CMOS Rail-to-Rail General-Purpose

Amplifiers

AD8541/AD8542/AD8544


FEATURES

2

1

Single-supply operation: 2.7 V to 5.5 V Low supply current: 45 μA/amplifier

PIN CONFIGURATIONS

Wide bandwidth: 1 MHz No phase reversal

Low input currents: 4 pA Unity gain stable

OUT A


AD8541

V–


+IN A

V+


4

5

00935-001

–IN A

3

Rail-to-rail input and output Qualified for automotive applications

APPLICATIONS

Figure 1. 5-Lead SC70 and 5-Lead SOT-23 (KS and RJ Suffixes)

ASIC input or output amplifiers Sensor interfaces

Piezoelectric transducer amplifiers Medical instrumentation

Mobile communications Audio outputs


NC


–IN A


+IN A V–


AD8541

2

7


3

6


4

5

8

1

NC = NO CONNECT


NC V+

00935-002

OUT A NC

Portable systems


GENERAL DESCRIPTION

The AD8541/AD8542/AD8544 are single, dual, and quad rail- to-rail input and output, single-supply amplifiers featuring very low supply current and 1 MHz bandwidth. All are guaranteed to operate from a 2.7 V single supply as well as a 5 V supply. These

parts provide 1 MHz bandwidth at a low current consumption


OUT A


–IN A


+IN A

Figure 2. 8-Lead SOIC

(R Suffix)


8

1

AD8542


2

7


3

6


V+ OUT B

–IN B

of 45 μA per amplifier.

Very low input bias currents enable the AD8541/AD8542/AD8544 to be used for integrators, photodiode amplifiers, piezoelectric sensors, and other applications with high source impedance.

The supply current is only 45 μA per amplifier, ideal for battery

V– +IN B


1

5

4

00935-003

Figure 3. 8-Lead SOIC, 8-Lead MSOP, and 8-Lead TSSOP (R, RM, and RU Suffixes)

2

operation.

Rail-to-rail inputs and outputs are useful to designers buffering ASICs in single-supply systems. The AD8541/AD8542/AD8544 are optimized to maintain high gains at lower supply voltages,

OUT A


–IN A


4

+IN A

OUT D


13

14

–IN D


11

AD8544

12

+IN D

5

3

making them useful for active filters and gain stages.

V+ V–

The AD8541/AD8542/AD8544 are specified over the extended industrial temperature range (–40°C to +125°C). The AD8541

+IN B


–IN B

+IN C


9

10

–IN C

is available in 5-lead SOT-23, 5-lead SC70, and 8-lead SOIC packages. The AD8542 is available in 8-lead SOIC, 8-lead MSOP, and 8-lead TSSOP surface-mount packages. The AD8544 is available in 14-lead narrow SOIC and 14-lead TSSOP surface- mount packages. All MSOP, SC70, and SOT versions are available in tape and reel only. See the Ordering Guide for automotive models.


8

7

6

00935-004

OUT B OUT C


Figure 4. 14-Lead SOIC and 14-Lead TSSOP (R and RU Suffixes)



Rev. G

Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibilityis assumedby AnalogDevices foritsuse, norforanyinfringements of patents or other rightsofthirdpartiesthatmayresultfromitsuse.Specificationssubjecttochangewithoutnotice.No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.


One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com

Fax: 781.461.3113 ©2008–2011 Analog Devices, Inc. All rights reserved.


TABLE OF CONTENTS

Features 1

Applications 1

General Description 1

Pin Configurations 1

Revision History 2

Specifications 3

Electrical Characteristics 3

Absolute Maximum Ratings 6

Thermal Resistance 6

ESD Caution 6

Typical Performance Characteristics 7

Theory of Operation 13

Notes on the AD854x Amplifiers 13

Applications 14

Notch Filter 14

Comparator Function 14

Photodiode Application 15

Outline Dimensions 16

Ordering Guide 19

Automotive Products 19


REVISION HISTORY

6/11—Rev. F to Rev. G

Changes to Features Section and General Description

Section 1

Changes to Table 5 6

Updated Outline Dimensions 16

Changes to Ordering Guide 19

Added Automotive Products Section 19

1/08—Rev. E to Rev. F

Inserted Figure 21; Renumbered Sequentially 9

Changes to Figure 22 Caption 9

Changes to Notch Filter Section, Figure 35, Figure 36, and Figure 37 13

Updated Outline Dimensions 16


1/07—Rev. D to Rev. E

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

Changes to Photodiode Application Section 14

Changes to Ordering Guide 17

8/04—Rev. C to Rev. D

Changes to Ordering Guide 5

Changes to Figure 3 10

Updated Outline Dimensions 12

1/03—Rev. B to Rev. C

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

Changes to General Description 1

Changes to Ordering Guide 5

Changes to Outline Dimensions 12

SPECIFICATIONS

ELECTRICAL CHARACTERISTICS

VS = 2.7 V, VCM = 1.35 V, TA = 25°C, unless otherwise noted.

