
Pin Descriptions (continued)
MAX4363
PIN
NAME
T1IN+
T1IN-
FUNCTION
1
First Driver Noninverting Input
First Driver Inverting Input
2
3
SHDN
T2IN-
Shutdown. Connect to GND for normal operation.
Second Driver Inverting Input
Second Driver Noninverting Input
Ground
4
5
T2IN+
GND
6
7
R1IN+
R1IN-
First Receiver Noninverting Input
First Receiver Inverting Input
Second Receiver Inverting Input
Second Receiver Noninverting Input
Second Receiver Output
8
9
R2IN-
10
11
12
13
R2IN+
R2OUT
R1OUT
GND (RX)
First Receiver Output
Ground for Receiver Amplifiers
Positive Power-Supply Voltage for Receiver Amplifiers. Bypass V+ (RX) to GND (RX) with a
separate 0.1µF capacitor.
14
V+ (RX)
15
16, 20
17
N.C.
No Connection. Not internally connected.
Ground for Driver Amplifier
GND (TX)
T2OUT
Second Driver Output
Positive Power-Supply Voltage for Driver Amplifiers. Bypass V+ (TX) to GND (TX) with a
separate 0.1µF capacitor.
18
19
V+ (TX)
T1OUT
First Driver Output
Uncommitted Dual Amplifier for ADSL
Detailed Description
Driver (MAX4362)
The MAX4362 is a dual amplifier with shutdown intend-
ed for use as a differential IN/differential OUT driver
with gain set with external resistors
The MAX4361/MAX4362/MAX4363 are a family of high-
performance ADSL drivers and drivers/receivers ideal
for the upstream transmit path and the downstream
receive path of customer premise equipment. These
devices operate from a single 5V supply and deliver up
to 12.5dBm average line power for DMT modulated sig-
nals, meeting the requirements of full-rate ADSL. SFDR
at full output power is typically -75dBc at 100kHz.
Uncommitted Quad Amplifier for ADSL
Driver/Receiver (MAX4363)
The MAX4363 is a quad amplifier with shutdown intended
for use as a differential IN/differential OUT driver/receiver
combination with gain set with external resistors.
Differential In/Differential Out ADSL Driver
(MAX4361)
The MAX4361 is a differential line driver with a fixed
gain of 3.1V/V. The gain is set by three internal resistors.
Shutdown
The MAX4362/MAX4363 feature a low-power shutdown
mode. When the SHDN pin is pulled high, the supply
current drops to 70µA, and the amplifier’s outputs are
placed in a high-impedance disable mode. Connect
SHDN to GND for normal operation.
8
_______________________________________________________________________________________
ADSL Drivers/Receivers for Customer Premise
Equipment
Applications Information
500Ω
1kΩ
Power Supply and Decoupling
The MAX4361/MAX4362/MAX4363 should be powered
from a well-regulated, low-noise, 4.5V to 5.5V supply in
order to optimize the ADSL upstream drive capability to
+12.5dBm and maintain the best SFDR.
3.1Ω
OUTPUT
MAX436 _
C
LOAD
INPUT
High-quality capacitors with low equivalent series resis-
tance (ESR) such as multilayer ceramic capacitors
(MLCCs) should be used to minimize supply voltage
ripple and power dissipation. A larger capacitor located
in proximity to the MAX4361/MAX4362/MAX4363
improves decoupling for lower frequency signals.
Figure 1. Driving Capacitive Load
5V
In addition, 0.1µF MLCC decoupling capacitors should
be located as close as possible to each of the power-
supply pins, no more than 1/8 inch away. An additional
large (4.7µF to 10µF) tantalum capacitor should be
placed on the board near the supply terminals to sup-
ply current for fast, large-signal changes at the
MAX4361/MAX4362/MAX4363 outputs.
R1
2.7kΩ
V
REF
R2
2.7kΩ
0.1µF
MAX4361/MAX4362
The MAX4361/MAX4362 require a single 0.1µF bypass
from V+ to ground located as close as possible to the
IC leads.
Figure 2. Voltage-Divider Reference
MAX4363
The MAX4363 features separate supply and ground
pins for the receiver and driver amplifiers. Bypass the
V+ (RX) supply to the GND (RX) pin with a 0.1µF capaci-
tor. Bypass the V+ (TX) supply to the GND (TX) pin with
a separate 0.1µF capacitor. Both capacitors should be
placed as close as possible to their respective IC leads.
and the load to reduce ringing on the output signal. In a
typical hybrid the back-matching resistors provide suffi-
cient isolation for most any capacitive-loading condition
(see Figure 1).
Method for Generating a Midsupply
Voltage
To operate an amplifier on a single-voltage supply, a
voltage midway between the supply and ground must be
generated to properly bias the inputs and the outputs.
USB Applications
The 5V supplied at the universal serial bus (USB) port
may be poorly regulated or unable to supply the peak
currents required by an ADSL modem. Improving the
quality of the supply will optimize the performance of
the MAX4361/MAX4362/MAX4363 in a USB-supplied
CPE ADSL modem. This can be accomplished through
the use of a step-up DC-to-DC converter or switching
power supply followed by a low-dropout (LDO) regula-
tor. Careful attention must be paid to decoupling the
power supply at the output of the DC-to-DC converter,
the output of the LDO regulator and the supply pins of
the MAX4361/MAX4362/MAX4363.
A voltage divider can be created with two equal-value
resistors (Figure 2). There is a trade-off between the
power consumed by the divider and the voltage drop
across these resistors due to the positive input bias
currents. Selecting 2.7kΩ for R1 and R2 will create a
voltage divider that draws less than 1mA from a 5V
supply. Use a decoupling capacitor (0.1µF) at the node
where V
is generated.
