Analog Devices AD8044AN, AD8044AR-14-REEL7, AD8044AR-14-REEL, AD8044AR-14 Datasheet

Quad 150 MHz

NORMALIZED GAIN – dB

1M 10M 100M

FREQUENCY – Hz

15

12

9

6

3

0

–3

–6

–9

VS = +5V
G = +1

–12

18

100k

a

FEATURES
Single AD8041 and Dual AD8042 Also Available
Fully Specified at +3 V, +5 V, and ⴞ5 V Supplies
Output Swings to Within 25 mV of Either Rail
Input Voltage Range Extends 200 mV Below Ground
No Phase Reversal with Inputs 1 V Beyond Supplies
Low Power of 2.75 mA/Amplifier
High Speed and Fast Settling on +5 V

150 MHz –3 dB Bandwidth (G = +1)
170 V/␮s Slew Rate
40 ns Settling Time to 0.1%

Good Video Specifications (R

Gain Flatness of 0.1 dB to 12 MHz

0.06% Differential Gain Error

0.15ⴗ Differential Phase Error

Low Distortion

–68 dBc Total Harmonic @ 5 MHz

Outstanding Load Drive Capability

Drives 30 mA 0.5 V from Supply Rails

APPLICATIONS
Active Filters
Video Switchers
Distribution Amplifiers
A/D Driver
Professional Cameras
CCD Imaging Systems
Ultrasound Equipment (Multichannel)

PRODUCT DESCRIPTION

The AD8044 is a quad low power, voltage feedback, high speed

amplifier designed to operate on +3 V, +5 V or ±5 V supplies.

It has true single-supply capability with an input voltage range
extending 200 mV below the negative rail and within 1 V of the
positive rail.

= 150 ⍀, G = +2)

L

Rail-to-Rail Amplifier

AD8044

CONNECTION DIAGRAM

14-Lead Plastic DIP and SOIC

1

OUT A

2

–IN A

3

+IN A

4

V+

AD8044

5

+IN B

6

–IN B

7

OUT B

TOP VIEW

The output voltage swing extends to within 25 mV of each rail,
providing the maximum output dynamic range. Additionally, it
features gain flatness of 0.1 dB to 12 MHz while offering differ-

ential gain and phase error of 0.04% and 0.22° on a single +5 V

supply. This makes the AD8044 useful for video electronics
such as cameras, video switchers or any high speed portable
equipment. The AD8044’s low distortion and fast settling make
it ideal for active filter applications.

The AD8044 offers low power supply current of 13.1 mA max
and can run on a single +3.3 V power supply. These features are
ideally suited for portable and battery powered applications
where size and power are critical.

The wide bandwidth of 150 MHz along with 170 V/µs of slew

rate on a single +5 V supply make the AD8044 useful in many
general purpose, high speed applications where dual power

supplies of up to ±6 V and single supplies from +3 V to +12 V

are needed. The AD8044 is available in 14-lead plastic DIP and
SOIC.

14

OUT D

13

–IN D
+IN D

12

V–

11
10

+IN C

9

–IN C

8

OUT C

REV. A

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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.

VS = +5V

5V

2.5V

0V

1V

2ms

Figure 1. Output Swing: Gain = –1, RL = 2 k

Ω

Figure 2. Frequency Response: Gain = +1, VS = +5 V

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] World Wide Web Site: http://www.analog.com
Fax: [phone] © Analog Devices, Inc., 1999

AD8044–SPECIFICATIONS

(@ TA = +25ⴗC, VS = +5 V, RL = 2 k⍀ to 2.5 V, unless otherwise noted)

AD8044A

Parameter Conditions Min Typ Max Units

DYNAMIC PERFORMANCE

–3 dB Small Signal Bandwidth, V
Bandwidth for 0.1 dB Flatness G = +2, R
Slew Rate G = –1, V
Full Power Response V
Settling Time to 1% G = –1, V

< 0.5 V p-p G = +1 80 150 MHz

O

= 2 V p-p 26 MHz

O

= 150 Ω 12 MHz

L

= 4 V Step 140 170 V/µs

O

= 2 V Step 30 ns

O

Settling Time to 0.1% 40 ns

NOISE/DISTORTION PERFORMANCE

Total Harmonic Distortion f

= 5 MHz, VO = 2 V p-p, G = +2, R

C

= 1 kΩ –68 dB

L

Input Voltage Noise f = 10 kHz 16 nV/√Hz
Input Current Noise f = 10 kHz 850 fA/√Hz

