ANALOG DEVICES AD8610, AD8620 Service Manual

Precision, Very Low Noise,

Low Input Bias Current, Wide

Bandwidth JFET Operational Amplifiers

FEATURES

Low noise: 6 nV/√Hz Low offset voltage: 100 μV maximum Low input bias current: 10 pA maximum Fast settling: 600 ns to 0.01% Low distortion Unity gain stable No phase reversal Dual-supply operation: ±5 V to ±13 V

APPLICATIONS

Photodiode amplifiers AT E Instrumentation Sensors and controls High performance filters Fast precision integrators High performance audio

GENERAL DESCRIPTION

The AD8610/AD8620 are very high precision JFET input amplifiers featuring ultralow offset voltage and drift, very low input voltage and current noise, very low input bias current, and wide bandwidth. Unlike many JFET amplifiers, the AD8610/AD8620 input bias current is low over the entire operating temperature range. The AD8610/AD8620 are stable with capacitive loads of over 1000 pF in noninverting unity gain; much larger capacitive loads can be driven easily at higher noise gains. The AD8610/ AD8620 swing to within 1.2 V of the supplies even with a 1 kΩ load, maximizing dynamic range even with limited supply voltages. Outputs slew at 50 V/μs in either inverting or noninverting gain configurations, and settle to 0.01% accuracy in less than 600 ns. Combined with high input impedance, great precision, and very high output drive, the AD8610/AD8620 are ideal amplifiers for driving high performance ADC inputs and buffering DAC converter outputs.

AD8610/AD8620

PIN CONFIGURATIONS

NULL

1

–IN

2

AD8610

+IN

3

TOP VIEW

(Not to Scale)

4

V–

NC = NO CONNECT

Figure 1. 8-Lead MSOP and 8-Lead SOIC_N

OUTA

1

–INA

2

AD8620

3

+INA

TOP VIEW

(Not to Scale)

4

V–

Figure 2. 8-Lead SOIC_N

Applications for the AD8610/AD8620 include electronic instruments; ATE amplification, buffering, and integrator circuits; CAT/MRI/ultrasound medical instrumentation; instrumentation quality photodiode amplification; fast precision filters (including PLL filters); and high quality audio.

The AD8610/AD8620 are fully specified over the extended industrial temperature range (−40°C to +125°C). The AD8610 is available in the narrow 8-lead SOIC and the tiny 8-lead MSOP surface-mount packages. The AD8620 is available in the narrow 8-lead SOIC package. The 8-lead MSOP packaged devices are avail-able only in tape and reel.

8 7 6 5

NC V+ OUT NULL

V+ OUTB –INB +INB

02730-001

2730-002

Rev. F

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.

AD8610/AD8620

REVISION HISTORY

5/08—Rev. E to Rev. F

Changes to Figure 17 ........................................................................ 8

Changes to Functional Description Section ............................... 13

Changes to THD Readings vs. Common-Mode Voltage

Section .............................................................................................. 17

Changes to Output Current Capability Section ......................... 18

Changes to Figure 66 and Figure 67 ............................................. 19

Changes to Figure 68 ...................................................................... 20

Replaced Second-Order Low-Pass Filter Section ....................... 20

11/06—Rev. D to Rev. E

Updated Format .................................................................. Universal

Changes to Table 1 ............................................................................ 3

Changes to Table 2 ............................................................................ 4

Changes to Outline Dimensions ................................................... 21

Changes to Ordering Guide .......................................................... 21

2/04—Rev. C to Rev. D.

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

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

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

Theory of Operation ...................................................................... 13

Functional Description .............................................................. 13

Outline Dimensions ....................................................................... 22

Ordering Guide .......................................................................... 22

Changes to Specifications ................................................................. 2

Changes to Ordering Guide ............................................................. 4

Updated Outline Dimensions ....................................................... 17

10/02—Rev. B to Rev. C.

