Analog Devices AD8601, AD8602, AD8604 Service Manual

Precision CMOS Single-Supply

14

13

12

11

10

9

8

1

2

3

4

5

6

7

ⴚIN A

ⴙIN A

Vⴙ

ⴙIN B

ⴚIN B

OUT B

OUT D

ⴚIN D

ⴙIN D

Vⴚ

ⴙIN C

ⴚIN C

OUT C

OUT A

AD8604

14

13

12

11

10

9

8

1

2

3

4

5

6

7

ⴚIN A

ⴙIN A

Vⴙ

ⴙIN B

ⴚIN B

OUT B

OUT D

ⴚIN D

ⴙIN D

Vⴚ

ⴙIN C

ⴚIN C

OUT C

OUT A

AD8604

Rail-to-Rail Input/Output Wideband

Operational Amplifiers

AD8601/AD8602/AD8604

FEATURES
Low Offset Voltage: 500 ␮V Max
Single-Supply Operation: 2.7 V to 5.5 V
Low Supply Current: 750 ␮A/Amplifier
Wide Bandwidth: 8 MHz
Slew Rate: 5 V/␮s
Low Distortion
No Phase Reversal
Low Input Currents
Unity Gain Stable

APPLICATIONS
Current Sensing
Barcode Scanners
PA Controls
Battery-Powered Instrumentation
Multipole Filters
Sensors
ASIC Input or Output Amplifiers
Audio

GENERAL DESCRIPTION

The AD8601, AD8602, and AD8604 are single, dual, and quad
rail-to-rail input and output single-supply amplifiers featuring very
low offset voltage and wide signal bandwidth. These amplifiers
use a new, patented trimming technique that achieves superior
performance without laser trimming. All are fully specified to
operate on a 3 V to 5 V single supply.

The combination of low offsets, very low input bias currents,
and high speed make these amplifiers useful in a wide variety of
applications. Filters, integrators, diode amplifiers, shunt current
sensors, and high impedance sensors all benefit from the combi­nation of performance features. Audio and other ac applications
benefit from the wide bandwidth and low distortion. For the
most cost-sensitive applications, the D grades offer this ac per­formance with lower dc precision at a lower price point.

Applications for these amplifiers include audio amplification for
portable devices, portable phone headsets, bar code scanners,
portable instruments, cellular PA controls, 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.

FUNCTIONAL BLOCK DIAGRAM

14-Lead TSSOP

(RU Suffix)

5-Lead SOT-23

(RT Suffix)

OUT A

1

Vⴚ

2

AD8601

ⴙIN

3

Vⴙ

5

ⴚIN

4

8-Lead MSOP

(RM Suffix)

14-Lead SOIC

(R Suffix)

1

OUT A

2

ⴚIN A

ⴙIN A

AD8602

3

VⴚⴙIN B

4

8

7

6

5

Vⴙ

OUT B

ⴚIN B

8-Lead SOIC

(R Suffix)

OUT A

ⴚIN A

ⴙIN A

Vⴚ

1

2

AD8602

3

4

8

7

6

5

Vⴙ

OUT B

ⴚIN B

ⴙIN B

The AD8601, AD8602, and AD8604 are specified over the
extended industrial (–40°C to +125°C) temperature range. The
AD8601, single, is available in the tiny 5-lead SOT-23 package.
The AD8602, dual, is available in 8-lead MSOP and narrow
SOIC surface-mount packages. The AD8604, quad, is available
in 14-lead TSSOP and narrow SOIC packages.

SOT, MSOP, and TSSOP versions are available in tape and
reel only.

REV. D

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. 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] © 2003 Analog Devices, Inc. All rights reserved.

AD8601/AD8602/AD8604–SPECIFICATIONS

ELECTRICAL CHARACTERISTICS

(VS = 3 V, VCM = VS/2, TA = 25ⴗC, unless otherwise noted.)

A Grade D Grade

Parameter Symbol Conditions Min Typ Max Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage (AD8601/AD8602) V

Offset Voltage (AD8604) V

Input Bias Current I

OS

OS

B

0 V ≤ VCM ≤ 1.3 V 80 500 1,100 6,000 µV
–40°C ≤ T
–40°C ≤ T
0 V ≤ VCM ≤ 3 V
–40°C ≤ T
–40°C ≤ T

≤ +85°C 700 7,000 µV

A

≤ +125°C 1,100 7,000 µV

A

*

≤ +85°C 1,800 7,000 µV

A

≤ +125°C 2,100 7,000 µV

A

350 750 1,300 6,000 µV

VCM = 0 V to 1.3 V 80 600 1,100 6,000 µV
–40°C ≤ T
–40°C ≤ T
VCM = 0 V to 3.0 V
–40°C ≤ T
–40°C ≤ T

≤ +85°C 800 7,000 µV

A

≤ +125°C 1,600 7,000 µV

A

A

A

*

350 800 1,300 6,000 µV
≤ +85°C 2,200 7,000 µV
≤ +125°C 2,400 7,000 µV

0.2 60 0.2 200 pA

–40°C ≤ T

≤ +85°C25100 25 200 pA

A

–40°C ≤ TA ≤ +125°C 150 1,000 150 1,000 pA

Input Offset Current I

OS

–40°C ≤ T

≤ +85°C50100 pA

A

0.1 30 0.1 100 pA

–40°C ≤ TA ≤ +125°C 500 500 pA

Input Voltage Range 0 3 0 3 V
Common-Mode Rejection Ratio CMRR V
Large Signal Voltage Gain A

