Datasheet AD8646, AD8648 Datasheet (ANALOG DEVICES)

24 MHz Rail-to-Rail Amplifiers

www.BDTIC.com/ADI

FEATURES

Offset voltage: 2.5 mV maximum
Single-supply operation: 2.7 V to 5.5 V
Low noise: 8 nV/√Hz
Wide bandwidth: 24 MHz
Slew rate: 11 V/μs
Short-circuit output current: 120 mA
No phase reversal
Low input bias current: 1 pA
Low supply current per amplifier: 2 mA maximum
Unity gain stable

APPLICATIONS

Battery-powered instruments
Multipole filters
ADC front ends
Sensors
Barcode scanners
ASIC input or output amplifiers
Audio amplifiers
Photodiode amplifiers
Datapath/mux/switch control

with Shutdown Option

AD8646/AD8647/AD8648

PIN CONFIGURATIONS

1

OUTA

–INA

2

AD8646

V–

TOP VIEW

3

(Not to Scale)

4

+INA

Figure 1. 8-Lead SOIC and MSOP

1

OUTA

–INA

2

V–

AD8647

3

TOP VIEW

(Not to Scale)

4

5

+INA

SDA

Figure 2. 10-Lead MS

1

1

OUTA

2

2

–INA

3

3

+INA

+INB

–INB

OUTB

V+

AD8648

AD8648

TOP VIEW

TOP VIEW

4

4

(Not to Scale)

(Not to Scale)

5

5

6

6

7

7

Figure 3. 14-Lead SOIC and TSSOP

8

7

6

5

10

9

8

7

6

14

14

13

13

12

12

11

11

10

10

V+

OUTB

–INB

+INB

OP

9

9

8

8

V+

OUTB

–INB

+INB

SDB

OUTD

–IND

+IND

V–

+INC

–INC

OUTC

06527-001

06527-002

06527-003

GENERAL DESCRIPTION

The AD8646 and the AD8647 are the dual, and the AD8648 is
the quad, rail-to-rail, input and output, single-supply amplifiers
featuring low offset voltage, wide signal bandwidth, low input
voltage, and low current noise. The AD8647 also has a low
power shutdown function.

The combination of 24 MHz bandwidth, low offset, low noise,

nd very low input bias current makes these amplifiers useful in

a
a wide variety of applications. Filters, integrators, photodiode
amplifiers, and high impedance sensors all benefit from the
combination of performance features. AC applications benefit

Rev. B

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.

from the wide bandwidth and low distortion. TheAD8646/
AD8647/AD8648 offer high output drive capability, which is
excellent for audio line drivers and other low impedance
applications.

Applications include portable and low powered instrumenta-

ion, audio amplification for portable devices, portable phone

t
headsets, barcode scanners, and multipole filters. The ability to
swing rail to rail at both the input and output enables designers
to buffer CMOS ADCs, DACs, ASICs, and other wide output
swing devices in single-supply systems.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] ©2006–2007 Analog Devices, Inc. All rights reserved.

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

TABLE OF CONTENTS

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

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

Pin Configurations ........................................................................... 1

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

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

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

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

Thermal Resistance ...................................................................... 6

REVISION HISTORY

Revision History: AD8646/AD8647/AD8648

10/07—Revision B: Initial Combined Version

Revision History: AD8646

10/07—Rev. 0 to Rev. B

Combined with AD8648....................................................Universal

Added AD8647 ...................................................................Universal

Deleted Figure 4 and Figure 7......................................................... 7

D

eleted Figure 33............................................................................ 11

8/07—Revision 0: Initial Version

Revision History: AD8648

10/0 7 — R e v. A to Re v. B

Combined with AD8646....................................................Universal

Added AD8647 ...................................................................Universal

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

Typical Performance Characteristics..............................................7

Theory of Operation ...................................................................... 15

Power-Down Operation ............................................................ 15

Multiplexing Operation............................................................. 15

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

Ordering Guide .......................................................................... 18

Deleted Figure 7.................................................................................6

D

eleted Figure 11...............................................................................7

Deleted Figure 16 and Figure 17 .....................................................8

Deleted Figure 24...............................................................................9

Deleted Figure 27, Figure 28, Figure 31, and Figure 32 ............ 10

6/07—Rev. 0 to Rev. A

Changes to General Description .....................................................1

Updated Outline Dimensions....................................................... 12

Changes to Ordering Guide.......................................................... 12

1/06—Revision 0: Initial Version

Rev. B | Page 2 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

SPECIFICATIONS

VSY = 5 V, VCM = VSY/2, TA = +25oC, unless otherwise noted.

