Analog Devices AD8397 Service Manual

Rail-to-Rail, High Output Current Amplifier

FEATURES

Dual operational amplifier
Voltage feedback
Wide supply range: from 3 V to 24 V
Rail-to-rail output

Output swing to within 0.5 V of supply rails

High linear output current

310 mA peak into 32 Ω on ±12 V supplies while maintaining

−80 dBc SFDR

Low noise

4.5 nV/√Hz voltage noise density @ 100 kHz

1.5 pA/√Hz current noise density @ 100 kHz

High speed

69 MHz bandwidth (G = 1, −3 dB)
53 V/µs slew rate (R

APPLICATIONS

Twisted-pair line drivers
Audio applications
General-purpose high current amplifiers

GENERAL DESCRIPTION

The AD8397 has two voltage feedback operational amplifiers
capable of driving heavy loads with excellent linearity. The
common-emitter, rail-to-rail output stage surpasses the output
voltage capability of typical emitter-follower output stages and
can swing to within 0.5 V of either rail while driving a 25 Ω
load. The low distortion, high output current, and wide output
dynamic range make the AD8397 ideal for applications that
require a large signal swing into a heavy load.

Fabricated with ADI’s high speed eXtra Fast Complementary
Bipolar High Voltage (XFCB-HV) process, the high bandwidth
and fast slew rate of the AD8397 keep distortion to a minimum
while also dissipating minimum power. The AD8397 is available
in a standard 8-lead SOIC package and, for higher power appli­cations, a thermally enhanced 8-lead SOIC EPAD package. Both
packages can operate from −40°C to +85°C.

LOAD

= 25 Ω)

PIN CONFIGURATION

1

OUT1

2

–IN1
+IN1

3

–V

4

S

Figure 1. 8-Lead SOIC

1.50

1.25

1.00

0.75

0.50

0.25

(V)

0

OUT

–0.25

V

–0.50
–0.75
–1.00
–1.25
–1.50

0 2 4 6 8 10 12 14 16 18 20

Figure 2. Output Swing, V

12

9

6

3

(V)

0

OUT

V

–3

–6

–9

–12

0 2 4 6 8 10 12 14 16 18 20

Figure 3. Output Swing, V

8

+V

7

OUT2
–IN2

6

+IN2

5

TIME (µs)

= ±1.5 V, RL = 25 Ω

S

TIME (µs)

= ±12 V, RL = 100 Ω

S

S

05069-001

AD8397

05069-031

05069-032

Rev. 0

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.

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Tel: [phone]
Fax: [phone] © 2005 Analog Devices, Inc. All rights reserved.

www.analog.com

AD8397

TABLE OF CONTENTS

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

Power Supply and Decoupling ................................................. 11

Absolute Maximum Ratings............................................................ 7

Maximum Power Dissipation ..................................................... 7

ESD Caution.................................................................................. 7

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

General Description....................................................................... 11

REVISION HISTORY

1/05—Revision 0: Initial Version

Layout Considerations............................................................... 11

Unity-Gain Output Swing ......................................................... 11

Capacitive Load Drive ............................................................... 12

Outline Dimensions....................................................................... 13

Ordering Guide .......................................................................... 13

Rev. 0 | Page 2 of 16

AD8397

SPECIFICATIONS

VS = ±1.5 V or +3 V (@ TA = 25°C, G = +1, RL = 25 Ω, unless otherwise noted).

Table 1.

Parameter Test Conditions/Comments Min Typ Max Unit

DYNAMIC PERFORMANCE

−3 dB Bandwidth V

0.1 dB Flatness V
Large Signal Bandwidth V
Slew Rate V

NOISE/DISTORTION PERFORMANCE

Distortion (Worst Harmonic) fC = 100 kHz, V
Input Voltage Noise f = 100 kHz 4.5 nV/√Hz
Input Current Noise f = 100 kHz 1.5 pA/√Hz

DC PERFORMANCE

Input Offset Voltage 1.0 2.5 mV
T
Input Offset Voltage Match 1.0 2.0 mV
Input Bias Current 200 900 nA
T
Input Offset Current 50 300 nA
Open-Loop Gain V

INPUT CHARACTERISTICS

Input Resistance f = 100 kHz 87 kΩ
Input Capacitance 1.4 pF
Common-Mode Rejection ∆VCM = ±1 V −71 −80 dB

OUTPUT CHARACTERISTICS

Output Resistance 0.2 Ω
+Swing R

−Swing R
+Swing R

−Swing R
Maximum Output Current SFDR ≤ −70 dBc, f = 100 kHz, V

POWER SUPPLY

Operating Range (Dual Supply) ±1.5 ±12.0 V
Supply Current 6 7 8.5 mA/Amp
Power Supply Rejection ∆VS = ±0.5 V −70 −82 dB

= 0.1 V p-p 50 MHz

OUT

= 0.1 V p-p 3.6 MHz

OUT

= 2.0 V p-p 9 MHz

OUT

= 0.8 V p-p 32 V/µs

OUT

= 1.4 V p-p, G = +2 −90 dBc

OUT

− T

MIN

MAX

− T

MIN

MAX

= ±0.5 V 81 88 dB

OUT

= 25 Ω +1.39 +1.43 V

LOAD

= 25 Ω −1.4 −1.37 V

LOAD

= 100 Ω +1.45 +1.48 V

LOAD

= 100 Ω −1.47 −1.44 V

LOAD

= 0.7 VP, R

OUT

= 4.1 Ω 170 mA

LOAD

2.5 mV

1.3 µA

P

P

P

P

Rev. 0 | Page 3 of 16

AD8397

VS = ±2.5V or +5 V (@ TA = 25°C, G = +1, RL = 25 Ω, unless otherwise noted).

