ad8141 Analog Devices, Inc., ad8141 Datasheet

ad8141

Manufacturer Part Number

ad8141

Description

Low Cost, Triple Differential Drivers For Wideband Video

Manufacturer

Analog Devices, Inc.

Datasheet

1.AD8141.pdf (24 pages)

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FEATURES

Triple, high speed differential drivers

Single 5 V or split supply operation

Fixed gain of 2

Internal common-mode feedback network

AD8142

High-Z output when disabled

Differential-to-differential or single-ended-to-differential

High isolation between amplifiers: −100 dB at 10 MHz

Low power: 44 mA at 5 V

Available in space-saving packaging: 4 mm × 4 mm LFCSP

APPLICATIONS

Keyboard-video-mouse (KVM) networking

Video distribution

Digital signage

Security cameras

GENERAL DESCRIPTION

The

single-ended-input-to-differential-output drivers. Each amplifier

has a fixed gain of 2 to compensate for the attenuation of the

line termination resistors. The

specifically designed for RGB signals but can be used for any

type of signals. The amplifiers have very fast slew rate and

settling time while being manufactured on a cost effective

CMOS process. They are optimized for high resolution video

performance with a 0.1 dB flatness of 65 MHz, which allows

driving high resolution video over any type of UTP cable.

The drivers have an internal common-mode feedback loop

that provides output amplitude and phase matching, achieving

−50 dB balance error at 50 MHz and thereby suppressing even-

order harmonics and minimizing radiated electromagnetic

interference (EMI).

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 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.

Trademarks and registered trademarks are the property of their respective owners.

255 MHz, −3 dB large signal bandwidth

65 MHz, 0.1 dB flatness

1150 V/μs slew rate

12 ns settling time

Output balance error −50 dB at 50 MHz

operation

AD8141

has integrated sync-on-common-mode circuitry

and

AD8142

are triple, low cost, differential or

AD8141

and

AD8142

are

Low Cost, Triple Differential Drivers

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

Fax: 781.461.3113

The

that allows the user to transmit balanced horizontal and vertical

video sync signals over the three common-mode channels.

Additionally, the

feature that, when asserted, produces high-Z outputs, allowing

line isolation and easy multiplexing.

The

LFCSP and operate over a temperature range of −40°C to +85°C.

They can be used with the

ended receiver,

line, and the

a high resolution video distribution system.

AD8141

AD8142

–OUT R

S–

–IN R

+IN R

/GND

–OUT A

S–

FUNCTIONAL BLOCK DIAGRAMS

DIS

AD8117

–IN A

+IN A

/GND

and

includes a unique sync-on-common-mode feature

DIS

AD8123

AD8141

AD8142

24 23 22 21 20 19

for Wideband Video

24 23 22 21 20 19

AD8175

–

triple equalizer,

AD8145

–

and

×2

are available in a 24-lead 4 mm × 4 mm

–

Figure 1.

Figure 2.

AD8141/AD8142

–

AD8142

crosspoint switches to produce

AD8141

triple differential-to-single-

–

both have a disable

AD8120

17 V

16 –IN C

15 +IN C

14 V

SYNC LEVEL

–IN B

+IN B

–OUT B

–OUT C

S+

S–

OCM

S+

S–

/GND

www.analog.com

/GND

triple delay

Related parts for ad8141

ad8141 Summary of contents

Page 1

... They can be used with the ended receiver, line, and the a high resolution video distribution system. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 Fax: 781.461.3113 for Wideband Video AD8141/AD8142 FUNCTIONAL BLOCK DIAGRAMS AD8141 V DIS /GND 2 S– – ...

Page 2

... AD8141/AD8142 TABLE OF CONTENTS Features .............................................................................................. 1 Applications....................................................................................... 1 General Description ......................................................................... 1 Functional Block Diagrams............................................................. 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 5 Thermal Resistance ...................................................................... 5 Maximum Power Dissipation ..................................................... 5 ESD Caution.................................................................................. 5 Pin Configurations and Function Descriptions ........................... 6 Typical Performance Characteristics ............................................. 8 Basic Test Circuit ........................................................................ 13 Terminology .................................................................................... 14 Theory of Operation ...................................................................... 15 Analyzing an Application Circuit............................................. 15 Closed-Loop Gain ...................................................................... 15 Calculating an Application Circuit’ ...

