ANALOG DEVICES AD8027 Service Manual

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Low Distortion, High Speed

FEATURES

High speed

190 MHz, –3 dB bandwidth (G = +1) 100 V/μs slew rate

Low distortion

120 dBc @ 1 MHz SFDR

80 dBc @ 5 MHz SFDR Selectable input crossover threshold Low noise

4.3 nV/√Hz

1.6 pA/√Hz Low offset voltage: 900 μV max Low power: 6.5 mA/amplifier supply current Power-down mode No phase reversal: V Wide supply range: 2.7 V to 12 V Small packaging: SOIC-8, SOT-23-6, MSOP-10

APPLICATIONS

Filters ADC drivers Level shifting Buffering Professional video Low voltage instrumentation

GENERAL DESCRIPTION

The AD8027/AD80281 are high speed amplifiers with rail-torail input and output that operate on low supply voltages and are optimized for high performance and wide dynamic signal range. The AD8027/AD8028 have low noise (4.3 nV/√Hz,

1.6 pA/√Hz) and low distortion (120 dBc at 1 MHz). In applications that use a fraction of, or the entire input dynamic range and require low distortion, the AD8027/AD8028 are ideal choices.

Many rail-to-rail input amplifiers have an input stage that swi

tches from one differential pair to another as the input signal crosses a threshold voltage, which causes distortion. The AD8027/AD8028 have a unique feature that allows the user to select the input crossover threshold voltage through the SELECT pin. This feature controls the voltage at which the complementary transistor input pairs switch. The AD8027/ AD8028 also have intrinsically low crossover distortion.

> |VS| + 200 mV

IN

Rail-to-Rail Input/Output Amplifiers

AD8027/AD8028

CONNECTION DIAGRAMS

V

–IN A +IN A

V

OUT

–V

OUTA

–V

+IN

AD8027

SOT-23-6

(RT)

1

2

S

3

1 2 3 4

S

5

+–

AD8028

MSOP-10

(RM)

– +

V

= +5V

S

03327-B-001

VS = ±5V

6

5

4

–

+

+V

S

DISABLE/SELECT

–IN

10

+V

S

9

V

OUTB

–IN B

8 7

+IN B

6

DISABLE/SELECT B

03327-A-063

0

AD8027

SOIC-8

(R)

NC

V

+IN

–V

OUTA

–IN A +IN A

–V

–IN

S

1 2 3 4

NC = NO CONNECT

AD8028

SOIC-8

1

–

2 3

+

4

8

DISABLE/SELECT +V

7

S

V

6

OUT

NC

5

(R)

8

+V

S

7

V

OUTB

–IN B

6

– +

5

+IN B

DISABLE/SELECT A

Figure 1. Connection Diagrams (Top View)

With their wide supply voltage range (2.7 V to 12 V) and wide bandwidth (190 MHz), the AD8027/AD8028 amplifiers are designed to work in a variety of applications where speed and performance are needed on low supply voltages. The high performance of the AD8027/AD8028 is achieved with a quiescent current of only 6.5 mA/amplifier typical. The AD8027/AD8028 have a shutdown mode that is controlled via the SELECT pin.

The AD8027/AD8028 are available in SOIC-8, MSOP-10, and

T-23-6 packages. They are rated to work over the industrial

SO temperature range of –40°C to +125°C.

–20

G = +1 FREQUENCY = 100kHz R

= 1kΩ

L

–40

–60

= +3V

V

S

–80

SFDR (dB)

–100

–120

–140

01234567891

1

Protected by U.S. patent numbers 6,486,737B1; 6,518,842B1

OUTPUT VOLTAGE (V p-p)

Figure 2. SFDR vs. Output Amplitude

Rev. C

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.

AD8027/AD8028

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TABLE OF CONTENTS

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

Wideband Operation ..................................................................... 19

Absolute Maximum Ratings............................................................ 6

Maximum Power Dissipation ..................................................... 6

ESD Caution.................................................................................. 6

Typical Performance Characteristics .............................................8

Theory of Operation ...................................................................... 17

Input Stage................................................................................... 17

Crossover Selection.................................................................... 17

Output Stage................................................................................ 18

DC Errors.................................................................................... 18

REVISION HISTORY

3/05—Rev. B to Rev. C

Updated Format..................................................................Universal

hange to Figure 1 ........................................................................... 1

C

10/03—Rev. A to Rev. B

Changes to Figure 1...........................................................................1

Circuit Considerations .............................................................. 19

Applications..................................................................................... 21

