ANALOG DEVICES AD8506 Service Manual

20 μA Maximum, Rail-to-Rail I/O,

www.BDTIC.com/ADI

Zero Input Crossover Distortion Amplifiers

FEATURES

PSRR: 100 dB minimum
CMRR: 105 dB typical
Very low supply current: 20 μA per amp maximum

1.8 V to 5.5 V single-supply operation
Rail-to-rail input and output
Low noise

2.8 μV p-p from 0.1 Hz to 10 Hz
45 nV/√Hz @ 1 kHz

2.5 mV offset voltage maximum
Very low input bias current: 1 pA typical

APPLICATIONS

Pressure and position sensors
Remote security
Bio sensors
IR thermometers
Battery-powered consumer equipment
Hazard detectors

GENERAL DESCRIPTION

The AD8506 is a dual micropower amplifier featuring rail-to­rail input and output swings while operating from a 1.8 V to 5.5 V
single power supply.

Using a novel circuit technology, these low cost amplifiers offer

ero crossover distortion (excellent PSRR and CMRR perform-

z
ance) and very low bias current, while operating with a supply
current of less than 20 μA per amplifier. This amplifier offers
the lowest noise in its power class.

This combination of features makes the AD8506 amplifier an

deal choice for battery-powered applications because it mini-

i
mizes errors due to power supply voltage variations over the

AD8506

PIN CONFIGURATION

1

OUT A

–IN A

+IN A

Figure 1. 8-Lead MSOP (RM Suffix)

V–

AD8506

2

TOP VIEW

3

(Not to Scale)

4

lifetime of the battery and maintains high CMRR even for a

il-to-rail input op amp.

ra

Remote battery-powered sensors, handheld instrumentation
a

nd consumer equipment, hazard detection (for example, smoke,
fire, and gas), and patient monitors can benefit from the features
of the AD8506 amplifier.

The AD8506 is specified for both the industrial temperature
r

ange of −40°C to +85°C and the extended industrial temperature
range of −40°C to +125°C. AD8506 dual amplifiers are available
in 8-lead MSOP packages.

8

7

6

5

V+

OUT B

–IN B

+IN B

06900-002

Rev. 0

Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
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] ©2007 Analog Devices, Inc. All rights reserved.

AD8506

www.BDTIC.com/ADI

TABLE OF CONTENTS

Features.............................................................................................. 1

Applications....................................................................................... 1

Pin Configuration............................................................................. 1

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

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

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

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

REVISION HISTORY

11/07—Revision 0: Initial Version

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

Thermal Resistance.......................................................................5

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

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

Outline Dimensions....................................................................... 12

Ordering Guide .......................................................................... 12

Rev. 0 | Page 2 of 12

AD8506

www.BDTIC.com/ADI

SPECIFICATIONS

ELECTRICAL CHARACTERISTICS

VSY = 5 V, VCM = VSY/2, TA = 25°C, RL = 100 kΩ to GND, unless otherwise noted.

Table 1.

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage VOS 0 V < VCM < 5 V 0.5 2.5 mV

−40°C < TA < +125°C 3 mV
Input Bias Current IB 1 10 pA

−40°C < TA < +85°C 100 pA

−40°C < TA < +125°C 600 pA
Input Offset Current IOS 0.5 5 pA

−40°C < TA < +85°C 50 pA

−40°C < TA < +125°C 130 pA
Input Voltage Range −40°C < TA < +125°C 0 5 V
Common-Mode Rejection Ratio CMRR VCM = 0 V to 5 V 90 105 dB