VO

= 0 V to 3 V 68 83 52 65 dB

CM

VO = 0.5 V to 2.5 V,
RL = 2 kΩ , VCM = 0 V 30 100 20 60 V/mV

Offset Voltage Drift ∆VOS/∆T22µV/°C

OUTPUT CHARACTERISTICS

Output Voltage High V

Output Voltage Low V

OH

OL

IL = 1.0 mA 2.92 2.95 2.92 2.95 V
–40°C ≤ T

≤ +125°C 2.88 2.88 V

A

IL = 1.0 mA 20 35 20 35 mV
–40°C ≤ TA ≤ +125°C50 50mV

Output Current I
Closed-Loop Output Impedance Z

OUT

OUT

f = 1 MHz, AV = 1 12 12 Ω

±30 ±30 mA

POWER SUPPLY

Power Supply Rejection Ratio PSRR VS = 2.7 V to 5.5 V 67 80 56 72 dB
Supply Current/Amplifier I

SY

VO = 0 V 680 1,000 680 1,000 µA
–40°C ≤ TA ≤ +125°C 1,300 1,300 µA

DYNAMIC PERFORMANCE

Slew Rate SR RL = 2 kΩ 5.2 5.2 V/µs
Settling Time t

S

To 0.01% <0.5 <0.5 µs

Gain Bandwidth Product GBP 8.2 8.2 MHz
Phase Margin ⌽o5050Degrees

NOISE PERFORMANCE

Voltage Noise Density e

Current Noise Density i

*For VCM between 1.3 V and 1.8 V, VOS may exceed specified value.

Specifications subject to change without notice.

n

e

n

n

f = 1 kHz 33 33 nV/√Hz
f = 10 kHz 18 18 nV/√Hz

0.05 0.05 pA/√Hz

REV. D–2–

AD8601/AD8602/AD8604

ELECTRICAL CHARACTERISTICS

(VS = 5.0 V, VCM = VS/2, TA = 25ⴗC, unless otherwise noted.)

A Grade D Grade

Parameter Symbol Conditions Min Typ Max Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage (AD8601/AD8602) V

Offset Voltage (AD8604) V

OS

OS

0 V ≤ VCM ≤ 5 V 80 500 1,300 6,000 µV
–40°C ≤ T

≤ +125°C 1,300 7,000 µV

A

VCM = 0 V to 5 V 80 600 1,300 6,000 µV
–40°C ≤ TA ≤ +125°C 1,700 7,000 µV

Input Bias Current I

B

–40°C ≤ T

≤ +85°C 100 200 pA

A

0.2 60 0.2 200 pA

–40°C ≤ TA ≤ +125°C 1,000 1,000 pA

Input Offset Current I

OS

–40°C ≤ T

≤ +85°C6506100 pA

A

0.1 30 0.1 100 pA

–40°C ≤ TA ≤ +125°C25500 25 500 pA

Input Voltage Range 0 5 0 5 V
Common-Mode Rejection Ratio CMRR V
Large Signal Voltage Gain A

VO

= 0 V to 5 V 74 89 56 67 dB

CM

VO = 0.5 V to 4.5 V, 30 80 20 60 V/mV

= 2 kΩ, VCM = 0 V

R

L

Offset Voltage Drift ∆VOS/∆T22µV/°C

OUTPUT CHARACTERISTICS

Output Voltage High V

OH

IL = 1.0 mA 4.925 4.975 4.925 4.975 V
IL = 10 mA 4.7 4.77 4.7 4.77 V
–40°C ≤ TA ≤ +125°C 4.6 4.6 V

Output Voltage Low V

OL

IL = 1.0 mA 15 30 15 30 mV
IL = 10 mA 125 175 125 175 mV
–40°C ≤ TA ≤ +125°C 250 250 mV

Output Current I
Closed-Loop Output Impedance Z

OUT

OUT

f = 1 MHz, AV = 1 10 10 Ω

±50 ±50 mA

POWER SUPPLY

Power Supply Rejection Ratio PSRR VS = 2.7 V to 5.5 V 67 80 56 72 dB
Supply Current/Amplifier I

SY

VO = 0 V 750 1,200 750 1,200 µA

–40°C ≤ TA ≤ +125°C 1,500 1,500 µA

DYNAMIC PERFORMANCE

Slew Rate SR RL = 2 kΩ 66V/µs
Settling Time t

S

To 0.01% <1.0 <1.0 µs

Full Power Bandwidth BWp < 1% Distortion 360 360 kHz
Gain Bandwidth Product GBP 8.4 8.4 MHz

Phase Margin ⌽o5555Degrees

NOISE PERFORMANCE

Voltage Noise Density e

Current Noise Density i

Specifications subject to change without notice.

n

e

n

n

f = 1 kHz 33 33 nV/√
f = 10 kHz 18 18 nV/√

f = 1 kHz 0.05 0.05 pA/√Hz

Hz
Hz

REV. D

–3–

AD8601/AD8602/AD8604

ABSOLUTE MAXIMUM RATINGS*

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 V

Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND to V

S

Differential Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . ± 6 V

Storage Temperature Range

R, RM, RT, RU Packages . . . . . . . . . . . . –65°C to +150°C

Operating Temperature Range

AD8601/AD8602/AD8604 . . . . . . . . . . . . –40°C to +125°C

Junction Temperature Range

R, RM, RT, RU Packages . . . . . . . . . . . . –65°C to +150°C

Lead Temperature Range (Soldering, 60 sec) . . . . . . . . 300°C

ESD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 kV HBM

*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 listed in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.

