ADR441_技术文档

Ultralow Noise, LDO XFET^®Voltage

References with Current Sink and Source

ADR440/ADR441/ADR443/ADR444/ADR445

FEATURES

PIN CONFIGURATIONS

Ultralow noise (0.1 Hz to 10 Hz)

ADR440: 1 μV p-p

ADR441: 1.2 μV p-p

TP

1

2

3

4

8

7

6

5

TP

ADR44x

V

NC

IN

TOP VIEW

NC

V

OUT

(Not to Scale)

GND

TRIM

ADR443: 1.4 μV p-p

ADR444: 1.8 μV p-p

NC = NO CONNECT

ADR445: 2.25 μV p-p

Figure 1. 8-Lead SOIC (R)

Superb temperature coefficient:

3 ppm/°C (B Grade)

10 ppm/°C (A Grade)

Low dropout operation: 500 mV

Input range: (V_OUT+ 500 mV) to 18 V

High output current: +10 mA/−5 mA

Wide temperature range: −40°C to +125°C

TP

1

2

3

4

8

7

6

5

TP

NC

V

ADR44x

V

IN

NC

TOP VIEW

(Not to Scale)

OUT

GND

TRIM

NC = NO CONNECT

Figure 2. 8-Lead MSOP (RM)

APPLICATIONS

Precision data acquisition systems

High resolution data converters

Battery-powered instrumentations

Portable medical instruments

Industrial process control systems

Precision instruments

Optical control circuits

GENERAL DESCRIPTION

Offered in two electrical grades, the ADR44x family is avail-

able in the 8-lead SOIC and MSOP packages. All versions

are specified over the extended industrial temperature range

(−40^oC to +125^oC).

The ADR44x series is a family of XFET® voltage references

featuring ultralow noise, high accuracy, and low temperature

drift performance. Using ADI’s patented temperature drift

curvature correction and XFET (eXtra implanted junction FET)

technology, the ADR44x family’s voltage change vs. temperature

nonlinearity is greatly minimized.

Table 1. Selection Guide

Temperature

V_OUT(V) Accuracy (mV) Coefficient (ppm/°C)

Model

ADR440B 2.048

ADR440A 2.048

ADR44±B 2.500

ADR44±A 2.500

ADR443B 3.000

ADR443A 3.000

ADR444B 4.096

ADR444A 4.096

ADR445B 5.000

ADR445A 5.000

±±

±3

±±

±3

±±.2

±4

±±.6

±5

±2

±6

3

±0

3

±0

3

±0

3

±0

3

±0

The XFET references offer better noise performance than

buried-Zener references, and XFET references operate off

low supply headroom (0.5 V). This combination of features

makes the ADR44x family ideally suited for precision signal

conversion applications in high-end data acquisition systems,

optical networks, and medical requirements.

The ADR44x family has the capability to source up to 10 mA

and sink up to 5 mA of output current. It also comes with a

TRIM terminal to adjust the output voltage over a 0.5% range

without compromising any performance.

Rev. 0

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 registeredtrademarks arethe property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

Fax: 781.461.3113

www.analog.com

ADR440/ADR441/ADR443/ADR444/ADR445

TABLE OF CONTENTS

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

Theory of Operation ...................................................................... 14

Power Dissipation Considerations........................................... 14

Basic Voltage Reference Connections ..................................... 14

Noise Performance..................................................................... 14

Turn-On Time ............................................................................ 14

Applications..................................................................................... 15

Output Adjustment .................................................................... 15

Bipolar Outputs .......................................................................... 15

Negative Reference..................................................................... 15

Programmable Voltage Source ................................................. 16

Programmable Current Source ................................................ 16

High Voltage Floating Current Source.................................... 16

Precision Output Regulator (Boosted Reference).................. 17

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

Ordering Guide .......................................................................... 19

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

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

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

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

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

ADR440—Electrical Characteristics.......................................... 3

ADR441—Electrical Characteristics.......................................... 4

ADR443—Electrical Characteristics.......................................... 5

ADR444—Electrical Characteristics.......................................... 6

ADR445—Electrical Characteristics.......................................... 7

Absolute Maximum Ratings............................................................ 8

Package Type................................................................................. 8

ESD Caution.................................................................................. 8

Typical Performance Characteristics ............................................. 9

REVISION HISTORY

10/05—Revision 0: Initial Version

Rev. 0 | Page 2 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

SPECIFICATIONS

ADR440—ELECTRICAL CHARACTERISTICS

V_IN= 3 V to 18 V; T_A= 25°C; C_IN, C_BYPASS= 0.1 μF, unless otherwise noted.

Table 2.

