ANALOG DEVICES ADA4861-3 Service Manual

High Speed, Low Cost,

www.BDTIC.com/ADI

FEATURES

High speed

730 MHz, −3 dB bandwidth
625 V/μs slew rate

13 ns settling time to 0.5%
Wide supply range: 5 V to 12 V
Low power: 6 mA/amplifier

0.1 dB flatness: 100 MHz
Differential gain: 0.01%
Differential phase: 0.02°
Low voltage offset: 100 μV (typical)
High output current: 25 mA
Power down

APPLICATIONS

Consumer video
Professional video
Broadband video
ADC buffers
Active filters

GENERAL DESCRIPTION

The ADA4861-3 is a low cost, high speed, current feedback,
triple op amp that provides excellent overall performance. The
730 MHz, −3 dB bandwidth, and 625 V/μs slew rate make this
amplifier well suited for many high speed applications. With its
combination of low price, excellent differential gain (0.01%),
differential phase (0.02°), and 0.1 dB flatness out to 100 MHz,
this amplifier is ideal for both consumer and professional video
applications.

The ADA4861-3 is designed to operate on supply voltages as
lo

w as +5 V and up to ±5 V using only 6 mA/amplifier of supply
current. To further reduce power consumption, each amplifier
is equipped with a power-down feature that lowers the supply
current to 0.3 mA/amplifier when not being used.

The ADA4861-3 is available in a 14-lead SOIC_N package and

ned to work over the extended temperature range of

is desig

−40°C to +105°C.

Triple Op Amp

ADA4861-3

PIN CONFIGURATION

+V

+IN 1

–IN 1

OUT 1

1

2

3

4

S

5

6

7

ADA4861-3

POWER DOW N 1

POWER DOW N 2

POWER DOW N 3

Figure 1.

6.1

6.0

5.9

5.8

5.7

5.6

5.5

5.4

CLOSED-LOOP GAIN (dB)

5.3

5.2

5.1

0.1 1 10 100 1000

FREQUENCY (MHz)

Figure 2. Large Signal 0.1 dB Flatness

VS = +5V

14

13

12

11

10

9

8

OUT 2

–IN 2

+IN 2

–V

S

+IN 3

–IN 3

OUT 3

G = +2
V

OUT

R

= RG = 301Ω

F

05708-001

= 2V p-p

= ±5V

V

S

05708-011

Rev. A

Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
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.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] ©2006 Analog Devices, Inc. All rights reserved.

ADA4861-3

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TABLE OF CONTENTS

Features.............................................................................................. 1

Gain Configurations .................................................................. 13

Applications....................................................................................... 1

Pin Configuration............................................................................. 1

General Description ......................................................................... 1

Revision History ............................................................................... 2

Specifications..................................................................................... 3

Absolute Maximum Ratings............................................................ 5

Thermal Resistance ...................................................................... 5

ESD Caution.................................................................................. 5

Typical Performance Characteristics ............................................. 6

Applications..................................................................................... 13

REVISION HISTORY

3/06—Rev 0 to Rev. A

Changes to 20 MHz Active Low-Pass Filter Section.................. 13

Changes to Figure 48 and Figure 49............................................. 13

10/05—Revision 0: Initial Version

20 MHz Active Low-Pass Filter................................................ 13

RGB Video Driver...................................................................... 14

Driving Two Video Loads ......................................................... 14

POWER-DOWN Pins ............................................................... 14

Single-Supply Operation........................................................... 15

Power Supply Bypassing............................................................ 15

Layout .......................................................................................... 15

Outline Dimensions....................................................................... 16

Ordering Guide .......................................................................... 16

Rev. A | Page 2 of 16

ADA4861-3

www.BDTIC.com/ADI

SPECIFICATIONS

VS = +5 V (@ TA = 25°C, G = +2, RL = 150 Ω, CL = 4 pF, unless otherwise noted); for G = +2, RF = RG = 301 Ω; and for G = +1, RF = 499 Ω.

Table 1.

Parameter Conditions Min Typ Max Unit

DYNAMIC PERFORMANCE

–3 dB Bandwidth VO = 0.2 V p-p 350 MHz
V
G = +1, VO = 0.2 V p-p 560 MHz

Bandwidth for 0.1 dB Flatness VO = 2 V p-p 85 MHz

+Slew Rate (Rising Edge) VO = 2 V p-p 590 V/μs

−Slew Rate (Falling Edge) VO = 2 V p-p 480 V/μs

Settling Time to 0.5% (Rise/Fall) VO = 2 V step 12/13 ns
NOISE/DISTORTION PERFORMANCE