Using the SELECT Pin............................................................... 21

Driving a 16-Bit ADC................................................................ 21

Band-Pass Filter.......................................................................... 22

Design Tools and Technical Support....................................... 22

Outline Dimensions .......................................................................23

Ordering Guide .......................................................................... 24

8/03—Rev. 0 to Rev. A

Addition of AD8028........................................................... Universal

hanges to GENERAL DESCRIPTION.........................................1

C

Changes to Figures 1, 3, 4, 8, 13, 15, 17......................... 1, 6, 7, 8, 9

Changes to Figures 58, 60........................................................ 18, 20

Changes to SPECIFICATIONS........................................................3

Updated OUTLINE DIMENSIONS .............................................22

Updated ORDERING GUIDE.......................................................23

3/03—Revision 0: Initial Version

Rev. C | Page 2 of 24

AD8027/AD8028

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SPECIFICATIONS

VS = ±5 V at TA = 25°C, RL = 1 kΩ to midsupply, G = 1, unless otherwise noted.

Table 1.

Parameter Conditions Min Typ Max Unit

DYNAMIC PERFORMANCE

G = 1, VO = 2 V p-p 20 32 MHz

NOISE/DISTORTION PERFORMANCE

f

DC PERFORMANCE

T

INPUT CHARACTERISTICS

SELECT PIN

OUTPUT CHARACTERISTICS

POWER SUPPLY

1

No sign or a plus sign indicates current into the pin; a minus sign indicates current out of the pin.

–3 dB Bandwidth G = 1, VO = 0.2 V p-p 138 190 MHz

Bandwidth for 0.1 dB Flatness G = 2, VO = 0.2 V p-p 16 MHz Slew Rate G = +1, VO = 2 V step/G = −1, VO = 2 V step 90/100 V/μs Settling Time to 0.1% G = 2, VO = 2 V step 35 ns

Spurious-Free Dynamic Range (SFDR) fC = 1 MHz, VO = 2 V p-p, RF = 24.9 Ω 120 dBc

= 5 MHz, VO = 2 V p-p, RF = 24.9 Ω 80 dBc

C

Input Voltage Noise f = 100 kHz 4.3 nV/√Hz Input Current Noise f = 100 kHz 1.6 pA/√Hz Differential Gain Error NTSC, G = 2, R Differential Phase Error NTSC, G = 2, R Crosstalk, Output to Output G = 1, RL = 100 Ω, V

= ±5 V @ 1 MHz

V

S

= 150 Ω 0.1 %

L

= 150 Ω 0.2 Degrees

L

= 2 V p-p,

OUT

−93 dB

Input Offset Voltage SELECT = three-state or open, PNP active 200 800 μV SELECT = high NPN active 240 900 μV Input Offset Voltage Drift T

Input Bias Current

1

V

MIN

to T

MAX

1.50 μV/°C

VCM = 0 V, NPN active 4 6 μA

to T

MIN

MAX

= 0 V, PNP active −8 −11 μA

CM

to T

MIN

MAX

4 μA

−8 μA Input Offset Current ±0.1 ±0.9 μA Open-Loop Gain VO = ±2.5 V 100 110 dB

Input Impedance 6 MΩ Input Capacitance 2 pF Input Common-Mode Voltage Range −5.2 to +5.2 V Common-Mode Rejection Ratio VCM = ±2.5 V 90 110 dB

Crossover Low, Selection Input Voltage Three-state < ±20 μA −3.3 to +5 V Crossover High, Selection Input Voltage −3.9 to −3.3 V Disable Input Voltage −5 to −3.9 V Disable Switching Speed 50% of input to <10% of final V

O

980 ns

Enable Switching Speed 45 ns

Output Overdrive Recovery Time

VI = +6 V to −6 V, G = −1 40/45 ns

(Rising/Falling Edge)

Output Voltage Swing −VS + 0.10 +VS − 0.06,

+ 0.06

−V

S

+V

− 0.10 V

S

Short-Circuit Output Sinking and Sourcing 120 mA Off Isolation VIN = 0.2 V p-p, f = 1 MHz, SELECT = low −49 dB

Capacitive Load Drive 30% overshoot 20 pF

Operating Range 2.7 12 V Quiescent Current/Amplifier 6.5 8.5 mA

Quiescent Current (Disabled) SELECT = low 370 500 μA Power Supply Rejection Ratio VS ± 1 V 90 110 dB

Rev. C | Page 3 of 24

AD8027/AD8028

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VS = 5 V at TA = 25°C, RL = 1 kΩ to midsupply, unless otherwise noted.