ORDERING GUIDE

Temperature Package Package

Model Range Description Option Branding

AD8601ART-R2 –40°C to +125°C 5-Lead SOT-23 RT-5 AAA
AD8601ART-REEL –40°C to +125°C 5-Lead SOT-23 RT-5 AAA
AD8601ART-REEL7 –40°C to +125°C 5-Lead SOT-23 RT-5 AAA
AD8601DRT-R2 –40°C to +125°C 5-Lead SOT-23 RT-5 AAD
AD8601DRT-REEL –40°C to +125°C 5-Lead SOT-23 RT-5 AAD
AD8601DRT-REEL7 –40°C to +125°C 5-Lead SOT-23 RT-5 AAD
AD8602AR –40°C to +125°C 8-Lead SOIC R-8
AD8602AR-REEL7 –40°C to +125°C 8-Lead SOIC R-8
AD8602AR-R2 –40°C to +125°C 8-Lead SOIC R-8
AD8602DR –40°C to +125°C 8-Lead SOIC R-8
AD8602DR-REEL –40°C to +125°C 8-Lead SOIC R-8
AD8602DR-REEL7 –40°C to +125°C 8-Lead SOIC R-8
AD8602ARM-R2 –40°C to +125°C 8-Lead MSOP RM-8 ABA
AD8602ARM-REEL –40°C to +125°C 8-Lead MSOP RM-8 ABA
AD8602DRM-REEL –40°C to +125°C 8-Lead MSOP RM-8 ABD
AD8604AR –40°C to +125°C 14-Lead SOIC R-14
AD8604AR-REEL –40°C to +125°C 14-Lead SOIC R-14
AD8604AR-REEL7 –40°C to +125°C 14-Lead SOIC R-14
AD8604DR –40°C to +125°C 14-Lead SOIC R-14
AD8604DR-REEL –40°C to +125°C 14-Lead SOIC R-14
AD8604ARU –40°C to +125°C 14-Lead TSSOP RU-14
AD8604ARU-REEL –40°C to +125°C 14-Lead TSSOP RU-14
AD8604DRU –40°C to +125°C 14-Lead TSSOP RU-14
AD8604DRU-REEL –40°C to +125°C 14-Lead TSSOP RU-14

Package Type ␪JA* ␪

JC

Unit

5-Lead SOT-23 (RT) 230 92 °C/W
8-Lead SOIC (R) 158 43 °C/W
8-Lead MSOP (RM) 210 45 °C/W
14-Lead SOIC (R) 120 36 °C/W
14-Lead TSSOP (RU) 180 35 °C/W

*␪JA is specified for worst-case conditions, i.e., ␪JA is specified for device in

socket for PDIP packages; ␪JA is specified for device soldered onto a circuit
board for surface-mount packages.

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
AD8601/AD8602/AD8604 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. D–4–