Harmonic Distortion HD2/HD3 fC = 1 MHz, VO = 2 V p-p −81/−89 dBc

Harmonic Distortion HD2/HD3 fC = 5 MHz, VO = 2 V p-p −69/−76 dBc

Input Voltage Noise f = 100 kHz 3.8 nV/√Hz

Input Current Noise f = 100 kHz, +IN/−IN 1.7/5.5 pA/√Hz

Differential Gain 0.02 %

Differential Phase 0.03 Degrees

All-Hostile Crosstalk

DC PERFORMANCE

Input Offset Voltage −13 −0.9 +13 mV

+Input Bias Current

−Input Bias Current −8 +2.3 +13 μA

Open-Loop Transresistance 400 620 kΩ
INPUT CHARACTERISTICS

Input Resistance +IN 14 MΩ

−IN 85 Ω

Input Capacitance +IN 1.5 pF

Input Common-Mode Voltage Range G = +1 1.2 to 3.8 V

Common-Mode Rejection Ratio VCM = 2 V to 3 V −54 −56.5 dB
POWER-DOWN PINS

Input Voltage Enabled 0.6 V

Power down 1.8 V

Bias Current Enabled −3 μA

Power down 115 μA

Turn-On Time 200 ns

Turn-Off Time 3.5 μs
OUTPUT CHARACTERISTICS

Output Overdrive Recovery Time (Rise/Fall) VIN = +2.25 V to −0.25 V 55/100 ns

Output Voltage Swing RL = 150 Ω 1.2 to 3.8 1.1 to 3.9 V

R

Short-Circuit Current Sinking and sourcing 65 mA
POWER SUPPLY

Operating Range 5 12 V

Total Quiescent Current Enabled 12.5 16.1 18.5 mA

Quiescent Current/Amplifier POWER DOWN pins = +VS 0.2 0.33 mA

Power Supply Rejection Ratio

+PSR +VS = 4 V to 6 V, −VS = 0 V −60 −64 dB

= 2 V p-p 145 MHz

O

Amplifier 1 and Amplifier 2 driven,
Amplifier 3 output measur

−2 −0.8 +1 μA

= 1 kΩ 0.9 to 4.1 0.85 to 4.15 V

L

ed, f = 1 MHz

−65 dB

Rev. A | Page 3 of 16

ADA4861-3

www.BDTIC.com/ADI

VS = ±5 V (@ TA = 25°C, G = +2, RL = 150 Ω, CL = 4 pF, unless otherwise noted); for G = +2, RF = RG = 301 Ω; and for G = +1, RF = 499 Ω.

Table 2.

Parameter Conditions Min Typ Max Unit

DYNAMIC PERFORMANCE

–3 dB Bandwidth VO = 0.2 V p-p 370 MHz
V
G = +1, VO = 0.2 V p-p 730 MHz

Bandwidth for 0.1 dB Flatness VO = 2 V p-p 100 MHz

+Slew Rate (Rising Edge) VO = 2 V p-p 910 V/μs

−Slew Rate (Falling Edge) VO = 2 V p-p 680 V/μs

Settling Time to 0.5% (Rise/Fall) VO = 2 V step 12/13 ns
NOISE/DISTORTION PERFORMANCE

Harmonic Distortion HD2/HD3 fC = 1 MHz, VO = 2 V p-p −85/−99 dBc

Harmonic Distortion HD2/HD3 fC = 5 MHz, VO = 2 V p-p −73/−86 dBc

Input Voltage Noise f = 100 kHz 3.8 nV/√Hz

Input Current Noise f = 100 kHz, +IN/−IN 1.7/5.5 pA/√Hz

Differential Gain 0.01 %

Differential Phase 0.02 Degrees

All-Hostile Crosstalk

DC PERFORMANCE

Input Offset Voltage −13 −0.1 +13 mV

+Input Bias Current

−Input Bias Current −8 +2.9 +13 μA

Open-Loop Transresistance 500 720 kΩ
INPUT CHARACTERISTICS

Input Resistance +IN 15 MΩ

−IN 90 Ω

Input Capacitance +IN 1.5 pF

Input Common-Mode Voltage Range G = +1 −3.7 to +3.7 V

Common-Mode Rejection Ratio VCM = ±2 V −55 −58 dB
POWER-DOWN PINS

Input Voltage Enabled −4.4 V

Power down −3.2 V

Bias Current Enabled −3 μA

Power down 250 μA

Turn-On Time 200 ns

Turn-Off Time 3.5 μs
OUTPUT CHARACTERISTICS

Output Overdrive Recovery Time (Rise/Fall) VIN = ±3.0 V 30/90 ns

Output Voltage Swing RL = 150 Ω ±2 −3.1 to +3.65 V

R

Short-Circuit Current Sinking and sourcing 100 mA
POWER SUPPLY

Operating Range 5 12 V

Total Quiescent Current Enabled 13.5 17.9 20.5 mA

Quiescent Current/Amplifier POWER DOWN pins = +VS 0.3 0.5 mA

Power Supply Rejection Ratio

+PSR +VS = 4 V to 6 V, −VS = −5 V −63 −66 dB

−PSR

= 2 V p-p 210 MHz

O

Amplifier 1 and Amplifier 2 driven,
Amplifier 3 output measur

−2 −0.7 +1 μA

= 1 kΩ ±3.9 ±4.05 V

L

= 5 V, −VS = −4 V to −6 V,

+V

S

POWER DOWN pins = −V

ed, f = 1 MHz

S

−65 dB

−59 −62 dB

Rev. A | Page 4 of 16

ADA4861-3

www.BDTIC.com/ADI

ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter Rating

Supply Voltage 12.6 V
Power Dissipation See Figure 3
Common-Mode Input Voltage −VS + 1 V to +VS − 1 V
Differential Input Voltage ±VS
Storage Temperature −65°C to +125°C
Operating Temperature Range −40°C to +105°C
Lead Temperature JEDEC J-STD-20
Junction Temperature 150°C

Stresses above those listed under Absolute Maximum Ratings

y cause permanent damage to the device. This is a stress

ma
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.

