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AD8391
xDSL Line Driver
3 V to 12 V with Power-Down
PRODUCT DESCRIPTION
The AD8391 consists of two parallel, low cost xDSL line drive
amplifiers capable of driving low distortion signals while running on
both 3 V to 12 V single-supply or equivalent dual-supply rails. It is
primarily intended for use in single-supply xDSL systems where low
power is essential, such as line powered and battery backup systems.
Each amplifier output drives more than 250 mA of current while
maintaining –82 dBc of SFDR at 100 kHz on 12 V, outstanding
performance for any xDSL CPE application.
The AD8391 provides a flexible power-down feature consisting of
a 1-pin digital control line. This allows biasing of the AD8391 to
full power (Logic “1”), Standby (Logic “tri-state” maintains low
amplifier output impedance), and Shutdown (Logic “0” places
amplifier outputs in a high impedance state). PWDN is refer-
enced to –V
S
.
Fabricated on ADI’s high-speed XFCB process, the high bandwidth
and fast slew rate of the AD8391 keep distortion to a minimum,
while dissipating a minimum of power. The quiescent current of the
AD8391 is low; 19 mA total static current draw. The AD8391
comes in a compact 8-lead SOIC “Thermal Coastline” package, and
operates over the temperature range –40°C to +85°C.
FREQUENCY – kHz
UPSTREAM PO
WER – 10dB/DIV
25 250137.5
EMPTY BIN
Figure 1. Upstream Transit Spectrum with Empty Bin
at 45kHz; Line Power = 12.5 dBm into 100 Ω
PIN CONFIGURATION
8-Lead SOIC
(Thermal Coastline)
IN2
V
MID
–V
S
V
OUT
2
1
2
3
4
IN1
PWDN
+V
S
V
OUT
1
AD8391
H11546 H11545 H11545 H11546
V
MID
H11545V
S
H11546V
S
8
7
6
5
FEATURES
Ideal xDSL Line Driver for VoDSL or Low Power
Applications such as USB, PCMCIA, or PCI-Based
Customer Premise Equipment (CPE)
High Output Voltage and Current Drive
340 mA Output Drive Current
Low Power Operation
3 V to 12 V Power Supply Range
1-Pin Logic Controlled Standby, Shutdown
Low Supply Current of 19 mA (Typical)
Low Distortion
–82 dBc SFDR, 12 V p-p into Differential 21 H9024 @ 100 kHz
4.5 nV/√Hz Input Voltage Noise Density, 100 kHz
Out-of-Band SFDR = –72 dBc, 144 kHz to 500 kHz,
Z
LINE
= 100 H9024, P
LINE
= 13.5 dBm
High Speed
40 MHz Bandwidth (–3 dB)
375 V/H9262s Slew Rate
APPLICATIONS
VoDSL Modems
xDSL USB, PCI, PCMCIA Cards
Line Powered or Battery Backup xDSL Modems