Parameter

OUTPUT VOLTAGE

A Grade

Symbol

Conditions

Min

Typ

Max

Unit

V_O

2.045

2.047

2.048

2.05±

2.049

V

B Grade

INITIAL ACCURACY

A Grade

V_OERR

3

0.±5

±

mV

%

mV

%

B Grade

0.05

TEMPERATURE DRIFT

A Grade SOIC-8

MSOP-8

B Grade SOIC-8

LINE REGULATION

LOAD REGULATION

TC V_O

−40°C < T_A< +±25°C

2

±

±0

3

ppm/°C

ppm/V

ΔV_O/ΔV_IN

V_IN= 3 V to ±8 V, −40°C < T_A< +±25°C

I_LOAD= 0 mA to ±0 mA, V_IN= 3.5 V

−40°C < T_A< +±25°C

I_LOAD= 0 mA to −5 mA, V_IN= 3.5 V

−40°C < T_A< +±25°C

−20

−50

+±0

+20

ΔV_O/ΔI_LOAD

+50

ppm/mA

ΔV_O/ΔI_LOAD

I_IN

+50

3.75

ppm/mA

mA

QUIESCENT CURRENT

No Load, −40°C < T_A< +±25°C

0.± Hz to ±0 Hz

3

VOLTAGE NOISE

e_Np-p

e_N

±

μV p-p

nV/√Hz

μs

VOLTAGE NOISE DENSITY

TURN-ON SETTLING TIME

LONG-TERM STABILITY^±

± kHz

60

±0

50

70

−75

27

t_R

V_O

±,000 Hours

f_IN= ±0 kHz

ppm

dB

OUTPUT VOLTAGE HYSTERISIS

RIPPLE REJECTION RATION

SHORT CIRCUIT TO GND

SUPPLY VOLTAGE OPERATING RANGE

SUPPLY VOLTAGE HEADROOM

V_{O_HYS}

RRR

I_SC

mA

V_IN

3

±8

V

V_IN− V_O

500

mV

^±The long-term stability specification is noncumulative. This drift in the subsequent ±,000-hour period is significantly lower than in the first ±,000-hour period.

Rev. 0 | Page 3 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

ADR441—ELECTRICAL CHARACTERISTICS

V_IN= 3 V to 18 V, T_A= 25°C, unless otherwise noted.

Table 3.

Parameter

OUTPUT VOLTAGE

A Grade

Symbol

Conditions

Min

Typ

Max

Unit

V_O

2.497

2.499

2.5

2.503

2.50±

V

B Grade

INITIAL ACCURACY

A Grade

V_OERR

3

0.±2

±

mV

%

mV

%

B Grade

0.04

TEMPERATURE DRIFT

A Grade SOIC-8

MSOP-8

B Grade SOIC-8

LINE REGULATION

TC V_O

−40°C < T_A< +±25°C

2

±

±0

3

ppm/°C

ppm/V

ΔV_O/ΔV_IN

V_IN= 3 V to ±8 V,

±0

20

−40°C < T_A< +±25°C

LOAD REGULATION

ΔV_O/ΔI_LOAD

I_LOAD= 0 mA to ±0 mA, V_IN= 4 V

−40°C < T_A< +±25°C

I_LOAD= 0 mA to −5 mA, V_IN= 4 V

−40°C < T_A< +±25°C

No Load, −40°C < T_A< +±25°C

0.± Hz to ±0 Hz

−50

+50

ppm/mA

+50

3.75

ppm/mA

mA

QUIESCENT CURRENT

I_IN

3

VOLTAGE NOISE

e_Np-p

e_N

±.2

48

±0

50

70

−75

27

μV p-p

nV/√Hz

μs

VOLTAGE NOISE DENSITY

TURN-ON SETTLING TIME

LONG-TERM STABILITY^±

OUTPUT VOLTAGE HYSTERISIS

RIPPLE REJECTION RATION

SHORT CIRCUIT TO GND

SUPPLY VOLTAGE OPERATING RANGE

SUPPLY VOLTAGE HEADROOM

± kHz

t_R

V_O

±,000 Hours

f_IN= ±0 kHz

ppm

dB

V_{O_HYS}

RRR

I_SC

mA

V_IN

3

±8

V

V_IN− V_O

500

mV

^±The long-term stability specification is noncumulative. This drift in subsequent ±,000-hour period is significantly lower than in the first ±,000-hour period.

Rev. 0 | Page 4 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

ADR443—ELECTRICAL CHARACTERISTICS

V_IN= 3.5 V to 18 V, T_A= 25°C, unless otherwise noted.

Table 4.