THERMAL RESISTANCE

θJA is specified for the worst-case conditions, that is, θJA is
specified for device soldered in circuit board for surface-mount
packages.

Table 4. Thermal Resistance

Package Type θJA Unit

14-lead SOIC_N 90 °C/W

Maximum Power Dissipation

The maximum safe power dissipation for the ADA4861-3 is
limited by the associated rise in junction temperature (T
the die. At approximately 150°C, which is the glass transition
temperature, the plastic changes its properties. Even temporarily
exceeding this temperature limit can change the stresses that the
package exerts on the die, permanently shifting the parametric
performance of the amplifiers. Exceeding a junction temperature of
150°C for an extended period can result in changes in silicon
devices, potentially causing degradation or loss of functionality.

) on

J

The power dissipated in the package (P
quiescent power dissipation and the power dissipated in the die
due to the amplifiers’ drive at the output. The quiescent power
is the voltage between the supply pins (V
current (I

).

S

= Quiescent Power + (Total Drive Power − Load Power)

P

D

VV

⎛

S

()

D

IVP

SS

OUT

×+×=

⎜

2

R

⎝

L

RMS output voltages should be considered.

Airflow increases heat dissipation, effectively reducing θ
In addition, more metal directly in contact with the package
leads and through holes under the device reduces θ

Figure 3 shows the maximum safe power dissipation in the

ackage vs. the ambient temperature for the 14-lead SOIC_N

p
(90°C/W) on a JEDEC standard 4-layer board. θ
approximations.

2.5

2.0

1.5

1.0

0.5

MAXIMUM POW ER DISSIPAT ION (W)

0

–55 125–45–35–25–15–5 5 152535455565758595105115

AMBIENT TEMPERATURE (°C)

Figure 3. Maximum Power Dissipation vs. Temperature for a 4-Layer Board

) is the sum of the

D

) times the quiescent

S

2

V

⎞

OUT

–

⎟

R

L

⎠

.

JA

values are

JA

.

JA

05708-002

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.

Rev. A | Page 5 of 16

ADA4861-3

www.BDTIC.com/ADI

TYPICAL PERFORMANCE CHARACTERISTICS

RL = 150 Ω and CL = 4 pF, unless otherwise noted.

1

0

VS = ±5V
V

= 0.2V p-p

OUT

G = +1,
R

= 499Ω

F

1

0

VS = 5V
V

OUT

= 0.2V p- p

G = +1, RF = 499Ω

–1

–2

–3

–4

NORMALIZED GAIN (dB)

–5

–6

0.1 1 10 100 1000

G = +2, RF = RG = 301Ω

G = –1, R

= RG = 301Ω

F

= 200Ω, RG = 49.9Ω

G = +5, R

F

G = +10, R

= 200Ω, RG = 22.1Ω

F

FREQUENCY (MHz)

Figure 4. Small Signal Frequency Response for Various Gains

1

VS = ±5V
V

= 2V p-p

OUT

0

–1

–2

–3

–4

NORMALIZED GAIN (dB)

–5

–6

G = +5, RF = 200Ω, RG = 49.9Ω

G = +1, RF = 499Ω

G = +2, RF = RG = 301Ω

G = +10, RF = 200Ω, RG = 22.1Ω

0.1 1 10 100 1000

FREQUENCY (MHz)

G = –1, RF = RG = 301Ω

–1

–2

–3

–4

NORMALIZED GAIN (dB)

–5

05708-038

–6

0.1 1 10 100 1000

G = –1, R

G = +5, R

G = +10, R

= RG = 301Ω

G = +2, R

F

= RG = 301Ω

F

= 200Ω, RG = 49.9Ω

F

= 200Ω, RG = 22.1Ω

F

FREQUENCY (MHz)

Figure 7. Small Signal Frequency Response for Various Gains

1

VS = 5V
V

= 2V p-p

OUT

0

–1

–2

–3

–4

NORMALIZED GAIN (dB)

–5

05708-028

–6

1 1 10 100 1000

0.

