Single Port VDSL2
Line Driver with Shutdown
AD8398A
FEATURES
Voltage feedback
Wide output swing
18.4 V p-p differential, R
LOAD, DIFF
= 20 Ω from 12 V supply
High output current
Linear output current of 450 mA peak
Low distortion
−65 dBc for Profile 8b @ 20.4 dBm
−55 dBc for Profile 17a @ 14.5 dBm
High speed
85 MHz bandwidth (A
V DIFF
= 5)
FUNCTIONAL BLOCK DIAGRAM
16 OUT A
15 NC
13 OUT B
14 V
CC
NC 1
−IN
A 2
+IN A 3
GND 4
PD0 8
V
EE
7
–
+
–
+
12 NC
11
−IN
B
10 +IN B
9 PD1
NC 5
NC 6
NC = NO CONNECT
APPLICATIONS
ADSL2+/VDSL2 CO/CPE line drivers
PLC line drivers
Consumer xDSL modems
Twisted pair line drivers
Figure 1. Thermally Enhanced, 4 mm × 4 mm, 16-Lead LFCSP_WQ
TYPICAL APPLICATION DIAGRAM
1/2
TIP
AD8398A
V
MID
*
07760-001
1/2
RING
AD8398A
*V
MID =
V
CC +
V
EE
2
07760-002
Figure 2. Typical VDSL2 Application
GENERAL DESCRIPTION
The AD8398A comprises two high speed, voltage feedback
operational amplifiers. When configured as a differential line
driver, the AD8398A is an ideal choice for ADSL2+, VDSL2, and
power line communications (PLC) applications. It has high
output current, high bandwidth, and fast slew rate, combined
with exceptional multitone power ratio (MTPR) and common-
mode stability. The AD8398A is available in a thermally enhanced
4 mm × 4 mm, 16-lead LFCSP.
The AD8398A incorporates power management functionality
via two CMOS-compatible control pins, PD0 and PD1. These
pins select one of four operating modes: full power, medium
power, low power, or complete power-down. In the power-down
mode, the quiescent current drops to 0.7 mA.
The AD8398A operates in the industrial temperature range of
−40°C to +85°C.
Rev. D
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113 ©2008–2010 Analog Devices, Inc. All rights reserved.
AD8398A
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
Functional Block Diagram .............................................................. 1
Typical Application Diagram .......................................................... 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 4
Thermal Resistance ...................................................................... 4
Maximum Power Dissipation ..................................................... 4
ESD Caution.................................................................................. 4
Pin Configuration and Function Descriptions............................. 5
Typical Performance Characteristics ..............................................6
Applications Information .................................................................8
Power Control Modes of Operation ...........................................8
Exposed Thermal Pad Connections ...........................................8
Power Supply Bypassing ...............................................................8
Board Layout..................................................................................8
Multitone Power Ratio..................................................................9
Lightning and AC Power Fault ....................................................9
Outline Dimensions ....................................................................... 10
Ordering Guide .......................................................................... 10
REVISION HISTORY
9/10—Rev.
C to Rev. D
Change to General Description Section ........................................ 1
3/10—Rev. B to Rev. C
Changes to Figure 14........................................................................ 9
12/09—Rev. A to Rev. B
Changes to Figure 13, Figure 14, and Figure 15 ........................... 9
10/09—Rev. Sp0 to Rev. A
Changed R
LOAD
to R
LOAD, Diff
Throughout........................................ 1
Changes to DC Performance, Differential Input Offset
Voltage Parameter, Table 1 .............................................................. 3
Changes to Figure 4.......................................................................... 5
Changes to Figure 8 and Figure 9................................................... 6
Changes to Exposed Thermal Pad Connections Section............ 8
11/08—Revision Sp0: Initial Version
Rev. D | Page 2 of 12
AD8398A
SPECIFICATIONS
V
S
= 12 V, ±6 V at T
A
= 25°C, A
V DIFF
= 5, R
LOAD, DIFF
= 20 Ω, PD1 = 0, PD0 = 0, unless otherwise noted.
Table 1.