Table 1.

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage V

OS

−40°C < TA < +125°C 3.2 mV
Offset Voltage Drift ∆VOS/∆T −40°C < TA < +125°C 1.8 7.5 V/°C
Input Bias Current I

B

−40°C < TA < +85°C 50 pA

−40°C < TA < +125°C 550 pA
Input Offset Current I

OS

−40°C < TA < +85°C 50 pA

−40°C < TA < +125°C 250 pA
Input Voltage Range V

CM

Common-Mode Rejection Ratio CMRR VCM = 0 V to 5 V 67 84 dB
Large Signal Voltage Gain AVO R
Input Capacitance

Differential C

DIFF

Common Mode CCM 6.7 pF

OUTPUT CHARACTERISTICS

Output Voltage High V

OH

−40°C < TA < +125°C 4.90 V
I

−40°C < TA < +125°C 4.70 V
Output Voltage Low V

OL

−40°C < TA < +125°C 40 mV
I

−40°C < TA < +125°C 200 mV
Output Current I
Closed-Loop Output Impedance Z

sc

OUT

POWER SUPPLY

Power Supply Rejection Ratio PSRR VSY = 2.7 V to 5.5 V 63 80 dB
Supply Current per Amplifier ISY 1.5 2.0 mA

−40°C < TA < +125°C 2.5 mA
Supply Current Shutdown Mode (AD8647) ISD Shutdown of both amplifiers (AD8647 only) 10

−40°C < TA < +125°C 1

SHUTDOWN INPUTS (AD8647)

Logic High Voltage (Enabled) V
Logic Low Voltage (Power-Down) V
Logic Input Current (Per Pin) I
Output Pin Leakage Current

DYNAMIC PERFORMANCE

INH

INL

IN

Slew Rate SR RL = 2 kΩ 11 V/s
Gain Bandwidth Product GBP 24 MHz
Phase Margin Øm 74 Degrees
Settling Time ts To 0.1% 0.5
Amplifier Turn-On Time (AD8647) t

Amplifier Turn-Off Time (AD8647) t

on

off

VCM = 0 V to 5V 0.6 2.5 mV

0.3 1 pA

0.1 0.5 pA

0 5 V

= 2 kΩ, VO = 0.5 V to 4.5 V 104 116 dB

L

2.5 pF

I

= 1 mA 4.98 4.99 V

OUT

= 10 mA 4.85 4.92 V

OUT

I

= 1 mA 8.4 20 mV

OUT

= 10 mA 78 145 mV

OUT

Short circuit ±120 mA

At 1 MHz, AV = 1 5 Ω

nA
μA

−40°C < TA < +125°C +2.0 V

−40°C < TA < +125°C +0.8 V

−40°C < TA < +125°C 1

−40°C < TA < +125°C (shutdown active) 1

μA
nA

μs
25°C, AV = 1, RL = 1 kΩ (see Figure 44)
25°C, AV = 1, RL = 1 kΩ (see Figure 45)

1
1

μs

μs

Rev. B | Page 3 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

Parameter Symbol Conditions Min Typ Max Unit

NOISE PERFORMANCE

Peak-to-Peak Noise en p-p 0.1 Hz to 10 Hz 2.3 V
Voltage Noise Density e
f = 10 kHz 6 nV/√Hz
Channel Separation CS f = 10 kHz −115 dB
f = 100 kHz −110 dB
Total Harmonic Distortion Plus Noise THD + N V p-p = 0.1 V, RL = 600 Ω, f = 25 kHz, TA = 25°C
A
A

n

f = 1 kHz 8 nV/√Hz

= +1 0.010 %

V

= −10 0.021 %

V

Rev. B | Page 4 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

VSY = 2.7 V, VCM = VSY/2, TA = +25oC, unless otherwise noted.