Table 2.

Parameter Conditions Min Typ Max Unit

DYNAMIC PERFORMANCE

−3 dB Bandwidth G = 1, VO = 0.2 V p-p 131 185 MHz

G = 1, VO = 2 V p-p 18 28 MHz

Bandwidth for 0.1 dB Flatness G = 2, V Slew Rate G = +1, VO = 2 V step/G = −1, VO = 2 V step 85/100 V/μs Settling Time to 0.1% G = 2, VO = 2 V step 40 ns

NOISE/DISTORTION PERFORMANCE

Spurious-Free Dynamic Range (SFDR) fC = 1 MHz, VO = 2 V p-p, RF = 24.9 Ω 90 dBc

f

C

Input Voltage Noise f = 100 kHz 4.3 nV/√Hz Input Current Noise f = 100 kHz 1.6 pA/√Hz Differential Gain Error NTSC, G = 2, R Differential Phase Error NTSC, G = 2, R Crosstalk, Output to Output G = 1, RL = 100 Ω, V

V

DC PERFORMANCE

Input Offset Voltage SELECT = three-state or open, PNP active 200 800 μV SELECT = high NPN active 240 900 μV Input Offset Voltage Drift T

Input Bias Current

1

VCM = 2.5 V, NPN active 4 6 μA

T

V T Input Offset Current ±0.1 ±0.9 μA Open-Loop Gain VO = 1 V to 4 V 96 105 dB

INPUT CHARACTERISTICS

Input Impedance 6 MΩ Input Capacitance 2 pF Input Common-Mode Voltage Range −0.2 to +5.2 V Common-Mode Rejection Ratio VCM = 0 V to 2.5 V 90 105 dB

SELECT PIN

Crossover Low, Selection Input Voltage Three-state < ±20 μA 1.7 to 5 V Crossover High, Selection Input Voltage 1.1 to 1.7 V Disable Input Voltage 0 to 1.1 V Disable Switching Speed 50% of input to <10% of final V

Enable Switching Speed 50 ns

OUTPUT CHARACTERISTICS

Overdrive Recovery Time

VI = −1 V to +6 V, G = −1 50/50 ns

(Rising/Falling Edge)

Output Voltage Swing RL = 1 kΩ −VS + 0.08 +VS − 0.04,

Off Isolation VIN = 0.2 V p-p, f = 1 MHz, SELECT = low −49 dB Short-Circuit Current Sinking and sourcing 105 mA Capacitive Load Drive 30% overshoot 20 pF

POWER SUPPLY

Operating Range 2.7 12 V Quiescent Current/Amplifier 6 8.5 mA

Quiescent Current (Disabled) SELECT = low 320 450 μA Power Supply Rejection Ratio VS ± 1 V 90 105 dB

1

No sign or a plus sign indicates current into the pin; a minus sign indicates current out of the pin.

= 0.2 V p-p 12 MHz

O

= 5 MHz, VO = 2 V p-p, RF = 24.9 Ω 64 dBc

= 150 Ω 0.1 %

L

= 150 Ω 0.2 Degrees

L

= 2 V p-p,

= ±5 V @ 1 MHz

S

to T

MIN

MAX

to T

MIN

MAX

= 2.5 V, PNP active −8 −11 μA

CM

to T

MIN

MAX

OUT

O

−92 dB

2 μV/°C

4 μA

−8 μA

1100 ns

+V

− 0.08 V

−V

+ 0.04

S

Rev. C | Page 4 of 24

AD8027/AD8028

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VS = 3 V at TA = 25°C, RL = 1 kΩ to midsupply, unless otherwise noted.

Table 3.

Parameter Conditions Min Typ Max Unit

DYNAMIC PERFORMANCE

–3 dB Bandwidth G = 1, VO = 0.2 V p-p 125 180 MHz

G = 1, VO = 2 V p-p 19 29 MHz

Bandwidth for 0.1 dB Flatness G = 2, VO = 0.2 V p-p 10 MHz Slew Rate G = +1, VO = 2 V step/G = –1, VO = 2 V step 73/100 V/μs Settling Time to 0.1% G = 2, VO = 2 V step 48 ns