−40°C < TA < +85°C 90 dB

−40°C < TA < +125°C 85 dB
Large Signal Voltage Gain AVO 0.05 V < V

−40°C < TA < +125°C 100 dB
Offset Voltage Drift

Input Capacitance

OUTPUT CHARACTERISTICS

Output Voltage High VOH R

−40°C < TA < +125°C 4.98 V
R

−40°C < TA < +125°C 4.9 V
Output Voltage Low VOL R

−40°C < TA < +125°C 5 mV
R

−40°C < TA < +125°C 25 mV
Short-Circuit Limit ISC ±55 mA

POWER SUPPLY

Power Supply Rejection Ratio PSRR VS = 1.8 V to 5 V 100 110 dB

−40°C < TA < +85°C 100 dB

−40°C < TA < +125°C 95 dB
Supply Current/Amplifier ISY V

−40°C < TA < +125°C 25 μA

DYNAMIC PERFORMANCE

Slew Rate SR RL = 100 kΩ, CL = 10 pF,

Gain Bandwidth Product GBP 100 kHz

−3 dB Bandwidth 150 kHz
Phase Margin ΦM 60 Degrees

NOISE PERFORMANCE

Peak-to-Peak Noise e
Voltage Noise Density en f = 1 kHz 45 nV/√Hz
Current Noise Density in f = 1 kHz 80 fA/√Hz

/ΔT

ΔV

OS

C

DIFF

CCM

f = 0.1 Hz to 10 Hz 2.8 μV p-p

n p-p

−40°C < T
3 pF

4.2 pF

= 100 kΩ to GND 4.98 4.99 V

L

= 10 kΩ to GND 4.9 4.95 V

L

= 100 kΩ to VS 2 5 mV

L

= 10 kΩ to VS 10 25 mV

L

= VS/2 15 20 μA

O

= +1

A

V

< 4.95 V 105 120 dB

OUT

< +125°C 2 μV/°C

A

13 mV/μs

Rev. 0 | Page 3 of 12

AD8506

www.BDTIC.com/ADI

VSY = 1.8 V, VCM = VSY/2, TA = 25°C, RL = 100 kΩ to GND, unless otherwise noted.

Table 2.

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage VOS 0 V < VCM < 1.8 V 0.5 2.5 mV

−40°C < TA < +125°C 3 mV
Input Bias Current IB 1 10 pA

−40°C < TA < +85°C 100 pA

−40°C < TA < +125°C 600 pA
Input Offset Current IOS 0.5 5 pA

−40°C < TA < +85°C 50 pA

−40°C < TA < +125°C 100 pA
Input Voltage Range −40°C < TA < +125°C 0 1.8 V
Common-Mode Rejection Ratio CMRR VCM = 0 V to 1.8 V 85 100 dB

−40°C < TA < +85°C 85 dB

−40°C < TA < +125°C 80 dB
Large Signal Voltage Gain AVO 0.05V < V

< 1.75V 95 115 dB

OUT

−40°C < TA < +125°C 95 dB
Offset Voltage Drift

Input Capacitance

ΔV
C

DIFF

CCM

OS

/ΔT

−40°C < T

< +125°C 2.5 μV/°C

A

3 pF

4.2 pF

OUTPUT CHARACTERISTICS

Output Voltage High VOH R

= 100 kΩ to GND 1.78 1.79 V

L

−40°C < TA < +125°C 1.78 V
R

= 10 kΩ to GND 1.65 1.75 V

L

−40°C < TA < +125°C 1.65 V
Output Voltage Low VOL R

= 100 kΩ to VS 2 5 mV

L

−40°C < TA < +125°C 5 mV
R

= 10 kΩ to VS 12 25 mV

L

−40°C < TA < +125°C 25 mV
Short-Circuit Limit ISC ±6.5 mA

POWER SUPPLY

Power Supply Rejection Ratio PSRR VS = 1.8 V to 5 V 100 110 dB

−40°C < TA < +85°C 100 dB

−40°C < TA < +125°C 95 dB
Supply Current/Amplifier ISY V

= VS/2 16.5 20 μA

O

−40°C < TA < +125°C 25 μA

DYNAMIC PERFORMANCE

Slew Rate SR

= 100 kΩ, C

R

L

A

= +1

V

= 10 pF,

L

13 mV/μs

Gain Bandwidth Product GBP 100 kHz

−3 dB Bandwidth 150 kHz
Phase Margin Φ

M

60 Degrees

NOISE PERFORMANCE

Peak-to-Peak Noise e

f = 0.1 Hz to 10 Hz 2.8 μV p-p

n p-p

Voltage Noise Density en f = 1 kHz 45 nV/√Hz
Current Noise Density in f = 1 KHz 80 fA/√Hz

Rev. 0 | Page 4 of 12

AD8506

www.BDTIC.com/ADI

ABSOLUTE MAXIMUM RATINGS

Table 3.