Table 2.

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage V

OS

−40°C < TA < +125°C 3.2 mV
Offset Voltage Drift ∆VOS/∆T −40°C < TA < +125°C 1.8 7.0 V/°C
Input Bias Current I

B

−40°C < TA < +85°C 50 pA

−40°C < TA < +125°C 550 pA
Input Offset Current I

OS

−40°C < TA < +85°C 50 pA

−40°C < TA < +125°C 250 pA
Input Voltage Range V

CM

Common-Mode Rejection Ratio CMRR VCM = 0 V to 2.7 V 62 79 dB
Large Signal Voltage Gain AVO R

Input Capacitance

Differential C

DIFF

Common Mode CCM 7.8 pF

OUTPUT CHARACTERISTICS

Output Voltage High V

OH

−40°C < TA < +125°C 2.60 V
Output Voltage Low V

OL

−40°C < TA < +125°C 30 mV
Output Current I
Closed-Loop Output Impedance Z

OUT

OUT

POWER SUPPLY

Power Supply Rejection Ratio PSRR VSY = 2.7 V to 5.5 V 63 80 dB
Supply Current per Amplifier ISY 1.6 2.0 mA

−40°C < TA < +125°C 2.5 mA
Supply Current Shutdown Mode (AD8647) ISD Shutdown of both amplifiers (AD8647 only) 10 nA

SHUTDOWN INPUTS (AD8647)

Logic High Voltage (Enabled) V
Logic Low Voltage (Power-Down) V
Logic Input Current (Per Pin) V
Output Pin Leakage Current

DYNAMIC PERFORMANCE

INH

INL

IN

Slew Rate SR RL = 2 kΩ 11 V/s
Gain Bandwidth Product GBP 24 MHz
Phase Margin Ø

m

Settling Time ts To 0.1% 0.3

Amplifier Turn-On Time (AD8647) t
Amplifier Turn-Off Time (AD8647) t

on

off

NOISE PERFORMANCE

Peak-to-Peak Noise en p-p 0.1 Hz to 10 Hz 2.3 V
Voltage Noise Density e

n

f = 10 kHz 6 nV/√Hz

Channel Separation CS f = 10 kHz −115 dB
f = 100 kHz −110 dB

VCM = 0 V to 2.7 V 0.6 2.5 mV

0.2 1 pA

0.1 0.5 pA

0 2.7 V

= 2 kΩ, VO = 0.5 V to 2.2 V 95 102 dB

L

2.5 pF

I

= 1 mA 2.65 2.68 V

OUT

I

= 1 mA 11 25 mV

OUT

Short circuit ±63 mA

At 1 MHz, AV = 1 5 Ω

−40°C < TA < +125°C 1 µA

−40°C < TA < +125°C +2.0 V

−40°C < TA < +125°C +0.8 V

−40°C < TA < +125°C 1 µA

−40°C < TA < +125°C (shutdown active) 1 nA

53 Degrees

μs
25°C, AV = 1, RL = 1 kΩ (see Figure 41)
25°C, AV = 1, RL = 1 kΩ (see Figure 42)

1.2
1

μs

μs

f = 1 kHz 8 nV/√Hz

Rev. B | Page 5 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter Rating

Supply Voltage 6 V
Input Voltage GND to V
Differential Input Voltage ±3 V
Output Short Circuit to GND Indefinite
Storage Temperature Range −65°C to +150°C
Operating Temperature Range −40°C to +125°C
Lead Temperature (Soldering 60 sec) 300°C
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.