Updated Ordering Guide ................................................................. 4

Edits to Figure 15 ............................................................................ 12

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

5/02—Rev. A to Rev. B

Addition of Part Number AD8620 ................................... Universal

Addition of 8-Lead SOIC (R-8 Suffix) Drawing ............................ 1

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

Additions to Specifications .............................................................. 2

Change to Electrical Specifications ................................................. 3

Additions to Ordering Guide ........................................................... 4

Replace TPC 29 .................................................................................. 8

Add Channel Separation Test Circuit Figure ................................. 9

Add Channel Separation Graph ...................................................... 9

Changes to Figure 26 ...................................................................... 15

Addition of High-Speed, Low Noise Differential Driver

section .............................................................................................. 16

Addition of Figure 30 ..................................................................... 16

Rev. F | Page 2 of 24

AD8610/AD8620

SPECIFICATIONS

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

Table 1.

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage (AD8610B) VOS 45 100 μV

−40°C < TA < +125°C 80 200 μV Offset Voltage (AD8620B) VOS 45 150 μV

−40°C < TA < +125°C 80 300 μV Offset Voltage (AD8610A/AD8620A) VOS 85 250 μV 25°C < TA < 125°C 90 350 μV

−40°C < TA < +125°C 150 850 μV Input Bias Current IB −10 +2 +10 pA

−40°C < TA < +85°C −250 +130 +250 pA

−40°C < TA < +125°C −2.5 +1.5 +2.5 nA Input Offset Current IOS −10 +1 +10 pA

−40°C < TA < +85°C −75 +20 +75 pA

−40°C < TA < +125°C −150 +40 +150 pA Input Voltage Range −2 +3 V Common-Mode Rejection Ratio CMRR VCM = –1.5 V to +2.5 V 90 95 dB Large Signal Voltage Gain AVO RL = 1 kΩ, VO = −3 V to +3 V 100 180 V/mV Offset Voltage Drift (AD8610B) ΔVOS/ΔT −40°C < TA < +125°C 0.5 1 μV/°C Offset Voltage Drift (AD8620B) ΔVOS/ΔT −40°C < TA < +125°C 0.5 1.5 μV/°C Offset Voltage Drift (AD8610A/AD8620A) ΔVOS/ΔT −40°C < TA < +125°C 0.8 3.5 μV/°C

OUTPUT CHARACTERISTICS

Output Voltage High VOH RL = 1 kΩ, −40°C < TA < +125°C 3.8 4 V Output Voltage Low VOL RL = 1 kΩ, −40°C < TA < +125°C −4 −3.8 V Output Current I

POWER SUPPLY

Power Supply Rejection Ratio PSRR VS = ±5 V to ±13 V 100 110 dB Supply Current per Amplifier ISY VO = 0 V 2.5 3.0 mA

−40°C < TA < +125°C 3.0 3.5 mA DYNAMIC PERFORMANCE

Slew Rate SR RL = 2 kΩ 40 50 V/μs Gain Bandwidth Product GBP 25 MHz Settling Time tS AV = +1, 4 V step, to 0.01% 350 ns

NOISE PERFORMANCE

Voltage Noise en p-p 0.1 Hz to 10 Hz 1.8 μV p-p Voltage Noise Density en f = 1 kHz 6 nV/√Hz Current Noise Density in f = 1 kHz 5 fA/√Hz Input Capacitance CIN

Differential Mode 8 pF Common Mode 15 pF

Channel Separation CS

f = 10 kHz 137 dB f = 300 kHz 120 dB

V

OUT

> ±2 V ±30 mA

OUT

Rev. F | Page 3 of 24

AD8610/AD8620

ELECTRICAL SPECIFICATIONS

@ 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 (AD8610B) VOS 45 100 μV

−40°C < TA < +125°C 80 200 μV Offset Voltage (AD8620B) VOS 45 150 μV

−40°C < TA < +125°C 80 300 μV Offset Voltage (AD8610A/AD8620A) VOS 85 250 μV 25°C < TA < 125°C 90 350 μV

−40°C < TA < +125°C 150 850 μV Input Bias Current IB −10 +3 +10 pA

−40°C < TA < +85°C −250 +130 +250 pA

−40°C < TA < +125°C −3.5 +3.5 nA Input Offset Current IOS −10 +1.5 +10 pA

−40°C < TA < +85°C −75 +20 +75 pA

−40°C < TA < +125°C −150 +40 +150 pA Input Voltage Range −10.5 +10.5 V Common-Mode Rejection Ratio CMRR VCM = −10 V to +10 V 90 110 dB Large Signal Voltage Gain AVO RL = 1 kΩ, VO = −10 V to +10 V 100 200 V/mV Offset Voltage Drift (AD8610B) ΔVOS/ΔT −40°C < TA < +125°C 0.5 1 μV/°C Offset Voltage Drift (AD8620B) ΔVOS/ΔT −40°C < TA < +125°C 0.5 1.5 μV/°C Offset Voltage Drift (AD8610A/AD8620A) ΔVOS/ΔT −40°C < TA < +125°C 0.8 3.5 μV/°C