Parameter Rating

Supply Voltage 5.5 V
Input Voltage ±VSY
Differential Input Voltage1 ±VSY
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, 60 sec) 300°C

1

Differential input voltage is limited to 5.5 V or the supply voltage, whichever

is less.

Stresses above those listed under Absolute Maximum Ratings

y cause permanent damage to the device. This is a stress

ma
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.

THERMAL RESISTANCE

θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.

Table 4. Thermal Resistance

Package Type θJA θ

8-Lead MSOP (RM) 190 44 °C/W

Unit

JC

ESD CAUTION

Rev. 0 | Page 5 of 12

AD8506

www.BDTIC.com/ADI

TYPICAL PERFORMANCE CHARACTERISTICS

250

VSY = 1.8V

250

VSY = 5V

200

150

100

NUMBER OF AMPLIFIERS

50

0

–4 –1–3 0–2 1 2 3 4

VOS (mV)

Figure 2. Input Offset Voltage Distribution

16

VSY = 1.8V
–40°C < T

NUMBER OF AMPLIFIERS

14

12

10

8

6

4

2

< +125°C

A

200

150

100

NUMBER OF AMPLIFIERS

50

0

–4 –1–3 0–2 1 2 3 4

06900-003

VOS (mV)

06900-006

Figure 5. Input Offset Voltage Distribution

12

VSY = 5V

NUMBER OF AMPLIFIERS

10

8

6

4

2

–40°C < T

< +125°C

A

0

012345678910111213

TCVOS (µV/°C)

Figure 3. Offset Voltage Drift Distribution

2000

1500

1000

500

(µV)

0

OS

V

–500

–1000

–1500

–2000

0 0.2 0.4 0.6 0.8 1.0 1.2 1. 4 1. 6 1. 8

VCM (V)

VSY = 1.8V

Figure 4. Input Offset Voltage vs. Input Common-Mode Voltage

0

012345678910111213

06900-004

TCVOS (µV/°C)

06900-007

Figure 6. Offset Voltage Drift Distribution

2000

1500

1000

500

(µV)

0

OS

V

–500

–1000

–1500

–2000

012345

06900-005

VCM (V)

VSY = 5V

06900-008

Figure 7. Input Offset Voltage vs. Input Common-Mode Voltage

Rev. 0 | Page 6 of 12

AD8506

www.BDTIC.com/ADI

–115

VSY = 1.8V

–120

VSY = 5V

–120

–125

(µV)

OS

V

–130

–135

–140

0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8

VCM (V)

Figure 8. Δ Input Offset Voltage vs. Input Common-Mode Voltage

600

550

500

450

400

(pA)

B

I

350

300

VSY = 1.8V

–125

–130

(µV)

–135

OS

V

–140

–145

–150

06900-037

054321

VCM (V)

06900-038

Figure 11. Δ Input Offset Voltage vs. Input Common-Mode Voltage

600

550

500

450

400

(pA)

B

I

350

300

VSY = 5V

250

200

0 0.2 0.4 0.6 0.8 1.0 1.2 1 .4 1.6 1. 8

VCM (V)

Figure 9. Input Bias Current vs. Common-Mode Voltage at 125°C

10k

VSY = 1.8V

1k

100

V

VDD – V

10

1

OUTPUT SATURATION VOLTAGE (mV)

0.1

0.001 10

0.01 0.1 1

OH

LOAD CURRENT (mA)

OL

Figure 10. Output Swing Saturation Voltage vs. Load Current

250

200

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

06900-009

VCM (V)

