ANALOG DEVICES AD8625 Service Manual

Precision Low Power

FEATURES

SC70 package
Very low I
Single-supply operation: 5 V to 26 V
Dual-supply operation: ±2.5 V to ±13 V
Rail-to-rail output
Low supply current: 630 μA/amp typ
Low offset voltage: 500 μV max
Unity gain stable
No phase reversal

APPLICATIONS

Photodiode amplifiers
AT Es
Line-powered/battery-powered instrumentation
Industrial controls
Automotive sensors
Precision filters
Audio

GENERAL DESCRIPTION

The AD862x is a precision JFET input amplifier. It features
true single-supply operation, low power consumption, and
rail-to-rail output. The outputs remain stable with capacitive
loads of over 500 pF; the supply current is less than 630 μA/amp.
Applications for the AD862x include photodiode transimpedance
amplification, ATE reference level drivers, battery management,
both line powered and portable instrumentation, and remote
sensor signal conditioning, which includes automotive sensors.

The AD862x’s ability to swing nearly rail-to-rail at the input
and rail-to-rail at the output enables it to be used to buffer
CMOS DACs, ASICs, and other wide output swing devices in
single-supply systems.

: 1 pA max

B

Single-Supply JFET Amplifiers

AD8625/AD8626/AD8627

PIN CONFIGURATIONS

8-Lead SOIC

(R-8 Suffix)

8

NC

1
2

–IN V+

AD8627

3

+IN OUT

V– NC

4

NC = NO CONNECT

8-Lead SOIC

(R-8 Suffix)

OUT A

1
2

–IN A OUT B

+IN A –IN B

OUT A OUT D

–IN A –IN D
+IN A +IN D

+IN B +IN C
–IN B –IN C

OUT B OUT C

AD8626

3

4

V– +IN B

14-Lead SOIC

(R-Suffix)

114
213
312

AD8625

V+ V–

411
510
69
78

NC
7

6

5

V+

8
7

6

5

Figure 1.

The 5 MHz bandwidth and low offset are ideal for precision filters.
The AD862x is fully specified over the industrial temperature

range. (−40°C to +85°C). The AD8627 is available in both
5-lead SC70 and 8-lead SOIC surface-mount packages (SC70
packaged parts are available in tape and reel only). The AD8626
is available in MSOP and SOIC packages, while the AD8625 is
available in TSSOP and SOIC packages.

5-Lead SC70

1
2

V–

+IN

3

8-Lead MSOP

1

4

14-Lead TSSOP

1

7

(KS Suffix)

AD8627

(RM-Suffix)

AD8626

(RU-Suffix)

AD8625

5OUT A

V+

–IN

4

8

V+OUT A
OUT B–IN A
–IN B+IN A
+IN BV–

5

14

OUT DOUT A
–IN D–IN A
+IN D+IN A
V–V+
+IN C+IN B
–IN C–IN B
OUT COUT B

8

03023-001

Rev. E

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] www.analog.com
Fax: [phone] ©2003–2010 Analog Devices, Inc. All rights reserved.

AD8625/AD8626/AD8627

TABLE OF CONTENTS

Features .............................................................................................. 1

Applications ....................................................................................... 1 

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

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

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

Specifications ..................................................................................... 3

Electrical Characteristics ............................................................. 3

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

ESD Caution .................................................................................. 5

REVISION HISTORY

12/10—Rev. D to Rev. E

Removed Table Summary Conditions Above Table 3 ................. 5

Updated Outline Dimensions ....................................................... 18

3/09—Rev. C to Rev. D

Updated Outline Dimensions ....................................................... 18

Changes to Ordering Guide .......................................................... 19

11/04—Rev. B to Rev. C

Updated Figure Codes ....................................................... Universal

Changes to Figure 17 and 18 ........................................................... 8

Changes to Figure 33 and Figure 37 ............................................. 11

Changes to Figure 38 ...................................................................... 12

Changes to Figure 39 and Figure 40 ............................................. 13

Changes to Figure 41 to Figure 44 ................................................ 14