Table 1.

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

INPUT CHARACTERISTICS







Offset Voltage

VOS



1

6

mV



−40°C ≤ TA ≤ +125°C



7

mV

Input Bias Current

IB



4

60

pA



−40°C ≤ TA ≤ +85°C



100

pA



−40°C ≤ TA ≤ +125°C



1000

pA

Input Offset Current

IOS



0.1

30

pA



−40°C ≤ TA ≤ +85°C



50

pA



−40°C ≤ TA ≤ +125°C



500

pA

Input Voltage Range



0


2.7

V

Common-Mode Rejection Ratio

CMRR

VCM = 0 V to 2.7 V

40

45


dB



−40°C ≤ TA ≤ +125°C

38



dB

Large Signal Voltage Gain

AVO

RL = 100 kΩ, VO = 0.5 V to 2.2 V

100

500


V/mV



−40°C ≤ TA ≤ +85°C

50



V/mV



−40°C ≤ TA ≤ +125°C

2



V/mV

Offset Voltage Drift

ΔVOS/ΔT

−40°C ≤ TA ≤ +125°C


4


μV/°C

Bias Current Drift

ΔIB/ΔT

−40°C ≤ TA ≤ +85°C


100


fA/°C



−40°C ≤ TA ≤ +125°C


2000


fA/°C

Offset Current Drift

ΔIOS/ΔT

−40°C ≤ TA ≤ +125°C


25


fA/°C

OUTPUT CHARACTERISTICS







Output Voltage High

VOH

IL = 1 mA

2.575

2.65


V



−40°C ≤ TA ≤ +125°C

2.550



V

Output Voltage Low

VOL

IL = 1 mA


35

100

mV



−40°C ≤ TA ≤ +125°C



125

mV

Output Current

IOUT

VOUT = VS − 1 V


15


mA


ISC



±20


mA

Closed-Loop Output Impedance

ZOUT

f = 200 kHz, AV = 1


50


Ω

POWER SUPPLY



VS = 2.5 V to 6 V

−40°C ≤ TA ≤ +125°C VO = 0 V

−40°C ≤ TA ≤ +125°C





dB dB μA μA

Power Supply Rejection Ratio


Supply Current/Amplifier

PSRR


ISY

65

60

76


38


55

75

DYNAMIC PERFORMANCE







Slew Rate

SR

RL = 100 kΩ

0.4

0.75


V/μs

Settling Time

tS

To 0.1% (1 V step)


5


μs

Gain Bandwidth Product

GBP



980


kHz

Phase Margin




63


Degrees


ΦM






NOISE PERFORMANCE





Voltage Noise Density

en

f = 1 kHz

40

nV/√Hz


en

f = 10 kHz

38

nV/√Hz

Current Noise Density

in


<0.1

pA/√Hz


VS = 3.0 V, VCM = 1.5 V, TA = 25°C, unless otherwise noted.

Table 2.

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

INPUT CHARACTERISTICS







Offset Voltage

VOS



1

6

mV



−40°C ≤ TA ≤ +125°C



7

mV

Input Bias Current

IB



4

60

pA



−40°C ≤ TA ≤ +85°C



100

pA



−40°C ≤ TA ≤ +125°C



1000

pA

Input Offset Current

IOS



0.1

30

pA



−40°C ≤ TA ≤ +85°C



50

pA



−40°C ≤ TA ≤ +125°C



500

pA

Input Voltage Range



0


3

V

Common-Mode Rejection Ratio

CMRR

VCM = 0 V to 3 V

40

45


dB



−40°C ≤ TA ≤ +125°C

38



dB

Large Signal Voltage Gain

AVO

RL = 100 kΩ, VO = 0.5 V to 2.2 V

100

500


V/mV



−40°C ≤ TA ≤ +85°C

50



V/mV



−40°C ≤ TA ≤ +125°C

2



V/mV

Offset Voltage Drift

ΔVOS/ΔT

−40°C ≤ TA ≤ +125°C


4


μV/°C

Bias Current Drift

ΔIB/ΔT

−40°C ≤ TA ≤ +85°C


100


fA/°C



−40°C ≤ TA ≤ +125°C


2000


fA/°C

Offset Current Drift

ΔIOS/ΔT

−40°C ≤ TA ≤ +125°C


25


fA/°C

OUTPUT CHARACTERISTICS







Output Voltage High

VOH

IL = 1 mA

2.875

2.955


V



−40°C ≤ TA ≤ +125°C

2.850



V

Output Voltage Low

VOL

IL = 1 mA


32

100

mV



−40°C ≤ TA ≤ +125°C



125

mV

Output Current

IOUT

VOUT = VS − 1 V


18


mA


ISC



±25


mA

Closed-Loop Output Impedance

ZOUT

f = 200 kHz, AV = 1


50


Ω

POWER SUPPLY

Power Supply Rejection Ratio


Supply Current/Amplifier

PSRR ISY


VS = 2.5 V to 6 V

−40°C ≤ TA ≤ +125°C VO = 0 V

−40°C ≤ TA ≤ +125°C


65

60


76


40


60

75


dB dB μA μA

DYNAMIC PERFORMANCE







Slew Rate

SR

RL = 100 kΩ

0.4

0.8


V/μs

Settling Time

tS

To 0.01% (1 V step)