Parameter

OUTPUT VOLTAGE

A Grade

Symbol

Conditions

Min

Typ Max

Unit

V_O

2.996

2.9988

3.0

3.004

3.00±2

V

B Grade

INITIAL ACCURACY

A Grade

V_OERR

4

mV

%

mV

%

0.±3

±.2

0.04

B Grade

TEMPERATURE DRIFT

A Grade SOIC-8

MSOP-8

B Grade SOIC-8

LINE REGULATION

LOAD REGULATION

TC V_O

−40°C < T_A< +±25°C

2

±

±0

3

ppm/°C

ppm/V

ΔV_O/ΔV_IN

ΔV_O/ΔI_LOAD

V_IN= 3.5 V to ±8 V, −40°C < T_A< +±25°C

I_LOAD= 0 mA to ±0 mA, V_IN= 5 V

−40°C < T_A< +±25°C

I_LOAD= 0 mA to −5 mA, V_IN= 5 V

−40°C < T_A< +±25°C

±0

20

−50

+50

ppm/mA

ΔV_O/ΔI_LOAD

+50

3.75

ppm/mA

mA

QUIESCENT CURRENT

VOLTAGE NOISE

I_IN

No Load, −40°C < T_A< +±25°C

0.± Hz to ±0 Hz

3

e_Np-p

±.4

μV p-p

VOLTAGE NOISE DENSITY

e_N

± kHz

64

±0

50

70

−75

27

nV/√Hz

μs

TURN-ON SETTLING TIME

LONG-TERM STABILITY^±

t_R

V_O

±,000 Hours

f_IN= ±0 kHz

ppm

dB

OUTPUT VOLTAGE HYSTERISIS

RIPPLE REJECTION RATION

SHORT CIRCUIT TO GND

V_{O_HYS}

RRR

I_SC

mA

V

SUPPLY VOLTAGE OPERATING RANGE

SUPPLY VOLTAGE HEADROOM

V_IN

3.5

±8

V_IN− V_O

500

mV

^±The long-term stability specification is noncumulative. This drift in the subsequent ±,000-hour period is significantly lower than in the first ±,000-hour period.

Rev. 0 | Page 5 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

ADR444—ELECTRICAL CHARACTERISTICS

V_IN= 4.6 V to 18 V, T_A= 25°C, unless otherwise noted.

Table 5.

Parameter

OUTPUT VOLTAGE

A Grade

Symbol

Conditions

Min

Typ

Max

Unit

V_O

4.09±

4.096 4.±0±

V

B Grade

4.0944 4.096 4.0976

INITIAL ACCURACY

A Grade

V_OERR

5

mV

%

mV

%

0.±3

±.6

0.04

B Grade

TEMPERATURE DRIFT

A Grade SOIC-8

MSOP-8

B Grade SOIC-8

LINE REGULATION

LOAD REGULATION

TC V_O

−40°C < T_A< +±25°C

−40°C < T_A< +±25^vC

2

±

±0

3

ppm/°C

ppm/V

ΔV_O/ΔV_IN

ΔV_O/ΔI_LOAD

V_IN= 4.6 V to ±8 V, −40°C < T_A< +±25°C

I_LOAD= 0 mA to ±0 mA, V_IN= 5.5 V

−40°C < T_A< +±25°C

I_LOAD= 0 mA to −5 mA, V_IN= 5.5 V

−40°C < T_A< +±25°C

±0

20

−50

+50

ppm/mA

ΔV_O/ΔI_LOAD

+50

3.75

ppm/mA

mA

QUIESCENT CURRENT

I_IN

No Load, −40°C < T_A< +±25°C

0.± Hz to ±0 Hz

3

VOLTAGE NOISE

e_Np-p

e_N

±.8

64

±0

50

70

−75

27

μV p-p

nV/√Hz

μs

VOLTAGE NOISE DENSITY

TURN-ON SETTLING TIME

LONG-TERM STABILITY^±

± kHz

t_R

V_O

±,000 Hours

f_IN= ±0 kHz

ppm

dB

OUTPUT VOLTAGE HYSTERISIS

RIPPLE REJECTION RATION

SHORT CIRCUIT TO GND

SUPPLY VOLTAGE OPERATING RANGE

SUPPLY VOLTAGE HEADROOM

V_{O_HYS}

RRR

I_SC

mA

V_IN

4.6

±8

V

V_IN− V_O

500

mV

^±The long-term stability specification is noncumulative. This drift in the subsequent ±,000-hour period is significantly lower than in the first ±,000-hour period.

Rev. 0 | Page 6 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

ADR445—ELECTRICAL CHARACTERISTICS

V_IN= 5.5 V to 18 V, T_A= 25°C unless otherwise noted.

Table 6.

