MAXIM MAX4361, MAX4362, MAX4363 Technical data

General Description

The MAX4361/MAX4362/MAX4363 are a family of high­performance 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 sig­nals, 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 differen­tial IN/differential OUT driver with gain set with external
resistors. 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.

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

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.

Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.

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

TOP VIEW

1

GND

T1IN+

T1IN-

SHDN

T2IN+

GND

R1IN+

R2IN-

2

3

4

5

6

7

8

9

10

SO/TSSOP

MAX4363

1 8 OUT+GND

27V+IN+

MAX4361 MAX4362

45

µMAX/SO

V+IN- 3 6

OUT-GND

T1IN+

T1IN-

SHDN

1

2

3

4

5

µMAX

10

GND

9

T1OUT

8

V+

7

T2OUTT2IN-

GNDT2IN+

6

T2IN+

MAX4362

SO

141 N.C.N.C.

132 GNDT1IN+

123 T1OUTT1IN-

114V+SHDN

105 T2OUTT2IN-

96

87 N.C.N.C.

20

19

18

17

16

15

14

13

12

11

GND (TX)

T1OUT

V+ (TX)

T2OUTT2IN-

GND (TX)

N.C.

V+ (RX)

GND (RX)R1IN-

R1OUT

R2OUTR2IN+

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= T

MIN

to T

MAX

, unless otherwise noted. Typical values specified at

T

A

= +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 (T

A

= +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) V

Supply Current I

Maximum Average Output
Power (Notes 2, 3)

Gain G MAX4361 (0.7V ≤ V

Open-Loop Gain A

Second Harmonic Distortion
(Notes 3, 4)

Third Harmonic Distortion
(Notes 3, 4)

Peak Output Current I

Input Offset Voltage V

Input Bias Current I

Input Offset Current I

Differential Input Resistance R

CC

Q

P

OUT

VOL

OUT

OS

B

OS

IN(DIFF

MAX4361, RL = ∞ 22 33 mA

MAX4362, RL = ∞

MAX4363, measured at
V+ (TX), R

MAX4363, measured at
V+ (RX), R

DMT modulation 15.5

CAP modulation 18

MAX4362/MAX4363 (0.7V ≤ V

G = 3.1, f = 100kHz, V

G = 3.1, f = 100kHz, V

Inferred from Output Voltage Swing test 280 330 mA

MAX4361 ±30 ±600
MAX4362/MAX4363 ±10 ±500
MAX4361 25 MΩ
MAX4362/MAX4363 40 kΩ

L

L

= ∞

= ∞

≤ (V+) - 0.7V) 3.0 3.1 3.2 V/V

OUT

OUT(DIFF)

OUT(DIFF)

4.5 5.5 V

SHDN = 0 22 33 mA

SHDN = 5V 60 200 µA

SHDN = 0 22 33 mA

SHDN = 5V 60 200 µA

SHDN = 0 4 6.5 mA

SHDN = 5V 70 200 µA

≤ (V+) - 0.7V) 68 81 dB

OUT

= 7.1V

= 7.1V

P-P

P-P

-66 -76 dBc

-68 -79 dBc

±0.5 ±10 mV

1.6 4.5 µA

dBm

nA

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= T

MIN

to T

MAX

, unless otherwise noted. Typical values specified at

T

A

= +25°C.)

)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Input Common-Mode Voltage
Range

Common-Mode Rejection
Ratio

V

CM

Inferred from CMRR test 1.25 4.50 V

CMRR 1.25V ≤ V

CM

≤ 4.5V

Power-Supply Rejection Ratio PSRR V+ = 4.5V to 5.5V

AC Power-Supply Rejection
Ratio

Differential Output-Voltage
Swing (Note 4)

PSRR

V

OU T ( D IF F )

f = 100kHz

AC

Inferred from Output Voltage Swing test 7.4 8.2 V

RL = 100Ω

Output-Voltage Swing
(Note 4)