G = +1, RF = 499Ω

G = +2, RF = RG = 301Ω

G = +10, RF = 200Ω, RG = 22.1Ω

G = +5, RF = 200Ω, RG = 49.9Ω

G = –1, RF = RG = 301Ω

FREQUENCY (MHz)

05708-037

05708-027

Figure 5. Large Signal Frequency Response for Various Gains

6.1

6.0

5.9

5.8

5.7

5.6

5.5

5.4

CLOSED-LOOP GAIN (dB)

5.3

5.2

5.1

0.1 1 10 100 1000

FREQUENCY (MHz)

VS = +5V

G = +2
V

= 2V p-p

OUT

R

= RG = 301Ω

F

V

S

= ±5V

05708-011

Figure 6. Large Signal 0.1 dB Flatness

Rev. A | Page 6 of 16

Figure 8. Large Signal Frequency Response for Various Gains

7

VS = ±5V
G = +2

6

5

= 2V p-p

V

V

OUT

OUT

= 4V p-p

4

3

2

CLOSED-LOOP GAIN (dB)

1

0

0.1 1 10 100 1000

FREQUENCY (MHz)

V

OUT

= 1V p-p

Figure 9. Large Signal Frequency Response for Various Output Levels

05708-029

ADA4861-3

–

–

–

–

www.BDTIC.com/ADI

7

= 301Ω

R

6

5

4

3

R

F

R

F

= 499Ω

= 604Ω

F

R

F

= 402Ω

7

= 301Ω

R

6

5

4

3

R

F

R

F

= 499Ω

= 604Ω

F

R

F

= 402Ω

2

CLOSED-LOOP GAIN (dB)

VS = ±5V

1

G = +2
R

= R

G

F

V

= 0.2V p- p

OUT

0

0.1 1 10 100 1000

FREQUENCY (MHz )

Figure 10. Small Signal Frequency Response vs. R

05708-012

F

2

CLOSED-LOOP GAIN (dB)

VS = ±5V

1

G = +2
R

= R

F

G

V

= 2V p-p

OUT

0

0.1 1 10 100 1000

Figure 13. Large Signal Frequency Response vs. R

40

VS = ±5V
G = +1

–50

–60

V

= 2V p-p

OUT

–70

HD2

–80

DISTORTION (dBc)

–90

–100

15

V

= 3V p-p

OUT

HD2

FREQUENCY (MHz)

V

= 3V p-p

OUT

HD3

10

V

= 2V p-p

OUT

HD3

05708-049

0

Figure 11. Harmonic Distortion vs. Frequency

40

VS=±5V
G=+2

–50

–60

V

=2Vp-p

OUT

HD2

150

DISTORTION (dBc)

–70

–80

–90

–100

Figure 14. Harmonic Distortion vs. Frequency

DISTORTION (dBc)

–50

–60

–70

–80

–90

–100

40

V

=5V

S

G=+1

V

V

OUT

OUT

=2Vp-p

HD2

=1Vp-p

HD2

V

OUT

V

OUT

=2Vp-p

HD3

=1Vp-p

HD3

DISTORTION (dBc)

–50

–60

–70

–80

–90

–100

40

VS=5V
G=+2

V

OUT

=2Vp-p

HD2

V

OUT

=3Vp-p

HD2

FREQUENCY (MHz )

V

FREQUENCY (MHz)

V

=2Vp-p

OUT

HD3

V

OUT

10

OUT

V

OUT

=2Vp-p

HD3

=1Vp-p

HD3

=3Vp-p

HD3

V

OUT

F

=1Vp-p

HD2

05708-013

05708-051

–110

15

FREQUENCY (MHz)

10

05708-048

0

Figure 12. Harmonic Distortion vs. Frequency

Rev. A | Page 7 of 16

–110

150

FREQUENCY (MHz)

10

05708-050

Figure 15. Harmonic Distortion vs. Frequency

ADA4861-3

www.BDTIC.com/ADI

200

2.7

200

2.7

VS = +5V

OUTPUT VOL TAGE (mV)

100

= 5V

S

±V

–100

–200

0

G = +1
V

OUT

TIME = 5ns/DIV

= ±5V

V

S

= 0.2V p-p

2.6

2.5

2.4

2.3

Figure 16. Small Signal Transient Response for Various Supplies

200

CL = 9pF

= 6pF

C

L

100

= 4pF

C

L

0

OUTPUT VOLTAGE (mV)

–100

–200

VS = ±5V
G = +1
V

= 0.2V p-p

OUT

TIME = 5ns/DIV

Figure 17. Small Signal Transient Response for Various Capacitor Loads

2.7
CL = 9pF

= 6pF

C

L

= +5V

V

S

100

= 0V

S

= 5V

0

S

= 5V, –V

S

+V

OUTPUT VO LTAGE (V )

05708-015

±V

OUTPUT VOL TAGE (mV)

–100

–200

VS = ±5V

G = +2

= 0.2V p-p

V

OUT

TIME = 5ns/DIV

Figure 19. Small Signal Transient Response for Various Supplies

200

CL = 9pF

100

0

OUTPUT VOLTAGE (mV)

–100

05708-040

–200

C

= 4pF

L

= 6pF

C

L

VS = ±5V
G = +2
V

= 0.2V p-p

OUT

TIME = 5ns/DIV

Figure 20. Small Signal Transient Response for Various Capacitor Loads

2.7

CL = 9pF

C

= 4pF

L

2.6

2.5

2.4

2.3

= 0V

S

= 5V, –V

S

+V

OUTPUT VO LTAGE (V )