Parameter

OUTPUT VOLTAGE

A Grade

Symbol

Conditions

Min

Typ

Max

Unit

V_O

4.994

4.998

5.000

5.006

5.002

V

B Grade

INITIAL ACCURACY

A Grade

V_OERR

6

0.±2

2

mV

%

mV

%

B Grade

0.04

TEMPERATURE DRIFT

A Grade SOIC-8

MSOP-8

B Grade SOIC-8

LINE REGULATION

LOAD REGULATION

TC V_O

−40°C < T_A< +±25°C

2

±

±0

3

ppm/°C

ppm/V

ΔV_O/ΔV_IN

ΔV_O/ΔI_LOAD

V_IN= 5.5 V to ±8 V, −40°C < T_A< +±25°C

I_LOAD= 0 mA to ±0 mA, V_IN= 6.5 V

−40°C < T_A< +±25°C

I_LOAD= 0 mA to −5 mA, V_IN= 6.5 V

−40°C < T_A< +±25°C

±0

20

−50

+50

ppm/mA

ΔV_O/ΔI_LOAD

+50

3.75

ppm/mA

mA

QUIESCENT CURRENT

I_IN

No Load, −40°C < T_A< +±25°C

0.± Hz to ±0 Hz

3

VOLTAGE NOISE

e_Np-p

e_N

2.25

64

±0

50

70

–75

27

μV p-p

nV/√Hz

μs

VOLTAGE NOISE DENSITY

TURN-ON SETTLING TIME

LONG-TERM STABILITY^±

± kHz

t_R

V_O

±,000 Hours

f_IN= ±0 kHz

ppm

dB

OUTPUT VOLTAGE HYSTERISIS

RIPPLE REJECTION RATION

SHORT CIRCUIT TO GND

SUPPLY VOLTAGE OPERATING RANGE

SUPPLY VOLTAGE HEADROOM

V_{O_HYS}

RRR

I_SC

mA

V_IN

5.5

±8

V

V_IN− V_O

500

mV

^±The long-term stability specification is noncumulative. This drift in the subsequent ±,000-hour period is significantly lower than in the first ±,000-hour period.

Rev. 0 | Page 7 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

ABSOLUTE MAXIMUM RATINGS

At 25°C, unless otherwise noted.

Table 7.

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.

Parameter

Rating

Supply Voltage

20 V

Output Short-Circuit Duration to GND

Storage Temperature Range

R, RM Packages

Operating Temperature Range

Junction Temperature Range

Lead Temperature Range (Soldering, 60 sec)

Indefinite

−65°C to +±25°C

−40°C to +±25°C

−65°C to +±50°C

300°C

PACKAGE TYPE

Table 8.

Package Type

1

θ_JA

θ_JC

Unit

°C/W

8-Lead SOIC (R)

8-Lead MSOP (RM)

±30

±90

43

^±θ_JAis specified for worst-case conditions (device soldered in circuit board for

surface mount packages). Contact sales for the latest information of release

dates.

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.

Rev. 0 | Page 8 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

TYPICAL PERFORMANCE CHARACTERISTICS

V_IN= 7V, T_A= 25^oC; C_IN, C_BYPASS= 0.1 μF; unless otherwise noted.

2.5020

2.5015

2.5010

2.5005

2.5000

4.0

3.5

+125°C

+25°C

3.0

–40°C

2.5

2.4995

2.4990

2.0

–40 –25 –10

5

20

35

50

65

80

95 110 125

4

6

8

10

12

14

16

18

TEMPERATURE (°C)

INPUT VOLTAGE (V)

Figure 6. ADR441 Supply Current vs. Input Voltage

Figure 3. ADR441 V_OUTvs. Temperature

3.0020

4.0

3.5

3.0

3.0015

3.0010

3.0005

3.0000

2.9995

2.9990

2.5

2.0

2.9985

2.9980

–40 –25 –10

5

20

35

50

65

80

95 110 125

–40 –25 –10

5

20

35

50

65

80

95 110 125

TEMPERATURE (°C)

Figure 4. ADR444 V_OUTvs. Temperature

Figure 7. ADR441 Supply Current vs. Temperature

4.0980

3.5

3.4

3.3

3.2

4.0975

4.0970

4.0965

4.0960

4.0955

4.0950

3.1

3.0

+125°C

2.9

2.8

+25°C

–40°C

2.7

4.0945

4.0940

2.6

2.5

–40 –25 –10

5

20

35

50

65

80

95 110 125

5.3

7.3

9.3

11.3

13.3

15.3

17.3

19.3

TEMPERATURE (°C)

INPUT VOLTAGE (V)

Figure 5. ADR445 V_OUTvs. Temperature

Figure 8. ADR445 Supply Current vs. Input Voltage

Rev. 0 | Page 9 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

3.25

7

6

5

4

3.15

3.05

3

2

2.95

2.85

2.75

1

0

–40 –25 –10

5

20

35

50

65

80

95 110 125

–40 –25 –10

5

20

35

50

65

80

95 110 125

TEMPERATURE (°C)