Differential Gain Error (NTSC) G = +2, R
Differential Phase Error (NTSC) G = +2, R
Crosstalk f = 5 MHz, R

= 150 Ω to 2.5 V 0.04 %

L

= 150 Ω to 2.5 V 0.22 Degrees

L

= 1 kΩ, G = +2 –60 dB

L

DC PERFORMANCE

Input Offset Voltage 1.0 6 mV

T

MIN–TMAX

8mV

Offset Drift 8 µV/°C
Input Bias Current 2 4.5 µA

T

MIN–TMAX

4.5 µA

Input Offset Current 0.2 1.2 µA

Open-Loop Gain R

= 1 kΩ 82 94 dB

L

T

MIN–TMAX

88 dB

INPUT CHARACTERISTICS

Input Resistance 225 kΩ

Input Capacitance 1.6 pF
Input Common-Mode Voltage Range –0.2 to 4 V
Common-Mode Rejection Ratio VCM = 0 V to 3.5 V 80 90 dB

OUTPUT CHARACTERISTICS

Output Voltage Swing R

Output Voltage Swing: R
Output Voltage Swing: R

Output Current T

= 10 kΩ to 2.5 V 0.03 to 4.975 V

L

= 1 kΩ to 2.5 V 0.25 to 4.75 0.075 to 4.91 V

L

= 150 Ω to 2.5 V 0.55 to 4.4 0.25 to 4.65 V

L

MIN–TMAX, VOUT

= 0.5 V to 4.5 V 30 mA

Short Circuit Current Sourcing 45 mA

Sinking 85 mA

Capacitive Load Drive G = +2 40 pF

POWER SUPPLY

Operating Range 312V
Quiescent Current 11 13.1 mA
Power Supply Rejection Ratio V

= 0, +5 V, ±1 V 70 80 dB

S

OPERATING TEMPERATURE RANGE –40 +85 °C

Specifications subject to change without notice.

–2–

REV. A

SPECIFICATIONS

(@ TA = +25ⴗC, VS = +3 V, RL = 2 k⍀ to 1.5 V, unless otherwise noted)

AD8044

AD8044A

Parameter Conditions Min Typ Max Units

DYNAMIC PERFORMANCE

–3 dB Small Signal Bandwidth, V
Bandwidth for 0.1 dB Flatness G = +2, R
Slew Rate G = –1, V
Full Power Response V
Settling Time to 1% G = –1, V

< 0.5 V p-p G = +1 80 135 MHz

O

O

= 150 Ω 10 MHz

L

= 2 V Step 110 150 V/µs

O

= 2 V p-p 22 MHz

= 2 V Step 35 ns

O

Settling Time to 0.1% 55 ns

NOISE/DISTORTION PERFORMANCE

Total Harmonic Distortion f

= 5 MHz, VO = 2 V p-p, G = –1, R

C

= 100 Ω –48 dB

L

Input Voltage Noise f = 10 kHz 16 nV/√Hz
Input Current Noise f = 10 kHz 600 fA/√Hz

Differential Gain Error (NTSC) G = +2, R
Differential Phase Error (NTSC) G = +2, R
Crosstalk f = 5 MHz, R

= 150 Ω to 1.5 V, Input V

L

= 150 Ω to 1.5 V, Input V

L

= 1 kΩ, G = +2 –60 dB

L

= 0.5 V 0.13 %

CM

= 0.5 V 0.3 Degrees

CM

DC PERFORMANCE

Input Offset Voltage 1.5 5.5 mV

T

MIN–TMAX

7.5 mV

Offset Drift 8 µV/°C
Input Bias Current 2 4.5 µA

T

MIN–TMAX

4.5 µA

Input Offset Current 0.2 1.2 µA

Open-Loop Gain R

= 1 kΩ 80 92 dB

L

T

MIN–TMAX

88 dB

INPUT CHARACTERISTICS

Input Resistance 225 kΩ

Input Capacitance 1.6 pF
Input Common-Mode Voltage Range –0.2 to 2 V
Common-Mode Rejection Ratio VCM = 0 V to 1.5 V 76 90 dB

OUTPUT CHARACTERISTICS

Output Voltage Swing R

Output Voltage Swing: R
Output Voltage Swing: R

Output Current T

= 10 kΩ to 1.5 V 0.025 to 2.98 V

L

= 1 kΩ to 1.5 V 0.17 to 2.82 0.06 to 2.93 V

L

= 150 Ω to 1.5 V 0.35 to 2.55 0.15 to 2.75 V

L

MIN–TMAX, VOUT

= 0.5 V to 2.5 V 25 mA

Short Circuit Current Sourcing 30 mA

Sinking 50 mA

Capacitive Load Drive G = +2 35 pF

POWER SUPPLY

Operating Range 312V
Quiescent Current 10.5 12.5 mA
Power Supply Rejection Ratio VS = 0, +3 V, +0.5 V 70 80 dB

OPERATING TEMPERATURE RANGE 0 +70 °C

Specifications subject to change without notice.

