Datasheet

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High Speed, Triple Differential

Receiver with Comparators

AD8143

Rev. 0

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FEATURES

High speed

160 MHz large signal bandwidth

1000 V/μs slew rate @ G = 1, V

= 2 V p-p

High CMRR: 65 dB @ 10 MHz

High differential input impedance: 5 MΩ

Input common-mode range: ±10.5 V (±12 V supplies)

User-adjustable gain

Wide power supply range: +5 V to ±12 V

Fast settling: 8 ns to 1%

Disable feature

Low offset: ±3.4 mV on 5 V supply

2 on-chip comparators

Small packaging: 32-lead, 5 mm × 5 mm LFCSP

APPLICATIONS

RGB video receivers

KVM (keyboard-video-mouse)

UTP (unshielded twisted pair) receivers

PIN CONFIGURATION

REF_G

GND

IN+_G

FB_G

REF_R

IN–_G

GND

FB_R

OUT_B

GND

OUT_R

OUT_G

COMPB_IN+

S+

GND

COMPB_IN–

IN–_B

GND

FB_B

IN+_B

DIS/PD

REF_B

GND

S–

IN+_R

GND

COMPA_IN+

IN–_R

COMPA_OUT

COMPA_IN–

GND

COMPB_OUT

AD8143

05538-001

32 31 30 29 28 27 26 25

9 10111213141516

Figure 1.

GENERAL DESCRIPTION

The AD8143 is a triple, low cost, differential-to-

single-ended receiver specifically designed for

receiving red-green-blue (RGB) signals over twisted

pair cable. It can also be used for receiving any type of

analog signal or high speed data transmission. Two

auxiliary comparators are provided to receive digital

or sync signals. The AD8143 can be used in conjunction

with the

AD8133 and AD8134 triple, differential

drivers to provide a complete low cost solution for

RGB over Category-5 UTP cable applications,

including KVM.

The excellent common-mode rejection (65 dB @

10 MHz) of the AD8143 allows for the use of low cost

unshielded twisted pair cables in noisy environments.

The AD8143 has a wide power supply range from single +5 V

supply to ±12 V, which allows for a wide common-mode range.

The wide common-mode input range of the AD8143 maintains

signal integrity in systems where the ground potential is a few

volts different between the drive and receive ends without the

use of isolation transformers.

The AD8143 is stable at a gain of 1. Closed-loop gain is easily

set using external resistors.

The AD8143 is available in a 5 mm × 5 mm, 32-lead LFCSP and

is rated to work over the extended industrial temperature range

of −40°C to +85°C.

Summary of content (24 pages)