05708-014

05708-042

2.6

= 4pF

C

L

2.5

OUTPUT VOLTAGE (V)

2.4

VS = 5V
G = +1
V

= 0.2V p-p

OUT

TIME = 5ns/DIV

2.3

05708-039

Figure 18. Small Signal Transient Response for Various Capacitor Loads

Rev. A | Page 8 of 16

2.6

= 6pF

C

L

2.5

OUTPUT VOLTAGE (V)

2.4
VS = 5V
G = +2
V

= 0.2V p-p

OUT

TIME = 5ns/DIV

2.3

Figure 21. Small Signal Transient Response for Various Capacitor Loads

05708-041

ADA4861-3

www.BDTIC.com/ADI

1.5
VS = +5V

4.0

1.5
VS = +5V

4.0

1.0

VS = ±5V

G = +1

= 2V p-p

V

OUT

TIME = 5ns/DIV

OUTPUT VO LTAGE (V )

= 5V

S

±V

–0.5

–1.0

–1.5

0.5

0

Figure 22. Large Signal Transient Response for Various Supplies

1.5
CL = 9pF

1.0

0.5

0

–0.5

OUTPUT VOLTAGE (V)

–1.0

–1.5

= 6pF

C

L

= 4pF

C

L

VS = ±5V
G = +1
V

= 2V p-p

OUT

TIME = 5ns/DIV

3.5

3.0

= 0V

S

2.5

= 5V, –V

S

2.0

+V

OUTPUT VO LTAGE (V )

1.5

05708-017

1.0

OUTPUT VO LTAGE (V )

= 5V

S

±V

–0.5

–1.0

–1.5

1.0

0.5

0

VS = ±5V

G = +2

= 2V p-p

V

OUT

TIME = 5ns/DIV

Figure 25. Large Signal Transient Response for Various Supplies

1.5
CL = 9pF

1.0

0.5

0

–0.5

OUTPUT VOLTAGE (V)

–1.0

05708-031

–1.5

C

= 6pF

L

= 4pF

C

L

VS = ±5V
G = +2
V

= 2V p-p

OUT

TIME = 5n s/DIV

3.5

3.0

2.5

2.0

1.5

1.0

= 0V

S

= 5V, –V

S

+V

OUTPUT VO LTAGE (V )

05708-016

05708-033

Figure 23. Large Signal Transient Response for Various Capacitor Loads

4.0
CL = 9pF

3.5

3.0

2.5

2.0

OUTPUT VOLTAGE (V)

1.5

1.0

C

= 6pF

L

C

= 4pF

L

VS = 5V
G = +1
V

= 2V p-p

OUT

TIME = 5ns/DIV

Figure 24. Large Signal Transient Response for Various Capacitor Loads

Figure 26. Large Signal Transient Response for Various Capacitor Loads

4.0
CL = 9pF

3.5

C

3.0

2.5

2.0

OUTPUT VOLTAGE (V)

1.5

05708-030

1.0

VS = 5V
G = +2
V

OUT

TIME = 5ns/DIV

= 4pF

L

= 2V p-p

C

= 6pF

L

05708-032

Figure 27. Large Signal Transient Response for Various Capacitor Loads

Rev. A | Page 9 of 16

ADA4861-3

www.BDTIC.com/ADI

1800

VS = ±5V
G = +1

160

0

1400

1200

1000

800

600

SLEW RATE (V/µs)

400

200

0

05

POSITIVE SLEW RATE

NEGATIVE SLEW RATE

INPUT VOLTAGE (V p-p)

05708-036

4.54.03.53.02.52.01.51.00.5

.0

Figure 28. Slew Rate vs. Input Voltage

700

= 5V

V

S

G = +1

600

500

400

POSITIVE SLEW RATE

NEGATIVE SLEW RATE

1400

1200

1000

SLEW RATE (V/µs)

= ±5V

V

S

G = +2

POSITIVE SLEW RATE

800

600

400

200

0

02.252.001.751.501.251.000.750.500.25 2.50

INPUT VOLTAGE (V p-p)

NEGATIVE SLEW RATE

Figure 31. Slew Rate vs. Input Voltage

700

= 5V

V

S

G = +2

600

500

400

POSITIVE SLEW RATE

NEGATIVE SLEW RATE

05708-018

300

SLEW RATE (V/µs)

200

100

0

022.01.51.00.5 3.0

INPUT VOLTAGE (V p-p)

Figure 29. Slew Rate vs. Input Voltage

–0.25

SETTLING TIME (%)

–0.50

–0.75

–1.00

1.00

0.75

0.50

0.25

1V

0

t = 0s

V

IN

VS = ±5V
G = +2
V
TIME = 5ns/DIV

Figure 30. Settling Time Rising Edge

300

SLEW RATE (V/µs)