OUTPUT CHARACTERISTICS

Output Voltage High VOH RL = 1 kΩ, −40°C < TA < +125°C +11.75 +11.84 V Output Voltage Low VOL RL = 1 kΩ, −40°C < TA < +125°C −11.84 −11.75 V Output Current I Short-Circuit Current ISC

POWER SUPPLY

Power Supply Rejection Ratio PSRR VS = ±5 V to ±13 V 100 110 dB Supply Current per Amplifier ISY VO = 0 V 3.0 3.5 mA

−40°C < TA < +125°C 3.5 4.0 mA DYNAMIC PERFORMANCE

Slew Rate SR RL = 2 kΩ 40 60 V/μs Gain Bandwidth Product GBP 25 MHz Settling Time tS AV = +1, 10 V step, to 0.01% 600 ns

NOISE PERFORMANCE

Voltage Noise en p-p 0.1 Hz to 10 Hz 1.8 μV p-p Voltage Noise Density en f = 1 kHz 6 nV/√Hz Current Noise Density in f = 1 kHz 5 fA/√Hz Input Capacitance CIN

Differential Mode 8 pF Common Mode 15 pF

Channel Separation CS

f = 10 kHz 137 dB f = 300 kHz 120 dB

V

OUT

> 10 V ±45 mA

OUT

±65 mA

Rev. F | Page 4 of 24

AD8610/AD8620

ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter Rating

Supply Voltage 27.3 V Input Voltage VS− to VS+ Differential Input Voltage ±Supply voltage Output Short-Circuit Duration to GND Indefinite Storage Temperature Range –65°C to +150°C Operating Temperature Range –40°C to +125°C Junction Temperature Range –65°C to +150°C Lead Temperature (Soldering, 10 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.

Table 4. Thermal Resistance

Package Type θ

8-Lead MSOP (RM) 190 44 °C/W 8-Lead SOIC (R) 158 43 °C/W

1

θJA is specified for worst-case conditions, that is, θJA is specified for a device

soldered in circuit board for surface-mount packages.

1

θ

JA

Unit

JC

ESD CAUTION

Rev. F | Page 5 of 24

AD8610/AD8620

TYPICAL PERFORMANCE CHARACTERISTICS

14

VS = ±13V

12

600

VS = ±5V

400

10

8

6

4

NUMBER OF AMPLIFIERS

2

0

–250 –150 –50 50 150 250

INPUT OFFSET VOLTAGE (µV)

Figure 3. Input Offset Voltage

600

400

200

0

–200

INPUT OFFSET VOLTAGE (µV)

–400

VS = ±13V

200

0

–200

INPUT OFFSET VOLTAGE (µV)

–400

02730-003

–600

–40 25 85 125

TEMPERATURE (°C)

02730-006

Figure 6. Input Offset Voltage vs. Temperature at ±5 V (300 Amplifiers)

14

12

10

8

6

4

NUMBER OF AMPLIFIERS

2

V

= ±5V OR ±13V

S

–600

–40 25 85 125

TEMPERATURE (° C)

Figure 4. Input Offset Voltage vs. Temperature at ±13 V (300 Amplifiers)

18

16

14

12

10

8

6

NUMBER OF AMPL IFIERS

4

2

0

–250 –150 –50 50 150 250

INPUT OFFSET VOLTAGE (µV)

VS = ±5V

02730-005

Figure 5. Input Offset Voltage

02730-004

Rev. F | Page 6 of 24

0

0 0.2 0.6 1.0 1.4 1.8 2.2 2.6

TCVOS (µV/°C)

Figure 7. Input Offset Voltage Drift

3.6

3.4

3.2

3.0

2.8

2.6

2.4

INPUT BIAS CURRENT (pA)