REF
Power Dissipation
It is important to consider the total power dissipation of
the MAX4361/MAX4362/MAX4363 in order to properly
size the heat sink area of an application. With some
simplifying assumptions we can estimate the total
power dissipated in the driver (see Typical Operating
Driving a Capacitive Load
The MAX4361/MAX4362/MAX4363 are capable of dri-
ving capacitive loads up to 2nF. Most hybrid circuits
are well under this limit. For additional capacitive-drive
capability use isolation resistors between the output
_______________________________________________________________________________________
9
ADSL Drivers/Receivers for Customer Premise
Equipment
Circuit). If the output current is large compared to the
2.5
quiescent current, computing the dissipation in the out-
MAX4362
14-PIN SO
put devices and adding it to the quiescent power dissi-
pation will give a close approximation of the total power
2.0
MAX4363
20-PIN SO
dissipation in the package.
MAX4363
20-PIN TSSOP
For a 12.5dBm average line power on a 100Ω line, the
RMS current is 13.4mA. With a one-to-four transformer
the driver therefore supplies 53.6mA RMS. It can be
shown for a DMT signal the ratio of RMS current to the
average rectified current is 0.8. The total power con-
sumption is approximately
1.5
1.0
0.5
0
MAX4361
8-PIN µMAX MAX4362
10-PIN µMAX
MAX4361
8-PIN SO
P
= 0.8 ✕ 53.6 x 5V = 214mW
CONS
-40
-20
0
20
40
60
80
of which 18mW is delivered as line power and 18mW is
dissipated in the back-matching resistors. Hence the
average power consumption of the IC is approximately
178mW + quiescent power (110mW), or 288mW. For
the MAX4361 in an 8-pin µMAX package, this corre-
sponds to a temperature rise of 64°C. With an ambient
temperature of +85°C this corresponds to a junction
temperature of +148°C, just below the absolute maxi-
mum of +150°C.
TEMPERATURE (°C)
Figure 3. Maximum Power Dissipation vs. Temperature
Receive Channel Considerations
A transformer used at the output of the differential line
driver to step up the differential output voltage to the line
has the inverse effect on signals received from the line.
A voltage reduction or attenuation equal to the inverse of
the turns ratio is realized in the receive channel of a typi-
cal bridge hybrid. The turns ratio of the transformer may
also be dictated by the ability of the receive circuitry to
resolve low-level signals in the noisy, twisted-pair tele-
phone plant. Higher turns-ratio transformers effectively
reduce the received signal-to-noise ratio due to the
reduction in the received signal strength.
Please note the part is capable of over 200mA RMS,
which could cause thermal shutdown in applications
with elevated ambient temperatures and/or signals with
low crest factors. See Figure 3 for a guide to power der-
ating for each of the MAX4361/MAX4362/MAX4363
packages.
Transformer Selection
Full-rate, customer premise ADSL requires the trans-
mission of a +12.5dBm (18mW) DMT signal. The DMT
signal has a typical crest factor of 5.3, requiring the line
driver to provide peak line power of 27.5dBm (560mW).
The 27.5dBm peak line power translates into a 28.4V
peak-to-peak differential voltage on the 100Ω telephone
line. The maximum low-distortion output swing available
from the MAX4361/MAX4362/MAX4363 line driver on a
5V supply is 3.8V and, taking into account the power
lost due to the back-matching resistance, a step-up
transformer with turns ratio of 3.8 or greater is needed.
In the Typical Operating Circuit, the MAX4363 is cou-
pled to the phone line through a step-up transformer
with a 1:4 turns ratio. R1 and R2 are back-matching
resistors, each 3.1Ω (100Ω / (2 ✕ 42)), where 100Ω is
the approximate phone-line impedance. The total differ-
ential load for the MAX4361/MAX4362/MAX4363,
including the termination resistors, is therefore 12.5Ω.
Even under these conditions the MAX4361/MAX4362/
MAX4363 provide low distortion signals to within 0.6V of
the power rails.
The MAX4363 includes an amplifier with typical voltage
noise of only 8.5nV/√Hz and a low-supply current of
2mA/amplifier to be used as the receive channel.
Layout Considerations
Good layout techniques optimize performance by
decreasing the amount of stray capacitance at the
amplifier’s inputs and outputs. Excess capacitance will
produce peaking in the amplifier’s frequency response.
To decrease stray capacitance, minimize trace lengths
by placing external components as close to the amplifi-
er as possible.
Chip Information
MAX4361 TRANSISTOR COUNT: 1400
MAX4362 TRANSISTOR COUNT: 1400
MAX4363 TRANSISTOR COUNT: 1750
PROCESS: Bipolar
10 ______________________________________________________________________________________
ADSL Drivers/Receivers for Customer Premise
Equipment
Typical Operating Circuit
5V
0.1µF
5V
1kΩ
2.7kΩ
1kΩ
0.1µF
2.7kΩ
10kΩ
V
CC
3.125Ω
3.125Ω
0.047µF
0.047µF
IN1+
IN1-
OUT+
OUT-
DRIVER
LINE IMPEDANCE
1kΩ
10kΩ
IN2-
IN2+
100Ω
1:4
TRANSFORMER
ADSL
CHIPSET
500Ω
1kΩ
MAX4363
1kΩ
5V
500Ω
OUT+
OUT-
IN1-
IN1+
IN2+
IN2-
RECEIVER
5V
10kΩ
GND
0.1µF
1kΩ
1kΩ
10kΩ
______________________________________________________________________________________ 11
ADSL Drivers/Receivers for Customer Premise
Equipment
Package Information
12 ______________________________________________________________________________________
ADSL Drivers/Receivers for Customer Premise
Equipment
Package Information (continued)
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 13
© 2002 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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