SY

THERMAL RESISTANCE

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

Table 4. Thermal Resistance

Package Type θJA θ

8-Lead SOIC_N 125 43 °C/W
8-Lead MSOP 210 45 °C/W
10-Lead MSOP 200 44 °C/W
14-Lead SOIC_N 120 36 °C/W
14-Lead TSSOP 180 35 °C/W

ESD CAUTION

Unit

JC

Rev. B | Page 6 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

TYPICAL PERFORMANCE CHARACTERISTICS

300

VSY = 2.7V
V

= 1.35V

CM

T

= 25°C

A

250

2244 AMPLIF IERS

200

150

100

NUMBER OF AMPLIFIERS

50

0
–2.0 2.01.51.00.50–0.5–1.0–1.5

VOS (mV)

06527-004

Figure 4. Input Offset Voltage Distribution

35

VSY = 2.7V

30

–40°C < T

< +125°C

A

200

VSY = 5V
V

= 2.5V

180

CM

T

= 25°C

A

2244 AMPLIF IERS

160

140

120

100

80

60

NUMBER OF AMPLIFIERS

40

20

0
–2.0 2.01.51.00.50–0.5–1.0–1.5

VOS (mV)

06527-007

Figure 7. Input Offset Voltage Distribution

35

VSY = 5V

30

–40°C < T

< +125°C

A

25

20

15

10

NUMBER OF AMPLIFIERS

5

0

07654321

Figure 5. V

TCVOS (µV/°C)

Drift (TCVOS) Distribution

OS

2500

2000

1500

1000

500

0

–500

–1000

INPUT OFFSET VOLTAGE (µV)

–1500

–2000

–2500

03.0

0.5 1. 0 1.5 2.0 2.5

INPUT COMMO N-MODE VOL TAGE (V)

Figure 6. Input Offset Voltage vs. Input Common-Mode Voltage

VSY = 2.7V
T

= 25°C

A

25

20

15

10

NUMBER OF AMPLIFIERS

5

0

087654321

06527-005

Figure 8. V

TCVOS (µV/°C)

Drift (TCVOS) Distribution

OS

06527-008

2500

2000

1500

1000

500

0

–500

–1000

INPUTOFFSETVOLTAGE(µV)

–1500

–2000

–2500

012345

06527-006

INPUT COM MON-M ODE VO LTAGE (V)

Figure 9. Input Offset Voltage vs. Input Common-Mode Voltage

VSY=5V

=25°C

T

A

06527-009

Rev. B | Page 7 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

10000

VSY = 2.7V
T

= 25°C

A

1000

VSY – V

10000

VSY = 5V
T

= 25°C

A

OH

1000

100

10

1

OUTPUT SAT URATION VO LTAGE (mV)

0.1

0.001 1001010.10.01

LOAD CURRENT (mA)

V

OL

Figure 10. Output Saturation Voltage vs. Load Current

25

VSY = 2.7V
I

= 1mA

L

20

V

– V

SY

15

10

5

OUTPUT SAT URATION VO LTAGE (mV)

0

–40 –25 –10 5 20 35 50 65 80 95 1 10 125

TEMPERATURE ( °C)

OH

V

OL

Figure 11. Output Saturation Voltage vs. Temperature

300

VSY = 2.7V
T

= 125°C

A

250

100

10

VSY – V

1

OUTPUT SAT URATION VO LTAGE (mV)

0.1

0.001 10001001010.10.01

06527-010

OH

V

OL

LOAD CURRENT (mA)

06527-013

Figure 13. Output Saturation Voltage vs. Load Current

120

VSY = 5V

100

80

60

40

20

OUTPUT SAT URATION VO LTAGE (mV)

0

–40 –25 –10 5 20 35 50 65 80 95 110 125

06527-011

VSY – VOH= 10mA

V

OL

V

– VOH= 1mA

SY

V

= 1mA

OL

TEMPERATURE ( °C)

= 10mA

06527-014

Figure 14. Output Saturation Voltage vs. Temperature

300

VSY = 5V
T

= 125°C

A

250

200

150

100

INPUT BIAS CURRENT (pA)

50

0

0.50 2.001. 751.501.251.000.75

COMMON-MODE VOLTAGE (V)

Figure 12. Input Bias Current vs. Common-Mode Voltage

06527-012

200

150

100

INPUT BIAS CURRENT (pA)

50

0

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

COMMON-MODE VOLTAGE (V)

Figure 15. Input Bias Current vs. Common-Mode Voltage

Rev. B | Page 8 of 20

06527-015

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

= 1kΩ

= 10pF

0

45

90

80

60

PHASE

40

VSY = 5V
R
CL = 10pF

L

= 1k

0

Ω

45

90

80

60

40

VSY = 2.7V
R

L

C

L

20

0

OPEN-LOOP GAIN (dB)