Page 3

... Input High Voltage SYNC LEVEL INPUT (AD8142) Input Voltage Range Setting to Achieve 0.5 V Pulse Levels Gain to Red Common-Mode Output Gain to Green Common-Mode Output Gain to Blue Common-Mode Output = 1.5 V (AD8141 and SYNC LEVEL = 0 V (AD8142), unless otherwise noted. OCM SYNC SYNC Test Conditions/Comments ...

Page 4

... DIS Assert Time DIS Deassert Time Differential Output Impedance Magnitude With DIS Asserted ISOLATION Input-to-Output Test Conditions/Comments Positive supply AD8141/AD8142 Disabled 1 MHz, each output, DIS input MHz, each output, DIS input MHz, each output, DIS input ...

Page 5

... Even temporarily exceeding this temperature limit can change the stresses that the package exerts on the die, permanently shifting the parametric performance of the AD8141/AD8142. Exceeding a junction temperature of 175°C for an extended period can result in changes in the silicon devices potentially causing failure. ...

Page 6

... AD8141/AD8142 PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS Table 4. AD8141 Pin Function Descriptions Pin No. Mnemonic Description 1 DIS Disable. This pin places outputs in high-Z condition and lowers supply current 14 /GND Negative Power Supply Voltage. S− 3 −IN A Inverting Input, Amplifier A. 4 +IN A Noninverting Input, Amplifier A. ...

Page 7

... Horizontal Sync Pulse Input with Respect to Ground. Vertical Sync Pulse Input with Respect to Ground. Noninverting Input, Green Amplifier. Inverting Input, Green Amplifier. Connect Exposed Paddle to Ground. Rev Page AD8141/AD8142 /GND controls the amplitude of the sync pulses S− ...

Page 8

... OUT, dm 6.6 6.5 6.4 6.3 6.2 6.1 6.0 5.9 5.8 AD8141 AD8142 5 FREQUENCY (MHz) Figure 8. Small Signal 0.1 dB Flatness = 1.5 V (AD8141 OCM SYNC SYNC 100 200mV p-p OUT, dm 100 1k = 2.5 V (AD8141) Figure 10. Large Signal Frequency Response at V OCM 100 1k Rev Page and SYNC LEVEL = 0 V (AD8142), unless otherwise noted. ...

Page 9

... Figure 16. –30 DIS INPUT VOLTAGE = 5V –40 –50 –60 –70 –80 – Figure 17. Disabled Input-to-Output Isolation vs. Frequency Rev Page AD8141/AD8142 100 1k 10k 100k 1M 10M FREQUENCY (Hz p-p HD2 HD3 1 10 FREQUENCY (MHz) AD8142 Harmonic Distortion vs. Frequency 10 100 ...

Page 10

... TIME (ns) Figure 22. Disable Response Time 1.5 AD8141 1.0 0.5 0 –0.5 –1.0 –1 TIME (ns) Figure 23. Large Signal Transient Response AD8141 V – S AD8142 V – +2.5V = –2. GND –5 360 400 AD8142 ...

Page 11

... Rev Page AD8141/AD8142 TIME (ns) = 2.5 V (AD8141) OCM V = +2. –2.5V S– OCM SINGLE-ENDED DRIVE 2× INPUT V _DIFF OUT 0 100 200 300 400 500 600 700 ...

Page 12

... Rev Page 4 2.5V OCM 3.5 3 1.5V OCM 2.5 2.0 1.5 1.0 0 TIME (ns) Figure 32. V Large Signal Transient Response (AD8141) OCM –40 ∆V /∆V OUT, dm OCM ∆ p-p OCM –45 –50 –55 –60 –65 –70 – 100 FREQUENCY (MHz) Figure 33. V Common-Mode Rejection vs. Frequency OCM ...

