General Description
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.
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.
The MAX4361 is offered in a space-saving 8-pin µMAX
package.
Applications
ADSL Line Interface
HDSL Line Driver
Features
♦Low-Noise Driver
4.8nV/√Hz Voltage-Noise Density
1.5pA/√Hz Current-Noise Density
♦Full-Rate ADSL ATU-R Line Drivers and Receivers
♦Single 5V Supply
♦-75dBc SFDR at Full Output Power at 100kHz
♦-95dB Driver-to-Receiver Crosstalk (MAX4363)
♦+12.5dBm Average Line Power (DMT)
♦280mA (min) Peak Output Current
♦Rail-to-Rail®Output Swing
♦Thermal and Short-Circuit Protection
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
________________________________________________________________ Maxim Integrated Products 1
1
2
3
4
5
10
9
8
7
6
GND
T1OUT
V+
T2OUTT2IN-
SHDN
T1IN-
T1IN+
µMAX
GNDT2IN+
27V+IN+
1 8 OUT+GND
µMAX/SO
TOP VIEW
V+IN- 3 6
OUT-GND 45
MAX4361 MAX4362
MAX4362
MAX4363
114V+SHDN
123 T1OUTT1IN-
132 GNDT1IN+
141 N.C.N.C.
87 N.C.N.C.
96 GND
T2IN+
105 T2OUTT2IN-
SO
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
GND (TX)
T1OUT
V+ (TX)
T2OUTT2IN-
SHDN
T1IN-
T1IN+
GND (TX)
N.C.
V+ (RX)
GND (RX)R1IN-
R1IN+
GND
T2IN+
12
11
9
10
R1OUT
R2OUTR2IN+
R2IN-
SO/TSSOP
Pin Configurations
Ordering Information
19-2299; Rev 0; 1/02
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.
PART TEMP RANGE PIN-PACKAGE
MAX4361EUA -40°C to +85°C 8 µMAX
MAX4361ESA -40°C to +85°C 8 SO
MAX4362EUB -40°C to +85°C 10 µMAX
MAX4362ESD -40°C to +85°C 14 SO
MAX4363EUP -40°C to +85°C 20 TSSOP
MAX4363ESP -40°C to +85°C 20 SO
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS—Driver
(V+ = 5V, GND = 0, VCM = 2.5V, RL= 12.5Ω, SHDN = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values specified at
TA= +25°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.
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
Continuous Power Dissipation (TA= +70°C)
8-Pin µMAX (derate 4.5mW/°C above +70°C) ..............362mW
10-Pin µMAX (derate 5.6mW/°C above +70°C) ............444mW
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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
S up p l y V ol tag e Rang e ( N ote 1) VCC 4.5 5.5 V
MAX4361, RL = ∞22 33 mA
SHDN = 0 22 33 mA
MAX4362, RL = ∞SHDN = 5V 60 200 µA
SHDN = 0 22 33 mA
MAX4363, measured at
V+ (TX), RL = ∞SHDN = 5V 60 200 µA
SHDN = 0 4 6.5 mA
Supply Current IQ
MAX4363, measured at
V+ (RX), RL = ∞SHDN = 5V 70 200 µA
DMT modulation 15.5
Maximum Average Output
Power (Notes 2, 3) POUT CAP modulation 18 dBm
Gain G MAX4361 (0.7V ≤ VOUT ≤ (V+) - 0.7V) 3.0 3.1 3.2 V/V