06900-012

Figure 12. Input Bias Current vs. Common-Mode Voltage at 125°C

10k

VSY = 5V

1k

100

10

1

0.1

OUTPUT SATURATION VOLTAGE (mV)

0.01

6900-010

0.001 10 100

VDD – V

OH

0.01 0.1 1
LOAD CURRENT (mA)

V

OL

6900-013

Figure 13. Output Swing Saturation Voltage vs. Load Current

Rev. 0 | Page 7 of 12

AD8506

www.BDTIC.com/ADI

14

12

10

VSY = 1.8V

VDD – VOH @ RL = 10kΩ

14

12

10

VSY = 5V

VDD – VOH @ RL = 10kΩ

8

@ RL = 10kΩ

V

6

4

– VOH @ RL = 100kΩ

V

DD

2

OUTPUT SAT URATION VO LTAGE (mV )

@ RL = 100kΩ

V

0

–40 –25 –10 5 20 35 50 65 80 95 110 125

OL

TEMPERATURE ( °C)

OL

Figure 14. Output Saturation Voltage vs. Temperature

40

35

30

25

20

15

10

TOTAL SUPPLY CURRENT (µA)

5

0

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 5.0

Figure 15. Total Supply Curr

SUPPLY VOLTAGE (V)

ent vs. Supply Voltage

4.5

8

V

@ RL = 10kΩ

6

4

– VOH @ RL = 100kΩ

V

DD

2

OUTPUT SAT URATION VO LTAGE (mV )

0

06900-011

–40 –25 –10 5 20 35 50 65 80 95 110 125

V

OL

@ RL = 100kΩ

OL

TEMPERATURE (°C)

06900-014

Figure 17. Output Saturation Voltage vs. Temperature

50

45

40

35

30

25

20

15

TOTAL SUPPLY CURRENT (µA)

10

5

0

–40 –25 5–10 203550658095110125

06900-015

VSY = 1.8V

TEMPERATURE ( °C)

VSY = 5V

06900-018

Figure 18. Total Supply Current vs. Temperature

100

80

60

40

20

0

–20

–40

OPEN-LOOP GAIN (dB)

–60

–80

–100

100 1M100k10k1k

PHASE

GAIN

FREQUENCY (Hz)

Figure 16. Open-Loop Gain and Phase vs. Frequency

VSY = 1.8V

225

180

135

90

45

0

–45

PHASE (Degrees)

–90

–135

–180

–225

06900-035

Rev. 0 | Page 8 of 12

100

80

60

40

20

0

–20

–40

OPEN-LOOP GAIN (dB)

–60

–80

–100

100 1M100k10k1k

PHASE

GAIN

FREQUENCY (Hz)

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

VSY = 5V

225

180

135

90

45

0

–45

–90

–135

–180

PHASE (Degrees)

06900-036

AD8506

www.BDTIC.com/ADI

50

G=100

40

30

G=10

20

10

G= 1

0

–10

–20

CLOSED-LOOP GAIN (dB)

–30

–40

–50

100 1M

1k 10k 100k

FREQUENCY (Hz)

Figure 20. Closed-Loop Gain vs. Frequency

3000

VSY = 1.8V

2500

2000

(Ω)

1500

OUT

Z

1000

500

G = 100

G = 10

G = 1

VSY = 1.8V

6900-017

50

G = 100

40

30

G = 10

20

10

G = 1

0

–10

–20

CLOSED-LOOP GAIN (dB)

–30

–40

–50

100 1M

1k 10k 100k

FREQUENCY (Hz)

Figure 23. Closed-Loop Gain vs. Frequency

2500

VSY = 5V

2000

1500

(Ω)

OUT

Z

1000

500

G = 100

G = 10

G = 1

VSY = 5V

6900-020

0

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

120

VSY = 1.8V
T

= 25°C

A

100

80

60

CMRR (dB)

40

20

0

100 1M100k10k1k

FREQUENCY (Hz)

Figure 21. Z

FREQUENCY (Hz)

vs. Frequency

OUT

Figure 22. CMRR vs. Frequency

0

6900-021

06900-022

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

120

VSY = 5V

100

80

60

CMRR (dB)

