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Электронный компонент: ADR443AR-REEL7

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Ultralow Noise, LDO XFET
Voltage
References with Current Sink and Source
ADR440/ADR441/ADR443/ADR444/ADR445
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 registered trademarks are the property of their respective owners.


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
2005 Analog Devices, Inc. All rights reserved.
FEATURES
Ultralow noise (0.1 Hz to 10 Hz)
ADR440: 1 V p-p
ADR441: 1.2 V p-p
ADR443: 1.4 V p-p
ADR444: 1.8 V p-p
ADR445: 2.25 V p-p
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: -40C to +125C
APPLICATIONS
Precision data acquisition systems
High resolution data converters
Battery-powered instrumentations
Portable medical instruments
Industrial process control systems
Precision instruments
Optical control circuits
PIN CONFIGURATIONS
05428-002
TP
1
V
IN
2
NC
3
GND
4
TP
8
NC
7
V
OUT
6
TRIM
5
NC = NO CONNECT
ADR44x
TOP VIEW
(Not to Scale)
Figure 1. 8-Lead SOIC (R)
TP
1
V
IN
2
NC
3
GND
4
TP
8
NC
7
V
OUT
6
TRIM
5
NC = NO CONNECT
ADR44x
TOP VIEW
(Not to Scale)
05428-001
Figure 2. 8-Lead MSOP (RM)
GENERAL DESCRIPTION
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.
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.
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
o
C to +125
o
C).
Table 1. Selection Guide
Model
V
OUT
(V)
Accuracy (mV)
Temperature
Coefficient (ppm/C)
ADR440B
2.048
1
3
ADR440A
2.048
3
10
ADR441B
2.500
1
3
ADR441A
2.500
3
10
ADR443B
3.000
1.2
3
ADR443A
3.000
4
10
ADR444B
4.096
1.6
3
ADR444A
4.096
5
10
ADR445B
5.000
2
3
ADR445A
5.000
6
10
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 2 of 20
TABLE OF CONTENTS
Features .............................................................................................. 1
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
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
REVISION HISTORY
10/05--Revision 0: Initial Version
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 3 of 20
SPECIFICATIONS
ADR440--ELECTRICAL CHARACTERISTICS
V
IN
= 3 V to 18 V; T
A
= 25C; C
IN
, C
BYPASS
= 0.1 F, unless otherwise noted.
Table 2.
Parameter Symbol
Conditions Min
Typ
Max
Unit
OUTPUT VOLTAGE
A Grade
V
O
2.045 2.048 2.051 V
B Grade
V
O
2.047 2.048 2.049 V
INITIAL
ACCURACY
A Grade
V
OERR
3
mV
0.15
%
B Grade
V
OERR
1
mV
0.05
%
TEMPERATURE
DRIFT
A Grade SOIC-8
TC V
O
-40C < T
A
< +125C
2
10
ppm/C
MSOP-8
TC V
O
-40C < T
A
< +125C
2
10
ppm/C
B Grade SOIC-8
TC V
O
-40C < T
A
< +125C
1
3
ppm/C
LINE REGULATION
V
O
/V
IN
V
IN
= 3 V to 18 V, -40C < T
A
< +125C
-20
+10
+20
ppm/V
LOAD REGULATION
I
LOAD
= 0 mA to 10 mA, V
IN
= 3.5 V
V
O
/I
LOAD
-40C < T
A
< +125C
-50
+50
ppm/mA
I
LOAD
= 0 mA to -5 mA, V
IN
= 3.5 V
V
O
/I
LOAD
-40C < T
A
< +125C
-50
+50
ppm/mA
QUIESCENT CURRENT
I
IN
No Load, -40C < T
A
< +125C
3
3.75
mA
VOLTAGE NOISE
e
N
p-p
0.1 Hz to 10 Hz
1
V p-p
VOLTAGE NOISE DENSITY
e
N
1 kHz
60
nV/Hz
TURN-ON SETTLING TIME
t
R
10
s
LONG-TERM STABILITY
1
V
O
1,000 Hours
50
ppm
OUTPUT VOLTAGE HYSTERISIS
V
O_HYS
70
ppm
RIPPLE REJECTION RATION
RRR
f
IN
= 10 kHz
-75
dB
SHORT CIRCUIT TO GND
I
SC
27
mA
SUPPLY VOLTAGE OPERATING RANGE
V
IN
3
18
V
SUPPLY VOLTAGE HEADROOM
V
IN
- V
O
500
mV
1
The long-term stability specification is noncumulative. This drift in the subsequent 1,000-hour period is significantly lower than in the first 1,000-hour period.