5


μs

Gain Bandwidth Product

GBP



980


kHz

Phase Margin

ΦM



64


Degrees

NOISE PERFORMANCE





Voltage Noise Density

en

f = 1 kHz

42

nV/√Hz


en

f = 10 kHz

38

nV/√Hz

Current Noise Density

in


<0.1

pA/√Hz


VS = 5.0 V, VCM = 2.5 V, TA = 25°C, unless otherwise noted.

Table 3.

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

INPUT CHARACTERISTICS







Offset Voltage

VOS



1

6

mV



−40°C ≤ TA ≤ +125°C



7

mV

Input Bias Current

IB



4

60

pA



−40°C ≤ TA ≤ +85°C



100

pA



−40°C ≤ TA ≤ +125°C



1000

pA

Input Offset Current

IOS



0.1

30

pA



−40°C ≤ TA ≤ +85°C



50

pA



−40°C ≤ TA ≤ +125°C



500

pA

Input Voltage Range



0


5

V

Common-Mode Rejection Ratio

CMRR

VCM = 0 V to 5 V

40

48


dB



−40°C ≤ TA ≤ +125°C

38



dB

Large Signal Voltage Gain

AVO

RL = 100 kΩ, VO = 0.5 V to 2.2 V

20

40


V/mV



−40°C ≤ TA ≤ +85°C

10



V/mV



−40°C ≤ TA ≤ +125°C

2



V/mV

Offset Voltage Drift

ΔVOS/ΔT

−40°C ≤ TA ≤ +125°C


4


μV/°C

Bias Current Drift

ΔIB/ΔT

−40°C ≤ TA ≤ +85°C


100


fA/°C



−40°C ≤ TA ≤ +125°C


2000


fA/°C

Offset Current Drift

ΔIOS/ΔT

−40°C ≤ TA ≤ +125°C


25


fA/°C

OUTPUT CHARACTERISTICS







Output Voltage High

VOH

IL = 1 mA

4.9

4.965


V



−40°C ≤ TA ≤ +125°C

4.875



V

Output Voltage Low

VOL

IL = 1 mA


25

100

mV



−40°C ≤ TA ≤ +125°C



125

mV

Output Current

IOUT

VOUT = VS − 1 V


30


mA


ISC



±60


mA

Closed-Loop Output Impedance

ZOUT

f = 200 kHz, AV = 1


45


Ω

POWER SUPPLY



VS = 2.5 V to 6 V

−40°C ≤ TA ≤ +125°C VO = 0 V

−40°C ≤ TA ≤ +125°C





dB dB μA μA

Power Supply Rejection Ratio


Supply Current/Amplifier

PSRR


ISY

65

60

76


45


65

85

DYNAMIC PERFORMANCE







Slew Rate

SR

RL = 100 kΩ, CL = 200 pF

0.45

0.92


V/μs

Full Power Bandwidth

BWP

1% distortion


70


kHz

Settling Time

tS

To 0.1% (1 V step)


6


μs

Gain Bandwidth Product

GBP



1000


kHz

Phase Margin

ΦM



67


Degrees

NOISE PERFORMANCE





Voltage Noise Density

en

f = 1 kHz

42

nV/√Hz


en

f = 10 kHz

38

nV/√Hz

Current Noise Density

in


<0.1

pA/√Hz


ABSOLUTE MAXIMUM RATINGS

Table 4.

Parameter

Rating

Supply Voltage (VS)

6 V

Input Voltage

GND to VS

Differential Input Voltage1

±6 V

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 For supplies less than 6 V, the differential input voltage is equal to ±VS.

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.


THERMAL RESISTANCE

θJA is specified for the worst-case conditions, that is, a device soldered in a circuit board for surface-mount packages and measured using a standard 4-layer board, unless otherwise specified.

Table 5.