REV. A –3–

AD8044–SPECIFICATIONS

(@ TA = +25ⴗC, VS = ⴞ5 V, RL = 2 k⍀ to 0 V, unless otherwise noted)

AD8044A

Parameter Conditions Min Typ Max Units

DYNAMIC PERFORMANCE

–3 dB Small Signal Bandwidth, V
Bandwidth for 0.1 dB Flatness G = +2, R
Slew Rate G = –1, V
Full Power Response V
Settling Time to 0.1% G = –1, V

< 0.5 V p-p G = +1 85 160 MHz

O

= 2 V p-p 29 MHz

O

= 150 Ω 15 MHz

L

= 8 V Step 150 190 V/µs

O

= 2 V Step 30 ns

O

Settling Time to 0.01% 40 ns

NOISE/DISTORTION PERFORMANCE

Total Harmonic Distortion f

= 5 MHz, VO = 2 V p-p, G = +2 –72 dB

C

Input Voltage Noise f = 10 kHz 16 nV/√Hz
Input Current Noise f = 10 kHz 900 fA/√Hz

Differential Gain Error (NTSC) G = +2, R
Differential Phase Error (NTSC) G = +2, R
Crosstalk f = 5 MHz, R

= 150 Ω 0.06 %

L

= 150 Ω 0.15 Degrees

L

= 1 kΩ, G = +2 –60 dB

L

DC PERFORMANCE

Input Offset Voltage 1.4 6.5 mV

T

MIN–TMAX

9mV

Offset Drift 10 µV/°C
Input Bias Current 2 4.5 µA

T

MIN–TMAX

4.5 µA

Input Offset Current 0.2 1.2 µA

Open-Loop Gain R

= 1 kΩ 82 96 dB

L

T

MIN–TMAX

92 dB

INPUT CHARACTERISTICS

Input Resistance 225 kΩ

Input Capacitance 1.6 pF
Input Common-Mode Voltage Range –5.2 to 4 V
Common-Mode Rejection Ratio VCM = –5 V to 3.5 V 76 90 dB

OUTPUT CHARACTERISTICS

Output Voltage Swing R

Output Voltage Swing: R
Output Voltage Swing: R

Output Current T

= 10 kΩ –4.97 to +4.97 V

L

= 1 kΩ –4.6 to +4.6 –4.85 to +4.85 V

L

= 150 Ω –4.0 to +3.8 –4.5 to +4.5 V

L

MIN–TMAX, VOUT

= –4.5 V to +4.5 V 30 mA

Short Circuit Current Sourcing 60 mA

Sinking 100 mA

Capacitive Load Drive G = +2 40 pF

POWER SUPPLY

Operating Range 312V
Quiescent Current 11.5 13.6 mA
Power Supply Rejection Ratio V

= –5, +5 V, ±1 V 70 80 dB

S

OPERATING TEMPERATURE RANGE –40 +85 °C

Specifications subject to change without notice.

REV. A–4–

AD8044

WARNING!

ESD SENSITIVE DEVICE

ABSOLUTE MAXIMUM RATINGS

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +12.6 V

Internal Power Dissipation

2

1

Plastic DIP Package (N) . . . . . . . . . . . . . . . . . . . 1.6 Watts

Small Outline Package (R) . . . . . . . . . . . . . . . . . . 1.0 Watts

Input Voltage (Common Mode) . . . . . . . . . . . . . . ±V

± 0.5 V

S

Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . ±3.4 V

Output Short Circuit Duration

. . . . . . . . . . . . . . . . . . . . . . Observe Power Derating Curves

Storage Temperature Range (N, R) . . . . . . . –65°C to +125°C

Lead Temperature Range (Soldering 10 sec) . . . . . . . . +300°C

NOTES

1

Stresses above those listed under Absolute Maximum Ratings may cause perma-

nent 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.