Figure 9. ADR445 Quiescent Current vs. Temperature

Figure 12. ADR445 Line Regulation vs. Temperature

10

8

50

40

30

20

10

0mA TO +10mA LOAD

0mA TO –5mA LOAD

6

0

4

–10

–20

–30

–40

–50

2

0

–40 –25 –10

5

20

35

50

65

80

95 110 125

–40 –25 –10

5

20

35

50

65

80

95 110 125

TEMPERATURE (°C)

Figure 10. ADR441 Line Regulation vs. Temperature

Figure 13. ADR445 Load Regulation vs. Temperature

60

0.7

0.6

0.5

0.4

55

50

45

V

= 18V

IN

+125°C

IL = 0mA TO 10 mA

V

= 6V

IN

+25°C

0.3

0.2

–40°C

40

35

30

0.1

0

–40 –25 –10

5

20

35

50

65

80

95 110 125

–10

–5

0

5

10

TEMPERATURE (°C)

LOAD CURRENT (mA)

Figure 14. ADR441 Minimum Input/Output

Differential Voltage vs. Load Current

Figure 11. ADR441 Load Regulation vs. Temperature

Rev. 0 | Page ±0 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

0.5

C

, C

= 0.1μF

OUT

IN

NO LOAD

0.4

0.3

0.2

V

= 5V/DIV

IN

0.1

0

V

= 1V/DIV

OUT

TIME = 10μs/DIV

–40 –25 –10

5

20

35

50

65

80

95 110 125

TEMPERATURE (°C)

Figure 15. ADR441 Minimum Headroom vs. Temperature

Figure 18. ADR441 Turn-On Response

1.0

0.9

0.8

0.7

0.6

0.5

C

, C

= 0.1μF

OUT

IN

+125°C

V

= 5V/DIV

IN

+25°C

0.4

0.3

0.2

–40°C

0.1

0

V

= 1V/DIV

OUT

–5

0

5

10

TIME = 200μs/DIV

LOAD CURRENT (mA)

Figure 19. ADR441 Turn-Off Response

Figure 16. ADR445 Minimum Input/Output

Differential Voltage vs. Load Current

C

= 0.1μF

IN

0.5

= 10μF

OUT

NO LOAD

0.4

0.3

0.2

V

= 5V/DIV

IN

V

= 1V/DIV

0.1

0

OUT

TIME = 200μs/DIV

–40 –25 –10

5

20

35

50

65

80

95 110 125

TEMPERATURE (°C)

Figure 17. ADR445 Minimum Headroom vs. Temperature

Figure 20. ADR441 Turn-On Response

Rev. 0 | Page ±± of 20

ADR440/ADR441/ADR443/ADR444/ADR445

C

= 0.1μF

OUT

IN

= 10μF

2V/DIV

4V

1μV/DIV

CH1 p-p

1.18μV

2mV/DIV

100μs/DIV

TIME = 1s/DIV

Figure 21. ADR441 Line Transient Response

Figure 24. ADR441 0.1 Hz to 10.0 Hz Voltage Noise

C

, C

= 0.1μF

OUT

IN

LOAD OFF

LOAD ON

50μV/DIV

CH1 p-p

1

49μV

5mV/DIV

200μs/DIV

TIME = 1s/DIV

Figure 22. ADR441 Load Transient Response

Figure 25. ADR441 10 Hz to 10 kHz Voltage Noise

C

= 0.1μF

IN

= 10μF

OUT

LOAD ON

LOAD OFF

1μV/DIV

CH1 p-p

2.24μV

5mV/DIV

200μs/DIV

TIME = 1s/DIV

Figure 26. ADR445 0.1 Hz to 10.0 Hz Voltage Noise

Figure 23. ADR441 Load Transient Response

Rev. 0 | Page ±2 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

10

9

8

7

ADR445

6

5

50μV/DIV

ADR443

CH1 p-p

4

66μV

3

2

ADR441

1

0

10

100

1k

10k

100k

TIME = 1s/DIV

FREQUENCY (Hz)

Figure 29. Output Impedance vs. Frequency

Figure 27. ADR445 10 Hz to 10 kHz Voltage Noise

16

14

12

10

8

0

–10

–20

–30

–40

–50

–60

–70

–80

–90

–100

6

4

2

0

100

1k

10k

100k

1M

FREQUENCY (Hz)

DEVIATION (PPM)

Figure 30. Ripple Rejection vs. Frequency

Figure 28. ADR441 Typical Hysteresis

Rev. 0 | Page ±3 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

THEORY OF OPERATION

The ADR44x series of references uses a new reference generation

technique known as XFET (eXtra implanted junction FET).

This technique yields a reference with low dropout, good

thermal hysteresis, and exceptionally low noise. The core of the

XFET reference consists of two junction field-effect transistors

(JFETs), one of which has an extra channel implant to raise its

pinch-off voltage. By running the two JFETs at the same drain

current, the difference in pinch-off voltage can be amplified

and used to form a highly stable voltage reference.