Open-Loop Gain AVOL MAX4362/MAX4363 (0.7V ≤ VOUT ≤ (V+) - 0.7V) 68 81 dB
Second Harmonic Distortion
(Notes 3, 4) G = 3.1, f = 100kHz, VOUT(DIFF) = 7.1VP-P -66 -76 dBc
Third Harmonic Distortion
(Notes 3, 4) G = 3.1, f = 100kHz, VOUT(DIFF) = 7.1VP-P -68 -79 dBc
Peak Output Current IOUT Inferred from Output Voltage Swing test 280 330 mA
Input Offset Voltage VOS ±0.5 ±10 mV
Input Bias Current IB1.6 4.5 µA
MAX4361 ±30 ±600
Input Offset Current IOS MAX4362/MAX4363 ±10 ±500 nA
MAX4361 25 MΩ
Differential Input Resistance RIN
(
DIFF
)
MAX4362/MAX4363 40 kΩ
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS—Driver (continued)
(V+ = 5V, GND = 0, VCM = 2.5V, RL= 12.5Ω, SHDN = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values specified at
TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Common-Mode Voltage
Range VCM Inferred from CMRR test 1.25 4.50 V
MAX4361 60 73
Common-Mode Rejection
Ratio CMRR 1.25V ≤ VCM ≤ 4.5V MAX4362/MAX4363 70 85 dB
MAX4361 60 89
Power-Supply Rejection Ratio PSRR V+ = 4.5V to 5.5V MAX4362/MAX4363 60 74 dB
MAX4361 63
AC Power-Supply Rejection
Ratio PSRRAC f = 100kHz MAX4362/MAX4363 49 dB
Differential Output-Voltage
Swing (Note 4) V
OU T
(
D IF F
)
Inferred from Output Voltage Swing test 7.4 8.2 VP-P
(V+) - VOH 215 550
RL = 100ΩVOL 230 550
(V+) - VOH 400 600
MAX4362/MAX4363
RL = 12.5ΩVOL 430 650
(V+) - VOH 400 600
Output-Voltage Swing
(Note 4)
VOH,
VOL
MAX4361, RL = 12.5Ω,
TA = -20°C to 85°CVOL 430 650
mV
Output Short-Circuit Current ISC ±650 mA
MAX4361 0.3
Output Resistance ROUT MAX4362/MAX4363, G = 1 0.001 Ω
SHDN Logic Low VIL 0.8 V
SHDN Logic High VIH 2.0 V
SHDN Input Current IIH, IIL SHDN = 0 or SHDN = V+ ±10 µA
Shutdown Output Impedance ZOUT
(
SD
)
f = 1MHz 1.8 kΩ
MAX4361 40
-3dB Bandwidth BW MAX4362/MAX4363, G = 1 60 MHz
Slew Rate SR VOUT(DIFF) = 7.1VP-P step 30 V/µs
MAX4361 115
Settling Time (1%) tSVOUT(DIFF) = 7.1VP-P
step MAX4362/MAX4363,
G = 3 165 ns
Voltage-Noise Density enf = 100kHz to 1.1MHz 4.8 nV /√ Hz
Current-Noise Density inf = 100kHz to 1.1MHz 1.5 p A/√ Hz
Capacitive-Load Stability 10 nF
Shutdown Delay Time tSHDN 400 ns
Enable Delay Time tENABLE 2.8 µs
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
4 _______________________________________________________________________________________
Note 1: Guaranteed by the Power-Supply Rejection Ratio (PSRR) test.
Note 2: Implied by worst-case output-voltage swing (VOUT(DIFF)), crest factor (Cr) and load resistance (RL):
PDriver = 10log((250 ✕(VOUT(DIFF) )^2 / ((Cr)^2 ✕RL)) dBmW
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).