2

Specification is for the device in free air:

14-Lead Plastic Package: θJA = 75°C/W
14-Lead SOIC Package: θJA = 120°C/W

MAXIMUM POWER DISSIPATION

The maximum power that can be safely dissipated by the
AD8044 is limited by the associated rise in junction tempera­ture. The maximum safe junction temperature for plastic encap­sulated devices is determined by the glass transition temperature

of the plastic, approximately +150°C. Exceeding this limit

temporarily may cause a shift in parametric performance due to
a change in the stresses exerted on the die by the package.

Exceeding a junction temperature of +175°C for an extended

period can result in device failure.

While the AD8044 is internally short circuit protected, this may
not be sufficient to guarantee that the maximum junction tem-

perature (+150°C) is not exceeded under all conditions. To

ensure proper operation, it is necessary to observe the maximum
power derating curves.

2.5
TJ = +150°C

2.0

1.5

1.0

MAXIMUM POWER DISSIPATION – Watts

0.5

14-LEAD SOIC

–50 90–40

–30 –20 –10 0 10 20 30 40 50 60 80

AMBIENT TEMPERATURE – 8C

14-LEAD PLASTIC DIP PACKAGE

70

Figure 3. Maximum Power Dissipation vs. Temperature

ORDERING GUIDE

Supply Temperature Package Package

Model Voltages Range Description Option

AD8044AN +5, ±5 –40°C to +85°C 14-Lead Plastic DIP N-14
AD8044AN +3 0°C to +70°C 14-Lead Plastic DIP N-14
AD8044AR-14 +5, ±5 –40°C to +85°C 14-Lead Plastic SOIC R-14
AD8044AR-14 +3 0°C to +70°C 14-Lead Plastic SOIC R-14
AD8044AR-14-REEL –40°C to +85°C 13" Tape and REEL
AD8044AR-14-REEL7 –40°C to +85°C 7" Tape and REEL

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 the AD8016 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