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 4 of 20
ADR441--ELECTRICAL CHARACTERISTICS
V
IN
= 3 V to 18 V, T
A
= 25C, unless otherwise noted.
Table 3.
Parameter Symbol
Conditions
Min
Typ
Max
Unit
OUTPUT VOLTAGE
A Grade
V
O
2.497
2.5
2.503
V
B Grade
V
O
2.499
2.5
2.501
V
INITIAL ACCURACY
A Grade
V
OERR
3
mV
0.12
%
B Grade
V
OERR
1
mV
0.04
%
TEMPERATURE DRIFT
A Grade SOIC-8
TC V
O
-40C < T
A
< +125C
2
10
ppm/C
MSOP-8 TC
V
O
-40C < T
A
< +125C
2
10
ppm/C
B Grade SOIC-8
TC V
O
-40C < T
A
< +125C
1
3
ppm/C
LINE REGULATION
V
O
/V
IN
V
IN
= 3 V to 18 V,
-40C < T
A
< +125C
10
20
ppm/V
LOAD REGULATION
V
O
/I
LOAD
I
LOAD
= 0 mA to 10 mA, V
IN
= 4 V
-40C
<
T
A
< +125C
-50
+50
ppm/mA
V
O
/I
LOAD
I
LOAD
= 0 mA to -5 mA, V
IN
= 4 V
-40C
<
T
A
< +125C
-50
+50
ppm/mA
QUIESCENT CURRENT
I
IN
No Load, -40C < T
A
< +125C
3
3.75
mA
VOLTAGE NOISE
e
N
p-p
0.1 Hz to 10 Hz
1.2
V p-p
VOLTAGE NOISE DENSITY
e
N
1 kHz
48
nV/Hz
TURN-ON SETTLING TIME
t
R
10
s
LONG-TERM STABILITY
1
V
O
1,000 Hours
50
ppm
OUTPUT VOLTAGE HYSTERISIS
V
O_HYS
70
ppm
RIPPLE REJECTION RATION
RRR
f
IN
= 10 kHz
-75
dB
SHORT CIRCUIT TO GND
I
SC
27
mA
SUPPLY VOLTAGE OPERATING RANGE
V
IN
3
18
V
SUPPLY VOLTAGE HEADROOM
V
IN
- V
O
500
mV
1
The long-term stability specification is noncumulative. This drift in subsequent 1,000-hour period is significantly lower than in the first 1,000-hour period.
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 5 of 20
ADR443--ELECTRICAL CHARACTERISTICS
V
IN
= 3.5 V to 18 V, T
A
= 25C, unless otherwise noted.
Table 4.