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

Applications Information .............................................................. 13

Minimizing Input Current ........................................................ 15

Photodiode Preamplifier Application ...................................... 15

Output Amplifier for DACs ...................................................... 16

Eight-Pole Sallen Key Low-Pass Filter ..................................... 17

Outline Dimensions ....................................................................... 18

Ordering Guide .......................................................................... 20

1/04—Rev. A to Rev. B

Change to General Description ....................................................... 1

Change to Figure 10 .......................................................................... 7

Change to Figure13 ........................................................................... 7

Change to Figure 37 ....................................................................... 11

Changes to Figure 38 ...................................................................... 12

Change to Output Amplifier for DACs Section ......................... 15

Updated Outline Dimensions ....................................................... 19

10/03—Rev. 0 to Rev. A

Addition of Two New Parts ............................................... Universal

Change to General Description ....................................................... 1

Changes to Pin Configurations ....................................................... 1

Change to Specifications Table ........................................................ 3

Changes to Figure 31 ...................................................................... 10

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

Changes to Figure 38 ...................................................................... 12

Changes to Figure 46 ...................................................................... 16

Changes to Figure 47 ...................................................................... 16

Changes to Figure 49 ...................................................................... 17

Updated Outline Dimensions ....................................................... 18

Changes to Ordering Guide .......................................................... 19

Rev. E | Page 2 of 20

AD8625/AD8626/AD8627

SPECIFICATIONS

ELECTRICAL CHARACTERISTICS

@VS = 5 V, VCM = 1.5 V, TA = 25°C, unless otherwise noted.

Table 1.

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage VOS 0.05 0.5 mV

−40°C < TA < +85°C 1.2 mV
Input Bias Current IB 0.25 1 pA
–40°C < TA < +85°C 60 pA
Input Offset Current IOS 0.5 pA
–40°C < TA < +85°C 25 pA
Input Voltage Range 0 3 V
Common-Mode Rejection Ratio CMRR VCM = 0 V to 2.5 V 66 87 dB
Large Signal Voltage Gain AVO R
Offset Voltage Drift ∆VOS/∆T –40°C < TA < +85°C 2.5 μV/°C

OUTPUT CHARACTERISTICS

Output Voltage High VOH 4.92 V
I
Output Voltage Low VOL 0.075 V
I
Output Current I

POWER SUPPLY

Power-Supply Rejection Ratio PSRR VS = 5 V to 26 V 80 104 dB

Supply Current/Amplifier ISY 630 785 μA
–40°C < TA < +85°C 800 μA
DYNAMIC PERFORMANCE

Slew Rate SR 5 V/μs

Gain Bandwidth Product GBP 5 MHz

Phase Margin ØM 60 Degrees
NOISE PERFORMANCE

Voltage Noise en p-p 0.1 Hz to 10 Hz 1.9 μV p-p

Voltage Noise Density en f = 1 kHz 17.5 nV/√Hz

Current Noise Density in f = 1 kHz 0.4 fA/√Hz

Channel Separation Cs f = 1 kHz 104 dB

±10 mA

OUT

= 10 kΩ, VO = 0.5 V to 4.5 V 100 230 V/mV

L

= 2 mA, –40°C < TA < +85°C 4.90 V

L

= 2 mA, –40°C < TA < +85°C 0.08 V

L

Rev. E | Page 3 of 20

AD8625/AD8626/AD8627

@VS = ±13 V; VCM = 0 V; TA = 25°C, unless otherwise noted.

Table 2.