Parameter
DYNAMIC PERFORMANCE
−3 dB Bandwidth
Test Conditions/Comments
A
V DIFF
= 5, V
OUT
= 2 V peak, measured differentially
PD1 = 0, PD0 = 0
PD1 = 0, PD0 = 1
PD1 = 1, PD0 = 0
V
OUT
= 4 V peak, measured differentially
Profile 8b at 20.4 dBm in VDSL2 application
Profile 17a at 14.5 dBm in VDSL2 application
PD1 = 1, PD0 = 1
f = 100 kHz
f = 100 kHz
f = 100 kHz in VDSL2 application
−2
Min
Typ
Max
Unit
Slew Rate
NOISE/DISTORTION PERFORMANCE
MTPR
Off Isolation
Input Voltage Noise
Input Current Noise
Differential Output Voltage Noise
DC PERFORMANCE
Differential Input Offset Voltage
Input Offset Voltage
Input Bias Current
Open-Loop Gain
Common-Mode Rejection
INPUT CHARACTERISTICS
Input Resistance
OUTPUT CHARACTERISTICS
Differential Swing
Linear Peak Output Current
POWER SUPPLY
Operating Range
Supply Current
85
85
75
600
−65
−55
−80
4.8
0.9
120
±0.1
16
0.5
63
−100
1.9
17.6
18.4
450
±6
12
33.2
22.9
13.3
0.7
−94
0.8
2
15
6
60
600
+2
55
1
−74
MHz
MHz
MHz
V/μs
dBc
dBc
dBc
nV/√Hz
pA/√Hz
nV/√Hz
mV
mV
μA
dB
dB
MΩ
V p-p
mA peak
V
V
mA
mA
mA
mA
dB
V
V
μA
μA
μs
μs
Measured differentially
f < 100 kHz
VDSL2 at 20.4 dBm, MTPR = −65 dBc
Dual supply
Single supply
PD1 = 0, PD0 = 0
PD1 = 0, PD0 = 1
PD1 = 1, PD0 = 0
PD1 = 1, PD0 = 1
Measured differentially
Referenced to GND
Referenced to GND
PD1, PD0 = 0 V
PD1, PD0 = 3 V
PD1, PD0 = (1, 1) − (0, 0)
PD1, PD0 = (0, 0) − (1, 1)
29
20
12
Power Supply Rejection
POWER-DOWN PINS
PD1, PD0 V
IL
PD1, PD0 V
IH
PD1, PD0 Bias Current
Enable Time
Disable Time
37
25.5
14.5
1.1
−74
30
17
Rev. D | Page 3 of 12
AD8398A
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
Power Supplies (V
CC
− V
EE
)
Power Dissipation
Storage Temperature Range
Operating Temperature Range
Lead Temperature (Soldering, 10 sec)
Junction Temperature
Rating
13.2 V
(T
J MAX
− T
A
)/θ
JA
−65°C to +125°C
−40°C to +85°C
300°C
150°C
MAXIMUM POWER DISSIPATION
The maximum safe power dissipation for the AD8398A is limited
by its junction temperature (T
J
) on the die. The maximum safe
T
J
of plastic encapsulated devices, as determined by the glass
transition temperature of the plastic, is 150°C. Temporarily
exceeding this limit may cause a shift in the parametric
performance due to a change in the stresses exerted on the
die by the package. Exceeding this limit for an extended period
can result in device failure.
Figure 3 shows the maximum safe power dissipation in the
package vs. the ambient temperature for the 16-lead LFCSP_WQ
on a 4-layer board with six vias connecting the exposed pad to
the GND plane layer.
6
T
J
= 150°C
MAXIMUM POWER DISSIPATION (W)
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
THERMAL RESISTANCE
θ
JA
is specified with the device soldered on a JEDEC circuit
board and the thermal pad connected to the GND plane layer
using six vias.
Table 3. Thermal Resistance
Package Type
16-Lead LFCSP_WQ
θ
JA
35.6
Unit
°C/W
5
4
3
2
1
0
10
20
30
40
50
60
70
80
AMBIENT TEMPERATURE (°C)
Figure 3. Maximum Safe Power Dissipation vs. Ambient Temperature,
4-Layer JEDEC Board with Six Thermal Vias
ESD CAUTION
Rev. D | Page 4 of 12
07760-003
0
–40 –30 –20 –10
AD8398A
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
16 OUT A
14 V
CC
15 NC
13 OUT B
NC 1
−IN
A 2
+IN A 3
GND 4
V
EE
7
PD0 8
NC 5
NC 6
12 NC
AD8398A
11
−IN
B
10 +IN B
9
PD1
TOP VIEW
(Not to Scale)
NOTES
1. NC = NO CONNECT
2. EXPOSED PADDLE (EPAD) IS
FLOATING, NOT ELECTRICALLY
CONNECTED INTERNALLY.
Figure 4. Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
1, 5, 6, 12, 15
2
3
4
7
8
9
10
11
13
14
16
EPAD
Mnemonic
NC
−IN A
+IN A
GND
V
EE
PD0
PD1
+IN B
−IN B
OUT B
V
CC
OUT A
Exposed Paddle (EPAD)
Description
No Connect.
Amplifier A Inverting Input.
Amplifier A Noninverting Input.
Ground.
Negative Power Supply Input.
Power Mode Control.
Power Mode Control.
Amplifier B Noninverting Input.
Amplifier B Inverting Input.
Amplifier B Output.
Positive Power Supply Input.
Amplifier A Output.
The exposed paddle is electrically isolated.
Rev. D | Page 5 of 12
07760-004
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