Parameter Symbol
Conditions Min
Typ
Max
Unit
OUTPUT
VOLTAGE
A Grade
V
O
2.996 3.0 3.004 V
B Grade
V
O
2.9988 3.0 3.0012 V
INITIAL
ACCURACY
A Grade
V
OERR
4
mV
0.13
%
B Grade
V
OERR
1.2
mV
0.04
%
TEMPERATURE
DRIFT
A Grade SOIC-8
TC V
O
-40C < T
A
< +125C
2
10
ppm/C
MSOP-8 TC
V
O
-40C < T
A
< +125C
2
10
ppm/C
B Grade SOIC-8
TC V
O
-40C < T
A
< +125C
1
3
ppm/C
LINE REGULATION
V
O
/V
IN
V
IN
= 3.5 V to 18 V, -40C < T
A
< +125C
10
20
ppm/V
LOAD REGULATION
V
O
/I
LOAD
I
LOAD
= 0 mA to 10 mA, V
IN
= 5 V
-40C
<
T
A
< +125C
-50
+50
ppm/mA
V
O
/I
LOAD
I
LOAD
= 0 mA to -5 mA, V
IN
= 5 V
-40C
<
T
A
< +125C
-50
+50
ppm/mA
QUIESCENT CURRENT
I
IN
No Load, -40C < T
A
< +125C
3
3.75
mA
VOLTAGE NOISE
e
N
p-p
0.1 Hz to 10 Hz
1.4
V p-p
VOLTAGE
NOISE
DENSITY
e
N
1
kHz
64
nV/Hz
TURN-ON SETTLING TIME
t
R
10
s
LONG-TERM STABILITY
1
V
O
1,000
Hours
50
ppm
OUTPUT VOLTAGE HYSTERISIS
V
O_HYS
70
ppm
RIPPLE REJECTION RATION
RRR
f
IN
= 10 kHz
-75
dB
SHORT CIRCUIT TO GND
I
SC
27
mA
SUPPLY VOLTAGE OPERATING RANGE
V
IN
3.5
18
V
SUPPLY VOLTAGE HEADROOM
V
IN
- V
O
500
mV
1
The long-term stability specification is noncumulative. This drift in the subsequent 1,000-hour period is significantly lower than in the first 1,000-hour period.
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 6 of 20
ADR444--ELECTRICAL CHARACTERISTICS
V
IN
= 4.6 V to 18 V, T
A
= 25C, unless otherwise noted.
Table 5.
Parameter Symbol
Conditions Min
Typ
Max
Unit
OUTPUT
VOLTAGE
A Grade
V
O
4.091 4.096
4.101 V
B Grade
V
O
4.0944 4.096 4.0976 V
INITIAL
ACCURACY
A Grade
V
OERR
5
mV
0.13
%
B Grade
V
OERR
1.6
mV
0.04
%
TEMPERATURE
DRIFT
A Grade SOIC-8
TC V
O
-40C < T
A
< +125C
2
10
ppm/C
MSOP-8 TC
V
O
-40C < T
A
< +125C
2
10
ppm/C
B Grade SOIC-8
TC V
O
-40C < T
A
< +125
v
C
1
3
ppm/C
LINE REGULATION
V
O
/V
IN
V
IN
= 4.6 V to 18 V, -40C < T
A
< +125C
10
20
ppm/V
LOAD REGULATION
V
O
/I
LOAD
I
LOAD
= 0 mA to 10 mA, V
IN
= 5.5 V
-40C
<
T
A
< +125C
-50
+50
ppm/mA
V
O
/I
LOAD
I
LOAD
= 0 mA to -5 mA, V
IN
= 5.5 V
-40C
<
T
A
< +125C
-50
+50
ppm/mA
QUIESCENT CURRENT
I
IN
No Load, -40C < T
A
< +125C
3
3.75
mA
VOLTAGE NOISE
e
N
p-p
0.1 Hz to 10 Hz
1.8
V p-p
VOLTAGE NOISE DENSITY
e
N
1
kHz
64
nV/Hz
TURN-ON SETTLING TIME
t
R
10
s
LONG-TERM STABILITY
1
V
O
1,000
Hours
50
ppm
OUTPUT VOLTAGE HYSTERISIS
V
O_HYS
70
ppm
RIPPLE REJECTION RATION
RRR
f
IN
= 10 kHz
-75
dB
SHORT CIRCUIT TO GND
I
SC
27
mA
SUPPLY VOLTAGE OPERATING RANGE
V
IN
4.6
18
V
SUPPLY VOLTAGE HEADROOM
V
IN
- V
O
500
mV
1
The long-term stability specification is noncumulative. This drift in the subsequent 1,000-hour period is significantly lower than in the first 1,000-hour period.