VOH,

V

OL

MAX4362/MAX4363

= 12.5Ω

R

L

MAX4361, RL = 12.5Ω,

= -20°C to 85°C

T

A

Output Short-Circuit Current I

Output Resistance R

SHDN Logic Low V

SHDN Logic High V

SHDN Input Current IIH, I

Shutdown Output Impedance Z

-3dB Bandwidth BW

Slew Rate SR V

Settling Time (1%) t

Voltage-Noise Density e

Current-Noise Density i

SC

OUT

IL

IH

IL

OUT(SD

S

n

n

MAX4361 0.3

MAX4362/MAX4363, G = 1 0.001

SHDN = 0 or SHDN = V+ ±10 µA
f = 1MHz 1.8 kΩ

MAX4361 40

MAX4362/MAX4363, G = 1 60

OUT(DIFF)

V

OUT(DIFF)

= 7.1V

= 7.1V

step

f = 100kHz to 1.1MHz 4.8 nV /√ Hz
f = 100kHz to 1.1MHz 1.5 p A/√ Hz

Capacitive-Load Stability 10 nF

Shutdown Delay Time t

Enable Delay Time t

SHDN

ENABLE

MAX4361 60 73

MAX4362/MAX4363 70 85

MAX4361 60 89

MAX4362/MAX4363 60 74

MAX4361 63

MAX4362/MAX4363 49

(V+) - V

V

OL

(V+) - V

V

OL

(V+) - V

V

OL

OH

OH

OH

215 550

230 550

400 600

430 650

400 600

430 650

±650 mA

0.8 V

2.0 V

step 30 V/µs

P-P

MAX4361 115

P-P

MAX4362/MAX4363,
G = 3

165

400 ns

2.8 µs

dB

dB

dB

P-P

mV

Ω

MHz

ns

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 (V

OUT(DIFF)

), crest factor (Cr) and load resistance (RL):

P

Driver

= 10log((250 ✕(V

OUT(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= T

MIN

to T

MAX

, unless otherwise noted. Typical values specified at

T

A

= +25°C.)

)

,

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Spurious-Free Dynamic Range SFDR G = 1, f = 1MHz, V

Gain-Bandwidth Product GBW 190 MHz

Open-Loop Gain A

Peak Output Current I

Input Offset Voltage V

Input Bias Current I

Input Offset Current I

Input Capacitance C

Differential Input Resistance R

IN(DIFF

Input Common-Mode Voltage
Range

Common-Mode Rejection Ratio C

VOL

OUT

OS

V

MRR

OS

B

IN

CM

1.5V ≤ V

OUT

RL = 50Ω, inferred from Output-Voltage
Swing test

Inferred from CMRR test 0.25 3.80 V

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

PSRR

f = 1MHz 47 dB

AC

RL = ∞

Output-Voltage Swing V

OH

V

OL

RL = 50Ω

Output Short-Circuit Current I

Output Resistance R

Slew Rate SR V

Settling Time (1%) t

Voltage-Noise Density e

Current-Noise Density i

Driver-Receiver Crosstalk X

SC

OUT

S

n

n

TALK

G = 1 0.001 Ω

= 1V

V

OUT

OUT

P-P

= 100mV

f = 1MHz 8.5 nV/√Hz
f = 1MHz 0.5 pA/√Hz

f = 100kHz 95 dB

OUT

= 1V

P-P

-75 dBc

≤ 3.5V 65 77 dB

18 25 mA

±0.5 ±10 mV

-0.75 -2 µA

±20 ±250 nA

1.6 pF

76 kΩ

(V+) - V

V

OL

(V+) - V

V

OL

OH

OH

0.64 1

0.73 1

1.27 1.5

1.37 1.6

±130 mA

step 160 V/µs

step, G = 1 40 ns

P-P

V

MAX4361/MAX4362/MAX4363

ADSL Drivers/Receivers for Customer Premise

Equipment

_______________________________________________________________________________________ 5

Typical Operating Characteristics

(V+ = 5V, GND = 0, VCM= 2.5V, RL= 12.5Ω, SHDN = 0, TA= +25°C.)