Package Type

θJA

θJC

Unit

5-Lead SC70 (KS)

376

126

°C/W

5-Lead SOT-23 (RJ)

190

92

°C/W

8-Lead SOIC (R)

120

45

°C/W

8-Lead MSOP (RM)

142

45

°C/W

8-Lead TSSOP (RU)

240

43

°C/W

14-Lead SOIC (R)

115

36

°C/W

14-Lead TSSOP (RU)

112

35

°C/W


ESD CAUTION


TYPICAL PERFORMANCE CHARACTERISTICS

180

VS = 5V


400


VS = 2.7V AND 5V

160


NUMBER OF AMPLIFIERS

140


120


100


80


60


40


00935-005

20

VCM = 2.5V TA = 25°C

350


INPUT BIAS CURRENT (pA)

300


250


200


150


100


50

VCM = VS/2


0

–4.5 –3.5


–2.5 –1.5 –0.5 0.5


1.5 2.5 3.5


4.5


0

00935-008

–40 –20 0 20 40 60 80 100 120 140

INPUT OFFSET VOLTAGE (mV)

Figure 5. Input Offset Voltage Distribution

TEMPERATURE (°C)

Figure 8. Input Bias Current vs. Temperature



1.0


0.5


INPUT OFFSET VOLTAGE (mV)

0


–0.5


–1.0


VS = 2.7V AND 5V VCM = VS/2

7

VS = 2.7V AND 5V

INPUT OFFSET CURRENT (pA)

6 VCM = VS/2 5

4


–1.5


–2.0


–2.5


–3.0


–3.5


–4.0

–55 –35 –15


5 25 45 65 85 105 125

TEMPERATURE (°C)


145


3


2


1


0


00935-009

–1

–55 –35 –15 5 25 45 65 85 105 125 145

TEMPERATURE (°C)

00935-006

Figure 6. Input Offset Voltage vs. Temperature Figure 9. Input Offset Current vs. Temperature


9

VS = 2.7V AND 5V

8 VCM = VS/2

INPUT BIAS CURRENT (pA)

7


6


5


4


3


2


1


0


160


140


POWER SUPPLY REJECTION (dB)

120


100


80


60


40


20


0


–20


–40


VS = 2.7V TA = 25°C


00935-007

+PSRR


–PSRR

–0.5 0.5 1.5 2.5 3.5 4.5 5.5

COMMON-MODE VOLTAGE (V)

Figure 7. Input Bias Current vs. Common-Mode Voltage

100 1k 10k 100k 1M 10M FREQUENCY (Hz)

00935-010

Figure 10. Power Supply Rejection vs. Frequency


10k


1k


VS = 2.7V TA = 25°C

60

VS = 2.7V RL = 10kΩ

SMALL SIGNAL OVERSHOOT (%)

50 TA = 25°C



∆ OUTPUT VOLTAGE (mV)

100


10


1


0.1


SOURCE


SINK

40 +OS


30 –OS


20


00935-011

10


0.01

0.001 0.01 0.1 1 10 100

LOAD CURRENT (mA)

Figure 11. Output Voltage to Supply Rail vs. Load Current

0

00935-014

10 100 1k 10k CAPACITANCE (pF)

Figure 14. Small Signal Overshoot vs. Load Capacitance


3.0


2.5


VS = 2.7V

VIN = 2.5V p-p RL = 2kΩ

TA = 25°C

60

VS = 2.7V RL = 2kΩ

SMALL SIGNAL OVERSHOOT (%)

50 TA = 25°C


OUTPUT SWING (V p-p)

2.0 40


1.5


1.0


0.5


+OS

30


–OS

20


10


0

1k 10k 100k 1M 10M

FREQUENCY (Hz)

0

00935-015

10 100 1k 10k CAPACITANCE (pF)

00935-012

Figure 12. Closed-Loop Output Voltage Swing vs. Frequency Figure 15. Small Signal Overshoot vs. Load Capacitance


60

VS = 2.7V RL =

SMALL SIGNAL OVERSHOOT (%)

50 TA = 25°C


40


30


20


10


+OS


–OS


00935-013

1.35V


VS = 2.7V RL = 100kΩ CL = 300pF AV = 1

TA = 25°C


0

10 100 1k 10k CAPACITANCE (pF)


Figure 13. Small Signal Overshoot vs. Load Capacitance


50mV 10µs


00935-016

Figure 16. Small Signal Transient Response



1.35V


VS = 2.7V RL = 2kΩ AV = 1

TA = 25°C
























































































500mV





10µs



00935-017

Figure 17. Large Signal Transient Response

90


80


COMMON-MODE REJECTION (dB)

70


60


50


40


30


20


10


0


–10


VS = 5V TA = 25°C


00935-020

1k 10k 100k 1M 10M FREQUENCY (Hz)


Figure 20. Common-Mode Rejection vs. Frequency



VS = 2.7V

RL = NO LOAD TA = 25°C


80


GAIN (dB)

60


40


20


0


45


PHASE SHIFT (Degrees)

90


135


180

5

VS = 5V

INPUT OFFSET VOLTAGE (mV)