–5–

LOAD RESISTANCE – V

100

95

70

0 250

OPEN-LOOP GAIN – dB

500 750 1000 1250 1500 2000

90

85

80

VS = +5V
T = +258C

75

1750

OUTPUT VOLTAGE – Volts

100

30

0

050.15

OPEN-LOOP GAIN – dB

0.35 0.75 1.25 1.75 2.25 2.75 3.253.75 4.45 4.65 4.85

90

40

20
10

70

50

80

60

RL = 500V

RL = 50V

VS = +5V

AD8044–Typical Performance Characteristics

11

VS = +5V

10

T

= +258C

A

9

62 PARTS
MEAN = 350mV

8

STD DEVIATION = 560mV

7
6
5
4
3

NUMBER OF PARTS IN BIN

2
1

0

Figure 4. Typical Distribution of V

–1.5 –0.5 0.5 1.5 2.5–2.5

V

– mV

3–2–1012–3

OS

Figure 7. Open-Loop Gain vs. RL to +2.5 V

15

MEAN = 7.9mV/8C
STD DEV = 2.3mV/8C

12

SAMPLE SIZE = 62
V

= +5

S

9

6

NUMBER OF PARTS IN BIN

3

0

2.0 14.03.0

4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0
V

DRIFT – mV/8C

OS

Figure 5. VOS Drift Over –40°C to +85°C

2.4

VS = +5V

2.2

100

VS = +5V

= 1kV TO +2.5V

R

L

97

94

91

OPEN-LOOP GAIN – dB

88

85

–40 –20

0 20 40 6 0 80 100

TEMPERATURE – 8C

Figure 8. Open-Loop Gain vs. Temperature

2.0

1.8

INPUT BIAS CURRENT – mA

0

–45 85–35 –25 –15 –5 5 15 25 35 45 55 65 75

TEMPERATURE – 8C

Figure 6. IB vs. Temperature

Figure 9. Open-Loop Gain vs. Output Voltage

–6– REV. A

300

DIFF PHASE – Degrees

0 10010 20 30 40 50 60 70 80 90

DIFF GAIN – %

–0.04

0.00

–0.02

0.02

0.01

–0.01

–0.03

0.03

VS = +5V
G = +2
R

L

= 150V

–0.15

0.05

–0.05

0.15

0.10

0.00

–0.10

0.20

–0.20

MODULATING RAMP LEVEL – IRE

VS = +5V
G = +2
R

L

= 150V

0 10010 20 30 40 50 60 70 80 90

0.3

–0.1

–0.6

0.2

0.1

0.0

–0.2

–0.3

–0.4

–0.5

1M 100M10M

NORMALIZED GAIN – dB

VS = +5V
R

F

= 200V

R

L

= 150V TO 2.5V

G = +2
Vi = 0.2V p-p

11.6MHz

FREQUENCY – Hz

80

40

–10

70
60

50

30
20
10

0

–20

30k 100k

OPEN-LOOP GAIN – dB

1M

10M 100M

GAIN

PHASE

80MHz

FREQUENCY – Hz

VS = +5V

R

L

= 2kV

C

L

= 5pF

180
135
90

45
0

PHASE MARGIN – Degrees

100

30

10

3

INPUT VOLTAGE NOISE – nV/ Hz

AD8044

1

10 100

1k 10k 100k

FREQUENCY – Hz

1M 10M

Figure 10. Input Voltage Noise vs. Frequency

–30

V

= 2V p-p

O

–40

VS = +3V,

= 100V

R

L

–50

= –1

A

V

–60

–70

–80

–90

TOTAL HARMONIC DISTORTION – dBc

–100

1108567 9234

VS = +5V,

= 100V

R

L

= +2

A

V

FUNDAMENTAL FREQUENCY – MHz

VS = +5V,

= 100V

R

L

= +1

A

V

VS = +5V,

= 1kV

R

L

= +2

A

V

VS = +5V,

= 1kV

R

L

= +1

A

V

Figure 11. Total Harmonic Distortion

Figure 13. Differential Gain and Phase Errors

Figure 14. 0.1 dB Gain Flatness

–30
–40

–50
–60
–70
–80
–90

–100
–110

WORST HARMONIC – dBc

REV. A

–120
–130

–140

0

Figure 12. Worst Harmonic vs. Output Voltage

10MHz

5MHz

1MHz

OUTPUT VOLTAGE – V p-p

VS = +5V
R

= 2kV TO 2.5V

L

G = +2

50.5 1 1.5 2 2.5 3 3.5 4 4.5

Figure 15. Open-Loop Gain and Phase Margin
vs. Frequency

–7–

INPUT STEPS – Volts p-p

60

0

40

30

20

10

50

70

TIME – ns

0.5 21 1.5

VS = +3V, 1%

VS = +3V, 0.1%

VS = +5V, 1% AND
V

S

= 65V, 1%

VS = +5V, 0.1% AND
V

S

= 65V, 0.1%

G = –1
R

L

= 2kV

LOAD CURRENT – mA

1.00

0.500

0.00

0.875

0.750

0.250

0.125

0.625

0.375

0303 6 9121518212427

OUTPUT SATURATION VOLTAGE – Volts

VS = +5V

+5V –VOH (+258C)

+5V –VOH (–558C)

+5V –VOH (+1258C)

VOL (+1258C)

VOL (+258C)

VOL (–558C)