200

100

.5

05708-021

1.00

0.75

0.50

0.25

–0.25

SETTLING TIME (%)

–0.50

OUT

= 2V p-p

05708-022

–0.75

–1.00

0

011.000.750.500.25 1.50

INPUT VOLTAGE (V p-p)

.25

Figure 32. Slew Rate vs. Input Voltage

t = 0s

1V

0

VS = ±5V
G = +2

= 2V p-p

V

OUT

TIME = 5ns/DIV

V

IN

Figure 33. Settling Time Falling Edge

05708-019

05708-020

Rev. A | Page 10 of 16

ADA4861-3

www.BDTIC.com/ADI

1000

100

PHASE

10

TRANSIMPEDANCE (kΩ)

1

0.1

0.01 0.1 1 10 100 1000

FREQUENCY (MHz)

TRANSIMPEDANCE

Figure 34. Transimpedance and Phase vs. Frequency

0

VS = ±5V
G = +2

–10

–20

–30

–40

–50

–60

POWER SUPPL Y REJECTIO N (dB)

–70

–80

0.01 0.1 1 10 100 1000

–PSR

+PSR

FREQUENCY (MHz)

VS = ±5V
G = +2

0

–45

–90

–135

–180

PHASE (Degrees)

05708-044

05708-023

0

VS = ±5V, +5V
G = +2

–10

V

= 2V p-p

OUT

–20

–30

–40

–50

–60

CROSSTALK ( dB)

–70

–80

–90

–100

0.1 1 10 100 1000

FREQUENCY (MHz)

Figure 37. Large Signal All-Hostile Crosstalk

0

VS = ±5V
G = +2
V

= 2V p-p

IN

–10

–20

–30

–40

–50

COMMON-MO DE REJECTI ON (dB)

–60

–70

0.01 0.1 1 10 100 1000

FREQUENCY (MHz )

05708-024

05708-045

Figure 35. Power Supply Reje

6

5

4

3

2

1

0

–1

–2

–3

OUTPUT AND INPUT VOL TAGE (V)

–4

–5

–6

0 1000900800700600500400300200100

Figure 36. Output Ove

ction vs. Frequency

INPUT VOLTAGE × 2

OUTPUT VOLTAGE

TIME (ns)

rdrive Recovery

VS = ±5V
G = +2
f = 1MHz

Figure 38. Common-Mode Rejection vs. Frequency

5.5

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

1.0

OUTPUT AND INPUT VOL TAGE (V)

0.5

05708-035

–0.

0

5

0 1000900800700600500400300200100

INPUT VOLTAGE × 2

OUTPUT VOLTAGE

TIME (ns)

VS = 5V
G = +2
f = 1MHz

Figure 39. Output Overdrive Recovery

Rev. A | Page 11 of 16

05708-034

ADA4861-3

V

www.BDTIC.com/ADI

35

VS = ±5V, +5V

30

60

VS = ±5V, +5V

50

25

20

15

10

INPUT VOLTAGE NOISE (nV/ Hz)

5

0

10 100 1k 10k 100k

FREQUENCY (Hz)

Figure 40. Input Voltage Noise vs. Frequency

19

18

17

16

15

TOTAL S UPPLY CURRENT (mA)

14

4 5 6 7 8 9 10 11 12

SUPPLY VOLTAGE (V)

40

30

20

NONINVERTI NG
INPUT

INPUT CURRENT NO ISE (pA/ Hz)

10

05708-052

0

10 100 1k 10k 100k

INVERTING INPUT

FREQUENCY (Hz)

Figure 43. Input Current Noise vs. Frequency

20

19

18

17

16

15

14

TOTAL S UPPLY CURRENT (mA)

13

05708-043

12

–40 1251109580655035205–10–25

VS = ±5V

V

= +5V

S

TEMPERATURE ( °C)

05708-053

05708-025

Figure 41. Total Supply Curr

25

20

15

10

5

(mV)

OS

0

–5

INPUT

–10

–15

–20

–25

VS = ±5V VS = +5V

–5–4–3–2–1012345

Figure 42. Input V

ent vs. Supply Voltage

VCM (V)

vs. Common-Mode Voltage

OS

Figure 44. Total Supply Current at Various Supplies vs. Temperature

20

15

10

5

0

–5

INPUT BIAS CURRE NT (μA)

–10

05708-046

–15

–5–4–3–2–1012345

VS= ±5V

OUTPUT VO LTAGE ( V)

= +5V

V

S

05708-026

Figure 45. Input Bias Current vs. Output Voltage

Rev. A | Page 12 of 16

ADA4861-3

V

V

www.BDTIC.com/ADI

APPLICATIONS

GAIN CONFIGURATIONS 20 MHz ACTIVE LOW-PASS FILTER

Unlike conventional voltage feedback amplifiers, the feedback
resistor has a direct impact on the closed-loop bandwidth and
stability of the current feedback op amp circuit. Reducing the
resistance below the recommended value can make the amplifier
response peak and even become unstable. Increasing the size
of the feedback resistor reduces the closed-loop bandwidth.
Tabl e 5 provides a convenient reference for quickly determining
the feedback and gain set resistor values and bandwidth for
common gain configurations.