–20

–40

10k 100M10M

100k 1M

FREQUENCY (Hz)

Figure 16. Open-Loop Gain and Phase vs. Frequency

60

40

20

0

–20

CLOSED-LOOP GAIN (dB)

–40

–60

1k 10k 100k 1M 10M 100M

AV = 100

= 10

A

V

= 1

A

V

FREQUENCY (Hz)

Figure 17. Closed-Loop Gain vs. Frequency

250

VSY = 2.7V
T

= 25°C

A

200

150

(Ω)

OUT

Z

100

= 100

A

50

V

ФM = 52°

A

V

= 10

AV = 1

VSY = 2.7V
T

= 25°C

A

135

180

225

270

20

0

OPEN-LOOP GAIN (dB)

OPEN-LOOP PHASE SHIFT (Degrees)

06527-016

–20

–40

10k 100k 1M 10M 100M

FREQUENCY (Hz)

GAIN

Ф

= 74°

M

135

180

225

270

OPEN-LOOP PHASE SHIFT (Degrees)

06527-019

Figure 19. Open-Loop Gain and Phase vs. Frequency

60

40

20

0

–20

CLOSED-LOOP GAIN (dB)

–40

–60

1k 10k 100k 1M 10M 100M

06527-017

AV = 100

= 10

A

V

= 1

A

V

FREQUENCY (Hz)

Figure 20. Closed-Loop Gain vs. Frequency

VSY = 5V
T

= 25°C

A

06527-020

120

VSY = 5V
T

= 25°C

A

100

= 1

A

80

(Ω)

60

OUT

Z

40

20

A

= 100

V

V

= 10

A

V

0

1 10 100 1k 10k 1M100k

FREQUENCY (kHz)

Figure 18. Z

vs. Frequency

OUT

06527-018

0

1 10 100 1k 10k 1M100k

Figure 21. Z

Rev. B | Page 9 of 20

FREQUENCY (kHz)

vs. Frequency

OUT

06527-021

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

100

VSY = 2.7V
T

= 25°C

A

80

100

VSY = 5V

= 25°C

T

A

80

60

CMRR (dB)

40

20

0

1k 100M10M1M100k10k

FREQUENCY (Hz)

06527-022

Figure 22. CMRR vs. Frequency

100

PSRR+

80

60

PSRR–

PSRR (dB)

40

20

VSY = 2.7V

= 25°C

T

A

60

CMRR (dB)

40

20

0

1k 100M10M1M100k10k

FREQUENCY (Hz)

06527-025

Figure 25. CMRR vs. Frequency

100

80

60

PSRR (dB)

40

20

PSRR+

PSRR–

VSY = 5V
T

= 25°C

A

0

1k 10M

10k 100k 1M

FREQUENCY (Hz)

06527-023

Figure 23. PSRR vs. Frequency

60

VSY = ±1.35V

= 25°C

T

A

50

40

30

OVERSHOOT (%)

20

10

0

1100010010

C

LOAD

Figure 24. Overshoot v

–OS

+OS

(pF)

s. Load Capacitance

06527-024

0

1k 10M

10k 100k 1M

FREQUENCY (Hz)

Figure 26. PSRR vs. Frequency

70

VSY = 5V
R

= 10kΩ

L

T

= 25°C

60

A

50

40

OS+

30

OVERSHOOT (%)

20

10

0

10 1000

C

100

LOAD

Figure 27. Overshoot v

OS–

(pF)

s. Load Capacitance

06527-026

06527-027

Rev. B | Page 10 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

VSY = 2.7V, VCM = 1.35V, VIN = 100mV p-p ,
T

= 25°C, RL = 10kΩ, CL = 100pF

A

VSY = 5V, VCM = 2.5V, VIN = 100mV p-p ,
T

= 25°C, RL = 10kΩ, CL = 100pF

A

(50mV/DIV)

(200ns/DIV )

06527-028

Figure 28. Small-Signal Transient Response

VSY = 2.7V, VIN = 2V p-p,
T

= 25°C, RL = 10kΩ, CL = 100pF

A

(2V/DIV)