Table 2.

Parameter Test Conditions/Comments Min Typ Max Unit

DYNAMIC PERFORMANCE

−3 dB Bandwidth V

0.1 dB Flatness V
Large Signal Bandwidth V
Slew Rate V

NOISE/DISTORTION PERFORMANCE

Distortion (Worst Harmonic) fC = 100 kHz, V
Input Voltage Noise f = 100 kHz 4.5 nV/√Hz
Input Current Noise f = 100 kHz 1.5 pA/√Hz

DC PERFORMANCE

Input Offset Voltage 1.0 2.4 mV
T
Input Offset Voltage Match 1.0 2.0 mV
Input Bias Current 200 900 nA
T
Input Offset Current 50 300 nA
Open-Loop Gain V

INPUT CHARACTERISTICS

Input Resistance f = 100 kHz 87 kΩ
Input Capacitance 1.4 pF
Common-Mode Rejection ∆VCM = ±1 V −76 −80 dB

OUTPUT CHARACTERISTICS

Output Resistance 0.2 Ω
+Swing R

−Swing R
+Swing R

−Swing R
Maximum Output Current SFDR ≤ −70 dBc, f = 100 kHz, V

POWER SUPPLY

Operating Range (Dual Supply) ±1.5 ±12.6 V
Supply Current 7 9 12 mA/Amp
Power Supply Rejection ∆VS = ±0.5 V −75 −85 dB

= 0.1 V p-p 60 MHz

OUT

= 0.1 V p-p 4.8 MHz

OUT

= 2.0 V p-p 14 MHz

OUT

= 2.0 V p-p 53 V/µs

OUT

= 2 V p-p, G = +2 −98 dBc

OUT

− T

MIN

MAX

− T

MIN

MAX

= ±1.0 V 85 90 dB

OUT

= 25 Ω +2.37 +2.42 V

LOAD

= 25 Ω −2.37 −2.32 V

LOAD

= 100 Ω +2.45 +2.48 V

LOAD

= 100 Ω −2.46 −2.42 V

LOAD

= 1.0 VP, R

OUT

= 4.3 Ω 230 mA

LOAD

2.5 mV

1.3 µA

P

P

P

P

Rev. 0 | Page 4 of 16

AD8397

VS = ±5 V or +10 V (@ TA = 25°C, G = +1, RL = 25 Ω, unless otherwise noted).

Table 3.

Parameter Test Conditions/Comments Min Typ Max Unit

DYNAMIC PERFORMANCE

−3 dB Bandwidth V

0.1 dB Flatness V
Large Signal Bandwidth V
Slew Rate V

NOISE/DISTORTION PERFORMANCE

Distortion (Worst Harmonic) fC = 100 kHz, V
Input Voltage Noise f = 100 kHz 4.5 nV/√Hz
Input Current Noise f = 100 kHz 1.5 pA/√Hz

DC PERFORMANCE

Input Offset Voltage 1.0 2.5 mV
T
Input Offset Voltage Match 1.0 2.0 mV
Input Bias Current 200 900 nA
T
Input Offset Current 50 300 nA
Open-Loop Gain V

INPUT CHARACTERISTICS

Input Resistance f = 100 kHz 87 kΩ
Input Capacitance 1.4 pF
Common-Mode Rejection ∆VCM = ±1 V −84 −94 dB

OUTPUT CHARACTERISTICS

Output Resistance 0.2 Ω
+Swing R

−Swing R
+Swing R

−Swing R
Maximum Output Current SFDR ≤ −80 dBc, f = 100 kHz, V

POWER SUPPLY

Operating Range (Dual Supply) ±1.5 ±12.6 V
Supply Current 7 9 12 mA/Amp
Power Supply Rejection ∆VS = ±0.5 V −76 −85 dB

= 0.1 V p-p 66 MHz

OUT

= 0.1 V p-p 6.5 MHz

OUT

= 2.0 V p-p 14 MHz

OUT

= 4.0 V p-p 53 V/µs

OUT

= 6 V p-p, G = +2 −94 dBc

OUT

− T

MIN

MAX

− T

MIN

MAX

= ±2.0 V 85 94 dB

OUT

= 25 Ω +4.7 +4.82 V

LOAD

= 25 Ω −4.74 −4.65 V

LOAD

= 100 Ω +4.92 +4.96 V

LOAD

= 100 Ω −4.92 −4.88 V

LOAD

= 3 VP, R

OUT

= 12 Ω 250 mA

LOAD

2.5 mV

1.3 µA

P

P

P

P

Rev. 0 | Page 5 of 16