DRIVER DIFFERENTIAL DISTORTION

vs. FREQUENCY

-40
V

= 7.2V

OUT

P-P

G = 3

-50

= 12.5Ω

R

L

-60

2ND HARMONIC

-70

-80

DIFFERENTIAL DISTORTION (dB)

-90

-100
10k 1M

FREQUENCY (Hz)

3RD HARMONIC

100k

DRIVER LINE POWER

vs. TURNS RATIO

16.0

15.5

15.0

14.5

14.0

13.5

(dBm)

13.0

LINE

P

12.5

12.0

11.5

11.0

10.5

10.0

3.0 5.0

V+ = 5.5V

V+ = 5V

V+ = 4.5V

TRANSFORMER TURNS RATIO

DRIVER GAIN AND PHASE

vs. FREQUENCY

20

15

10

5

0

-5

GAIN (dB)

-10

-15

-20

-25

-30
10k 1G

GAIN

PHASE

FREQUENCY (Hz)

MAX4361 toc07

G = 3

= 12.5Ω

R

L

100M10M1M100k

MAX4361 toc01

MAX4361 toc04

4.84.64.2 4.43.4 3.6 3.8 4.03.2

120

90

60

30

0

-30

-60
PHASE (DEGREES)

-90

-120

-150

-180

DRIVER DIFFERENTIAL DISTORTION

vs. PEAK-TO-PEAK OUTPUT VOLTAGE

-40
f = 100kHz
G = 3

-50

= 12.5

W

R

L

-60

-70

-80

DIFFERENTIAL DISTORTION (dBc)

-90

-100
28

PEAK-TO-PEAK OUTPUT VOLTAGE (V)

DRIVER CURRENT AND VOLTAGE NOISE

vs. FREQUENCY

100

10

INPUT CURRENT NOISE (pA/√Hz)

1

DRIVER POWER-SUPPLY REJECTION

RATIO vs. FREQUENCY

10

G = 1

0

-10

-20

-30

-40

PSRR (dB)

-50

-60

-70

-80
1k 1G

3RD HARMONIC

2ND HARMONIC

FREQUENCY (Hz)

FREQUENCY (Hz)

DRIVER DIFFERENTIAL DISTORTION

-60

MAX4361 toc02

76543

MAX4361 toc05

100

10

V

NOISE

I

NOISE

100k10k

10M1M100k10k

1M1k

1

MAX4361 toc08

-70

-80

-90

DIFFERENTIAL DISTORTION (dBc)

-100

100k

10k

1k

100

10

1

OUTPUT IMPEDANCE (Ω)

INPUT VOLTAGE NOISE (nV/√Hz)

0.1

0.01
100k 100M

2.5

2.4

2.3

2.2

2.1

2.0

1.9

1.8

1.7

1.6

OUTPUT SWING (V)

1.5

1.4

1.3

1.2

1.1

1.0

vs. LOAD RESISTANCE

V

= 5V

OUT

P-P

f = 100kHz
G = 3

= 12.5Ω

R

L

3RD HARMONIC

2ND HARMONIC

5

R

(Ω)

LOAD

85654525

DRIVER OUTPUT IMPEDANCE

vs. FREQUENCY

SHDN = V

CC

SHDN = GND

10M1M

FREQUENCY (Hz)

DRIVER OUTPUT SWING

vs. LOAD RESISTANCE

+SWING

-SWING

1 10k

LOAD RESISTANCE (Ω)

1k10010

MAX4361 toc03

MAX4361 toc06

MAX4361 toc09

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

V

OUT

= 1V

P-P

G = 1
R

L

= 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)