AD8044–Typical Performance Characteristics

4

VS = +5V

3

= 2kV TO 2.5V

R

L

= 5pF

C

L

2

G = +1

= 0.2V p-p

V

O

1

0

–1

–2

CLOSED-LOOP GAIN – dB

–3

–4

–5

1M 10M

FREQUENCY – Hz

+858C
+258C
–408C

100M

Figure 16. Closed-Loop Frequency Response
vs. Temperature

6

G = +1

5

R

= 2kV

4

3
2

1
0

–1

CLOSED-LOOP GAIN – dB

–2
–3

–4
100k

L

C

= 5pF

L

= 0.2V p-p

V

O

1M 10M 100M

FREQUENCY – Hz

+3V
+5V
65V

65V

+3V

+5V

Figure 17. Closed-Loop Frequency Response vs. Supply

Figure 19. Settling Time vs. Input Step

0

–10

–20

–30

–40

CMRR – dB

–50

–60

–70

–80

0.03

1 10 100

FREQUENCY – MHz

VS = +3V

Figure 20. CMRR vs. Frequency

VS = 65V

5000.1

100

G = +1
V

= +5V

10

1

0.1

OUTPUT RESISTANCE – V

0.01

0.03 5000.1

Figure 18. Output Resistance vs. Frequency

S

R

BT

FREQUENCY – MHz

V

OUT

1 10 100

RBT = 50V

RBT = 0V

Figure 21. Output Saturation Voltage vs. Load Current

–8–

REV. A

AD8044

3

–1

–6

100k 1M

10M 100M 500M

2
1

0

–2
–3
–4

–5

–7

NORMALIZED OUTPUT – dB

FREQUENCY – Hz

VS = +5V
R

L

= 5kV TO 2.5V

RF = 2kV

G = +5

G = +10

G = +2

R

L

= 150V TO 2.5V

R

F

= 200V

G = +2

–10

–50

–100

–20
–30

–40

–60
–70
–80

–90

–110

0.1

CROSSTALK – dB

1 10 100

FREQUENCY – MHz

400

VS = 65V
V

IN

= 1V p-p
G = +2
R

F

= 1kV

RL = 1kV

RL = 100V

12.0
VS = 65V

11.5

VS = +5V

11.0

VS = +3V

10.5

10.0

SUPPLY CURRENT – mA

9.5

9.0
–40

–20 0 20 40 60 80 100

TEMPERATURE – 8C

Figure 22. Supply Current vs. Temperature

20

10

VS = +5V

0

–10

–20

–30

–40

PSRR – dB

–50

–60

–70

–80

0.01

–PSRR

+PSRR

1 50010 1000.1

FREQUENCY – MHz

60

G = +2, RS = 0V,
VO = 100mV STEP

50

40

30

% OVERSHOOT

20

10

0

G = +1, RS = 40V,
VO = 100mV STEP

RF = 0, RG =

0 25050 100 150 200

RF = RG = 750V
G = +1, RS = 20V,
VO = 100mV STEP

RF = 0, RG =

LOAD CAPACITANCE – pF

R

G

V

IN

50V

G = +3, RS = 0V,
VO = 150mV STEP

RF = 750V
RG = 375V

R

F

+2.5V

V

OUT

R

S

–2.5V

Figure 25. % Overshoot vs. Capacitive Load

REV. A

Figure 23. PSRR vs. Frequency

10

9
8

7
6
5

p-p – Volts

4

OUT

V

3

2
1
0

0.1 1 10 100 500

Figure 24. Output Voltage Swing vs. Frequency

FREQUENCY – MHz

VS = 65V

= 2kV

R

L

Figure 26. Frequency Response vs. Closed-Loop Gain

Figure 27. Crosstalk (Output to Output) vs. Frequency

–9–

AD8044–Typical Performance Characteristics

2.6V

2.55V

2.5V

2.45V

2.4V

VS = +5V
G = +1

R

L

= 2kV

CL = 5pF

40ns

50mV

3V

2.5V

2V

1.5V

1V

0.5V

0V

200ms

500mV

VIN = 3V p-p
R

L

= 2kV

C

L

= 5pF

V

S

= +3V

G = –1

+22mV

+2.920V

5V

4.656V
VS = +5V

R

= 150V TO +2.5V

L

C

= 5pF

L

G = –1

2.5V

0V

500mV

0.211V

100ms

a.

5V

2.5V

500mV

4.309V

+10mV

VS = +5V
R

= 150V TO GND

L

= 5pF

C

L

G = –1

100ms

b.
Figure 28a, b. Output Swing vs. Load Reference Voltage,
V

= +5 V, G = –1

S

Figure 30. 100 mV Step Response, VS = +5 V, G = +1

Figure 31. Output Swing, VS = +3 V

4.5V

VS = +5V
G = +2

= 2kV

R

3.5V

2.5V

1.5V

0.5V

V
C

L

= 1V p-p

IN

= 5pF

L

20ns500mV

Figure 29. One Volt Step Response, VS = +5 V, G = +2

1.60V

1.58V

1.56V

1.54V

1.52V

1.50V

1.48V

1.46V

1.44V

1.42V

1.40V

20mV

V

= 0.1V p-p

I

N

R

=

2kV

L

C

=

5pF

L

VS = +3V
G = +1

20ns

Figure 32. Step Response, G = +1, VIN = 100 mV

–10– REV. A

AD8044

SIN

R21

R3

V

EE

Q11

Q3

I10

R26 R39

Q5

Q4

Q40

I7

R2R15

Q13

Q17

R5

C7

Q2

SIP

Q22

Q7

Q21

Q24

R23

R27

I2 I3

I1

Q51

Q25

Q50

Q39

Q47

Q27

Q31

Q23

I9

I5

V

EE

V

CC

I8

Q36

Q8

V

OUT

C3

C9

V

CC

VINP
VINN

V

EE

I11

Overdrive Recovery

Overdrive of an amplifier occurs when the output and/or input
range are exceeded. The amplifier must recover from this over­drive condition. As shown in Figure 33, the AD8044 recovers
within 50 ns from negative overdrive and within 25 ns from
positive overdrive.