PAGE 1
High Speed, Triple Differential Receiver with Comparators AD8143 IN–_B IN+_B FB_B REF_B DIS/PD VS– GND PIN CONFIGURATION High speed 160 MHz large signal bandwidth 1000 V/μs slew rate @ G = 1, VO = 2 V p-p High CMRR: 65 dB @ 10 MHz High differential input impedance: 5 MΩ Input common-mode range: ±10.5 V (±12 V supplies) User-adjustable gain Wide power supply range: +5 V to ±12 V Fast settling: 8 ns to 1% Disable feature Low offset: ±3.
PAGE 2
AD8143 TABLE OF CONTENTS Features .............................................................................................. 1 Overview ..................................................................................... 18 Applications....................................................................................... 1 Basic Closed-Loop Gain Configurations ................................ 18 Pin Configuration.............................................................................
PAGE 3
AD8143 SPECIFICATIONS VS = ±12 V, TA = 25°C, REF = 0 V, RL = 150 Ω, CL = 2 pF, G = 1, TMIN to TMAX = −40°C to +85°C, unless otherwise noted. Table 1. Parameter DYNAMIC PERFORMANCE −3 dB Bandwidth Bandwidth for 0.
PAGE 4
AD8143 Parameter POWER-DOWN PERFORMANCE Power-Down VIH Power-Down VIL Power-Down IIH Power-Down IIL Power-Down Assert Time POWER SUPPLY Operating Range Quiescent Current, Positive Supply Quiescent Current, Negative Supply PSRR, Positive Supply PSRR, Negative Supply Conditions Min Typ VS+ − 1.5 VS+ − 2.5 1.0 800 0.5 PD = VCC PD = GND 4.5 44.0 37.0 −75 −82 DC DC Rev. 0 | Page 4 of 24 Max Unit V V μA μA μs 24 57.5 51.
PAGE 5
AD8143 VS = ±5 V, TA = 25°C, REF = 0 V, RL = 150 Ω, CL = 2 pF, G = 1, TMIN to TMAX = −40°C to +85°C, unless otherwise noted. Table 2. Parameter DYNAMIC PERFORMANCE −3 dB Bandwidth Bandwidth for 0.
PAGE 6
AD8143 Parameter POWER-DOWN PERFORMANCE Power-Down VIH Power-Down VIL Power-Down IIH Power-Down IIL Power-Down Assert Time POWER SUPPLY Operating Range Quiescent Current, Positive Supply Quiescent Current, Negative Supply PSRR, Positive Supply PSRR, Negative Supply Conditions Min Typ Max VS+ − 1.5 VS+ − 2.5 1 230 0.5 PD = VCC PD = GND 4.5 39.0 34.5 −80 −80 DC DC Rev. 0 | Page 6 of 24 Unit V V μA μA μs 24 49.5 43.
PAGE 7
AD8143 VS = 5 V, TA = 25°C, REF = +2.5 V, RL = 150 Ω, CL = 2 pF, G = 1, TMIN to TMAX = −40°C to +85°C, unless otherwise noted. Table 3. Parameter DYNAMIC PERFORMANCE −3 dB Bandwidth Bandwidth for 0.
PAGE 8
AD8143 Parameter POWER SUPPLY Operating Range Quiescent Current, Positive Supply PSRR, Positive Supply Conditions Min Typ Max Unit 31.5 −86 24 38.8 −76 V mA dB 4.5 DC Rev.
PAGE 9
AD8143 ABSOLUTE MAXIMUM RATINGS Table 4. Rating 24 V See Figure 2 –65°C to +125°C –40°C to +85°C 300°C 150°C Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
PAGE 10
AD8143 GND IN–_B IN+_B FB_B REF_B DIS/PD VS– GND PIN CONFIGURATION AND FUNCTION DESCRIPTIONS 32 31 30 29 28 27 26 25 GND 1 24 GND REF_G 2 23 OUT_B FB_G 3 22 OUT_G IN+_G 4 21 OUT_R IN–_G 5 20 VS+ REF_R 6 19 COMPB_IN+ 18 COMPB_IN– 17 GND AD8143 TOP VIEW (Not to Scale) 12 13 14 15 16 GND 11 COMPB_OUT 10 COMPA_OUT GND 9 COMPA_IN– 8 COMPA_IN+ GND A IN–_R 7 IN+_R FB_R 05538-050 B Figure 3.
PAGE 11
AD8143 TYPICAL PERFORMANCE CHARACTERISTICS Unless otherwise noted, G = 1, RL = 150 Ω, CL = 2 pF, VS = ±5 V, TA = 25°C. Refer to the circuit in Figure 38. 3 3 2 2 VS = ±5 1 1 0 0 –1 GAIN (dB) GAIN (dB) VS = ±12 VS = ±12 –2 –3 –4 –1 –2 VS = ±5 –3 –4 VS = +5 –5 –6 –7 1 VOUT = 2V p-p 05538-002 VOUT = 0.2V p-p 10 VS = +5 05538-005 –5 –6 –7 100 1 10 FREQUENCY (MHz) 100 FREQUENCY (MHz) Figure 4. Small Signal Frequency Response at Various Power Supplies, G = 1 Figure 7.
PAGE 12
AD8143 5 5 4 4 G = 1, CL = 10pF, RSNUB = 40Ω 3 3 G = 1, CL = 2pF 2 1 0 –1 G = 2, CL = 2pF G = 2, CL = 10pF, RSNUB = 40Ω 1 GAIN (dB) 0 G = 2, CL = 2pF –1 –2 G = 1, CL = 2pF –2 –3 –3 –4 05538-013 RL = 1kΩ VOUT = 0.2V p-p –5 1 10 100 RL = 1kΩ VOUT = 2V p-p –4 05538-014 GAIN (dB) G = 1, CL = 10pF, RSNUB = 40Ω G = 2, CL = 10pF, RSNUB = 40Ω 2 –5 1 1000 10 FREQUENCY (MHz) 100 1000 FREQUENCY (MHz) Figure 10.
PAGE 13
AD8143 100 100 VS = ±12V 80 70 60 +5V 50 40 ±5V 30 20 10 0 0.1 1 10 10 0.00001 1000 100 05538-021 INPUT VOLTAGE NOISE (nV/√Hz) ±12V 05538-020 COMMON-MODE REJECTION (dB) 90 0.0001 0.001 FREQUENCY (MHz) 0.01 0.1 10 1 FREQUENCY (MHz) Figure 16. Common-Mode Rejection Ratio vs. Frequency at Various Supplies Figure 19. Input Referred Voltage Noise vs. Frequency 200 1.5 VOUT = 0.2V p-p VOUT = 2V p-p 150 1.0 0.