POWER DISSIPATION CONSIDERATIONS

The ADR44x family of references is guaranteed to deliver load

currents to 10 mA with an input voltage that ranges from 2.6 V

to 18 V. When these devices are used in applications at higher

currents, users should use the following equation to account for

the temperature effects due to the power dissipation increases.

T_J=P_D× θ_JA+ T_A

(2)

where:

T_Jand T_Aare the junction and ambient temperatures.

P_Dis the device power dissipation.

θ_JAis the device package thermal resistance.

The intrinsic reference voltage is around 0.5 V with a negative

temperature coefficient of about –120 ppm/°C. This slope is

essentially constant to the dielectric constant of silicon and can

be closely compensated for by adding a correction term generated

in the same fashion as the proportional-to-temperature (PTAT)

term used to compensate band gap references. The advantage

of an XFET reference is the correction term is approximately

20 times lower and requires less correction than a band gap

reference. This results in much lower noise, because most of

the noise of a band gap reference results from the temperature

compensation circuitry.

BASIC VOLTAGE REFERENCE CONNECTIONS

The ADR44x family requires a 0.1 μF capacitor on the input

and output for stability. While not required for operation,

a 10 μF capacitor at the input can help with line voltage

transient performance.

1

TP

8

7

6

V

IN

NIC

2

3

4

ADR44x

TOP VIEW

(Not to Scale)

+

OUTPUT

Figure 31 shows the basic topology of the ADR44x series. The

temperature correction term is provided by a current source

with a value designed to be proportional to absolute temperature.

The general equation is

10μF

NIC

0.1μF

5

TRIM

NOTES

1. NIC = NO INTERNAL CONNECTION

2. TP = TEST PIN (DO NOT CONNECT)

V_OUT= G ×

(

ΔV_P− R1 × I_PTAT

)

(1)

Figure 32. Basic Voltage Reference Configuration

where:

NOISE PERFORMANCE

G is the gain of the reciprocal of the divider ratio.

The noise generated by the ADR44x family of references is

typically less than 1.4 μV p-p over the 0.1 Hz to 10.0 Hz band

ꢀV_Pis the difference in pinch-off voltage between the two JFETs.

I_PTATis the positive temperature coefficient correction current.

for ADR440, ADR441, and ADR443. Figure 24 shows the 0.1 Hz

to 10 Hz noise of the ADR441, which is only 1.2 μV p-p. The

noise measurement is made with a band-pass filter made of a 2-

pole high-pass filter with a corner frequency at 0.1 Hz and a 2-

pole low-pass filter with a corner frequency at 10.0 Hz.

ADR44x devices are created by on-chip adjustment of R2 and

R3 to achieve the different voltage option at the reference

output.

V

IN

I

1

ADR44x

I

TURN-ON TIME

PTAT

Upon application of power (cold start), the time required for

the output voltage to reach its final value within a specified

error band is defined as the turn-on settling time. Two compo-

nents normally associated with this are the time for the active

circuits to settle, and the time for the thermal gradients on the

chip to stabilize. Figure 18 and Figure 19 show the turn-on and

turn-off settling times for the ADR441.

V

OUT

R2

1

ΔV

P

R3

R1

1

EXTRA CHANNEL IMPLANT

= G(ΔV R1 × I

V

–

)

PTAT

OUT

P

GND

Figure 31. Simplified Schematic Device

Rev. 0 | Page ±4 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

+V

DD

APPLICATIONS

OUTPUT ADJUSTMENT

2

V

IN

The ADR44x family features a TRIM pin that allows the user to

adjust the output voltage of the part over a limited range. This

allows both errors from the reference and overall system errors

to be trimmed out by connecting a potentiometer between the

output and ground, with the wiper connected to the TRIM pin.

Figure 33 shows the optimal trim configuration. R1 allows fine

adjustment of the output and is not always required. R_Pshould

be sufficiently large so that the maximum output current from

the ADR44x is not exceeded.

ADR445

0.1μF

V

OUT

6

+5V

–5V

R1

10kΩ

R2

0.1μF

GND

10kΩ

4

+10V

R3

5kΩ

–10V

Figure 34. ADR 44x Bipolar Outputs

0.1μF

NEGATIVE REFERENCE

2

V

IN

V

Figure 35 shows how to connect the ADR44x and a standard

op amp, such as the OP1177, to provide negative voltage.

This configuration provides two main advantages: First, it

only requires two devices; therefore, it does not require

excessive board space. Second, and more importantly, it does

not require any external resistors. This means the performance

of this circuit does not rely on choosing low TC resistors to

ensure accuracy.

V

= ±0.5%

O

6

5

OUT

0.1μF

ADR44x

R

TRIM

GND

4

P

R1

R2

Figure 33. ADR44x Trim Function

+V

DD

Using the trim function had a negligible effect on the

temperature performance of the ADR44x family. However, all

resistors used need to be low temperature coefficient resistors,

or errors can occur.