Page 13

... AD8142 Output Common-Mode Signals for Various Sync Pulse Inputs + AD8141/AD8142 50Ω 1kΩ 2kΩ 52.3Ω 52.3Ω 50Ω 1kΩ 2kΩ MIDSUPPLY V S– Figure 35. Basic Test Circuit Rev Page AD8141/AD8142 17.5 SYNC LEVEL = 0.5V 12.5 7.5 V SYNC 2.5 –2 100 0.1µF ON ALL V PINS S+ – 200Ω ...

Page 14

... AD8141/AD8142 TERMINOLOGY Differential Voltage Differential voltage refers to the difference between two node voltages that are balanced with respect to each other. For example, in Figure 36, the output differential voltage (or output differential mode voltage) is defined − OUT Common-mode voltage refers to the average of two node voltages with respect to a common reference (usually the local ground) ...

Page 15

... The input impedance of the circuit is higher than for a conventional op amp connected as an inverter because a fraction of the differential output voltage appears at the inputs as a common-mode signal, partially bootstrapping the voltage across the input resistor R Rev Page AD8141/AD8142 and V in Figure 36. For most purposes, this ...

Page 16

... R = 38.3 Ω. Note that the lower feedback loop 2kΩ 38.8Ω 1kΩ AD8141 AD8142 G 1kΩ – 38.3Ω – 2kΩ is increased in both loops Ω alone. These T and R , however, the ...

Page 17

... MIRROR R Figure 41. Sync-On-Common-Mode Simplified Circuit Rev Page AD8141/AD8142 includes on-chip, sync-on-common-mode circuitry and V SYNC SYNC , the common-mode output of all drivers is set at 1.5 V S− and SYNC LEVEL that determines the S− and V inputs is determined by SYNC ...

Page 18

... VIDEO SOURCE 38.3Ω 2kΩ DISABLE DIS V S– in Single-Ended-to-Differential Application on Single 5 V Supply (Sync Pulse Encoding Not Shown) Rev Page AD8141/AD8142 0.1µF ON ALL V S+ PINS 49.9Ω RED UTP 49.9Ω 49.9Ω GREEN UTP 49.9Ω 49.9Ω BLUE UTP 49.9Ω ...

Page 19

... – + – V SHIFT Figure 43. End-to-End Common-Mode Shifts due to Ground Shifts Rev Page AD8141/AD8142 = and SHIFT This is because the receiver ground is shifted AD8142on a single 5 V supply, but can be accomplished ...

Page 20

... The AD8141/AD8142output is disabled when the disable input AD8142 outputs, is driven to its high state, and the AD8141/AD8142operates in its normal fashion when the disable input is driven to its low state. An unavoidable common-mode glitch occurs at the outputs when switching between disabled and enabled states and vice versa ...

Page 21

... As described in the Theory of Operation section, the level sync pulses (see Table 1 for the exact levels). In many cases, the sync pulses can be applied directly from video card VGA connector outputs. Rev Page AD8141/AD8142 100Ω 0.7V –1.0V PULSES SYNC ...

Page 22

... AMPLIFIER-TO-AMPLIFIER ISOLATION The least amount of isolation between the three exists between the green and red channels (Amplifier A and Amplifier B for the AD8141). This is, therefore, viewed as the worst-case isolation, which is reflected in Table 1 and the Theory of Operation section. EXPOSED PADDLE (EPAD) The 24-lead LFCSP package has an exposed paddle on the underside of its body ...

Page 23

... + 80.6Ω 38.3Ω Figure 49. Typical AD8142 Application Circuit on a Single 5 V Supply Rev Page AD8141/AD8142 49.9Ω – 0.01µF DIFFERENTIAL BLUE VIDEO OUT 49.9Ω + 49.9Ω – 49.9Ω DIFFERENTIAL GREEN VIDEO OUT + 49.9Ω + 0.01µF DIFFERENTIAL RED VIDEO OUT 49.9Ω ...

Page 24

... SEATING PLANE ORDERING GUIDE 1 Model Temperature Package AD8141ACPZ-R2 −40°C to +85°C AD8141ACPZ-RL −40°C to +85°C AD8141ACPZ-R7 −40°C to +85°C AD8142ACPZ-R2 −40°C to +85°C AD8142ACPZ-RL −40°C to +85°C AD8142ACPZ-R7 −40°C to +85°C AD8142-EVALZ RoHS Compliant Part. ...

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