3,000

TCVOS – ␮V/ⴗC

60

30

0

0101

QUANTITY – Amplifiers

23456789

50

40

20

10

VS = 5V
T

A

= 25ⴗC TO 85ⴗC

VS = 3V

= 25ⴗC

T

A

2,500

2,000

1,500

1,000

QUANTITY – Amplifiers

500

= 0V TO 3V

V

CM

Typical Performance Characteristics–

AD8601/AD8602/AD8604

0

ⴚ1.0

ⴚ0.6 ⴚ0.4 ⴚ0.2

ⴚ0.8

INPUT OFFSET VOLTAGE – mV

0

0.2 0.4 0.6 0.8

TPC 1. Input Offset Voltage Distribution

3,000

VS = 5V

= 25ⴗC

T

A

2,500

2,000

1,500

1,000

QUANTITY – Amplifiers

500

0

ⴚ1.0

= 0V TO 5V

V

CM

ⴚ0.8

ⴚ0.6 ⴚ0.4 ⴚ0.2

INPUT OFFSET VOLTAGE – mV

0

0.2 0.4 0.6 0.8

TPC 2. Input Offset Voltage Distribution

60

50

VS = 3V
TA = 25ⴗC TO 85ⴗC

1.0

1.0

TPC 4. Input Offset Voltage Drift Distribution

1.5
VS = 3V

= 25ⴗC

T

0

03.00.5

A

1.0 1.5 2.0 2.5

COMMON-MODE VOLTAGE – V

1.0

0.5

ⴚ0.5

ⴚ1.0

INPUT OFFSET VOLTAGE – mV

ⴚ1.5

ⴚ2.0

TPC 5. Input Offset Voltage vs. Common-Mode Voltage

1.5
VS = 5V

= 25ⴗC

T

A

1.0

REV. D

40

30

20

QUANTITY – Amplifiers

10

0

0101

23456789

TCVOS – ␮V/ⴗC

TPC 3. Input Offset Voltage Drift Distribution

0.5

0

ⴚ0.5

ⴚ1.0

INPUT OFFSET VOLTAGE – mV

ⴚ1.5

ⴚ2.0

01

2345

COMMON-MODE VOLTAGE – V

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

–5–

AD8601/AD8602/AD8604

300

VS = 3V

250

200

150

100

INPUT BIAS CURRENT – pA

50

0

ⴚ40

ⴚ25 ⴚ10

535508095110

TEMPERATURE – ⴗC

TPC 7. Input Bias Current vs. Temperature

300

VS = 5V

250

200

150

30

VS = 3V

25

20

15

10

INPUT OFFSET CURRENT – pA

5

0

ⴚ40

12520 65

ⴚ25 ⴚ10

535508095110

TEMPERATURE – ⴗC

12520 65

TPC 10. Input Offset Current vs. Temperature

30

VS = 5V

25

20

15

100

INPUT BIAS CURRENT – pA

50

0

ⴚ40

ⴚ25 ⴚ10

535508095110

TEMPERATURE – ⴗC

12520 65

TPC 8. Input Bias Current vs. Temperature

5

VS = 5V

= 25ⴗC

T

A

4

3

2

INPUT BIAS CURRENT – pA

1

0

0 0.5 1.0 1.5 4.5 5.0

2.0 2.5 3.0 3.5

COMMON-MODE VOLTAGE – V

4.0

TPC 9. Input Bias Current vs. Common-Mode Voltage

10

INPUT OFFSET CURRENT – pA

5

0

ⴚ40

ⴚ25 ⴚ10

535508095110

TEMPERATURE – ⴗC

12520 65

TPC 11. Input Offset Current vs. Temperature

10k

VS = 2.7V
T

= 25ⴗC

A

1k

100

10

OUTPUT VOLTAGE – mV

1

0.1

0.001 1000.01

SOURCE

0.1 1 10

LOAD CURRENT – mA

SINK

TPC 12. Output Voltage to Supply Rail vs. Load Current

REV. D–6–

AD8601/AD8602/AD8604

ⴚ40

12520 65

ⴚ25 ⴚ10

535508095110

TEMPERATURE – ⴗC

2.67

2.66

2.62

OUTPUT VOLTAGE – V

2.64

VOH @ 1mA LOAD

VS = 2.7V

2.63

2.65

FREQUENCY – Hz

1k 100M10k

GAIN – dB

100k 1M 10M

80

60

40

20

0

45

90

135

180

PHASE SHIFT – Degrees

VS = 3V
R

L

= NO LOAD

T

A

= 25ⴗC

100

–20

–40

–60

10k

VS = 5V

= 25ⴗC

T

A

1k

100

10

OUTPUT VOLTAGE – mV

1

0.1

0.001 1000.01

0.1 1 10

LOAD CURRENT – mA

SOURCE

SINK

TPC 13. Output Voltage to Supply Rail vs. Load Current

5.1

VS = 5V

5.0

VOH @ 1mA LOAD

4.9

4.8

@ 10mA LOAD

V

OH

4.7

OUTPUT VOLTAGE – V

35

VS = 2.7V

30

25

20

15

10

OUTPUT VOLTAGE – mV

5

0

ⴚ40

ⴚ25 ⴚ10

535508095110

VOL @ 1mA LOAD

12520 65

TEMPERATURE – ⴗC

TPC 16. Output Voltage Swing vs. Temperature

REV. D

4.6

4.5

ⴚ40

ⴚ25 ⴚ10

535508095110

TEMPERATURE – ⴗC

TPC 14. Output Voltage Swing vs. Temperature

250

VS = 5V

200

150

VOL @ 10mA LOAD

100

OUTPUT VOLTAGE – mV

50

VOL @ 1mA LOAD

0

ⴚ40

ⴚ25 ⴚ10

TPC 15. Output Voltage Swing vs. Temperature

535508095110

TEMPERATURE – ⴗC

12520 65

TPC 17. Output Voltage Swing vs. Temperature

12520 65

TPC 18. Open-Loop Gain and Phase vs. Frequency

–7–

AD8601/AD8602/AD8604

VS = 5V

100

= NO LOAD

R

L

TA = 25ⴗC

80

60

40

20

GAIN – dB

0

–20

–40

–60

1k 100M10k

100k 1M 10M

FREQUENCY – Hz

45

90

135

180

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

VS = 3V

= 25ⴗC

T

A

40

20

0

CLOSED-LOOP GAIN – dB

AV = 100

AV = 10

AV = 1

PHASE SHIFT – Degrees

OUTPUT SWING – V p-p

TPC 22. Closed-Loop Output Voltage Swing vs. Frequency

OUTPUT SWING – V p-p

3.0

2.5
VS = 2.7V

= 2.6V p-p

V

IN

= 2k⍀

R

2.0

L

= 25ⴗC

T

A

= 1

A

V

1.5

1.0

0.5

0

1k 10M10k

6

5

VS = 5V

= 4.9V p-p

V

IN

4

R

= 2k⍀

L

= 25ⴗC

T

A

= 1

A

V

3

2

1

100k 1M

FREQUENCY – Hz

1k 100M10k

100k 1M 10M

FREQUENCY – Hz

TPC 20. Closed-Loop Gain vs. Frequency

VS = 5V

= 25ⴗC

T

A

40

20

0

CLOSED-LOOP GAIN – dB

1k 100M10k

AV = 100

AV = 10

AV = 1

100k 1M 10M

FREQUENCY – Hz

TPC 21. Closed-Loop Gain vs. Frequency

0

1k 10M10k

100k 1M

FREQUENCY – Hz

TPC 23. Closed-Loop Output Voltage Swing vs. Frequency

200

VS = 3V

180

= 25ⴗC

T

A

160

140

120

100

80

60

OUTPUT IMPEDANCE – ⍀

40

20

0

100 10M1k

FREQUENCY – Hz