4 RL = NO LOAD TA = 25°C

3


2


1


0


–1


–2


–3


00935-018

1k 10k 100k 1M 10M FREQUENCY (Hz)


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


–4


00935-040

–5

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

COMMON-MODE VOLTAGE (V)


Figure 21. Input Offset Voltage vs. Common-Mode Voltage


160


POWER SUPPLY REJECTION RATIO (dB)

140


120


100


80


60


40


20


0


–20


–40


VS = 5V TA = 25°C


–PSRR


+PSRR

10k


∆ OUTPUT VOLTAGE (mV)

1k


100


10


1


0.1


00935-021

0.01


VS = 5V TA = 25°C


SOURCE


00935-019

SINK

100 1k 10k 100k 1M 10M FREQUENCY (Hz)

Figure 19. Power Supply Rejection Ratio vs. Frequency

0.001 0.01 0.1 1 10 100

LOAD CURRENT (mA)

Figure 22. Output Voltage to Supply Rail vs. Load Current


5.0


4.5


4.0


OUTPUT SWING (V p-p)

3.5


3.0


2.5


2.0


1.5

60

VS = 5V RL = 2kΩ

SMALL SIGNAL OVERSHOOT (%)

50 TA = 25°C


40


30


20


+OS


–OS


1.0


0.5


0





















VS = 5V

VIN = 4.9V p-p RL = NO LOAD

TA = 25°C




































































































































































































































1k 10k 100k 1M 10M FREQUENCY (Hz)


10


00935-025

0

10 100 1k 10k CAPACITANCE (pF)

00935-022

Figure 23. Closed-Loop Output Voltage Swing vs. Frequency, Figure 26. Small Signal Overshoot vs. Load Capacitance


5.0


4.5


4.0


OUTPUT SWING (V p-p)

3.5


3.0


2.5


2.0


1.5


1.0


0.5


VS = 5V

VIN = 4.9V p-p RL = 2kΩ

TA = 25°C

60

VS = 5V RL =

SMALL SIGNAL OVERSHOOT (%)

50 TA = 25°C


40


30


20


10


+OS


–OS


0

1k 10k 100k 1M 10M

FREQUENCY (Hz)


0

00935-026

10 100 1k 10k CAPACITANCE (pF)

00935-023

Figure 24. Closed-Loop Output Voltage Swingvs. Frequency Figure 27. Small Signal Overshoot vs. Load Capacitance


60

VS = 5V RL = 10kΩ

SMALL SIGNAL OVERSHOOT (%)

50 TA = 25°C


40


30


20


10


+OS


00935-024

–OS


2.5V


VS = 5V

RL = 100kΩ CL = 300pF AV = 1

TA = 25°C


0

10 100 1k 10k CAPACITANCE (pF)

Figure 25. Small Signal Overshoot vs. Load Capacitance


50mV 10µs


00935-027

Figure 28. Small Signal Transient Response



2.5V

VS = 5V RL = 2kΩ AV = 1

TA = 25°C
























































































1V





10µs



00935-028

Figure 29. Large Signal Transient Response


2.5V


VIN VOUT

VS = 5V RL = 10kΩ AV = 1

TA = 25°C


00935-030

1V 20µs


Figure 31. No Phase Reversal



VS = 5V

RL = NO LOAD TA = 25°C


80


GAIN (dB)

60


40


20


0


45


PHASE SHIFT (Degrees)

90


135


180

60

TA = 25°C

SUPPLY CURRENT/AMPLIFIER (µA)

50


40


30


20


00935-029

10



1k 10k 100k 1M 10M FREQUENCY (Hz)


Figure 30. Open-Loop Gain and Phase vs. Frequency

0

00935-031

0 1 2 3 4 5 6

SUPPLY VOLTAGE (V)


Figure 32. Supply Current per Amplifier vs. Supply Voltage


55


SUPPLY CURRENT/AMPLIFIER (µA)

50

VS = 5V

45


40

VS = 2.7V

35


30


25


20

–55 –35 –15 5 25 45 65 85 105 125 145

TEMPERATURE (°C)


Figure 33. Supply Current per Amplifier vs. Temperature


VS = 5V

15nV/DIV

MARKER SET @ 10kHz MARKER READING: 37.6nV/ Hz TA = 25°C


00935-034

0 5 10 15 20 25

FREQUENCY (kHz)


Figure 35. Voltage Noise


00935-032



























VS = 2.7V AND 5V AV = 1

TA = 25°C




























































































































































































































1000


900


800


IMPEDANCE (Ω)

700


600


500


400


300


200


100


00935-033

0

1k 10k 100k 1M 10M 100M FREQUENCY (Hz)

Figure 34. Closed-Loop Output Impedance vs. Frequency


THEORY OF OPERATION

NOTES ON THE AD854X AMPLIFIERS

The AD8541/AD8542/AD8544 amplifiers are improved performance, general-purpose operational amplifiers. Performance has been improved over previous amplifiers in several ways, including lower supply current for 1 MHz gain bandwidth, higher output current, and better performance at lower voltages.