ELECTRICAL CHARACTERISTICS—Receiver (MAX4363 only)
(V+ = 5V, GND = 0, VCM = 2.5V, RL= ∞, SHDN = 0, TA= TMIN to TMAX, unless otherwise noted. Typical values specified at
TA= +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Spurious-Free Dynamic Range SFDR G = 1, f = 1MHz, VOUT = 1VP-P -75 dBc
Gain-Bandwidth Product GBW 190 MHz
Open-Loop Gain AVOL 1.5V ≤ VOUT ≤ 3.5V 65 77 dB
Peak Output Current IOUT RL = 50Ω, inferred from Output-Voltage
Swing test 18 25 mA
Input Offset Voltage VOS ±0.5 ±10 mV
Input Bias Current IB-0.75 -2 µA
Input Offset Current IOS ±20 ±250 nA
Input Capacitance CIN 1.6 pF
Differential Input Resistance RIN
(
DIFF
)
76 kΩ
Input Common-Mode Voltage
Range VCM Inferred from CMRR test 0.25 3.80 V
Common-Mode Rejection Ratio CMRR 0.25V ≤ VCM ≤ 3.8V 70 87 dB
Power-Supply Rejection Ratio PSRR V+ = 4.5V to 5.5V 60 75 dB
AC Power-Supply Rejection
Ratio PSRRAC f = 1MHz 47 dB
(V+) - VOH 0.64 1
RL = ∞VOL 0.73 1
(V+) - VOH 1.27 1.5
Output-Voltage Swing VOH
,
VOL
RL = 50ΩVOL 1.37 1.6
V
Output Short-Circuit Current ISC ±130 mA
Output Resistance ROUT G = 1 0.001 Ω
Slew Rate SR VOUT = 1VP-P step 160 V/µs
Settling Time (1%) tSVOUT = 100mVP-P step, G = 1 40 ns
Voltage-Noise Density enf = 1MHz 8.5 nV/√Hz
Current-Noise Density inf = 1MHz 0.5 pA/√Hz
Driver-Receiver Crosstalk XTALK f = 100kHz 95 dB
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
_______________________________________________________________________________________ 5
DRIVER DIFFERENTIAL DISTORTION
vs. FREQUENCY
MAX4361 toc01
FREQUENCY (Hz)
DIFFERENTIAL DISTORTION (dB)
100k
-90
-80
-70
-60
-50
-40
-100
10k 1M
VOUT = 7.2VP-P
G = 3
RL = 12.5Ω
3RD HARMONIC
2ND HARMONIC
MAX4361 toc02
PEAK-TO-PEAK OUTPUT VOLTAGE (V)
DIFFERENTIAL DISTORTION (dBc)
76543
-90
-80
-70
-60
-50
-40
-100
28
DRIVER DIFFERENTIAL DISTORTION
vs. PEAK-TO-PEAK OUTPUT VOLTAGE
f = 100kHz
G = 3
RL = 12.5
W
3RD HARMONIC
2ND HARMONIC
MAX4361 toc03
RLOAD (Ω)
DIFFERENTIAL DISTORTION (dBc)
85654525
-90
-80
-70
-60
-100
5
DRIVER DIFFERENTIAL DISTORTION
vs. LOAD RESISTANCE
VOUT = 5VP-P
f = 100kHz
G = 3
RL = 12.5Ω
3RD HARMONIC
2ND HARMONIC
MAX4361 toc04
TRANSFORMER TURNS RATIO
PLINE (dBm)
4.84.64.2 4.43.4 3.6 3.8 4.03.2
10.5
11.0
11.5
12.0
12.5
13.0
13.5
14.0
14.5
15.0
15.5
16.0
10.0
3.0 5.0
DRIVER LINE POWER
vs. TURNS RATIO
V+ = 5.5V
V+ = 4.5V
V+ = 5V
FREQUENCY (Hz)
100k10k
10
1M1k
100
1
10
100
1
MAX4361 toc05
DRIVER CURRENT AND VOLTAGE NOISE
vs. FREQUENCY
INPUT CURRENT NOISE (pA/√Hz)
INPUT VOLTAGE NOISE (nV/√Hz)
VNOISE
INOISE
MAX4361 toc06
FREQUENCY (Hz)
OUTPUT IMPEDANCE (Ω)
10M1M
0.1
1
10
100
1k
10k
100k
0.01
100k 100M
DRIVER OUTPUT IMPEDANCE
vs. FREQUENCY
SHDN = VCC
SHDN = GND
FREQUENCY (Hz)
GAIN (dB)
100M10M1M100k
-25
-20
-15
-10
-5
0
5
10
15
20
-30
-150
-120
-90
-60
-30
0
30
60
90
120
-180
10k 1G
MAX4361 toc07
DRIVER GAIN AND PHASE
vs. FREQUENCY
PHASE (DEGREES)
GAIN
PHASE
G = 3
RL = 12.5Ω
MAX4361 toc08
FREQUENCY (Hz)
PSRR (dB)
10M1M100k10k
-70
-60
-50
-40
-30
-20
-10
0
10
-80
1k 1G
DRIVER POWER-SUPPLY REJECTION
RATIO vs. FREQUENCY
G = 1
DRIVER OUTPUT SWING
vs. LOAD RESISTANCE
MAX4361 toc09
LOAD RESISTANCE (Ω)
OUTPUT SWING (V)
1k10010
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
1.1
1 10k
1.0
-SWING
+SWING
Typical Operating Characteristics
(V+ = 5V, GND = 0, VCM = 2.5V, RL= 12.5Ω, SHDN = 0, TA= +25°C.)