AV = 100

AV = 10

AV = 1

10k 100k 1M

TPC 24. Output Impedance vs. Frequency

REV. D–8–

200

FREQUENCY – Hz

100 10M1k

POWER SUPPLY REJECTION – dB

10k 100k 1M

120

80

40

VS = 5V
T

A

= 25ⴗC

ⴚ40

ⴚ20

0

20

60

100

140

160

VS = 5V

180

= 25ⴗC

T

A

160

140

120

100

80

60

OUTPUT IMPEDANCE – ⍀

40

20

0

100 10M1k

AV = 100

AV = 10

10k 100k 1M

FREQUENCY – Hz

TPC 25. Output Impedance vs. Frequency

AD8601/AD8602/AD8604

AV = 1

TPC 28. Power Supply Rejection Ratio vs. Frequency

160

140

120

100

80

60

40

20

0

COMMON-MODE REJECTION – dB

ⴚ20

ⴚ40

1k 20M10k

TPC 26. Common-Mode Rejection Ratio vs. Frequency

160

140

120

100

80

60

40

20

0

COMMON-MODE REJECTION – dB

ⴚ20

ⴚ40

1k 20M10k

TPC 27. Common-Mode Rejection Ratio vs. Frequency

REV. D

VS = 3V

= 25ⴗC

T

A

VS = 5V
TA = 25ⴗC

100k 1M

FREQUENCY – Hz

100k 1M

FREQUENCY – Hz

10M

10M

70

VS = 2.7V

60

=

R

L

= 25ⴗC

T

A

AV = 1

50

ⴚOS

40

30

20

10

SMALL SIGNAL OVERSHOOT – %

0

10 1k100

CAPACITANCE – pF

+OS

TPC 29. Small Signal Overshoot vs. Load Capacitance

70

VS = 5V

60

=

R

L

= 25ⴗC

T

A

= 1

A

V

50

40

30

20

10

SMALL SIGNAL OVERSHOOT – %

0

10 1k100

ⴚOS

+OS

CAPACITANCE – pF

TPC 30. Small Signal Overshoot vs. Load Capacitance

–9–

AD8601/AD8602/AD8604

1.2

VS = 5V

1.0

0.8

0.6

0.4

0.2

SUPPLY CURRENT PER AMPLIFIER – mA

0

ⴚ40

ⴚ25 ⴚ10

535508095110

TEMPERATURE – ⴗC

12520 65

TPC 31. Supply Current per Amplifier vs. Temperature

1.0

VS = 3V

0.8

0.6

0.4

0.1

VS = 5V

= 25ⴗC

T

A

G = 10

0.01

THD + N – %

0.001

0.0001
20 20k

100 1k 10k

RL = 600

G = 1

FREQUENCY – Hz

⍀

RL = 600

RL = 10k

RL = 2k

⍀

⍀

⍀

RL = 2k

RL = 10k

⍀

⍀

TPC 34. Total Harmonic Distortion + Noise vs. Frequency

64

VS = 2.7V

56

48

40

32

24

T

A

= 25ⴗC

0.2

SUPPLY CURRENT PER AMPLIFIER – mA

0

ⴚ40

ⴚ25 ⴚ10

535508095110

TEMPERATURE – ⴗC

12520 65

TPC 32. Supply Current per Amplifier vs. Temperature

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

SUPPLY CURRENT PER AMPLIFIER – mA

0

0

SUPPLY VOLTAGE – V

612345

TPC 33. Supply Current per Amplifier vs. Supply Voltage

16

VOLTAGE NOISE DENSITY – nV/ Hz

8

0

051015 20 25

FREQUENCY – kHz

TPC 35. Voltage Noise Density vs. Frequency

208

VS = 2.7V

182

156

130

104

78

52

VOLTAGE NOISE DENSITY – nV/ Hz

26

= 25ⴗC

T

A

0

0 0.5 1.0 1.5 2.0 2.5

FREQUENCY – kHz

TPC 36. Voltage Noise Density vs. Frequency

REV. D–10–

AD8601/AD8602/AD8604

208

VS = 5V

182

156

130

104

78

52

VOLTAGE NOISE DENSITY – nV/ Hz

26

= 25ⴗC

T

A

0

0 0.5 1.0 1.5 2.0 2.5

FREQUENCY – kHz

TPC 37. Voltage Noise Density vs. Frequency

64

VS = 5V

56

48

40

32

T

= 25ⴗC

A

VS = 5V

= 25ⴗC

T

A

V/DIV

␮

VOLTAGE – 2.5

TIME – 1s/DIV

TPC 40. 0.1 Hz to 10 Hz Input Voltage Noise

VS = 5V

= 10k⍀

R

L

= 200pF

C

L

TA = 25ⴗC

24

16

VOLTAGE NOISE DENSITY – nV/ Hz

8

0

051015 20 25

FREQUENCY – kHz

TPC 38. Voltage Noise Density vs. Frequency

VS = 2.7V

= 25ⴗC

T

A

VOLTAGE – 2.5␮V/DIV

TIME – 1s/DIV

TPC 39. 0.1 Hz to 10 Hz Input Voltage Noise

50.0mV/DIV

200ns/DIV

TPC 41. Small Signal Transient Response

VS = 2.7V

= 10k

R

⍀

L

= 200pF

C

L

TA = 25ⴗC

50.0mV/DIV

200ns/DIV

TPC 42. Small Signal Transient Response

REV. D

–11–

AD8601/AD8602/AD8604

VS = 5V
RL = 10k⍀

= 200pF

C

L

= 1

A

V

= 25ⴗC

T

A

VOLTAGE – 1.0V/DIV

TIME – 400ns/DIV

TPC 43. Large Signal Transient Response

VS = 2.7V
RL = 10k⍀

= 200pF

C

L

= 1

A

V

= 25ⴗC

T

A

VOLTAGE – 500mV/DIV

VOLTAGE – 1V/DIV

+0.1%

ERROR

ⴚ0.1%

VOLTAGE – V

ERROR

VS = 5V

= 10k⍀

R

L

V

IN

= 1

A

V

= 25ⴗC

T

A

V

OUT

TIME – 2.0␮s/DIV

TPC 46. No Phase Reversal

V

V

OUT

IN

VS = 5V
RL = 10k⍀

= 2V p-p

V

O

T

= 25ⴗC

A

TIME – 400ns/DIV

TPC 44. Large Signal Transient Response

VS = 2.7V
R

= 10k⍀

L

= 1

A

V

= 25ⴗC

V

V

OUT

VOLTAGE – 1V/DIV

T

IN

A

TIME – 2.0␮s/DIV

TPC 45. No Phase Reversal

VIN TRACE – 0.5V/DIV

TRACE – 10mV/DIV

V

OUT

TIME – 100ns/DIV

TPC 47. Settling Time

2.0

VS = 2.7V

1.5
= 25ⴗC

T

A

1.0

0.5

0

ⴚ0.5

OUTPUT SWING – V

ⴚ1.0

ⴚ1.5

ⴚ2.0

300 600350 400 450 500 550

0.1% 0.01%

0.01%0.1%

SETTLING TIME – ns

TPC 48. Output Swing vs. Settling Time

REV. D–12–

AD8601/AD8602/AD8604

VCM – V

0.7

0.4

ⴚ

1.4
0

51

V

OS

– mV

234

ⴚ

0.2

ⴚ

0.5

ⴚ

0.8

ⴚ

1.1

0.1

5

VS = 5V

4

= 25ⴗC

T

A

3

2

1

0

ⴚ1

OUTPUT SWING – V

ⴚ2

ⴚ3

ⴚ4

ⴚ5

01,000200 400 600 800

0.1% 0.01%

0.01%0.1%

SETTLING TIME – ns

TPC 49. Output Swing vs. Settling Time

THEORY OF OPERATION