2.2

2.0

COMMON-MODE VOLTAGE (V)

Figure 8. Input Bias Current vs. Common-Mode Voltage

V

S

= ±13V

02730-007

02730-008

10–10 5–5 0

AD8610/AD8620

–

3.0

2.5

2.0

1.5

1.0

SUPPLY CURRENT (mA)

0.5

0

0321 4 5 6 7 8 9 10 11 12 13

SUPPLY VOLTAGE (±V)

Figure 9. Supply Current vs. Supply Voltage

02730-009

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

OUTPUT VO LTAGE T O SUPPLY RAI L (V)

0

100 10k 100k1k 1M 10M 100M

RESISTANCE LOAD (Ω)

VS= ±13V

Figure 12. Output Voltage to Supply Rail vs. Resistance Load

02730-012

3.05

VS = ±13V

2.95

2.85

2.75

SUPPLY CURRENT (mA)

2.65

2.55 –40 1258525

TEMPERATURE ( °C)

02730-010

Figure 10. Supply Current vs. Temperature

2.65

VS = ±5V

2.60

2.55

2.50

2.45

4.25

4.20

4.15

4.10

4.05

OUTPUT VO LTAGE HI GH (V)

4.00

3.95

VS= ±5V

= 1kΩ

R

L

25 85–40 125

TEMPERATURE ( °C)

Figure 13. Output Voltage High vs. Temperature

3.95

–4.00

–4.05

–4.10

–4.15

VS= ±5V

= 1kΩ

R

L

02730-013

2.40

SUPPLY CURRENT (mA)

2.35

2.30 –40 1258525

TEMPERATURE ( °C)

02730-011

Figure 11. Supply Current vs. Temperature

–4.20

OUTPUT VOLTAGE LOW (V)

–4.25

–4.30

25 85–40 125

TEMPERATURE ( °C)

Figure 14. Output Voltage Low vs. Temperature

02730-014

Rev. F | Page 7 of 24

AD8610/AD8620

–

12.05

12.00

VS= ±13V

= 1kΩ

R

L

60

40

G = +100

VS= ±13V R

= 2kΩ

L

C

= 20pF

L

11.95

11.90

OUTPUT VO LTAGE HI GH (V)

11.85

11.80 25 85–40 125

TEMPERATURE ( °C)

Figure 15. Output Voltage High vs. Temperature

11.80

–11.85

–11.90

–11.95

OUTPUT VO LTAGE L OW (V)

–12.00

–12.05

25 85–40 125

TEMPERATURE ( °C)

Figure 16. Output Voltage Low vs. Temperature

VS= ±13V

= 1kΩ

R

L

20

0

CLOSED-LOOP GAIN (dB)

–20

02730-015

–40

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

G = +10

G = +1

02730-018

FREQUENCY (Hz)

Figure 18. Closed-Loop Gain vs. Frequency

260

VS= ±13V V

240

220

200

180

(V/mV)

VO

A

160

140

120

02730-016

100

–40 25 85 125

TEMPERATURE (°C)

O

R

L

= ±10V = 1kΩ

02730-019

Figure 19. AVO vs. Temperature

120

100

80

60

40

AD8610

20

V

= ±13V

S

C

= 20pF

L

0

GAIN AND PHASE (d B AND DEGREES)

–20

1kHz 10kHz 100kHz 1MHz 10MHz 50MHz

FREQUENCY

Figure 17. Open-Loop Gain and Phase vs. Frequency

02730-017

Rev. F | Page 8 of 24

190

180

170

160

150

(V/mV)

140

VO

A

130

120

110

100

–40 25 85 125

TEMPERATURE (°C)

VS= ±5V V

= ±3V

O

R

= 1kΩ

L

02730-020

Figure 20. AVO vs. Temperature

ANALOG DEVICES AD8610, AD8620 Service Manual

FEATURES

APPLICATIONS

GENERAL DESCRIPTION

PIN CONFIGURATIONS

TABLE OF CONTENTS

REVISION HISTORY

SPECIFICATIONS

ELECTRICAL SPECIFICATIONS

ABSOLUTE MAXIMUM RATINGS

ESD CAUTION

TYPICAL PERFORMANCE CHARACTERISTICS