2

V

IN

6

V

OUT

BIPOLAR OUTPUTS

ADR44x

By connecting the output of the ADR44x to the inverting

terminal of an op amp, it is possible to obtain both positive

and negative reference voltages. Care must be taken when

choosing Resistor R1 and Resistor R2 (see Figure 34). They

must be matched as closely as possible to ensure minimal

differences between the negative and positive outputs. In

addition, care must be taken to ensure performance over

temperature. Use low temperature coefficient resistors if the

circuit is to be used over temperature; otherwise, differences will

exist between the two outputs.

GND

4

–V

REF

–V

DD

Figure 35. Negative Reference

V_OUTis at virtual ground, and the negative reference is taken

directly from the output of the op amp. If the negative supply

voltage is close to the reference output, the op amp must be

dual supply and have low offset and rail-to-rail capability.

Rev. 0 | Page ±5 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

PROGRAMMABLE VOLTAGE SOURCE

PROGRAMMABLE CURRENT SOURCE

To obtain different voltages than those offered by the ADR44x,

some extra components are needed. In Figure 36,

It is possible to build a programmable current source using a

similar setup as the programmable voltage source, as shown in

Figure 37. The constant voltage on the gate of the transistor sets

the current through the load. Varying the voltage on the gate

changes the current. This circuit does not require a dual digital

potentiometer.

two potentiometers are used to set the desired voltage, while the

buffering amplifier provides current drive. The potentiometer

connected between V_OUTand ground, with its wiper connected

to the noninverting input of the op amp, takes care of coarse

trim. The second potentiometer, with its wiper connected to

the trim terminal of the ADR44x, is used for fine adjustment.

Resolution depends on the end-to-end resistance value and the

resolution of the selected potentiometer.

V

CC

2

0.1μF

V

IN

R

SENSE

V

OUT

6

+V

DD

GND

4

0.1μF

2

AD5259

V

IN

ADJ V

REF

ADR445

LOAD

V

OUT

6

R1

R2

GND

Figure 37. Programmable Current Source

10kΩ 10kΩ

4

HIGH VOLTAGE FLOATING CURRENT SOURCE

Figure 36. Programmable Voltage Source

Use the circuit in Figure 38 to generate a floating current source

with minimal self-heating. This particular configuration can

operate on high supply voltages determined by the breakdown

voltage of the N-channel JFET.

For a completely programmable solution, replace the two

potentiometers in Figure 36 with one of ADI’s dual digital

potentiometers, which offer either SPI® or I²C interfaces. These

interfaces set the position of the wiper on both potentiometers

and allow the output voltage to be set. Table 9 lists compatible

ADI digital potentiometers.

+V

S

SST111

VISHAY

Table 9. Digital Potentiometer Parts

2

Part No.

AD525±

AD5207

AD5242

AD5262

AD5282

AD5252

AD5232

AD5235

No. Chan No. Pos

ITF R (kΩ)

I²C ±, ±0, 50, ±00 5.5

SPI ±0, 50, ±00

I²C ±0, ±00, ±M

SPI 20, 50, 200

I²C 20, 50, ±00

VDD^±

V

IN

ADR44x

2.00

64.00

V

OUT

6

256.00

5.5

±5

2N3904

OP90

GND

4

±5

I²C ±, ±0, 50, 200 5.5

SPI ±0, 50, ±00

–V

S

5.5

Figure 38. Floating Current Source

±024.00 SPI 25, 250

ADN2850 2.00

^±Can also use a negative supply.

By adding a negative supply to the op amp, it is possible for

the user to also produce a negative programmable reference

by connecting the reference output to the inverting terminal

of the op amp. Choose feedback resistors to minimize errors

over temperature.

Rev. 0 | Page ±6 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

PRECISION OUTPUT REGULATOR (BOOSTED

REFERENCE)

V

IN

2

V

IN

2N7002

C

15V

IN

0.1μF

ADR44x

V

OUT

6

V

O

R

C

L

1μF

L

C

OUT

0.1μF

200Ω

GND

–V

4

Figure 39. Boosted Output Reference

Higher current drive capability without sacrificing accuracy

can be obtained using the circuit in Figure 39. The op amp

regulates the MOSFET turn-on, which forces V_Oto equal the

VREF. Current is then drawn from V_IN, which allows increased

current drive capability. The circuit allows a 50 mA load; if

higher current drive is required, use a larger MOSFET. For fast

transient response, add a buffer at V_Oto aid with capacitive

loading.