The AD8601/AD8602/AD8604 family of amplifiers are rail-to­rail input and output precision CMOS amplifiers that operate
from 2.7 V to 5.0 V of power supply voltage. These amplifiers

®

use Analog Devices’ DigiTrim

technology to achieve a higher
degree of precision than available from most CMOS amplifiers.
DigiTrim technology is a method of trimming the offset volt­age of the amplifier after it has already been assembled. The
advantage in post-package trimming lies in the fact that it cor­rects any offset voltages due to the mechanical stresses of
assembly. This technology is scalable and used with every
package option, including SOT-23-5, providing lower offset
voltages than previously achieved in these small packages.

The DigiTrim process is done at the factory and does not add
additional pins to the amplifier. All AD860x amplifiers are
available in standard op amp pinouts, making DigiTrim com­pletely transparent to the user. The AD860x can be used in any
precision op amp application.

The input stage of the amplifier is a true rail-to-rail architecture,
allowing the input common-mode voltage range of the op amp
to extend to both positive and negative supply rails. The voltage
swing of the output stage is also rail-to-rail and is achieved by
using an NMOS and PMOS transistor pair connected in a com­mon-source configuration. The maximum output voltage swing
is proportional to the output current, and larger currents will
limit how close the output voltage can get to the supply rail.
This is a characteristic of all rail-to-rail output amplifiers. With
1 mA of output current, the output voltage can reach within
20 mV of the positive rail and within 15 mV of the negative rail.
At light loads of >100 kΩ, the output swings within ~1 mV of
the supplies.

The open-loop gain of the AD860x is 80 dB, typical, with a load
of 2 kΩ. Because of the rail-to-rail output configuration, the
gain of the output stage and the open-loop gain of the amplifier
are dependent on the load resistance. Open-loop gain will de­crease with smaller load resistances. Again, this is a characteristic
inherent to all rail-to-rail output amplifiers.

REV. D

Rail-to-Rail Input Stage

The input common-mode voltage range of the AD860x extends
to both positive and negative supply voltages. This maximizes the
usable voltage range of the amplifier, an important feature for
single-supply and low voltage applications. This rail-to-rail
input range is achieved by using two input differential pairs, one
NMOS and one PMOS, placed in parallel. The NMOS pair is
active at the upper end of the common-mode voltage range, and
the PMOS pair is active at the lower end.

The NMOS and PMOS input stages are separately trimmed
using DigiTrim to minimize the offset voltage in both differen­tial pairs. Both NMOS and PMOS input differential pairs are
active in a 500 mV transition region, when the input common­mode voltage is between approximately 1.5 V and 1 V below the
positive supply voltage. Input offset voltage will shift slightly in
this transition region, as shown in TPCs 5 and 6. Common­mode rejection ratio will also be slightly lower when the input
common-mode voltage is within this transition band. Compared
to the Burr Brown OPA2340 rail-to-rail input amplifier, shown
in Figure 1, the AD860x, shown in Figure 2, exhibits lower
offset voltage shift across the entire input common-mode range,
including the transition region.

Figure 1. Burr Brown OPA2340UR Input Offset
Voltage vs. Common-Mode Voltage, 24 SOIC
Units @ 25°C

0.7

0.4

0.1

ⴚ0.2

– mV

OS

ⴚ0.5

V

ⴚ0.8

ⴚ1.1

ⴚ1.4

0

234

VCM – V

Figure 2. AD8602AR Input Offset Voltage vs.
Common-Mode Voltage, 300 SOIC Units @ 25°C

–13–

51

AD8601/AD8602/AD8604

Input Overvoltage Protection

As with any semiconductor device, if a condition could exist
that would cause the input voltage to exceed the power supply,
the device’s input overvoltage characteristic must be considered.
Excess input voltage will energize internal PN junctions in the
AD860x, allowing current to flow from the input to the supplies.

This input current will not damage the amplifier, provided it is
limited to 5 mA or less. This can be ensured by placing a resis­tor in series with the input. For example, if the input voltage
could exceed the supply by 5 V, the series resistor should be at
least (5 V/5 mA) = 1 kΩ. With the input voltage within the
supply rails, a minimal amount of current is drawn into the
inputs, which, in turn, causes a negligible voltage drop across
the series resistor. Therefore, adding the series resistor will
not adversely affect circuit performance.

