Analog Devices AD8671 2 4 b Datasheet

Precision, Very Low Noise, Low Input

–

+

–

+

FEATURES

Very low noise: 2.8 nV/√Hz, 77 nV p-p
Wide bandwidth: 10 MHz
Low input bias current: 12 nA max

Low offset voltage: 75 µV max
High open-loop gain: 120 dB min
Low supply current: 3 mA per amplifier
Dual-supply operation: ±5 V to ±15 V
Unity gain stable
No phase reversal

APPLICATIONS

PLL filters
Filters for GPS
Instrumentation
Sensors and controls
Professional quality audio

GENERAL DESCRIPTION

The AD8671/AD8672/AD8674 are very high precision
amplifiers featuring very low noise, very low offset voltage and
drift, low input bias current, 10 MHz bandwidth, and low power
consumption. Outputs are stable with capacitive loads of over
1000 pF. Supply current is less than 3 mA per amplifier at 30 V.

The AD8671’s combination of ultralow noise, high precision,
speed, and stability is unmatched, while the MSOP version
requires only half the board space of comparable amplifiers.

Applications for these amplifiers include high quality PLL
filters, precision filters, medical and analytical instrumentation,
precision power supply controls, ATE, data acquisition, and
precision controls as well as professional quality audio.

Bias Current

NC

1

AD8671

2

IN

TOP VIEW

IN

3

(Not to Scale)

V–

4

NC = NO CONNECT

Figure 1. 8-Lead SOIC (R Suffix)

1

OUT A

–IN A
+IN A

Figure 3. 8-Lead SOIC (R Suffix)

OUT A

–IN A
+IN A

+IN B
–IN B

OUT B

Figure 5. 14-Lead SOIC (R Suffix) Figure 6. 14-Lead TSSOP (RU Suffix)

V–

V+

AD8672

2

TOP VIEW

3

(Not to Scale)

4

1
2
3

AD8674

4

TOP VIEW

(Not to Scale)

5
6
7

Operational Amplifiers

AD8671/AD8672/AD8674

PIN CONFIGURATIONS

NC

8
7
6
5

14
13
12
11
10

9
8

8
7
6
5

V+
OUT
NC

V+
OUT B
–IN B
+IN B

OUT D
–IN D
+IN D
V–
+IN C
–IN C
OUT C

03718-B-001

NC

1

AD8671

2

IN

TOP VIEW

IN

3

(Not to Scale)

V–

4

NC = NO CONNECT

Figure 2. 8-Lead MSOP (RM Suffix)

OUT A

1

V–

AD8672

2

TOP VIEW

3

(Not to Scale)

4

–IN A
+IN A

03718-B-003

Figure 4. 8-Lead MSOP (RM Suffix)

OUT A

1
2

–IN A
+IN A

3

AD8674

V+

4

TOP VIEW

(Not to Scale)

–IN B

5
6

+IN B

OUT B

03718-B-005

7

8
7
6
5

14
13
12
11
10

9
8

8
7
6
5

NC
V+
OUT
NC

03718-B-002

V+
OUT B
–IN B
+IN B

OUT D
–IN D
+IN D
V–
+IN C
–IN C
OUT C

03718-B-004

03718-B-006

The AD8671/AD8672/AD8674 are specified over the extended
industrial (–40°C to +125°C) temperature range.

The AD8671/AD8672 are available in the 8-lead SOIC and
8-lead MSOP packages. The AD8674 is available in 14-lead
SOIC and 14-lead TSSOP packages.

Surface-mount devices in MSOP packages are available in tape
and reel only.

