a
FEATURES
High Speed
400 MHz –3 dB Full Power Bandwidth
2000 V/ s Slew Rate
Fixed Gain of 2 with No External Components
Internal Common-Mode Feedback to Improve Gain
and Phase Balance
–60 dB @10 MHz
Separate Input to Set the Common-Mode Output
Voltage
Low Distortion
68 dB SFDR @ 5 MHz 200
Load
Low Power 7.5 mA @ 3 V
Power Supply Range +2.7 V to 5 V
APPLICATIONS
Video Line Driver
Digital Line Driver
Low Power Differential ADC Driver
Differential In/Out Level Shifting
Single-Ended Input to Differential Output Driver
–D
IN
Low-Cost, High-Speed
Differential Driver
AD8131
FUNCTIONAL BLOCK DIAGRAM
1
750
V
OCM
2
750
7 NC
6 V–
1.5k
+OUT 4
1.5k
5 –OUT
8 +D
IN
V+ 3
AD8131
NC = NO CONNECT
–20
V
OUT
,dm = 2V p-p
V
OUT
,cm/ V
OUT
, dm
–30
BALANCE ERROR – dB
–40
–50
V
S
= +5V
–60
–70
V
S
=
–80
5V
1
10
100
FREQUENCY – MHz
1000
GENERAL DESCRIPTION
Figure 1. Output Balance Error vs. Frequency
The AD8131 is a differential or single-ended input to differen-
tial output driver requiring no external components for a fixed
gain of 2. The AD8131 is a major advancement over op amps
for driving signals over long lines or for driving differential input
ADCs. The AD8131 has a unique internal feedback feature that
provides output gain and phase matching that are balanced to
–60 dB at 10 MHz, reducing radiated EMI and suppressing
harmonics. Manufactured on ADI’s next generation XFCB
bipolar process, the AD8131 has a –3 dB bandwidth of 400 MHz
and delivers a differential signal with very low harmonic distortion.
The AD8131 is a differential driver for the transmission of
high-speed signals over low-cost twisted pair or coax cables.
The AD8131 can be used for either analog or digital video
signals or for other high-speed data transmission. The AD8131
driver is capable of driving either Cat3 or Cat5 twisted pair or coax
with minimal line attenuation. The AD8131 has considerable
cost and performance improvements over discrete line driver
solutions.
The AD8131 can replace transformers in a variety of applica-
tions preserving low frequency and dc information. The AD8131
does not have the susceptibility to magnetic interference and
hysteresis of transformers, while being smaller in size, easier
to work with, and has the high reliability associated with ICs.
The AD8131’s differential output also helps balance the input
for differential ADCs, optimizing the distortion performance of
the ADCs. The common-mode level of the differential output
is adjustable by a voltage on the V
OCM
pin, easily level-shifting
the input signals for driving single supply ADCs with dual supply
signals. Fast overload recovery preserves sampling accuracy.
The AD8131 will be available in both SOIC and
µSOIC
packages
for operation over –40 C to +85 C.
REV. 0
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 1999
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