Table 5. Recommended Values and Frequency Performance

Large Signal

(Ω) RG (Ω) −3 dB SS BW (MHz)

F

0.1 dB Flatness Gain R

+1 499 N/A 730 90

−1 301 301 350 60
[phone]
+5 200 49.9 180

100
30

+10 200 22.1 80 15

1

Conditions: VS = ±5 V, TA = 25°C, RL = 150 Ω.

Figure 46 and Figure 47 show the typical noninverting and
inverting configurations and recommended bypass capacitor
values.

+

S

10µF

0.1µF

V

IN

R

V

IN

+

ADA4861-3

–

–V

S

R

F

G

Figure 46. Noninverting Gain

R

F

+V

S

R

G

–

ADA4861-3

+

–V

S

Figure 47. Inverting Gain

0.1µF

10µF

10µF

0.1µF

0.1µF

10µF

V

OUT

5708-005

V

OUT

5708-006

1

The ADA4861-3 triple amplifier lends itself to higher order
active filters. Figure 48 shows a 28 MHz, 6-pole, Sallen-Key

w-pass filter.

lo

R12

301Ω

–

U1

OP AMP

+

C2
10pF

R9

210Ω

C3
10pF

R5

562ΩR6562Ω

C5
10pF

C4
10pF

R7

210Ω

OUT

R10

301Ω

–

U2

OP AMP

+

C6
10pF

R8

301Ω

–

U3

OP AMP

+

OUT

OUT

V

OUT

562ΩR2562Ω

IN

R1

R11

210kΩ

C1
10pF

R3

562ΩR4562Ω

Figure 48. 28 MHz, 6-Pole Low-Pass Filter

The filter has a gain of approximately 23 dB and flat frequency
response out to 22 MHz. This type of filter is commonly used at
the output of a video DAC as a reconstruction filter. The frequency
response of the filter is shown in

30

20

10

0

–10

–20

–30

MAGNITUDE (dB)

–40

–50

–60

–70

1 10 100 200

Figure 49. 20 MHz Low-Pass Filter Frequency Response

Figure 49.

FREQUENCY (MHz )

05708-047

05708-007

Rev. A | Page 13 of 16

ADA4861-3

V

V

V

www.BDTIC.com/ADI

RGB VIDEO DRIVER

Figure 50 shows a typical RGB driver application using bipolar

V

V

OUT

OUT

= RG =

F

(R)

(G)

supplies. The gain of the amplifier is set at +2, where R
301 Ω. The amplifier inputs are terminated with shunt 75 Ω
resistors, and the outputs have series 75 Ω resistors for proper
video matching. In

wn connected to any signal source for simplicity. If the

sho

Figure 50, the POWER-DOWN pins are not

power-down function is not used, it is recommended that the
power-down pins be tied to the negative supply and not be left
floating (not connected).

For applications that require a fixed gain of +2, consider using

ADA4862-3 with integrated RF and RG. The ADA4862-3 is

the
another high performance triple current feedback amplifier that
can simplify design and reduce board area.

+

S

10µF

0.1µF

4

75Ω

7

75Ω

8

VIN (R)

(G)

IN

75Ω

75Ω

R

301Ω

G

PD1

PD2

PD3

123

5

6

R

F

301Ω

10

9

R

F

301Ω

75Ω

10µF

+V

S

R

301Ω

G

–

0.1µF

ADA4861-3

75Ω

+

0.1µF

10µF

–V

S

75Ω

CABLE

IN

75Ω

75Ω

CABLE

75Ω

CABLE

Figure 51. Video Driver Schematic for Two Video Loads

0.1

0

–0.1

–0.2

–0.3

–0.4

–0.5

–0.6

NORMALIZED GAIN (dB)

–0.7

–0.8

–0.9

1 10 100 400

FREQUENCY (MHz)

VS = ±5V
R

= 75Ω

L

V

= 2V p-p

OUT

Figure 52. Large Signal Frequency Response for Various Supplies, R

V

75Ω

V

75Ω

= 75 Ω

L

05708-010

OUT

OUT

1

2

05708-004

VIN (B)

75Ω

R

301Ω

R

301Ω

G

12

13

G

R

301Ω

R

301Ω

F

75Ω

14

F

11

0.1µF

10µF

–V

S

V

(B)

OUT

05708-003

Figure 50. RGB Video Driver

DRIVING TWO VIDEO LOADS

In applications that require two video loads be driven
simultaneously, the ADA4861-3 can deliver. Figure 51 shows

e ADA4861-3 configured with dual video loads. Figure 52

th
s

hows the dual video load 0.1 dB bandwidth performance.