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(V+ = 5V, GND = 0, VCM = 2.5V, RL= 12.5Ω, SHDN = 0, TA= +25°C.)
MAX4361 toc010
FREQUENCY (Hz)
DIFFERENTIAL DISTORTION (dB)
100k
-90
-80
-70
-60
-50
-40
-100
10k 1M
RECEIVER DIFFERENTIAL DISTORTION
vs. FREQUENCY
3RD HARMONIC
2ND HARMONIC
VOUT = 1VP-P
G = 1
RL = 150Ω
FREQUENCY (Hz)
100k10k
1
1M1k
100
0.1
1
10 10
100
0.1
MAX4361 toc11
RECEIVER CURRENT AND VOLTAGE
NOISE vs. FREQUENCY
INPUT CURRENT NOISE (pA/√Hz)
INPUT VOLTAGE NOISE (nV/√Hz)
VNOISE
INOISE
RECEIVER GAIN AND PHASE
vs. FREQUENCY
MAX4361 toc12
FREQUENCY (Hz)
GAIN (dB)
100M10M1M100k
-20
-10
0
10
20
30
40
50
60
70
-30
10k 1G
GAIN
PHASE
G = 1000
RL = 500Ω
PHASE (DEGREES)
-150
-120
-90
-60
-30
0
30
60
90
120
-180
MAX4361 toc13
FREQUENCY (Hz)
PSRR (dB)
10M1M100k10k
-70
-60
-50
-40
-30
-20
-10
0
10
-80
1k 100M
RECEIVER POWER-SUPPLY REJECTION
RATIO vs. FREQUENCY
G = 1
DRIVER-TO-RECEIVER CROSSTALK
vs. FREQUENCY
MAX4361 toc14
FREQUENCY (Hz)
CROSSTALK (dB)
100M10M1M100k
-100
-80
-60
-40
-20
0
-120
10k 1G
RL = 12.5Ω
NO LOAD
RECEIVER OUTPUT AMPLITUDE
vs. FREQUENCY
MAX4361 toc16
FREQUENCY (Hz)
100M10M1M100k
-8
-6
-4
-2
0
2
4
-10
10k 1G
RF = 100Ω
RF = 1kΩ
RF = 500Ω
G = -1
RL = 150Ω
VP-P = 100mV
GAIN (dB)
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
_______________________________________________________________________________________ 7
Pin Descriptions
PIN NAME FUNCTION
1, 4 GND Ground
2 IN+ First Driver Input
3 IN- Second Driver Input
5 OUT- Second Driver Output
6, 7 V+ Positive Power-Supply Voltage. Bypass V+ to GND with a 0.1µF capacitor.
8 OUT+ First Driver Output
MAX4361
PIN
µMAX SO NAME FUNCTION
1 2 T1IN+ First Driver Noninverting Input
2 3 T1IN- First Driver Inverting Input
3 4 SHDN Shutdown. Connect to GND for normal operation.
4 5 T2IN- Second Driver Inverting Input
5 6 T2IN+ Second Driver Noninverting Input
6, 10 9, 13 GND Ground
7 10 T2OUT Second Driver Output
8 11 V+ Positive Power-Supply Voltage. Bypass V+ to GND with a 0.1µF capacitor.