Lower Supply Current for 1 MHz Gain Bandwidth

The AD854x series typically uses 45 μA of current per amplifier, which is much less than the 200 μA to 700 μA used in earlier generation parts with similar performance. This makes the AD854x series a good choice for upgrading portable designs

for longer battery life. Alternatively, additional functions and performance can be added at the same current drain.


Higher Output Current

At 5 V single supply, the short-circuit current is typically 60 μA. Even 1 V from the supply rail, the AD854x amplifiers can provide a 30 mA output current, sourcing, or sinking.

Sourcing and sinking are strong at lower voltages, with 15 mA available at 2.7 V and 18 mA at 3.0 V. For even higher output currents, see the AD8531/AD8532/AD8534 parts for output currents to 250 mA. Information on these parts is available from your Analog Devices, Inc. representative, and data sheets are available at www.analog.com.

Better Performance at Lower Voltages

The AD854x family of parts was designed to provide better ac performance at 3.0 V and 2.7 V than previously available parts. Typical gain bandwidth product is close to 1 MHz at 2.7 V. Voltage gain at 2.7 V and 3.0 V is typically 500,000. Phase margin is typically over 60°C, making the part easy to use.


APPLICATIONS

NOTCH FILTER

The AD854x have very high open-loop gain (especially with a supply voltage below 4 V), which makes it useful for active filters of all types. For example, Figure 36 illustrates the AD8542 in the classic twin-T notch filter design. The twin-T notch is desired for simplicity, low output impedance, and minimal use of op amps. In fact, this notch filter can be designed with only one op amp if Q adjustment is not required. Simply remove U2 as illustrated in Figure 37. However, a major drawback to this circuit topology is ensuring that all the Rs and Cs closely match.


Figure 38 is an example of the AD8544 in a notch filter circuit. The frequency dependent negative resistance (FDNR) notch filter has fewer critical matching requirements than the twin-T notch, where as the Q of the FDNR is directly proportional to a single resistor R1. Although matching component values is still important, it is also much easier and/or less expensive to accomplish in the FDNR circuit. For example, the twin-T notch uses three capacitors with two unique values, whereas the FDNR circuit uses only two capacitors, which may be of the same value. U3 is simply a buffer that is added to lower the output impedance of the circuit.

The components must closely match or notch frequency offset

R1 9

1/4 AD8544

and drift causes the circuit to no longer attenuate at the ideal notch frequency. To achieve desired performance, 1% or better component tolerances or special component screens are usually required. One method to desensitize the circuit-to-component

mismatch is to increase R2 with respect to R1, which lowers Q.

VIN

2.5V

REF

Q ADJUST 8

200Ω 10 U3

C1

1µF


R

VOUT

A lower Q increases attenuation over a wider frequency range but reduces attenuation at the peak notch frequency.


5.0V


1/4 AD8544

6

7

U2 5

2.61kΩ


C2 1µF


R 2.61kΩ


3 4

2 U1


1/4 AD8544

1


11

R 100kΩ

R 100kΩ

3 8 1/2 AD8542

R

1 2.61kΩ

VIN


2.5VREF


2C

53.6µF


R/2 50kΩ

U1 VOUT

2 1

4


VIN

f =

2π LC1

L = R2C2


R 2.61kΩ


2.5VREF

13 1/4 AD8544

U4

14

12 NC


f0 = 1

2πRC

f0 =

C 26.7nF


1

R1

C 26.7nF

1/2 AD8542 5

7

U2 6

R2 2.5kΩ


00935-035

R1 97.5kΩ

2.5VREF

00935-037

Figure 38. FDNR 60 Hz Notch Filter with Output Buffer

COMPARATOR FUNCTION

A comparator function is a common application for a spare op

4 1 – R1 + R2

2.5V


REF

amp in a quad package. Figure 39 illustrates ¼ of the AD8544 as a

Figure 36. 60 Hz Twin-T Notch Filter, Q = 10


5.0V

comparator in a standard overload detection application. Unlike many op amps, the AD854x family can double as comparators because this op amp family has a rail-to-rail differential input range, rail-to-rail output, and a great speed vs. power ratio.

R R


2C

VIN



R/2

2.5VREF

3 7

2 U1

AD8541

6

4


VOUT

R2 is used to introduce hysteresis. The AD854x, when used as comparators, have 5 μs propagation delay at 5 V and 5 μs overload recovery time.