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 7 of 20
ADR445--ELECTRICAL CHARACTERISTICS
V
IN
= 5.5 V to 18 V, T
A
= 25C unless otherwise noted.
Table 6.
Parameter Symbol
Conditions Min
Typ
Max
Unit
OUTPUT VOLTAGE
A Grade
V
O
4.994 5.000 5.006 V
B Grade
V
O
4.998 5.000 5.002 V
INITIAL
ACCURACY
A Grade
V
OERR
6
mV
0.12
%
B Grade
V
OERR
2
mV
0.04
%
TEMPERATURE
DRIFT
A Grade SOIC-8
TC V
O
-40C < T
A
< +125C
2
10
ppm/C
MSOP-8 TC
V
O
-40C < T
A
< +125C
2
10
ppm/C
B Grade SOIC-8
TC V
O
-40C < T
A
< +125C
1
3
ppm/C
LINE REGULATION
V
O
/V
IN
V
IN
= 5.5 V to 18 V, -40C < T
A
< +125C
10
20
ppm/V
LOAD REGULATION
V
O
/I
LOAD
I
LOAD
= 0 mA to 10 mA, V
IN
=
6.5
V
-40C
<
T
A
< +125C
-50
+50
ppm/mA
V
O
/I
LOAD
I
LOAD
= 0 mA to -5 mA, V
IN
=
6.5
V
-40C
<
T
A
< +125C
-50
+50
ppm/mA
QUIESCENT CURRENT
I
IN
No Load, -40C < T
A
< +125C
3
3.75
mA
VOLTAGE NOISE
e
N
p-p
0.1 Hz to 10 Hz
2.25
V p-p
VOLTAGE NOISE DENSITY
e
N
1
kHz
64
nV/Hz
TURN-ON SETTLING TIME
t
R
10
s
LONG-TERM STABILITY
1
V
O
1,000
Hours
50
ppm
OUTPUT VOLTAGE HYSTERISIS
V
O_HYS
70
ppm
RIPPLE REJECTION RATION
RRR
f
IN
= 10 kHz
75
dB
SHORT CIRCUIT TO GND
I
SC
27
mA
SUPPLY VOLTAGE OPERATING RANGE
V
IN
5.5
18
V
SUPPLY VOLTAGE HEADROOM
V
IN
- V
O
500
mV
1
The long-term stability specification is noncumulative. This drift in the subsequent 1,000-hour period is significantly lower than in the first 1,000-hour period.
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 8 of 20
ABSOLUTE MAXIMUM RATINGS
At 25C, unless otherwise noted.
Table 7.
Parameter Rating
Supply Voltage
20 V
Output Short-Circuit Duration to GND
Indefinite
Storage Temperature Range
R, RM Packages
-65C to +125C
Operating Temperature Range
-40C to +125C
Junction Temperature Range
-65C to +150C
Lead Temperature Range (Soldering, 60 sec)
300C
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.
PACKAGE TYPE
Table 8.
Package Type
JA
1
JC
Unit
8-Lead SOIC (R)
130
43
C/W
8-Lead MSOP (RM)
190
C/W
1
JA
is 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.
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 9 of 20
TYPICAL PERFORMANCE CHARACTERISTICS
V
IN
= 7V, T
A
= 25
o
C; C
IN
, C
BYPASS
= 0.1 F; unless otherwise noted.