9 12 T1OUT First Driver Output
—1, 7, 8, 14 N.C. No Connection. Not internally connected.
MAX4362
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
8 _______________________________________________________________________________________
Detailed Description
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.
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.
Uncommitted Dual Amplifier for ADSL
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
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.
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.
PIN NAME FUNCTION
1 T1IN+ First Driver Noninverting Input
2 T1IN- First Driver Inverting Input
3 SHDN Shutdown. Connect to GND for normal operation.
4 T2IN- Second Driver Inverting Input
5 T2IN+ Second Driver Noninverting Input
6 GND Ground
7 R1IN+ First Receiver Noninverting Input
8 R1IN- First Receiver Inverting Input
9 R2IN- Second Receiver Inverting Input
10 R2IN+ Second Receiver Noninverting Input
11 R2OUT Second Receiver Output
12 R1OUT First Receiver Output
13 GND (RX) Ground for Receiver Amplifiers
14 V+ (RX) Positive Power-Supply Voltage for Receiver Amplifiers. Bypass V+ (RX) to GND (RX) with a
separate 0.1µF capacitor.
15 N.C. No Connection. Not internally connected.
16, 20 GND (TX) Ground for Driver Amplifier
17 T2OUT Second Driver Output
18 V+ (TX) Positive Power-Supply Voltage for Driver Amplifiers. Bypass V+ (TX) to GND (TX) with a
separate 0.1µF capacitor.
19 T1OUT First Driver Output
MAX4363
Pin Descriptions (continued)
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
_______________________________________________________________________________________ 9
Applications Information
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.
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.
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.
MAX4361/MAX4362
The MAX4361/MAX4362 require a single 0.1µF bypass
from V+ to ground located as close as possible to the
IC leads.
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.
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.
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
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.
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 2.7kΩfor 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 VREF is generated.
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
Figure 2. Voltage-Divider Reference
Figure 1. Driving Capacitive Load
1kΩ
500Ω
3.1Ω
CLOAD
OUTPUT
INPUT
MAX436 _
R1
2.7kΩ
R2
2.7kΩ0.1µF
VREF
5V
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
10 ______________________________________________________________________________________
Circuit). If the output current is large compared to the
quiescent current, computing the dissipation in the out-
put devices and adding it to the quiescent power dissi-
pation will give a close approximation of the total power
dissipation in the package.
For a 12.5dBm average line power on a 100Ωline, 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
PCONS = 0.8 ✕53.6 x 5V = 214mW
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.
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 100Ωtelephone
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 100Ωis
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.
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.
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
0
0.5
1.5
1.0
2.0
2.5
-40 0-20 20 40 60 80
TEMPERATURE (°C)
MAXIMUM POWER DISSIPATION (W)
MAX4362
14-PIN SO
MAX4363
20-PIN SO MAX4363
20-PIN TSSOP
MAX4361
8-PIN µMAX MAX4362
10-PIN µMAX
MAX4361
8-PIN SO
Figure 3. Maximum Power Dissipation vs. Temperature
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
______________________________________________________________________________________ 11
0.1µF
0.1µF
2.7kΩ
2.7kΩ
1kΩ
3.125Ω
100Ω
1:4
TRANSFORMER
3.125Ω
1kΩ
IN1+
IN1-
OUT+
OUT-
OUT+
OUT-
IN2-
IN2+
IN1-
IN1+
IN2+
IN2-
1kΩ
GND
1kΩ
1kΩ
500Ω
500Ω
LINE IMPEDANCE
VCC
DRIVER
RECEIVER
1kΩ
1kΩ
5V
5V
5V
5V
10kΩ
10kΩ
0.047µF
0.047µF
ADSL
CHIPSET
0.1µF
10kΩ
10kΩ
MAX4363
Typical Operating Circuit
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
12 ______________________________________________________________________________________
Package Information
8LUMAXD.EPS
10LUMAX.EPS
MAX4361/MAX4362/MAX4363
ADSL Drivers/Receivers for Customer Premise
Equipment
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.
Package Information (continued)
SOICN.EPS