Driving Capacitance Loads

The capacitive load drive of the AD8044 can be increased by
adding a low valued resistor in series with the load. Figure 35
shows the effects of a series resistor on capacitive drive for vary­ing voltage gains. As the closed-loop gain is increased, the larger
phase margin allows for larger capacitive loads with less over­shoot. Adding a series resistor with lower closed-loop gains
accomplishes this same effect. For large capacitive loads, the

VS = +5V

= +2

A

V

= 2kV

R

F

= 2kV

R

L

V

IN

2V/DIV

2V

V

OUT

1V/DIV

50ns1V

frequency response of the amplifier will be dominated by the
roll-off of the series resistor and capacitive load.

Figure 33. Overdrive Recovery, VS + 5 V, VIN = 4 V Step

Circuit Description

The AD8044 is fabricated on Analog Devices’ proprietary
eXtra-Fast Complementary Bipolar (XFCB) process which
enables the construction of PNP and NPN transistors with
similar f

s in the 2 GHz–4 GHz region. The process is dielectri-

T

Figure 34. AD8044 Simplified Schematic

cally isolated to eliminate the parasitic and latch-up problems
caused by junction isolation. These features allow the construc­tion of high frequency, low distortion amplifiers with low supply
currents. This design uses a differential output input stage to
maximize bandwidth and headroom (see Figure 34). The
smaller signal swings required on the first stage outputs (nodes
S1P, S1N) reduce the effect of nonlinear currents due to
junction capacitances and improve the distortion performance.
With this design harmonic distortion of better than –85 dB

@ 1 MHz into 100 Ω with V

= 2 V p-p (Gain = +2) on a

OUT

single 5 volt supply is achieved.

The AD8044’s rail to rail output range is provided by a comple­mentary common-emitter output stage. High output drive capa­bility is provided by injecting all output stage predriver currents
directly into the bases of the output devices Q8 and Q36. Bias­ing of Q8 and Q36 is accomplished by I8 and I5, along with a
common-mode feedback loop (not shown). This circuit topol­ogy allows the AD8044 to drive 50 mA of output current with
the outputs within 0.5 V of the supply rails.

On the input side, the device can handle voltages from –0.2 V
below the negative rail to within 1.2 V of the positive rail. Ex­ceeding these values will not cause phase reversal; however, the
input ESD devices will begin to conduct if the input voltages
exceed the rails by greater than 0.5 V.

REV. A

–11–

A

1kV

10mF

+3V OR +5V

75V

0.1mF

1kV

75V

RGB

MONITOR #2

V+

B

1kV

75V

1kV

C

1kV

75V

1kV

V–

75V

75V

75V

75V

75V

RGB

MONITOR #1

75V

75V

75V

R

G

B

+5V

GRAPHICS

IC

AD8044

AD8044

AD8044

V

IN

GND

GND

V

OUT

10

0%

100

90

5ms

500mV

500mV

AD8044

1000

VS = +5V
< 30% OVERSHOOT

100

CAPACITIVE LOAD – pF

V

IN

100mV STEP

10

162

Figure 35. Capacitive Load Drive vs. Closed-Loop Gain

APPLICATIONS
RGB Buffer

The AD8044 can provide buffering of RGB signals that include
ground while operating from a single +3 V or +5 V supply.

When driving two monitors from the same RGB video source it
is necessary to provide an additional driver for one of the moni­tors to prevent the double termination situation that the second
monitor presents. This has usually required a dual supply op
amp because the level of the input signal from the video driver
goes all the way to ground during horizontal blanking. In single
supply systems it can be a major inconvenience and expense to
add an additional negative supply.

A single AD8044 can provide the necessary drive capability and
yet does not require a negative supply in this application. Fig­ure 36 is a schematic that uses three amplifiers out of a single
AD8044 to provide buffering for a second monitor.

The source of the RGB signals is shown to be from a set of three
current output DACs that are within a single supply graphics
IC. This is typically the situation in most PCs and workstations
which might use either a stand-alone triple DAC or DACs that
are integrated into a larger graphics chip.

During horizontal blanking, the current output from the DACs
is turned off and the RGB outputs are pulled to ground by the
termination resistors. If voltage sources were used for the RGB
signals, then the termination resistors near the graphics IC
would be in series and the rest of the circuit would remain the
same. This is because a voltage source is an ac short circuit, so a
series resistor is required to make the drive end of the line see

75 Ω to ac ground. On the other hand, a current source has a

very high output impedance, so a shunt resistor is required to

make the drive end of the line see 75 Ω to ground. In either
case, the monitor terminates its end of the line with 75 Ω.