PAGE 14
AD8143 1.25 0.5 1.00 0.4 0.75 INPUT 0.3 0.50 0.2 1400 0 0 –0.25 –0.1 –0.50 –0.2 +SR, RL = 150Ω –SR, RL = 150Ω +SR, RL = 1kΩ –SR, RL= 1kΩ 600 400 –0.3 OUTPUT –1.00 –1.25 0 800 –0.4 10 20 30 40 50 60 70 80 90 –0.5 100 200 05538-023 –0.75 SLEW RATE (V/μs) 0.1 ERROR ERROR (%) 0.25 1000 05538-027 VOLTAGE (V) 1200 0 0 Figure 22. Settling Time (0.1%) at Various Loads 1.0 1.5 2.0 2.5 –50 –30 –55 –40 VS = ±12V –65 4.0 4.
PAGE 15
54 4 52 3 OUTPUT VOLTAGE (V) IS+ 50 48 46 44 IS– 42 2 1 0 –1 –2 VS = ±12V RL = ∞ 38 –5 –4 –3 –2 –1 0 1 2 3 –3 –4 –5 5 4 05538-026 40 05538-022 –4 –3 DIFFERENTIAL INPUT VOLTAGE (V) Figure 28. Power Supply Current vs. Differential Input Voltage at ±12 V Supplies 60 0 1 2 3 4 5 Figure 31.
PAGE 16
AD8143 15 10 3.5 VS = ±12V +VSAT_±12V 3.0 VS = ±5V 5 2.5 +VSAT_±5V VOUT (V) OUTPUT VOLTAGE (V) 4.0 G = +2 (RF = RG = 499Ω) AND VS = ±5V G = +5 (RF = 8.06kΩ RG = 2kΩ) AND VS = ±12V 0 2.0 1.5 –5 –VSAT_±5V 1.0 –10 0 100 200 300 400 500 600 700 800 900 0 –25 1000 OUTPUT LOAD (Ω) 2 × VIN G=2 4 3 1 0 –1 OUTPUT –3 –4 05538-029 VOLTAGE (V) 2 –5 –6 0 100 200 300 400 500 600 –15 –10 –5 0 5 10 Figure 36. Comparator Hysteresis 6 –2 –20 VIN (mV) Figure 34.
PAGE 17
AD8143 THEORY OF OPERATION The AD8143 amplifiers use an architecture called active feedback, which differs from that of conventional op amps. The most obvious differentiating feature is the presence of two separate pairs of differential inputs compared to a conventional op amp’s single pair. Typically, for the active-feedback architecture, one of these input pairs is driven by a differential input signal, while the other is used for the feedback.
PAGE 18
AD8143 APPLICATIONS The AD8143 contains three independent active-feedback amplifiers that can be effectively applied as differential line receivers for red-green-blue (RGB) signals or component video, such as YPbPr, signals transmitted over unshielded-twisted-pair (UTP) cable.
PAGE 19
AD8143 In many dual-supply applications, VREF can be directly connected to ground right at the device. INPUT CLAMPING TERMINATING THE INPUT One of the key benefits of the active-feedback architecture is the separation that exists between the differential input signal and the feedback network. Because of this separation, the differential input maintains its high CMRR and provides high differential and common-mode input impedances, making line termination a simple task.
PAGE 20
AD8143 A simple way to implement a clamp is to use a number of diodes in series. The resultant clamping voltage is then the sum of the clamping voltages of individual diodes. A 1N4448 diode has a forward voltage of approximately 0.70 V to 0.75 V at typical current levels that are seen when it is being used as a clamp, and 2 pF maximum capacitance at 0 V bias. (The capacitance of a diode decreases as its reverse bias voltage is increased.
PAGE 21
AD8143 Typically, the input signals are received over 100 Ω differential transmission lines. A 100 Ω differential transmission line is readily realized on the printed circuit board using two wellmatched, closely-spaced 50 Ω single-ended traces that are coupled through the ground plane. The traces that carry the single-ended output signals are most often 75 Ω for video signals.
PAGE 22
AD8143 DRIVING A CAPACITIVE LOAD The AD8143 typically drives either high impedance loads, such as crosspoint switch inputs, or doubly terminated coaxial cables. A gain of 1 is commonly used in the high impedance case because the 6 dB transmission line termination loss is not incurred. A gain of 2 is required when driving cables to compensate for the 6 dB termination loss.
PAGE 23
AD8143 where: The AD8134 encoding equations are given in Equation 3, Equation 4, and Equation 5. [ Green VCM = Blue VCM ] [ [ K is a an adjustable gain constant that is set by the AD8134. ] (4) ] (5) K −2 V 2 K = V +H 2 (3) Red VCM, Green VCM, and Blue VCM are the transmitted commonmode voltages of the respective color signals.
PAGE 24
AD8143 OUTLINE DIMENSIONS 0.60 MAX 5.00 BSC SQ 0.60 MAX 25 24 PIN 1 INDICATOR TOP VIEW 0.50 BSC 4.75 BSC SQ 0.50 0.40 0.30 12° MAX 1.00 0.85 0.80 PIN 1 INDICATOR 32 1 EXPOSED PAD (BOTTOM VIEW) 17 16 3.45 3.30 SQ 3.15 9 8 0.25 MIN 3.50 REF 0.80 MAX 0.65 TYP 0.05 MAX 0.02 NOM SEATING PLANE 0.30 0.23 0.18 0.20 REF COPLANARITY 0.08 COMPLIANT TO JEDEC STANDARDS MO-220-VHHD-2 Figure 49.