R2 1MΩ


00935-036

C C VIN

R1

1kΩ


VOUT

Figure 37. 60 Hz Twin-T Notch Filter, Q = ∞ (Ideal)


2.5VREF


2.5VDC

1/4 AD8541


00935-038

Figure 39. AD854x Comparator Application—Overload Detector

PHOTODIODE APPLICATION

The AD854x family has very high impedance with an input bias current typically around 4 pA. This characteristic allows the AD854x op amps to be used in photodiode applications and other applications that require high input impedance. Note that the AD854x has significant voltage offset that can be removed


OR 2

3


C 100pF


R 10MΩ


V+

7


6 VOUT

by capacitive coupling or software calibration.

Figure 40 illustrates a photodiode or current measurement application. The feedback resistor is limited to 10 MΩ to avoid

D


2.5VREF


    1. VREF

      4 AD8541

      00935-039

      excessive output offset. In addition, a resistor is not needed on the noninverting input to cancel bias current offset because the bias current-related output offset is not significant when compared to the voltage offset contribution. For best performance, follow the standard high impedance layout techniques, which include the following:

      • Shielding the circuit.

      • Cleaning the circuit board.

      • Putting a trace connected to the noninverting input around the inverting input.

      • Using separate analog and digital power supplies.

Figure 40. High Input Impedance Application—Photodiode Amplifier


OUTLINE DIMENSIONS


3.00

2.90

2.80



1.70

1.60

1.50


5

4


1 2 3

3.00

2.80

2.60



1.30

1.15

0.90


1.90 BSC

0.95 BSC


1.45 MAX

0.95 MIN


0.20 MAX

0.08 MIN


0.55

0.15 MAX

0.05 MIN


0.50 MAX

0.35 MIN


SEATING PLANE

10°

5°


0.60

BSC

0.45

0.35


11-01-2010-A

COMPLIANT TO JEDEC STANDARDS MO-178-AA

Figure 41. 5-Lead Small Outline Transistor Package [SOT-23] (RJ-5)

Dimensions shown in millimeters


5.10

5.00

4.90



4.50

4.40

4.30


14 8


6.40

BSC

1 7


PIN 1


0.65 BSC

1.05

1.00 1.20

MAX

0.80

0.20

0.09 0.75

0.15

0.05 0.30

SEATING

PLANE

0.60

0.45

COPLANARITY 0.10

0.19


061908-A

COMPLIANT TO JEDEC STANDARDS MO-153-AB-1

Figure 42. 14-Lead Thin Shrink Small Outline Package [TSSOP] (RU-14)

Dimensions shown in millimeters


2.20

2.00

1.80



1.35

1.25

1.15


5


1 2 3

2.40

4

2.10

1.80



1.00

0.65 BSC


1.10


0.40

0.90

0.70

0.80


SEATING

0.10


0.22


0.46

0.10 MAX

COPLANARITY 0.10

0.30

0.15

PLANE

0.08

0.36

0.26


072809-A

COMPLIANT TO JEDEC STANDARDS MO-203-AA

Figure 43. 5-Lead Thin Shrink Small Outline Transistor Package [SC70] (KS-5)

Dimensions shown in millimeters


8.75 (0.3445)

8.55 (0.3366)



4.00 (0.1575)

3.80 (0.1496)

6.20 (0.2441)

7

8

14

1

5.80 (0.2283)



0.25 (0.0098)

0.10 (0.0039) COPLANARITY

1.27 (0.0500) BSC


0.10 PLANE 0.25 (0.0098)


0.31 (0.0122)


0.17 (0.0067)

0.51 (0.0201)


1.75 (0.0689)

1.35 (0.0531) SEATING


0.50 (0.0197)

0.25 (0.0098)


1.27 (0.0500)

0.40 (0.0157)


45°


060606-A

COMPLIANT TO JEDEC STANDARDS MS-012-AB 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.

Figure 44. 14-Lead Standard Small Outline Package [SOIC_N]

Narrow Body (R-14)

Dimensions shown in millimeters and (inches)


3.20

3.00

2.80

3.10

3.00

2.90



3.20

3.00

2.80


8 5 5.15

4.90

4.65

1 4


8 5


4.50

4.40

4.30


6.40 BSC

PIN 1 1 4

IDENTIFIER

0.95

0.65 BSC

15° MAX

PIN 1

0.65 BSC

0.15

0.85

1.10 MAX

0.05

1.20

0.75

MAX

0.15

0.05

10-07-2009-B

COPLANARITY


0.40

0.25

0.23

0.09

0.80

0.55

0.40


COPLANARITY 0.10

0.30

0.19

SEATING PLANE

0.20 0.09

0.75

0.60

0.45

0.10 COMPLIANT TO JEDEC STANDARDS MO-153-AA


COMPLIANT TO JEDEC STANDARDS MO-187-AA

Figure 45. 8-Lead Mini Small Outline Package [MSOP] (RM-8)

