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Differential Driver. AD8148 Datasheet |
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Data Sheet
FEATURES
Triple high speed fully differential driver
700 MHz, −3 dB, 2 V p-p bandwidth (AD8146/AD8148)
600 MHz, −3 dB, 2 V p-p bandwidth (AD8147)
200 MHz, 0.1 dB, 2 V p-p bandwidth
3000 V/μs slew rate
Fixed gain (AD8146/AD8147: G = 2, AD8148: G = 4)
Differential or single-ended input to differential output
Can be used as differential-to-differential receiver
Drives one or two 100 Ω UTP cables
Adjustable output common-mode voltage (AD8146)
Internal common-mode feedback network
Output balance error −50 dB @ 50 MHz
On-chip, sync-on common-mode encoding (AD8147/AD8148)
Output pull-down feature for line isolation
Low power: 57 mA @ 5 V for 3 drivers (AD8146)
Wide supply voltage range: +5 V to ±5 V
Available in a small 4 mm × 4 mm LFCSP
APPLICATIONS
QXGA or 1080p video transmission
KVM networking
Video over unshielded twisted pair (UTP)
Differential signal multiplexing
Triple Differential Driver
for Wideband Video
AD8146/AD8147/AD8148
FUNCTIONAL BLOCK DIAGRAMS
OPD 1
VS– 2
–IN A 3
+IN A 4
VS– 5
–OUT A 6
24 23 22 21 20 19
A
78
AD8146 18 VOCMC
17 VS+
16 –IN C
15 +IN C
B
C 14 VS–
13 –OUT C
9 10 11 12
Figure 1.
OPD 1
VS– 2
–IN R 3
+IN R 4
VS– 5
–OUT R 6
24 23 22 21 20 19
AD8147/
AD8148
×2
B
AC
7 8 9 10 11 12
18 SYNC LEVEL
17 VS+ (SYNC)
16 –IN B
15 +IN B
14 VS–
13 –OUT B
GENERAL DESCRIPTION
The AD8146/AD8147/AD8148 are high speed triple, differential or
single-ended input to differential output drivers. The AD8146
and AD8147 have a fixed gain of 2, and the AD8148 has a fixed
gain of 4. They are all specifically designed for the highest
resolution component video signals but can be used for any
type of analog signals or high speed data transmission over
either Category 5 UTP cable or differential printed circuit
board (PCB) transmission lines.
These drivers can be used with the AD8145 triple differential-
to-singled-ended receiver, and the AD8117 crosspoint switch to
produce a video distribution system capable of supporting
UXGA or 1080p signals.
Manufactured on the Analog Devices, Inc. second generation
XFCB bipolar process, the drivers have large signal bandwidths
Rev. B
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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.
Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.
Figure 2.
of 700 MHz and fast slew rates. They have an internal common-
mode feedback feature that provides output amplitude and
phase matching that is balanced to −60 dB at 50 MHz, suppressing
even-order harmonics and minimizing radiated
electromagnetic interference (EMI).
The common-mode voltage of each AD8146 output can be set
to any level, allowing transmission of signals over the common-
mode voltages. The AD8147 and AD8148 encode the vertical
and horizontal sync signals on the common-mode voltages of
the outputs. All outputs can be independently set to low voltage
states to be used with series diodes for line isolation, allowing
easy differential multiplexing over the same twisted pair cable.
The AD8146/AD8147/AD8148 are available in a 24-lead LFCSP
and operate over a temperature range of −40°C to +85°C.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 ©2007–2014 Analog Devices, Inc. All rights reserved.
Technical Support
www.analog.com
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AD8146/AD8147/AD8148
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
Functional Block Diagrams............................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 7
Thermal Resistance ...................................................................... 7
ESD Caution.................................................................................. 7
Pin Configurations and Function Descriptions ........................... 8
Typical Performance Characteristics ........................................... 10
Theory of Operation ...................................................................... 14
Definition of Terms.................................................................... 14
Analyzing an Application Circuit............................................. 14
Closed-Loop Gain ...................................................................... 14
Calculating the Input Impedance............................................. 15
REVISION HISTORY
3/14—Rev. A to Rev. B
Changed LFCSP_VQ to LFCSP_WQ (Throughout)................... 7
Updated Outline Dimensions ....................................................... 22
Changes to Ordering Guide .......................................................... 22
8/10—Rev. 0 to Rev. A
Changes to Table 1............................................................................ 3
Changes to Table 2............................................................................ 5
Changes to Pin Configurations and Function Descriptions
Section................................................................................................ 8
Changes to Adding Pre-Emphasis to the AD8148 Section ....... 20
Updated Outline Dimensions ....................................................... 22
5/07—Revision 0: Initial Version
Data Sheet
Input Common-Mode Voltage Range in Single-Supply
Applications ................................................................................ 15
Output Common-Mode Control ............................................. 15
Sync-On Common-Mode ......................................................... 15
Applications..................................................................................... 16
Driving RGB Video Signals Over Category-5 UTP Cable.... 16
Video Sync-On Common-Mode.............................................. 16
Driving Two UTP Cables With One Driver ........................... 18
Using the AD8146 as a Receiver ............................................... 18
Output Pull-Down (OPD) ........................................................ 19
Layout and Power Supply Decoupling Considerations......... 19
Driving a Capacitive Load......................................................... 19
Adding Pre-Emphasis to the AD8148...................................... 20
Exposed Paddle (EP).................................................................. 21
Outline Dimensions ....................................................................... 22
Ordering Guide .......................................................................... 22
Rev. B | Page 2 of 24
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