(200ns/DIV )

06527-029

Figure 29. Large-Signal Transient Response

0.08
VSY = ±2.5V

R

= 600Ω

L

0.07
A

= 1

V

T

= 25°C

A

0.06

(50mV/DIV)

(200ns/DIV )

06527-031

Figure 31. Small-Signal Transient Response

VSY = 5V, VIN = 4V p-p,
T

= 25°C, RL = 10kΩ, CL = 100pF

A

(2V/DIV)

(200ns/DIV )

06527-032

Figure 32. Large-Signal Transient Response

0.08
VSY = ±2.5V

R

= 600Ω

L

0.07
A

= –10

V

T

= 25°C

A

0.06

0.05

0.04

THD + N (%)

0.03

0.02

0.01

0

10 100 1k 10k 100k

FREQUENCY (Hz)

Figure 30. THD + Noise vs. Frequency

06527-030

0.05

0.04

THD + N (%)

0.03

0.02

0.01

0

10 100 1k 10k 100k

Figure 33. THD + Noise vs. Frequency

Rev. B | Page 11 of 20

FREQUENCY (Hz)

06527-033

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

0.01

THD + N (%)

0.001

0.0001

1000

100

1

0.1

VSY = 5V
A

= 1

V

BW = 30kHz
R

= 100kΩ

L

f = 1kHz

0.010.001 0.1

OUTPUT AMPLITUDE (V rms)

Figure 37. THD + Noise vs. Output Amplitude

VSY = 5V

10

1

06527-034

VSY = 2.7V TO 5V

= 25°C

T

A

VOLTAGE (1µV/DIV)

TIME (1s/DIV)

6527037

Figure 34. 0.1 Hz to 10 Hz Voltage Noise

1000

100

VSY = 2.7V TO 5V

= 25°C

T

A

10

1

INPUT BIAS CURRENT (pA)

VOLTAGE NOISE DENSI TY (nV/ √Hz)

1

10 10k

100 1k

FREQUENCY (Hz)

06527-035

Figure 35. Voltage Noise Density vs. Frequency

2.5

TA = 25°C

2.0

1.5

1.0

0.5

SUPPLY CURRENT PER AMPLIFIER (mA)

0

05

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

SUPPLY VOLTAGE (V)

Figure 36. Supply Current per Amplifier vs. Supply Voltage

.0

06527-039

0.1
25 125105806545

TEMPERATURE ( °C)

06527-038

Figure 38. Input Bias Current vs. Temperature

5.0

4.5

4.0

3.5

3.0

2.5

2.0

1.5

OUTPUT SWING (V p-p)

1.0

0.5

0

100 1k 10k

FREQUENCY (kHz)

Figure 39. Maximum Output Swing vs. Frequency

VSY = 5V
V

= 4.9V

IN

A

= 1

V

R

= 10kΩ

L

T

= 25°C

A

06527-036

Rev. B | Page 12 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

4.0

3.5

3.0

2.5

2.0

1.5

1.0

0.5

SUPPLY CURRENT PER AMPLIFIER (mA)

0

–40 120

–200 20406080100

TEMPERATURE ( °C)

V

OUT

VSY = 2.7V

VSY = 5V

= VSY/2

06527-040

0

VSY = 5V
R

= 2kΩ

L

A

= –100

V

–20

T

= 25°C

A

–40

–60

–80

CHANNEL SEPARATION (dB)

–100

–120

1k 10k 10 0k

CS (dB) = 20 log (V

V+

3

V+

+

V

2

IN

V–

–

0

V–

FREQUENCY (Hz)

/100 = VIN)

OUT

U1

VIN = 2V p-p

R3
2kΩ

0

20Ω

U2

5

R1

V–

V–
V+

V+

= 0.5V p-p

V

IN

R2

200Ω

6

7

0

0

06527-042

Figure 40. Supply Current per Amplifier vs. Temperature

SHUTDOWN PIN

VSY = 2.7V
R

= 1kΩ

L

A

= 1

V

T

= 25°C

A

VOLTAGE (1V/DIV)

AMPLIFI ER OUTPUT

TIME (200ns/DIV)