Overdrive Recovery

Overdrive recovery is defined as the time it takes the output of
an amplifier to come off the supply rail when recovering from
an overload signal. This is tested by placing the amplifier in a
closed-loop gain of 10 with an input square wave of 2 V p-p while
the amplifier is powered from either 5 V or 3 V.

The AD860x has excellent recovery time from overload condi­tions. The output recovers from the positive supply rail within
200 ns at all supply voltages. Recovery from the negative rail is
within 500 ns at 5 V supply, decreasing to within 350 ns when
the device is powered from 2.7 V.

Power-On Time

Power-on time is important in portable applications, where the
supply voltage to the amplifier may be toggled to shut down the
device to improve battery life. Fast power-up behavior ensures
that the output of the amplifier will quickly settle to its final
voltage, improving the power-up speed of the entire system.
Once the supply voltage reaches a minimum of 2.5 V, the AD860x
will settle to a valid output within 1 µs. This turn-on response
time is faster than many other precision amplifiers, which can
take tens or hundreds of microseconds for their outputs to settle.

Using the AD8602 in High Source Impedance Applications

The CMOS rail-to-rail input structure of the AD860x allows
these amplifiers to have very low input bias currents, typically

0.2 pA. This allows the AD860x to be used in any application
that has a high source impedance or must use large value resis­tances around the amplifier. For example, the photodiode
amplifier circuit shown in Figure 3 requires a low input bias
current op amp to reduce output voltage error. The AD8601
minimizes offset errors due to its low input bias current and low
offset voltage.

The current through the photodiode is proportional to the inci­dent light power on its surface. The 4.7 MΩ resistor converts
this current into a voltage, with the output of the AD8601
increasing at 4.7 V/µA. The feedback capacitor reduces excess
noise at higher frequencies by limiting the bandwidth of the
circuit to

BW

=

1

247π . Ω

MC

()

F

(1)

Using a 10 pF feedback capacitor limits the bandwidth to approxi­mately 3.3 kHz.

10pF

(OPTIONAL)

4.7M⍀

V

D1

AD8601

OUT

4.7V/␮A

Figure 3. Amplifier Photodiode Circuit

High- and Low-Side Precision Current Monitoring

Because of its low input bias current and low offset voltage, the
AD860x can be used for precision current monitoring. The true
rail-to-rail input feature of the AD860x allows the amplifier to
monitor current on either high-side or low-side. Using both
amplifiers in an AD8602 provides a simple method for monitoring
both current supply and return paths for load or fault detec­tion. Figures 4 and 5 demonstrate both circuits.

3V

R2

2N3904

R1

100⍀

Q1

2.49k⍀

R

SENSE

0.1⍀

3V

1/2 AD8602

RETURN TO
GROUND

MONITOR

OUTPUT

Figure 4. A Low-Side Current Monitor

R

3V

MONITOR

OUTPUT

R1

100⍀

Q1

2N3905

SENSE

0.1⍀

R2

2.49k⍀

I

3V

1/2

AD8602

L

V+

Figure 5. A High-Side Current Monitor

Voltage drop is created across the 0.1 Ω resistor that is propor­tional to the load current. This voltage appears at the inverting
input of the amplifier due to the feedback correction around the
op amp. This creates a current through R1 which, in turn, pulls
current through R2. For the low-side monitor, the monitor
output voltage is given by

Monitor Output V R

=×

32

–



R



SENSE







R



1





I

×



L







(2)

REV. D–14–

AD8601/AD8602/AD8604

U1-A

R2

2k⍀

4

C1

100␮F

5V

1

8

2

3

5V

V

DD

V

DD

LEFT

OUT

AD1881

(AC'97)

RIGHT

OUT

V

SS

R4

20⍀

5

6

7

R5

20⍀

C2

100␮F

NOTE: ADDITIONAL PINS
OMITTED FOR CLARITY

U1-B

U1 = AD8602D

R3

2k⍀

28

35

36

For the high-side monitor, the monitor output voltage is

Monitor Output R

=×






SENSE

R

1



I

×2



L



(3)

R

Using the components shown, the monitor output transfer func­tion is 2.5 V/A.

Using the AD8601 in Single-Supply Mixed-Signal Applications

Single-supply mixed-signal applications requiring 10 or more
bits of resolution demand both a minimum of distortion and a
maximum range of voltage swing to optimize performance. To
ensure that the A/D or D/A converters achieve their best perfor­mance, an amplifier often must be used for buffering or signal
conditioning. The 750 µV maximum offset voltage of the
AD8601 allows the amplifier to be used in 12-bit applications
powered from a 3 V single supply, and its rail-to-rail input
and output ensure no signal clipping.

Figure 6 shows the AD8601 used as an input buffer amplifier to
the AD7476, a 12-bit 1 MHz A/D converter. As with most A/D
converters, total harmonic distortion (THD) increases with
higher source impedances. By using the AD8601 in a buffer
configuration, the low output impedance of the amplifier mini­mizes THD while the high input impedance and low bias current
of the op amp minimizes errors due to source impedance. The
8 MHz gain-bandwidth product of the AD8601 ensures no
signal attenuation up to 500 kHz, which is the maximum Nyquist
frequency for the AD7476.

The AD8601, AD7476, and AD5320 are all available in space­saving SOT-23 packages.

PC100 Compliance for Computer Audio Applications

Because of its low distortion and rail-to-rail input and output,
the AD860x is an excellent choice for low-cost, single-supply
audio applications, ranging from microphone amplification to
line output buffering. TPC 34 shows the total harmonic distor­tion plus noise (THD + N) figures for the AD860x. In unity
gain, the amplifier has a typical THD + N of 0.004%, or –86 dB,
even with a load resistance of 600 Ω. This is compliant with the
PC100 specification requirements for audio in both portable
and desktop computers.