Rev. B

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.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone]
Fax: [phone] © 2004 Analog Devices, Inc. All rights reserved.

www.analog.com

AD8671/AD8672/AD8674

TABLE OF CONTENTS

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

Tot a l N o is e v s . So u rc e Re si s ta nc e ............................................. 11

Electrical Characteristics, ±5.0 V................................................ 3

Electrical Characteristics, ±15 V................................................. 4

Absolute Maximum Ratings............................................................ 5

Typical Performance Characteristics............................................. 6

Applications..................................................................................... 11

Unity Gain Follower Applications............................................ 11

Output Phase Reversal............................................................... 11

REVISION HISTORY

4/04—Data Sheet Changed from Rev. A to Rev. B

Changes to Figure 32.................................................................. 11

Changes to Figures 36, 37, and 38............................................. 12

1/04—Data Sheet Changed from Rev. 0 to Rev. A

Added AD8672 and AD8674 parts ..............................Universal

Changes to Specifications............................................................ 3

Deleted Figure 3............................................................................ 6

Changes to Figures 7, 8, and 9..................................................... 6

Changes to Figure 37.................................................................. 12

Added new Figure 32 ................................................................. 10

THD + Noise............................................................................... 12

Driving Capacitive Loads.......................................................... 12

GPS Receiver............................................................................... 13

Band-Pass Filter.......................................................................... 13

PLL Synthesizers and Loop Filters........................................... 13

Outline Dimensions....................................................................... 14

Ordering Guide............................................................................... 16

Rev. B | Page 2 of 16

AD8671/AD8672/AD8674

SPECIFICATIONS

ELECTRICAL CHARACTERISTICS, ±5.0 V

Table 1. VS = ±5.0 V, VCM = 0 V, TA = 25°C, unless otherwise noted

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage V

OS

–40°C < TA < +125°C 30 125 µV
Offset Voltage Drift ∆VOS/∆T –40°C < TA < +125°C

AD8671 0.3 0.5 µV/°C
AD8672/AD8674 0.3 0.8 µV/°C

Input Bias Current I

B

+25°C < TA < +125°C –20 +5 +20 nA
–40°C < TA < +125°C –40 +8 +40 nA
Input Offset Current I

OS

+25°C < TA < +125°C –20 +6 +20 nA
–40°C < TA < +125°C –40 +8 +40 nA
Input Voltage Range –2.5 +2.5 V
Common-Mode Rejection Ratio CMRR VCM = –2.5 V to +2.5 V 100 120 dB
Large Signal Voltage Gain A
Input Capacitance, Common Mode C
Input Capacitance, Differential Mode C
Input Resistance, Common Mode R
Input Resistance, Differential Mode R

VO

INCM

INDM

IN

INDM

OUTPUT CHARACTERISTICS

Output Voltage High V
Output Voltage Low V
Output Voltage High V
Output Voltage Low V
Output Current I

OH

OL

OH

OL

OUT

POWER SUPPLY

Power Supply Rejection Ratio PSRR VS = ±4 V to ±18 V

AD8671/AD8672 110 130 dB
AD8674 106 115 dB

Supply Current/Amplifier I

SY

–40°C <TA < +125°C 4.2 mA
DYNAMIC PERFORMANCE

Slew Rate SR RL = 2 kΩ 4 V/µs
Settling Time t

S

To 0.01% (4 V Step, G = 1) 5.1 µs
Gain Bandwidth Product GBP 10 MHz

NOISE PERFORMANCE

Peak-to-Peak Noise e
Voltage Noise Density e

Current Noise Density i

n p-p

n

n

Channel Separation

AD8672/AD8674 Cs f = 1 kHz –130 dB

f = 10 kHz –105 dB

20 75 µV

–12 +3 +12 nA

–12 +6 +12 nA

RL = 2 kΩ, VO = –3 V to +3 V 1000 6000 V/mV

6.25 pF

7.5 pF

3.5 GΩ
15 MΩ

RL = 2 kΩ, –40°C to +125°C +3.8 +4.0 V
RL = 2 kΩ, –40°C to +125°C –3.9 –3.8 V
RL = 600 Ω +3.7 +3.9 V
RL = 600 Ω –3.8 –3.7 V
±10 mA