06527-045

VSY = 5V
R
A
T

VOLTAGE (1V/DIV)

Figure 41. Turn-On Time

Figure 43. Channel Separation

= 1kΩ

L

= 1

V

= 25°C

A

TIME (200ns/DIV)

Figure 44. Turn-On Time

SHUTDOWN PIN

AMPLIFI ER OUTPUT

06527-043

SHUTDOWN PIN

VSY = 2.7V
R

= 1kΩ

L

A

= 1

V

T

= 25°C

A

VSY = 5V
R

= 1kΩ

L

A

= 1

V

T

= 25°C

A

VOLTAGE (1V/DIV)

AMPLIFI ER OUTPUT

TIME (200n s/DIV)

06527-046

Figure 42. Turn-Off Time

VOLTAGE (1V/DIV)

Figure 45. Turn-Off Time

Rev. B | Page 13 of 20

SHUTDOWN PIN

AMPLIFIER OUTPUT

TIME (200ns/DIV)

06527-044

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

100

VSY = 2.7V

100

VSY = 5V

10

1

(nA)

SY

I

0.1

0.01
–40 80

–25 –10 5 20 35 50 65 12595 110

TEMPERATURE (° C)

Figure 46. Supply Current with Op-Amp Shutdown

vs. Temperature

10

1

(nA)

SY

I

0.1

0.01
–40 80

–25 –10 5 20 35 50 65 12595 110

06527-048

Figure 47. Supply Current with Op-Amp Shutdown

TEMPERATURE (° C)

vs. Temperature

06527-047

Rev. B | Page 14 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

THEORY OF OPERATION

POWER-DOWN OPERATION

The shutdown function of the AD8647 is referenced to the
negative supply voltage of the operational amplifier. A logic
level high (> 2.0 V) enables the device, while a logic level low
(< 0.8 V) disables the device and places the output in a high
impedance condition. Several outputs can be wire-OR’ed, thus
eliminating a multiplexer. The logic input is a high impedance
CMOS input. If dual or split supplies are used, the logic signals
must be properly referred to the negative supply voltage.

MULTIPLEXING OPERATION

Because each op amp has a separate logic input enable pin, the
outputs can be connected together if it can be guaranteed that
only one op amp is active at any time. By connecting the op amps
as shown in

asonably short turn-on and turn-off times, low frequency signal

re
paths can be smoothly selected. The turn-off time is slightly faster
than the turn-on time so, even when using sections from two
different packages, the overlap is less than 300 nanoseconds.

Figure 48, a multiplexer can be eliminated. With the

5kHz

13kHz

1

2kHz

Figure 48. AD8647 Output Switching

2V

1V

0V

8

7

2

3

AD8647

6

5V

10

4

2

1/2

9

1/2

AD8647

1

5

06527-049

5V

0V

TIME (200µs/DIV)

Figure 49. Switching Waveforms

06527-050

Rev. B | Page 15 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

OUTLINE DIMENSIONS

5.00 (0.1968)

4.80 (0.1890)

4.00 (0.1574)

3.80 (0.1497)

0.25 (0.0098)

0.10 (0.0040)

COPLANARITY

0.10

CONTROLL ING DIMENSI ONS ARE IN MILLIMETERS; INCH DI MENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRI ATE FOR USE IN DES IGN.

85

1

1.27 (0.0500)

SEATING

PLANE

COMPLIANT TO JEDEC STANDARDS MS-012-A A

BSC

6.20 (0.2441)

5.80 (0.2284)

4

1.75 (0.0688)

1.35 (0.0532)

0.51 (0.0201)

0.31 (0.0122)

8°
0°

0.25 (0.0098)

0.17 (0.0067)

0.50 (0.0196)

0.25 (0.0099)

1.27 (0.0500)

0.40 (0.0157)

45°

012407-A

Figure 50. 8-Lead Standard Small Outline Package [SOIC_N]

Nar

row Body

(R-8)

Dimensions shown in millimeters and (inches)