TEMPERATURE (
C)
OUTPUT VOLTAGE (V)
2.5020
2.5015
2.5005
2.5010
2.5000
2.4995
2.4990
40
5
10
25
50
35
20
110
95
80
65
125
05428-003
Figure 3. ADR441 V
OUT
vs. Temperature
TEMPERATURE (
C)
V
OUT
(V
)
3.0020
3.0015
3.0000
3.0005
3.0010
2.9995
2.9985
2.9990
2.9980
40
5
10
25
50
35
20
110
95
80
65
125
05428-004
Figure 4. ADR444 V
OUT
vs. Temperature
TEMPERATURE (
C)
V
OUT
(V
)
4.0980
4.0975
4.0960
4.0965
4.0970
4.0955
4.0945
4.0950
4.0940
40
5
10
25
50
35
20
110
95
80
65
125
05428-005
Figure 5. ADR445 V
OUT
vs. Temperature
INPUT VOLTAGE (V)
S
U
P
P
L
Y
CURRE
NT (mA)
4.0
3.5
3.0
2.5
2.0
4
6
10
8
1
14
12
18
05428-006
6
+125
C
40
C
+25
C
Figure 6. ADR441 Supply Current vs. Input Voltage
TEMPERATURE (
C)
S
U
P
P
LY
CURRE
NT (mA)
4.0
3.5
3.0
2.5
2.0
40
5
10
25
50
35
20
110
95
80
65
125
05428-007
Figure 7. ADR441 Supply Current vs. Temperature
INPUT VOLTAGE (V)
S
U
P
P
LY
CURRE
NT (mA)
3.5
3.4
3.2
3.3
3.0
2.9
2.8
2.7
2.6
3.1
2.5
5.3
9.3
7.3
13.3
11.3
17.3
15.3
19.3
05428-008
40
C
+125
C
+25
C
Figure 8. ADR445 Supply Current vs. Input Voltage
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 10 of 20
TEMPERATURE (
C)
QUIE
S
C
E
N
T CURRE
NT (mA)
3.25
3.15
3.05
2.95
2.85
2.75
40
5
10
25
50
35
20
110
95
80
65
125
05428-009
Figure 9. ADR445 Quiescent Current vs. Temperature
TEMPERATURE (
C)
LINE REGULATION (ppm/V)
10
8
6
2
4
0
40
5
10
25
50
35
20
110
95
80
65
125
05428-010
Figure 10. ADR441 Line Regulation vs. Temperature
TEMPERATURE (
C)
LOAD REGULATION (ppm/mA)
60
55
50
40
35
45
30
40
5
10
25
50
35
20
110
95
80
65
125
05428-011
V
IN
= 18V
IL = 0mA TO 10 mA
V
IN
= 6V
Figure 11. ADR441 Load Regulation vs. Temperature
TEMPERATURE (
C)
LINE REGULATIOIN (ppm/V)
7
6
5
4
1
2
3
0
40
5
10
25
50
35
20
110
95
80
65
125
05428-012
Figure 12. ADR445 Line Regulation vs. Temperature
TEMPERATURE (
C)
LOAD REGULATION (ppm/mA)
50
40
30
20
30
40
20
10
0
10
50
40
5
10
25
50
35
20
110
95
80
65
125
05428-013
0mA TO +10mA LOAD
0mA TO 5mA LOAD
Figure 13. ADR445 Load Regulation vs. Temperature
LOAD CURRENT (mA)
DIFFERENTIAL VOLTAGE (V)
0.7
0.6
0.5
0.3
0.2
0.1
0.4
0
10
5
0
5
10
05428-014
+125
C
40
C
+25
C
Figure 14. ADR441 Minimum Input/Output
Differential Voltage vs. Load Current
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 11 of 20
TEMPERATURE (
C)
MINIMUM HE
ADROOM (V
)
0.5
0.4
0.3
0.2
0.1
0
40
5
10
25
50
35
20
110
95
80
65
125
05428-015
NO LOAD
Figure 15. ADR441 Minimum Headroom vs. Temperature
LOAD CURRENT (mA)
DIFFERENTIAL VOLTAGE (V)
1.0
0.9
0.8
0.7
0.6
0.5
0.3
0.2
0.1
0.4
0
5
0
5
10
05428-016
+125
C
40
C
+25
C
Figure 16. ADR445 Minimum Input/Output
Differential Voltage vs. Load Current
TEMPERATURE (
C)
MINIMUM HE