VO = 0 V 3 3.5 mA

To 0.1% (4 V Step, G = 1) 1.4 µs

0.1 Hz to 10 Hz 77 100 nV p-p
f = 1 kHz 2.8 3.8

f = 1 kHz 0.3

nV/√
pA/√

Hz
Hz

Rev. B | Page 3 of 16

AD8671/AD8672/AD8674

ELECTRICAL CHARACTERISTICS, ±15 V

Table 2. VS = ±15 V, VCM = 0 V, TA = 25°C, unless otherwise noted

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage V

OS

–40°C < TA < +125°C 30 125 µV
Offset Voltage Drift ∆VOS/∆T –40°C < TA < +125°C

AD8671 0.3 0.5 µV/°C
AD8672/AD8674 0.3 0.8 µV/°C

Input Bias Current I

B

+25°C < TA < +125°C –20 +5 +20 nA
–40°C < TA < +125°C –40 +8 +40 nA
Input Offset Current I

OS

+25°C < TA < +125°C –20 +6 +20 nA
–40°C < TA < +125°C –40 +8 +40 nA
Input Voltage Range –12 +12 V
Common-Mode Rejection Ratio CMRR VCM = –12 V to +12 V 100 120 dB
Large Signal Voltage Gain A
Input Capacitance, Common Mode C
Input Capacitance, Differential Mode C
Input Resistance, Common Mode R
Input Resistance, Differential Mode R

VO

INCM

INDM

IN

INDM

OUTPUT CHARACTERISTICS

Output Voltage High V
Output Voltage Low V
Output Voltage High V
Output Voltage Low V
Output Current I
Short Circuit Current I

OH

OL

OH

OL

OUT

SC

POWER SUPPLY

Power Supply Rejection Ratio PSRR VS = ±4 V to ±18 V

AD8671/AD8672 110 130 dB
AD8674 106 115 dB

Supply Current/Amplifier I

SY

–40°C <TA < +125°C 4.2 mA
DYNAMIC PERFORMANCE

Slew Rate SR RL = 2 kΩ 4 V/µs
Settling Time t

S

To 0.01% (10 V Step, G = 1) 6.3 µs
Gain Bandwidth Product GBP 10 MHz

NOISE PERFORMANCE

Peak-to-Peak Noise e
Voltage Noise Density e

Current Noise Density i

n p-p

n

n

Channel Separation

AD8672/AD8674 Cs f = 1 kHz –130 dB

f = 10 kHz –105 dB

20 75 µV

–12 +3 +12 nA

–12 +6 +12 nA

RL = 2 kΩ, VO = –10 V to +10 V 1000 6000 V/mV

6.25 pF

7.5 pF

3.5 GΩ
15 MΩ

RL = 2 kΩ, –40°C to +125°C +13.2 +13.8 V
RL = 2 kΩ, –40°C to +125°C –13.8 –13.2 V
RL = 600 Ω +11 +12.3 V
RL = 600 Ω –12.4 –11 V
±20 mA
±30 mA

VO = 0 V 3 3.5 mA

To 0.1% (10 V Step, G = 1) 2.2 µs

0.1 Hz to 10 Hz 77 100 nV p-p
f = 1 kHz 2.8 3.8

f = 1 kHz 0.3

nV/√
pA/√

Hz

Hz

Rev. B | Page 4 of 16

AD8671/AD8672/AD8674

ABSOLUTE MAXIMUM RATINGS

Table 3. AD8671/AD8672/AD8674 Stress Ratings

Parameter Rating

Supply Voltage 36 V
Input Voltage VS– to VS+
Differential Input Voltage ±0.7 V
Output Short-Circuit Duration Indefinite
Storage Temperature Range

All Packages –65°C to +150°C

Operating Temperature Range

All Packages –40°C to +125°C

Junction Temperature Range

All Packages –65°C to +150°C

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

1

Absolute maximum ratings apply at 25°C, unless otherwise noted.

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.

1

Table 4. Package Characteristics

Package Type θ

2

JA

8-Lead MSOP (RM) 190 44 °C/W
8-Lead SOIC (R) 158 43 °C/W
14-Lead SOIC (R) 120 36 °C/W
14-Lead TSSOP (RU) 180 35 °C/W

2

θJA is specified for the worst-case conditions, i.e., θJA is specified for device

soldered in circuit board for surface-mount packages.

θ

JC

Unit

Rev. B | Page 5 of 16