Triple Differential Driver
With Sync-On-Common-Mode
AD8134
Rev. A
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2005 Analog Devices, Inc. All rights reserved.
FEATURES
Triple high speed differential driver
225 MHz, 3 dB large signal bandwidth
450 MHz, 3 dB small signal bandwidth
Easily drives 1.4 V p-p video signal into doubly terminated
100 Ω UTP cable
1600 V/μs slew rate
Fixed internal gain of 2
Internal common-mode feedback network
Output balance error 60 dB @ 50 MHz
On-chip sync-on-common-mode circuitry
Output pull-down feature for line isolation
Differential input and output
Differential-to-differential or single-ended-to-differential
operation
High isolation between amplifiers: 80 dB @ 10 MHz
Low distortion: 64 dB SFDR @ 10 MHz on 5 V supply,
RL, dm = 200 Ω
Low offset: 3 mV typical output-referred on 5 V supply
Low power: 26.5 mA @ 5 V for three drivers and sync circuitry
Wide supply voltage range: +5 V to ±5 V
Available in space-saving packaging: 4 mm × 4 mm LFCSP
APPLICATIONS
Keyboard-video-mouse (KVM) networking
GENERAL DESCRIPTION
The AD8134 is a major advancement beyond using discrete
op amps for driving differential RGB signals over twisted pair
cable. The AD8134 is a triple, low cost differential or single-
ended input to differential output driver, and each amplifier has
a fixed gain of 2 to compensate for the attenuation of the line
termination resistors. The AD8134 is specifically designed for
RGB signals but can be used for any type of analog signals or
high speed data transmission. The AD8134 is capable of driving
either Category 5 (Cat-5) unshielded twisted pair (UTP) cable
or differential printed circuit board transmission lines with
minimal signal degradation.
A unique feature that allows the user to transmit balanced
horizontal and vertical video sync signals over the three
common-mode channels with minimal electromagnetic
interference (EMI) radiation is included on-chip.
The outputs of the AD8134 can be set to a low voltage state that
allows easy differential multiplexing of multiple drivers on the
same twisted pair cable, when used with external series diodes.
FUNCTIONAL BLOCK DIAGRAM
AD8134
OPD
1
VS– 2
–IN R
3
+IN R
4
VS– 5
SYNC LEVEL
VS+ (SYNC)
–IN B
+IN B
VS–
18
17
16
15
14
–OUT R
6
–OUT B
13
V
S+
–IN
G
+I
N
G
V
S–
(S
Y
NC)
V
SYN
C
24
23
22
21
20
H
SYN
C
19
+O
UT
R
V
S+
+O
UT
G
–O
UT
G
V
S+
7
8
9
10
11
+O
UT
B
12
×2
R
G
B
04770-001
Figure 1.
FREQUENCY (MHz)
OUTPUT
BALANCE
ERROR
(
d
B)
0
–20
–10
–40
–30
–60
–50
–80
–70
–100
–90
1
10
100
500
VS = +5V
VS = ±5V
ΔV
OUT, dm = 2V p-p
ΔV
OUT, cm/ΔVOUT, dm
04770-
018
Figure 2. Output Balance vs. Frequency
The AD8134 driver is a natural complement to the AD8143,
Manufactured on the Analog Devices next generation XFCB
bipolar process, the AD8134 has a large signal bandwidth of
225 MHz and a slew rate of 1600 V/μs. The AD8134 has an
internal common-mode feedback feature that provides output
gain and phase matching that is balanced to 60 dB at 50 MHz,
suppressing harmonics and reducing radiated EMI.
The AD8134 is available in a 24-lead LFCSP and can operate
over the 40°C to +85°C extended industrial temperature range.