ADROOM (V
)
0.5
0.4
0.3
0.2
0.1
0
40
5
10
25
50
35
20
110
95
80
65
125
05428-017
NO LOAD
Figure 17. ADR445 Minimum Headroom vs. Temperature
05428-018
V
OUT
= 1V/DIV
V
IN
= 5V/DIV
C
IN
, C
OUT
= 0.1
F
TIME = 10
s/DIV
Figure 18. ADR441 Turn-On Response
05428-019
V
OUT
= 1V/DIV
V
IN
= 5V/DIV
C
IN
, C
OUT
= 0.1
F
TIME = 200
s/DIV
Figure 19. ADR441 Turn-Off Response
05428-
020
V
OUT
= 1V/DIV
V
IN
= 5V/DIV
C
IN
= 0.1
F
C
OUT
= 10
F
TIME = 200
s/DIV
Figure 20. ADR441 Turn-On Response
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 12 of 20
05428-021
2V/DIV
4V
2mV/DIV
C
IN
= 0.1
F
C
OUT
= 10
F
100
s/DIV
Figure 21. ADR441 Line Transient Response
05428-022
LOAD OFF
LOAD ON
5mV/DIV
C
IN
, C
OUT
= 0.1
F
200
s/DIV
Figure 22. ADR441 Load Transient Response
05428-023
LOAD OFF
LOAD ON
5mV/DIV
C
IN
= 0.1
F
C
OUT
= 10
F
200
s/DIV
Figure 23. ADR441 Load Transient Response
05428-024
CH1 p-p
1.18
V
1
V/DIV
TIME = 1s/DIV
Figure 24. ADR441 0.1 Hz to 10.0 Hz Voltage Noise
05428-025
50
V/DIV
TIME = 1s/DIV
CH1 p-p
49
V
1
Figure 25. ADR441 10 Hz to 10 kHz Voltage Noise
05428-026
CH1 p-p
2.24
V
1
V/DIV
TIME = 1s/DIV
Figure 26. ADR445 0.1 Hz to 10.0 Hz Voltage Noise
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 13 of 20
05428-027
50
V/DIV
TIME = 1s/DIV
CH1 p-p
66
V
Figure 27. ADR445 10 Hz to 10 kHz Voltage Noise
DEVIATION (PPM)
NUMBE
R OF P
ARTS
16
0
05428-028
14
12
10
8
6
4
2

130

150
110
90
70
50
10
30
10
30
50
70
110
90
130
150
Figure 28. ADR441 Typical Hysteresis
FREQUENCY (Hz)
OUTP
UT IMP
E
DANCE
(
)
100k
10k
1k
100
10
05428-029
ADR445
ADR443
ADR441
10
9
8
7
5
6
4
3
2
1
0
Figure 29. Output Impedance vs. Frequency
FREQUENCY (Hz)
RIP
P
LE
RE
J
E
CTION (dB)
100k
1M
10k
1k
100
05428-030
10
0
20
30
40
50
60
70
80
90
100
Figure 30. Ripple Rejection vs. Frequency
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 14 of 20
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.
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.
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
(
)
PTAT
P
OUT
I
R1
V
G
V
-
=
(1)
where:
G
is the gain of the reciprocal of the divider ratio.
V
P
is the difference in pinch-off voltage between the two JFETs.
I
PTAT
is the positive temperature coefficient correction current.
ADR44x devices are created by on-chip adjustment of R2 and
R3 to achieve the different voltage option at the reference
output.
I
PTAT
I
1
1
I
1
1
EXTRA CHANNEL IMPLANT
V
OUT
= G(
V
P
R1
I
PTAT
)
R2
V
IN
V
OUT
GND
R3
R1
V
P
05428-033
ADR44x
Figure 31. Simplified Schematic Device
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.
A
JA
D
J
T
P
T
+
=
(2)
where:
T
J
and T
A
are the junction and ambient temperatures.