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage VOS 0.35 0.75 mV
–40°C < TA < +85°C 1.35 mV
Input Bias Current IB 0.25 1 pA
–40°C < TA < +85°C 60 pA
Input Offset Current IOS 0.5 pA
–40°C < TA < +85°C 25 pA
Input Voltage Range –13 +11 V
Common-Mode Rejection Ratio CMRR V
Large Signal Voltage Gain AVO R
Offset Voltage Drift ∆VOS/∆T –40°C < TA < +85°C 2.5 μV/°C

OUTPUT CHARACTERISTICS

Output Voltage High VOH +12.92 V
V

I

OH

Output Voltage Low VOL –12.92 V
V
Output Current I

I

OL

±15 mA

OUT

POWER SUPPLY

Power-Supply Rejection Ratio PSRR VS = ±2.5 V to ±13 V 80 104 dB

Supply Current/Amplifier ISY 710 850 μA
–40°C < TA < +85°C 900 μA
DYNAMIC PERFORMANCE

Slew Rate SR 5 V/μs

Gain Bandwidth Product GBP 5 MHz

Phase Margin ØM 60 Degrees
NOISE PERFORMANCE

Voltage Noise en p-p 0.1 Hz to 10 Hz 2.5 μV p-p

Voltage Noise Density en f = 1 kHz 16 nV/√Hz

Current Noise Density in f = 1 kHz 0.5 fA/√Hz

Channel Separation Cs f = 1 kHz 105 dB

= –13 V to +10 V 76 105 dB

CM

= 10 kΩ, VO = –11 V to +11 V 150 310 V/mV

L

= 2 mA, –40°C < TA < +85°C +12.91 V

L

= 2 mA, –40°C < TA < +85°C –12.91 V

L

Rev. E | Page 4 of 20

AD8625/AD8626/AD8627

ABSOLUTE MAXIMUM RATINGS

θ

is specified for worst-case conditions when devices are

Table 3.

Parameter Ratings

Supply Voltage 27 V
Input Voltage VS– to VS+
Differential Input Voltage ± Supply Voltage
Output Short-Circuit Duration Indefinite
Storage Temperature Range, R Package

Operating Temperature Range
Junction Temperature Range, R Package
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.

−65°C to +125°C

−40°C to +85°C

−65°C to +150°C

JA

soldered in circuit boards for surface-mount packages.

Table 4.

Package Type θJA θJC Unit

5-Lead SC70 (KS) 376 126 °C/W
8-Lead MSOP (RM) 210 45 °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

ESD CAUTION

Rev. E | Page 5 of 20

AD8625/AD8626/AD8627

TYPICAL PERFORMANCE CHARACTERISTICS

25

20

VSY =±12V

= 25°C

T

A

16

14

12

VSY = +3.5V/–1.5V

15

10

NUMBER OF AMPLIFIERS

5

0

–600 –400

–200

VOLTAGE (μV)

0 200 400 600

03023-002

Figure 2. Input Offset Voltage

12

VSY =±13V

10

8

6

4

NUMBER OF AMPLIFIERS

2

0

012345678910

OFFSET VO LTAGE (μV/°C)

03023-003

Figure 3. Offset Voltage Drift

18

VSY = +3.5V/–1.5V

16

14

12

10

8

6

NUMBER OF AMPLIFIERS

4

2

0

–400 –300 –200 –100 0 100 200 300

VOLTAGE (μV)

Figure 4. Input Offset Voltage

03023-004

10

8

6

NUMBER OF AMPLIFIERS

4

2

0

012345678910

OFFSET VO LTAGE (μV/°C)

03023-005

Figure 5. Offset Voltage Drift

50

VSY =±13V
T

= 25°C

40

A

30

20

10

0

–10

–20

INPUT BIAS CURRENT (pA)

–30

–40

–50

–15.0–12.5–10.0 –7.5 –5.0 –2.5 0 2.5 5.0 7.5 10.0 12.5 15.0

Figure 6. Input Bias Current vs. V

VCM (V)

CM

03023-006

0

VSY =±13V

–0.1

= 25°C

T

A

–0.2

–0.3

–0.4

–0.5

–0.6

INPUT BIAS CURRENT (pA)

–0.7

–0.8

–0.9

–15.0–12.5–10.0 –7.5 –5.0 –2.5 0 2.5 5.0 7.5 10.0 12.5 15.0

VCM (V)

Figure 7. Input Bias Current vs. VCM

03023-007

Rev. E | Page 6 of 20