Dimensions shown in millimeters


Figure 46. 8-Lead Thin Shrink Small Outline Package [TSSOP] (RU-8)

Dimensions shown in millimeters


5.00 (0.1968)

4.80 (0.1890)



4.00 (0.1574)

3.80 (0.1497)

8

5

6.20 (0.2441)

4

1

5.80 (0.2284)


1.27 (0.0500) 0.50 (0.0196)


45°


0.25 (0.0098)

0.10 (0.0040)

BSC

1.75 (0.0688)

1.35 (0.0532)

0.25 (0.0099)

COPLANARITY

0.51 (0.0201)


1.27 (0.0500)

0.10

SEATING PLANE

0.31 (0.0122)

0.25 (0.0098)

0.17 (0.0067)

0.40 (0.0157)


COMPLIANT TO JEDEC STANDARDS MS-012-AA

012407-A

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.

Figure 47. 8-Lead Standard Small Outline Package [SOIC_N]

Narrow Body (R-8)

Dimensions shown in millimeters and (inches)

ORDERING GUIDE

Model1 , 2

Temperature Range

Package Description

Package Option

Branding

AD8541AKSZ-R2

–40°C to +125°C

5-Lead SC70

KS-5

A12

AD8541AKSZ-REEL7

–40°C to +125°C

5-Lead SC70

KS-5

A12

AD8541ARTZ-R2

–40°C to +125°C

5-Lead SOT-23

RJ-5

A4A

AD8541ARTZ-REEL

–40°C to +125°C

5-Lead SOT-23

RJ-5

A4A

AD8541ARTZ-REEL7

–40°C to +125°C

5-Lead SOT-23

RJ-5

A4A

AD8541ARZ

–40°C to +125°C

8-Lead SOIC_N

R-8


AD8541ARZ-REEL

–40°C to +125°C

8-Lead SOIC_N

R-8


AD8541ARZ-REEL7

–40°C to +125°C

8-Lead SOIC_N

R-8


AD8542ARZ

–40°C to +125°C

8-Lead SOIC_N

R-8


AD8542ARZ-REEL

–40°C to +125°C

8-Lead SOIC_N

R-8


AD8542ARZ-REEL7

–40°C to +125°C

8-Lead SOIC_N

R-8


AD8542ARM-REEL

–40°C to +125°C

8-Lead MSOP

RM-8

AVA

AD8542ARMZ

–40°C to +125°C

8-Lead MSOP

RM-8

AVA

AD8542ARMZ-REEL

–40°C to +125°C

8-Lead MSOP

RM-8

AVA

AD8542ARU-REEL

–40°C to +125°C

8-Lead TSSOP

RU-8


AD8542ARUZ

–40°C to +125°C

8-Lead TSSOP

RU-8


AD8542ARUZ-REEL

–40°C to +125°C

8-Lead TSSOP

RU-8


AD8544ARZ

–40°C to +125°C

14-Lead SOIC_N

R-14


AD8544ARZ-REEL

–40°C to +125°C

14-Lead SOIC_N

R-14

AD8544ARZ-REEL7

–40°C to +125°C

14-Lead SOIC_N

R-14

AD8544ARUZ

–40°C to +125°C

14-Lead TSSOP

RU-14

AD8544ARUZ-REEL

–40°C to +125°C

14-Lead TSSOP

RU-14

AD8544WARZ-RL

–40°C to +125°C

14-Lead SOIC_N

R-14

AD8544WARZ-R7

–40°C to +125°C

14-Lead SOIC_N

R-14

1 Z = RoHS Compliant Part.

2 W = Qualified for Automotive Applications.


AUTOMOTIVE PRODUCTS

The AD8544W models are available with controlled manufacturing to support the quality and reliability requirements of automotive applications. Note that these automotive models may have specifications that differ from the commercial models; therefore, designers should review the Specifications section of this data sheet carefully. Only the automotive grade products shown are available for use in automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to obtain the specific Automotive Reliability reports for these models.


NOTES


©2008–2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners.

D00935-0-6/11(G)

Mouser Electronics


Authorized Distributor


Click to View Pricing, Inventory, Delivery & Lifecycle Information:


Analog Devices Inc.:

AD8541AKSZ-R2 AD8541AKSZ-REEL7 AD8541ARTZ-R2 AD8541ARTZ-REEL7 AD8541ARZ AD8542ARMZ AD8542ARMZ-REEL AD8542ARUZ AD8542ARZ AD8542ARZ-REEL7 AD8544ARUZ AD8544ARZ AD8541ARTZ- REEL AD8541ARZ-REEL AD8541ARZ-REEL7 AD8542ARUZ-REEL AD8542ARZ-REEL AD8544ARUZ-REEL AD8544ARZ-REEL AD8544ARZ-REEL7 AD8544WARZ-R7 AD8544WARZ-RL