NOISE/DISTORTION PERFORMANCE

Spurious-Free Dynamic Range (SFDR) fC = 1 MHz, VO = 2 V p-p, RF = 24.9 Ω 85 dBc

f

Input Voltage Noise f = 100 kHz 4.3 nV/√Hz Input Current Noise f = 100 kHz 1.6 pA/√Hz Differential Gain Error NTSC, G = 2, R Differential Phase Error NTSC, G = 2, R Crosstalk, Output to Output G = 1, RL = 100 Ω, V

DC PERFORMANCE

Input Offset Voltage SELECT = three-state or open, PNP active 200 800 μV SELECT = high NPN active 240 900 μV Input Offset Voltage Drift T Input Bias Current

1

T V T

Input Offset Current ±0.1 ±0.9 μA Open-Loop Gain VO = 1 V to 2 V 90 100 dB

INPUT CHARACTERISTICS

Input Impedance 6 MΩ Input Capacitance 2 pF Input Common-Mode Voltage Range RL = 1 kΩ –0.2 to +3.2 V

Common-Mode Rejection Ratio VCM = 0 V to 1.5 V 88 100 dB

SELECT PIN

Crossover Low, Selection Input Voltage Three-state < ±20 μA 1.7 to 3 V Crossover High, Selection Input Voltage 1.1 to 1.7 V Disable Input Voltage 0 to 1.1 V Disable Switching Speed 50% of input to <10% of final V

Enable Switching Speed 50 ns

OUTPUT CHARACTERISTICS

Output Overdrive Recovery Time

(Rising/Falling Edge)

Output Voltage Swing RL = 1 kΩ –VS + 0.07 +VS – 0.03,

Short-Circuit Current Sinking and sourcing 72 mA Off Isolation VIN = 0.2 V p-p, f = 1 MHz, SELECT = low –49 dB Capacitive Load Drive 30% Overshoot 20 pF

POWER SUPPLY

Operating Range 2.7 12 V Quiescent Current/Amplifier 6.0 8.0 mA Quiescent Current (Disabled) SELECT = low 300 420 μA Power Supply Rejection Ratio VS ± 1 V 88 100 dB

1

No sign or a plus sign indicates current into the pin; a minus sign indicates current out of the pin.

= 5 MHz, VO = 2 V p-p, RF = 24.9 Ω 64 dBc

C

= 150 Ω 0.15 %

L

= 150 Ω 0.20 Degrees

L

= 3 V @ 1 MHz

V

S

to T

MIN

MAX

= 2 V p-p,

OUT

–89 dB

2 μV/°C

VCM = 1.5 V, NPN active 4 6 μA

to T

MIN

MAX

= 1.5 V, PNP active –8 –11 μA

CM

to T

MIN

MAX

O

V

= –1 V to +4 V, G = –1 55/55 ns

I

4 μA

–8 μA

1150 ns

+V

– 0.07 V

–V

+ 0.03

S

Rev. C | Page 5 of 24

AD8027/AD8028

(

)

(

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ABSOLUTE MAXIMUM RATINGS

Table 4.

Parameter Rating

Supply Voltage 12.6 V Power Dissipation See Figure 3 Common-Mode Input Voltage ±VS ± 0.5 V Differential Input Voltage ±1.8 V Storage Temperature –65°C to +125°C Operating Temperature Range –40°C to +125°C Lead Temperature Range

(Soldering 10 sec)

Junction Temperature 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.

MAXIMUM POWER DISSIPATION

The maximum safe power dissipation in the AD8027/AD8028 package is limited by the associated rise in junction temperature (T

) on the die. The plastic encapsulating the die locally reaches

J

the junction temperature. At approximately 150°C, which is the glass transition temperature, the plastic changes its properties. Even temporarily exceeding this temperature limit may change the stresses that the package exerts on the die, permanently shifting the parametric performance of the AD8027/AD8028. Exceeding a junction temperature of 175°C for an extended period of time can result in changes in the silicon devices, potentially causing failure.

The still-air thermal properties of the package and PCB (θ ambient temperature (T package (P

) determine the junction temperature of the die.

D

The junction temperature can be calculated as

), and the total power dissipated in the

A

300°C

),

JA

The power dissipated in the package (P

) is the sum of the

D

quiescent power dissipation and the power dissipated in the package due to the load drive for all outputs. The quiescent power is the voltage between the supply pins (V quiescent current (I

). Assuming the load (RL) is referenced to

S

midsupply, then the total drive power is V which is dissipated in the package and some in the load (V I

). The difference between the total drive power and the load

OUT

/2 × I

S

) times the

S

, some of

OUT

power is the drive power dissipated in the package.