Rev. 0 | Page ±7 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

OUTLINE DIMENSIONS

5.00 (0.1968)

4.80 (0.1890)

8

1

5

4

6.20 (0.2440)

5.80 (0.2284)

4.00 (0.1574)

3.80 (0.1497)

1.27 (0.0500)

BSC

0.50 (0.0196)

0.25 (0.0099)

× 45°

1.75 (0.0688)

1.35 (0.0532)

0.25 (0.0098)

0.10 (0.0040)

8°

0.51 (0.0201)

0.31 (0.0122)

0° 1.27 (0.0500)

COPLANARITY

0.10

0.25 (0.0098)

0.17 (0.0067)

SEATING

PLANE

0.40 (0.0157)

COMPLIANT TO JEDEC STANDARDS MS-012-AA

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 40. 8-Lead Standard Small Outline Package [SOIC_N]

Narrow Body

(R-8)

Dimensions shown in millimeters and (inches)

3.00

BSC

8

1

5

4

4.90

BSC

3.00

BSC

PIN 1

0.65 BSC

1.10 MAX

0.15

0.00

0.80

0.60

0.40

8°

0°

0.38

0.22

0.23

0.08

COPLANARITY

0.10

SEATING

PLANE

COMPLIANT TO JEDEC STANDARDS MO-187-AA

Figure 41. 8-Lead Mini Small Outline Package [MSOP}

(RM-8)

Dimensions show in millimeters

Rev. 0 | Page ±8 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

ORDERING GUIDE

Temperature

Coefficient

Package

Output

Voltage

Initial

Accuracy

Package

Description

Temperature

Range (°C)

Ordering

Quantity

Model

ADR440ARZ^±

ADR440ARZ-REEL7^±

ADR440ARMZ^±

ADR440ARMZ-REEL7^±

ADR440BRZ^±

ADR440BRZ-REEL7^±

ADR44±ARZ^±

ADR44±ARZ-REEL7^±

ADR44±ARMZ^±

ADR44±ARMZ-REEL7^±

ADR44±BRZ^±

ADR44±BRZ-REEL7^±

ADR443ARZ^±

ADR443ARZ-REEL7^±

ADR443ARMZ^±

ADR443ARMZ-REEL7^±

ADR443BRZ^±

ADR443BRZ-REEL7^±

ADR444ARZ^±

ADR444ARZ-REEL7^±

ADR444ARMZ^±

ADR444ARMZ-REEL7^±

ADR444BRZ^±

ADR444BRZ-REEL7^±

ADR445ARZ^±

ADR445ARZ-REEL7^±

ADR445ARMZ^±

Branding

(V_O) V

2.048

2.500

3.000

4.096

5.000

(mV)

3

(%)

(ppm/°C)

0.±5 ±0

8-lead SOIC_N

8-Lead SOIC_N

8-Lead MSOP

8-lead SOIC_N

8-Lead SOIC_N

8-Lead MSOP

8-Lead SOIC_N

8-Lead MSOP

8-Lead SOIC_N

8-Lead MSOP

8-Lead SOIC_N

8-Lead MSOP

8-Lead SOIC_N

–40 to +±25

–40°C to +±25°C

–40 to +±25

98

±,000

98

±,000

98

±,000

98

±,000

98

±,000

98

±,000

98

±,000

98

±,000

98

±,000

98

±,000

98

±,000

98

±,000

98

±,000

98

±,000

98

±,000

0.±5 ±0

0.05

R0±

±

3

±

0.±2 ±0

0.04

R02

3

4

±.2

5

0.±2 ±0

0.05 3F

R03

0.05

3

0.±3 ±0

0.04

R04

5

±.6

6

2

3

0.±2 ±0

0.04

R05

ADR445ARMZ-REEL7^±

ADR445BRZ^±

ADR445BRZ-REEL7^±

3

^±Z = Pb-free part.

Rev. 0 | Page ±9 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

NOTES

Purchase of licensed I²C components of Analog Devices or one of its sublicensed Associated Companies conveys a license for the purchaser under the Philips I²C Patent

Rights to use these components in an I²C system, provided that the system conforms to the I²C Standard Specification as defined by Philips.

registered trademarks are the property of their respective owners.

D05428-0-10/05(0)

Rev. 0 | Page 20 of 20


型号：	ADR441
厂家：	ADI
描述：	2.048 V High Precision, LDO XFET® References for High Performance Sigma-Delta and PulSAR® Converters 2.048 V ，精度高， LDO XFET ＆章;高性能的Σ-Δ和PulSAR系列＆章参考;转换器转换器
文件：	总20页 (文件大小：532K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

ADR441 [ADI]

相关型号：

ADR441A

ADR441ARMZ

ADR441ARMZ-REEL7

ADR441ARZ

ADR441ARZ-REEL7

ADR441B

ADR441BRZ

ADR441BRZ-REEL7

ADR441TRZ-EP

ADR441TRZ-EP-R7

ADR441_15

ADR443