POWER-DOWN PINS

The ADA4861-3 is equipped with three independent POWER
DOWN pins, one for each amplifier. This allows the user the
ability to reduce the quiescent supply current when an amplifier
is inactive. The power-down threshold levels are derived from
the voltage applied to the −V
applications, this is especially useful with conventional logic
levels. The amplifier is powered down when the voltage applied
to the POWER DOWN pins is greater than −V
single-supply application, this is > +1 V (that is, 0 V + 1 V), in a
±5 V supply application, the voltage is > −4 V. The amplifier is
enabled whenever the POWER DOWN pins are left either open
or the voltage on the POWER DOWN pins is lower than 1 V
above −V

. If the POWER DOWN pins are not used, it is best to

S

connect them to the negative supply.

pin. When used in single-supply

S

+ 1 V. In a

S

Rev. A | Page 14 of 16

ADA4861-3

V

www.BDTIC.com/ADI

SINGLE-SUPPLY OPERATION POWER SUPPLY BYPASSING

The ADA4861-3 can also be operated from a single power
supply.

Figure 53 shows the schematic for a single 5 V supply

eo driver. The input signal is ac-coupled into the amplifier

vid
via C1. Resistor R2 and Resistor R4 establish the input midsupply
reference for the amplifier. Capacitor C5 prevents constant
current from being drawn through the gain set resistor and
enables the ADA4861-3 at dc to provide unity gain to the input
midsupply voltage, thereby establishing the output voltage dc
operating point. Capacitor C6 is the output coupling capacitor.
For more information on single-supply operation of op amps,
see

www.analog.com/library/analogDialogue/archives/35-

voiding/.

02/a

C2

1µF

R4

R2

50kΩ

50kΩ

+5V

R3

1kΩ

V

IN

C1

R1

22µF

50Ω

C5

22µF

Figure 53. Single-Supply Video Driver Schematic

+5

C3

2.2µF

C4

0.01µF

–V

S

C6

220µF

R5

75Ω

ADA4861-3

R6
75Ω

V

OUT

5708-054

Careful attention must be paid to bypassing the power supply
pins of the ADA4861-3. High quality capacitors with low
equivalent series resistance (ESR), such as multilayer ceramic
capacitors (MLCCs), should be used to minimize supply voltage
ripple and power dissipation. A large, usually tantalum, 2.2 μF
to 47 μF capacitor located in proximity to the ADA4861-3 is
required to provide good decoupling for lower frequency
signals. The actual value is determined by the circuit transient
and frequency requirements. In addition, 0.1 μF MLCC
decoupling capacitors should be located as close to each of the
power supply pins as is physically possible, no more than 1/8
inch away. The ground returns should terminate immediately
into the ground plane. Locating the bypass capacitor return
close to the load return minimizes ground loops and improves
performance.

LAYOUT

As is the case with all high-speed applications, careful attention
to printed circuit board (PCB) layout details prevents associated
board parasitics from becoming problematic. The ADA4861-3
can operate at up to 730 MHz; therefore, proper RF design
techniques must be employed. The PCB should have a
ground plane covering all unused portions of the component
side of the board to provide a low impedance return path.
Removing the ground plane on all layers from the area near
and under the input and output pins reduces stray capacitance.
Signal lines connecting the feedback and gain resistors should
be kept as short as possible to minimize the inductance and
stray capacitance associated with these traces. Termination
resistors and loads should be located as close as possible to their
respective inputs and outputs. Input and output traces should
be kept as far apart as possible to minimize coupling (crosstalk)
through the board. Adherence to microstrip or stripline design
techniques for long signal traces (greater than 1 inch) is
recommended. For more information on high speed board
layout, go to:

www.analog.com/library/analogDialogue/archives/39­09/l

ayout.html.

www.analog.com and

Rev. A | Page 15 of 16

ADA4861-3

www.BDTIC.com/ADI

OUTLINE DIMENSIONS

8.75 (0.3445)

8.55 (0.3366)

4.00 (0.1575)

3.80 (0.1496)

0.25 (0.0098)

0.10 (0.0039)

COPLANARITY

0.10

CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.

14

1

1.27 (0.0500)
BSC

0.51 (0.0201)

0.31 (0.0122)

COMPLIANT TO JEDEC STANDARDS MS-012-AB

8

6.20 (0.2441)

7

5.80 (0.2283)

1.75 (0.0689)

1.35 (0.0531)

SEATING
PLANE

0.25 (0.0098)

0.17 (0.0067)

0.50 (0.0197)

0.25 (0.0098)

8°
0°

1.27 (0.0500)

0.40 (0.0157)

× 45°

Figure 54. 14-Lead Standard Small Outline Package [SOIC_N]

row Body

Nar

(R-14)

Dimensions shown in millimeters and (inches)

ORDERING GUIDE

Model Temperature Range Package Description Package Option Ordering Quantity

ADA4861-3YRZ –40°C to +105°C 14-Lead SOIC_N R-14 1
ADA4861-3YRZ-RL –40°C to +105°C 14-Lead SOIC_N R-14 2,500

1

Z = Pb-free part.

1

1

1

14-Lead SOIC_N ADA4861-3YRZ-RL7 –40°C to +105°C R-14 1,000

©2006 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05708-0-3/06(A)

Rev. A | Page 16 of 16