Figure 8 shows how an AD8602 can be interfaced with an AC’97
codec to drive the line output. Here, the AD8602 is used as a
unity-gain buffer from the left and right outputs of the AC’97
codec. The 100 µF output coupling capacitors block dc cur­rent and the 20 Ω series resistors protect the amplifier from
short circuits at the jack.

V

IN

Figure 7 demonstrates how the AD8601 can be used as an output
buffer for the DAC for driving heavy resistive loads. The AD5320
is a 12-bit D/A converter that can be used with clock frequen­cies up to 30 MHz and signal frequencies up to 930 kHz. The
rail-to-rail output of the AD8601 allows it to swing within 100 mV
of the positive supply rail while sourcing 1 mA of current. The
total current drawn from the circuit is less than 1 mA, or 3 mW
from a 3 V single supply.

REV. D

3V

1␮F

680nF

4

5

R

S

1

3

2

AD8601

TANT

V

DD

V

IN

GND

AD7476/AD7477

REF193

0.1␮F

SDATA

SCLK

CS

SERIAL

INTERFACE

Figure 6. A Complete 3 V 12-Bit 1 MHz A/D
Conversion System

3V

3-WIRE

1␮F

4

5

6

AD5320

2

1

4

5

3

2

V
0V TO 3.0V

1

AD8601

SERIAL

INTERFACE

Figure 7. Using the AD8601 as a DAC Output
Buffer to Drive Heavy Loads

OUT

0.1␮F10␮F

5V
SUPPLY

␮C/␮P

R

L

Figure 8. A PC100 Compliant Line Output Amplifier

SPICE Model

The SPICE macro-model for the AD860x amplifier is available
and can be downloaded from the Analog Devices website at
www.analog.com. The model will accurately simulate a number
of both dc and ac parameters, including open-loop gain,
bandwidth, phase margin, input voltage range, output voltage
swing versus output current, slew rate, input voltage noise,
CMRR, PSRR, and supply current versus supply voltage. The
model is optimized for performance at 27°C. Although it will
function at different temperatures, it may lose accuracy with
respect to the actual behavior of the AD860x.

–15–

AD8601/AD8602/AD8604

OUTLINE DIMENSIONS

14-Lead Thin Shrink Small Outline Package [TSSOP]

(RU-14)

Dimensions shown in millimeters

5.10

5.00

4.90

1.05

1.00

0.80

4.50

4.40

4.30

PIN 1

14

0.65
BSC

0.15

0.05

COMPLIANT TO JEDEC STANDARDS MO-153AB-1

0.30

0.19

8

6.40

BSC

71

1.20
MAX

SEATING
PLANE

0.20

0.09

COPLANARITY

0.10

8ⴗ
0ⴗ

14-Lead Standard Small Outline Package [SOIC]

(R-14)

Dimensions shown in millimeters and (inches)

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

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)

0.10

0.31 (0.0122)

COMPLIANT TO JEDEC STANDARDS MS-012AB

8

6.20 (0.2441)

7

5.80 (0.2283)

SEATING
PLANE

1.75 (0.0689)

1.35 (0.0531)

0.25 (0.0098)

0.17 (0.0067)

0.50 (0.0197)

0.25 (0.0098)

8ⴗ
0ⴗ

1.27 (0.0500)

0.40 (0.0157)

0.75

0.60

0.45

ⴛ 45ⴗ

5-Lead Small Outline Transistor Package [SOT-23]

(RT-5)

Dimensions shown in millimeters

2.90 BSC

4 5

0.50

0.30

2.80 BSC

0.95 BSC

1.45 MAX

SEATING
PLANE

0.22

0.08
10ⴗ

5ⴗ
0ⴗ

1.60 BSC

1.30

1.15

0.90

0.15 MAX

1 3

2

PIN 1

1.90

BSC

COMPLIANT TO JEDEC STANDARDS MO-178AA

8-Lead Mini Small Outline Package [MSOP]

(RM-8)

Dimensions shown in millimeters

3.00
BSC

85

3.00
BSC

1

PIN 1

0.65 BSC

0.15

0.00

0.38

0.22

COPLANARITY

0.10

COMPLIANT TO JEDEC STANDARDS MO-187AA

4

SEATING
PLANE

4.90
BSC

1.10 MAX

0.23

0.08

8ⴗ
0ⴗ

0.80

0.60

0.40

0.60

0.45

0.30

8-Lead Standard Small Outline Package [SOIC]

(R-8)

Dimensions shown in millimeters and (inches)

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

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

85

1.27 (0.0500)

SEATING

PLANE

COMPLIANT TO JEDEC STANDARDS MS-012AA

BSC

6.20 (0.2440)

5.80 (0.2284)

41

1.75 (0.0688)

1.35 (0.0532)

0.51 (0.0201)

0.31 (0.0122)

0.25 (0.0098)

0.17 (0.0067)

0.50 (0.0196)

0.25 (0.0099)

8ⴗ
0ⴗ

1.27 (0.0500)

0.40 (0.0157)

ⴛ 45ⴗ

REV. D–16–

AD8601/AD8602/AD8604

Revision History

Location Page

11/03—Data Sheet changed from REV. C to REV. D.

Changes to FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Changes to ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3/03—Data Sheet changed from REV. B to REV. C.

Changes to FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

3/03—Data Sheet changed from REV. A to REV. B.

Change to FEATURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Change to FUNCTIONAL BLOCK DIAGRAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Change to TPC 39 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Changes to Figures 4 and 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Changes to Equations 2 and 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14, 15

Updated OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

REV. D

–17–

–18–

–19–

C01525–0–11/03(D)

–20–