ADA4320-1 Datasheet, PDF (1/16 Pages) Analog Devices – High Power, Low Distortion Upstream

High Power, Low Distortion Upstream
CATV Line Driver
ADA4320-1
FEATURES
Supports CableLabs® DOCSIS 3.0/2.0 and EuroDOCSIS
3.0/2.0 specifications for customer premises equipment
(CPE) upstream transmission
5 V single-supply operation
Excellent adjacent channel rejection performance
−66 dBc ACPR for a single QPSK channel
−63 dBc ACPR for 4× QAM64 channels
Gain programmable in 1 dB steps over a 59 dB range
Gain range: −27 dB to +32 dB
Current-scaled output stage
Low between-burst output noise level
−70 dB mV in 160 kHz bandwidth
Maintains constant output impedance in enable, disable,
and sleep conditions
Selectable low power modes
12 mA in Tx disable
12 μA in sleep mode (full power-down)
3-wire, SPI-compatible interface
4 mm × 5 mm 24-lead LFCSP, RoHS compliant
APPLICATIONS
DOCSIS 3.0 and EuroDOCSIS cable modems/E-MTAs
DOCSIS 3.0 set-top boxes
CATV telephony modems
Coaxial or twisted pair line drivers
GENERAL DESCRIPTION
The ADA4320-1 is a high power, ultralow distortion amplifier
designed for CATV reverse channel line driving. Its features and
specifications make the ADA4320-1 ideally suited for DOCSIS 3.0-
and EuroDOCSIS 3.0-based applications. Both gain and output
stage current are controlled via a 3-wire (SPI-compatible) interface.
A single 8-bit serial word selects one of four available supply
current presets and one of sixty gain codes.
The ADA4320-1 has been tailored to address both the high output
drive and stringent fidelity requirements of DOCSIS 3.0. The
part is able to maintain excellent adjacent channel rejection
performance over the full 5 MHz to 85 MHz range, even with
multiple bonded channels at maximum specified output levels.
The ADA4320-1 accepts a differential or single-ended input
signal. The output is specified for driving a single-ended 75 Ω
load through a 4:1 impedance transformer.
FUNCTIONAL BLOCK DIAGRAM
VIN–
VIN+
DIFF OR
SINGLE
INPUT
AMP
VERNIER
Z_IN (SINGLE) = 320Ω
Z_IN (DIFF) = 640Ω
ADA4320-1
ATTENUATION
CORE
POWER
AMP
8
DECODE
8
DATA LATCH
8
SHIFT
REGISTER
Z_OUT DIFF =
300Ω
POWER-DOWN
LOGIC
VOUT+
VOUT–
RAMP
GND DATEN SDATA CLK
Figure 1.
TXEN SLEEP
The ADA4320-1 features an output driver stage that scales
quiescent current consumption according to gain setting. In
multichannel mode at maximum gain (32 dB), the device draws
260 mA from a single 5 V supply, enabling the high power,
ultralow distortion performance required by multiple DOCSIS 3.0
upstream channels. For lifeline E-MTA applications, the ADA4320-1
output stage current can be throttled via SPI commands, reducing
the power requirement for single-channel transmission by up to
30%. In transmit-disable mode, the ADA4320-1 draws only 12 mA.
The device also features a full power-down sleep mode that
further reduces current draw to12 μA typical.
The ADA4320-1 is packaged in a RoHS-compliant, 24-lead
exposed pad LFCSP and is rated for operation over the −40°C
to +85°C temperature range.
Rev. 0
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