3.20

3.00

2.80

3.20

3.00

2.80

8

1

5

5.15

4.90

4.65

4

PIN 1

0.65 BSC

0.95

0.85

0.75

0.15

0.00

COPLANARITY

0.38

0.22

0.10

COMPLIANT TO JEDEC STANDARDS MO-187-AA

1.10 MAX

SEATING
PLANE

0.23

0.08

8°
0°

0.80

0.60

0.40

Figure 51. 8-Lead Mini Small Outline Package [MSOP]

(RM-8)

Dim

ensions shown in millimeters

Rev. B | Page 16 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

3.10

3.00

2.90

6

3.10

3.00

2.90

PIN 1

0.95

0.85

0.75

0.15

0.05

10

1

0.50 BSC

0.33

0.17

COPLANARITY

0.10

COMPLIANT TO JEDEC STANDARDS MO-187-BA

5.15

4.90

4.65

5

1.10 MAX

0.80

0.60

0.40

SEATING
PLANE

0.23

0.08

8°
0°

Figure 52. 10 Lead Mini Small Outline Package [MSOP]

(R

M-10)

Dimensions shown in millimeters

5.10

5.00

4.90

1.05

1.00

0.80

14

4.50

4.40

4.30

PIN 1

0.65

BSC

0.15

0.30

0.05

0.19

COMPLIANT TO JEDEC STANDARDS MO-153-AB-1

Figure 53. 14-Lead Thin Shrink S

8

6.40

BSC

71

0.20

1.20

0.09

MAX

SEATING
PLANE

COPLANARITY

0.10

mall Outline Package [TSSOP]

(RU-14)

Dimensions shown in millimeters

8°
0°

0.75

0.60

0.45

Rev. B | Page 17 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

4.00 (0.1575)

3.80 (0.1496)

0.25 (0.0098)

0.10 (0.0039)

COPLANARIT Y

0.10

CONTROLL ING DIMENSIONS ARE IN MILLI METERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-O FF MIL LIMETE R EQUIVALENTS FOR
REFERENCE ON LY AND ARE NOT APPROPRI ATE FOR USE IN DESIGN.

8.75 (0.3445)

8.55 (0.3366)

BSC

8

7

6.20 (0.2441)

5.80 (0.2283)

1.75 (0.0689)

1.35 (0.0531)

SEATING
PLANE

0.25 (0.0098)

0.17 (0.0067)

14

1

1.27 (0.0500)

0.51 (0.0201)

0.31 (0.0122)

COMPLIANT TO JEDEC STANDARDS MS-012-AB

0.50 (0.0197)

0.25 (0.0098)

8°
0°

1.27 (0.0500)

0.40 (0.0157)

45°

060606-A

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

Nar

row Body

(R-14)

Dimensions shown in millimeters and (inches)

ORDERING GUIDE

Model Temperature Range Package Description Package Option Branding

AD8646ARZ
AD8646ARZ-REEL
AD8646ARZ-REEL7
AD8646ARMZ-R2
AD8646ARMZ-REEL
AD8647ARMZ-R2
AD8647ARMZ-REEL
AD8648ARZ
AD8648ARZ-REEL
AD8648ARZ-REEL7
AD8648ARUZ
AD8648ARUZ-REEL

1

Z = RoHS Compliant Part.

1

1

1

1

1

1

1

1

1

1

1

1

−40°C to +125°C 8-Lead SOIC_N R-8

−40°C to +125°C 8-Lead SOIC_N R-8

−40°C to +125°C 8-Lead SOIC_N R-8

−40°C to +125°C 8-Lead MSOP RM-8 A1V

−40°C to +125°C 8-Lead MSOP RM-8 A1V

−40°C to +125°C 10-Lead MSOP RM-10 A1W

−40°C to +125°C 10-Lead MSOP RM-10 A1W

−40°C to +125°C 14-Lead SOIC_N R-14

−40°C to +125°C 14-Lead SOIC_N R-14

−40°C to +125°C 14-Lead SOIC_N R-14

−40°C to +125°C 14-Lead TSSOP RU-14

−40°C to +125°C 14-Lead TSSOP RU-14

Rev. B | Page 18 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

NOTES

Rev. B | Page 19 of 20

AD8646/AD8647/AD8648

www.BDTIC.com/ADI

NOTES

©2006–2007 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D06527-0-10/07(B)

Rev. B | Page 20 of 20