The circuit of Figure 36 shows minimum signal degradation
when using a single supply for the AD8044. The circuit per­forms equally well on either a +3 V or +5 V supply.

= 10V

S

R

R

G

345

ACL – V/V

R

R

F

= 0V

S

R

S

C

L

V

OUT

Figure 36. Single Supply RGB Video Driver

Figure 37 is an oscilloscope photo of the circuit in Figure 36
operating from a +3 V supply and driven by the Blue signal of a
color bar pattern. Note that the input and output are at ground
during the horizontal blanking interval. The RGB signals are
specified to output a maximum of 700 mV peak. The output of
the AD8044 is 1.4 V with the termination resistors providing a
divide-by-two.

Figure 37. +3 V, RGB Buffer

–12–

REV. A

AD8044

Active Filters

Active filters at higher frequencies require wider bandwidth op
amps to work effectively. Excessive phase shift produced by
lower frequency op amps can significantly impact active filter
performance.

Figure 38 shows an example of a 2 MHz biquad bandwidth
filter that uses three op amps of an AD8044 package. Such
circuits are sometimes used in medical ultrasound systems to
lower the noise bandwidth of the analog signal before A/D
conversion.

R6

1kV

C1

50pF

R2

2kV

R1

3kV

V

IN

2
3

1

AD8044

R3

2kV

6

5

R4

2kV

AD8044

C2

50pF

R5

2kV

9

7

10

AD8044

8

V

OUT

Figure 38. 2 MHz Biquad Bandpass Filter Using AD8044

The frequency response of the circuit is shown in Figure 39.

0

Layout Considerations

The specified high speed performance of the AD8044 requires
careful attention to board layout and component selection.
Proper RF design techniques and low-pass parasitic component
selection are necessary.

The PCB should have a ground plane covering all unused por­tions of the component side of the board to provide a low im­pedance path. The ground plane should be removed from the
area near the input pins to reduce the stray capacitance.

Chip capacitors should be used for the supply bypassing. One
end should be connected to the ground plane and the other

within 1/8 inch of each power pin. An additional large (0.47 µF
– 10 µF) tantalum electrolytic capacitor should be connected in

parallel, but not necessarily so close, to supply current for fast,
large signal changes at the output.

The feedback resistor should be located close to the inverting
input pin in order to keep the stray capacitance at this node to a
minimum. Capacitance variations of less than 1 pF at the in­verting input will significantly affect high speed performance.

Stripline design techniques should be used for long signal traces
(greater than about 1 inch). These should be designed with a

characteristic impedance of 50 Ω or 75 Ω and be properly termi-

nated at each end.

–10

–20

GAIN – dB

–30

–40

10k 100M100k

1M 10M

FREQUENCY – Hz

Figure 39. Frequency Response of 2 MHz Bandpass
Biquad Filter

REV. A

–13–

AD8044

0.210 (5.33)
MAX

0.160 (4.06)

0.115 (2.93)

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

14-Lead Plastic DIP

(N-14)

0.795 (20.19)

0.725 (18.42)

14

17

PIN 1

0.022 (0.558)

0.014 (0.356)

0.100
(2.54)

BSC

8

0.280 (7.11)

0.240 (6.10)

0.060 (1.52)

0.015 (0.38)

0.070 (1.77)

0.045 (1.15)

0.130
(3.30)
MIN

SEATING
PLANE

14-Lead SOIC

(R-14)

0.3444 (8.75)

0.3367 (8.55)

0.325 (8.25)

0.300 (7.62)

0.015 (0.381)

0.008 (0.204)

0.195 (4.95)

0.115 (2.93)

C2075a–10–8/99

0.1574 (4.00)

0.1497 (3.80)

0.0098 (0.25)

0.0040 (0.10)

SEATING

PLANE

14 8

PIN 1

0.0500

0.0192 (0.49)

(1.27)

0.0138 (0.35)

BSC

0.2440 (6.20)

71

0.2284 (5.80)

0.0688 (1.75)

0.0532 (1.35)

0.0098 (0.25)

0.0075 (0.19)

0.0196 (0.50)

0.0099 (0.25)

8°
0°

0.0500 (1.27)

0.0160 (0.41)

x 45°

–14–

PRINTED IN U.S.A.

REV. A