40

20

0

100 1M100k10k1k

FREQUENCY (Hz)

Figure 24. Z

FREQUENCY (Hz)

vs. Frequency

OUT

6900-024

06900-025

Figure 25. CMRR vs. Frequency

Rev. 0 | Page 9 of 12

AD8506

www.BDTIC.com/ADI

100

90

80

70

60

50

PSRR (dB)

40

30

20

10

0

10 100 1k 10k 100k 1M

PSRR–

FREQUENCY (Hz)

VSY = 1.8V

PSRR+

Figure 26. PSRR vs. Frequency

06900-023

100

90

80

70

60

50

PSRR (dB)

40

30

20

10

0

10 100 1k 10k 100k 1M

FREQUENCY (Hz)

PSRR–

PSRR+

Figure 29. PSRR vs. Frequency

VSY = 5V

06900-026

80

VSY = 1.8V
R

= 100kΩ

L

70

60

50

40

30

OVERSHOOT (%)

–OVERSHOO T

20

10

+OVERSHOO T

0

10 1k100

C

LOAD

(pF)

Figure 27. Small Signal Overshoot vs. Load Capacitance

80

VSY = 5V
R

= 100kΩ

L

70

60

50

40

30

OVERSHOOT (%)

06900-027

–OVERSHOO T

20

10

+OVERSHOO T

0

10 1k100

C

LOAD

(pF)

06900-030

Figure 30. Small Signal Overshoot vs. Load Capacitance

VOLTAGE (500mV/DIV)

TIME (100µs/DIV)

VSY = 1.8V
R

= 100kΩ

L

C

= 100pF

L

06900-028

Figure 28. Large Signal Transient Response

VOLTAGE (1V/DIV)

Figure 31. Large Signal Transient Response

Rev. 0 | Page 10 of 12

VSY = 5V
R
C

TIME (100µs/DIV)

= 100kΩ

L

= 100pF

L

06900-031

AD8506

www.BDTIC.com/ADI

VOLTAGE (2mV/DIV)

TIME (100µs/DIV)

VSY = 1.8V
R

= 100kΩ

L

C

= 100pF

L

06900-029

VOLTAGE (2mV/DIV)

TIME (100µs/DIV)

VSY = 5V
R

= 100kΩ

L

C

= 100pF

L

06900-032

Figure 32. Small Signal Transient Response Figure 34. Small Signal Transient Response

100

VSY = 5V

10

(nV/ Hz)

N

e

VOLTAGE (0.5µV/DIV)

1

100 1M10k1k

FREQUENCY (Hz)

Figure 33. Voltage Noise Density vs. Frequency

06900-033

Figure 35. Voltage Noise 0.1 Hz to 10 Hz

TIME (4s/ DIV)

VSY = 1.8V AND 5V

2.78µV p-p

06900-034

Rev. 0 | Page 11 of 12

AD8506

www.BDTIC.com/ADI

OUTLINE DIMENSIONS

3.20

3.00

2.80

8

5

3.20

3.00

1

2.80

PIN 1

0.65 BSC

0.95

0.85

0.75

0.15

0.38

0.00

0.22

COPLANARITY

0.10

COMPLIANT TO JEDEC STANDARDS MO-187-AA

Figure 36. 8-Lead Mini Small Outline Package [MSOP]

ORDERING GUIDE

Model Temperature Range Package Description Package Option Branding

AD8506ARMZ-R2
AD8506ARMZ-REEL

1

Z = RoHS Compliant Part.

1

–40°C to +125°C 8-Lead Mini Small Outline Package [MSOP] RM-8 A1X

1

–40°C to +125°C 8-Lead Mini Small Outline Package [MSOP] RM-8 A1X

5.15

4.90

4.65

4

1.10 MAX

0.23

SEATING
PLANE

0.08

(RM-8)

Dim

ensions shown in millimeters

8°
0°

0.80

0.60

0.40

©2007 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D06900-0-11/07(0)

Rev. 0 | Page 12 of 12