V

NOISE

I

NOISE

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
R

L

= 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-TO-RECEIVER CROSSTALK

vs. FREQUENCY

MAX4361 toc15

FREQUENCY (Hz)

CROSSTALK (dB)

100M10M1M100k

-100

-80

-60

-40

-20

0

-120
10k 1G

NO LOAD

RL = 150Ω

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
R

L

= 150Ω

V

P-P

= 100mV

GAIN (dB)

MAX4361/MAX4362/MAX4363

ADSL Drivers/Receivers for Customer Premise

Equipment

_______________________________________________________________________________________ 7

Pin Descriptions

MAX4361

MAX4362

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

µMAX SO

PIN

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.

NAME FUNCTION

MAX4361/MAX4362/MAX4363

ADSL Drivers/Receivers for Customer Premise
Equipment

8 _______________________________________________________________________________________

Detailed Description

The MAX4361/MAX4362/MAX4363 are a family of high­performance 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 sig­nals, 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 intend­ed 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.

MAX4363

Pin Descriptions (continued)

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)

15 N.C. No Connection. Not internally connected.

16, 20 GND (TX) Ground for Driver Amplifier

17 T2OUT Second Driver Output

18 V+ (TX)

19 T1OUT First Driver Output

Positive Power-Supply Voltage for Receiver Amplifiers. Bypass V+ (RX) to GND (RX) with a
separate 0.1µF capacitor.

Positive Power-Supply Voltage for Driver Amplifiers. Bypass V+ (TX) to GND (TX) with a
separate 0.1µF capacitor.

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 resis­tance (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 power­supply 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 sup­ply 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 capaci­tor. 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) regula­tor. 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 dri­ving 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 suffi­cient 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 2.7kΩ 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

REF

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

500Ω

INPUT

2.7kΩ

2.7kΩ

1kΩ

MAX436 _

5V

R1

R2

3.1Ω

0.1µF

OUTPUT

C

LOAD

V

REF

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 out­put devices and adding it to the quiescent power dissi­pation will give a close approximation of the total power
dissipation in the package.

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 con­sumption is approximately

P

CONS

= 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 corre­sponds 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 maxi­mum 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 der­ating for each of the MAX4361/MAX4362/MAX4363
packages.

Transformer Selection

Full-rate, customer premise ADSL requires the trans­mission 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 cou­pled 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 differ­ential 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 typi­cal 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 tele­phone 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 amplifi­er as possible.

Chip Information

MAX4361 TRANSISTOR COUNT: 1400

MAX4362 TRANSISTOR COUNT: 1400

MAX4363 TRANSISTOR COUNT: 1750

PROCESS: Bipolar

Figure 3. Maximum Power Dissipation vs. Temperature

2.5

2.0

1.5

1.0

0.5

MAXIMUM POWER DISSIPATION (W)

0

-40 0-20 20 40 60 80

MAX4361

8-PIN µMAX

MAX4362
14-PIN SO

MAX4363

20-PIN SO

MAX4362

10-PIN µMAX

TEMPERATURE (

MAX4363

20-PIN TSSOP

MAX4361

8-PIN SO

°C)

MAX4361/MAX4362/MAX4363

ADSL Drivers/Receivers for Customer Premise

Equipment

______________________________________________________________________________________ 11

Typical Operating Circuit

ADSL

CHIPSET

2.7kΩ

2.7kΩ

0.047µF

0.047µF

5V

V

CC

DRIVER

0.1µF

OUT+

OUT-

IN1­IN1+

IN2+

IN2-

1kΩ

3.125Ω

LINE IMPEDANCE

3.125Ω

TRANSFORMER

500Ω

1kΩ

500Ω

5V

100Ω

1:4

5V

1kΩ

1kΩ

0.1µF

10kΩ

IN1+
IN1-

10kΩ

1kΩ

IN2-

IN2+

OUT+

OUT-

MAX4363

5V

RECEIVER

10kΩ

GND

1kΩ

1kΩ

10kΩ

0.1µF

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