= Quiescent Power + (Tota l Dri v e P o we r − Load Power)

P

D

⎛

V

()

D

⎜

IVP

SS

⎜

2

⎝

×+×=

⎞

V

OUTS

⎟ ⎟

R

L

⎠

RMS output voltages should be considered. If R

, as in single-supply operation, then the total drive power

to V

S−

is V

× I

.

S

OUT

2

V

OUT

–

R

L

is referenced

L

If the rms signal levels are indeterminate, then consider the

case, when V

worst

()

D

In single-supply operation with R is V

= VS/2.

OUT

Airflow increases heat dissipation, effectively reducing θ

= VS/4 for RL to midsupply.

OUT

2

)

4/

V

S

+×=

IVP

SS

R

L

referenced to VS–, worst case

L

. Also,

JA

more metal directly in contact with the package leads from metal traces, through holes, ground, and power planes reduces the θ

. Care must be taken to minimize parasitic capacitances

JA

at the input leads of high speed op amps, as discussed in the PCB Layout section.

×

θPTT ×+=

J

D

A

JA

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. C | Page 6 of 24

AD8027/AD8028

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Figure 3 shows the maximum safe power dissipation in the package vs. the ambient temperature for the SOIC-8 (125°C/W), SOT-23-6 (170°C/W), and MSOP-10 (130°C/W) packages on a JEDEC standard 4-layer board.

Output Short Circuit

Shorting the output to ground or drawing excessive current from the AD8027/AD8028 can likely cause catastrophic failure.

2.0

1.5

1.0

MSOP-10

0.5

MAXIMUM POWER DISSIPATION (W)

0

–55 –35 –15 5 25 45 65 85 105 125

Figure 3. Maximum Power Dissipation vs. Ambient Temperature

SOT-23-6

SOIC-8

AMBIENT TEMPERATURE (°C)

03327-A-002

Rev. C | Page 7 of 24

AD8027/AD8028

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TYPICAL PERFORMANCE CHARACTERISTICS

Default conditions: VS = 5 V at TA = 25°C, RL = 1 kΩ, unless otherwise noted.

2

V

= 200mV p-p

OUT

1

0 –1 –2 –3 –4 –5 –6 –7 –8

NORMALIZED CLOSED-LOOP GAIN (dB)

–9

–10

0.1 1 10 100 1000

G = +10

G = –1

FREQUENCY (MHz)

Figure 4. Small Signal Frequency Response for Various Gains

2

G = +1

1

V

= 200mV p-p

OUT

0 –1 –2 –3 –4 –5 –6 –7

CLOSED- LOOP GAIN (dB)

–8 –9

–10

0.1 1 10 100 1000

VS = +3V RF = 24.9Ω

VS = +5V

FREQUENCY (MHz)

Figure 5. AD8027 Small Signal Frequency Response for Various Supplies

2

G = +1

1

V

= 2V p-p

OUT

0 –1 –2 –3 –4 –5 –6 –7

CLOSED-LOOP GAIN (dB)

–8 –9

–10

0.1 1 10 1000

VS = +3V

FREQUENCY (MHz)

VS = ±5V

VS = +5V

Figure 6. Large Signal Frequency Response for Various Supplies

100

AD8027 G = +1

G = +2

AD8028 G = +1

03327-A-003

VS = +3V

VS = ±5V

03327-A-004

03327-A-005

8

G = +2

7

V

= 200mV p-p

OUT

6 5 4 3 2 1 0

–1

CLOSED-LOOP GAIN (dB)

–2 –3 –4

0.1 1 10 100 1000

VS = +3V

VS = +5V

FREQUENCY (MHz)

VS = ±5V

03327-A-006

Figure 7. Small Signal Frequency Response for Various Supplies

2

G = +1

1

V

= 200mV p-p

OUT

0 –1 –2 –3 –4 –5 –6 –7

CLOSED-LOOP GAIN (dB)

–8 –9

–10

0.1 1 10 100 1000 FREQUENCY (MHz)

V

S

= +5V

VS = ±5V

= +3V

V

S

03327-A-007

Figure 8. AD8028 Small Signal Frequency Response for Various Supplies

8

G = +2

7

= 2V p-p

V

OUT

6 5 4 3 2 1 0

–1

CLOSED-LOOP GAIN (dB)

–2 –3 –4

0.1 1 10 100 1000

VS = +5V

VS = +3V

FREQUENCY (MHz)

VS = ±5V

03327-A-008

Figure 9. Large Signal Frequency Response for Various Supplies

Rev. C | Page 8 of 24