P
D
is the device power dissipation.
JA
is the device package thermal resistance.
BASIC VOLTAGE REFERENCE CONNECTIONS
The ADR44x family requires a 0.1 F capacitor on the input
and output for stability. While not required for operation,
a 10 F capacitor at the input can help with line voltage
transient performance.
+
NOTES
1. NIC = NO INTERNAL CONNECTION
2. TP = TEST PIN (DO NOT CONNECT)
1
2
3
4
5
8
6
7
ADR44x
TOP VIEW
(Not to Scale)
TP
NIC
OUTPUT
TRIM
TP
NIC
V
IN
10
F
0.1
F
0.1
F
05428-034
Figure 32. Basic Voltage Reference Configuration
NOISE PERFORMANCE
The noise generated by the ADR44x family of references is
typically less than 1.4 V p-p over the 0.1 Hz to 10.0 Hz band
for ADR440, ADR441, and ADR443. Figure 24 shows the 0.1 Hz
to 10 Hz noise of the ADR441, which is only 1.2 V 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.
TURN-ON TIME
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.
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 15 of 20
APPLICATIONS
OUTPUT ADJUSTMENT
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
P
should
be sufficiently large so that the maximum output current from
the ADR44x is not exceeded.
TRIM
V
IN
V
O
=
0.5%
0.1
F
0.1
F
GND
R2
R
P
ADR44x
05428-035
V
OUT 6
2
5
4
R1
Figure 33. ADR44x Trim Function
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.
BIPOLAR OUTPUTS
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.
6
2
4
V
IN
V
OUT
GND
R1
10k
R2
10k
R3
5k
10V
+10V
5V
+5V
0.1
F
0.1
F
ADR445
05428-036
+V
DD
Figure 34. ADR 44x Bipolar Outputs
NEGATIVE REFERENCE
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
DD
V
REF
GND
V
IN
V
OUT
ADR44x
V
DD
05428-037
2
6
4
Figure 35. Negative Reference
V
OUT
is 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.
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 16 of 20
PROGRAMMABLE VOLTAGE SOURCE
To obtain different voltages than those offered by the ADR44x,
some extra components are needed. In Figure 36,
two potentiometers are used to set the desired voltage, while the
buffering amplifier provides current drive. The potentiometer
connected between V
OUT
and 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.
6
2
4
V
IN
V
OUT
GND
R2
10k
ADJ V
REF
ADR445
05428-038
+V
DD
R1
10k
Figure 36. Programmable Voltage Source
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 I
2
C 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.
Table 9. Digital Potentiometer Parts
Part No.
No. Chan
No. Pos
ITF
R (k)
VDD
1
AD5251
2.00 64.00
I
2
C
1, 10, 50, 100
5.5
AD5207
2.00
256.00
SPI
10, 50, 100
5.5
AD5242
2.00 256.00
I
2
C
10, 100, 1M
5.5
AD5262
2.00
256.00
SPI
20, 50, 200
15
AD5282
2.00 256.00
I
2
C
20, 50, 100
15
AD5252
2.00 256.00
I
2
C
1, 10, 50, 200
5.5
AD5232
2.00
256.00
SPI
10, 50, 100
5.5
AD5235
2.00 1024.00
SPI
25,
250 5.5
ADN2850
2.00 1024.00
SPI
25,
250 5.5
1
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.
PROGRAMMABLE CURRENT SOURCE
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.
V
IN
V
OUT
GND
LOAD
V
CC
R
SENSE
AD5259
2
6
4
0.1
F
0.1
F
05428-039
Figure 37. Programmable Current Source
HIGH VOLTAGE FLOATING CURRENT 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.
V
IN
V
OUT
GND
OP90
+V
S
SST111
VISHAY
2N3904
V
S
ADR44x
05428-040
2
6
4
Figure 38. Floating Current Source
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 17 of 20
PRECISION OUTPUT REGULATOR (BOOSTED
REFERENCE)
6
2
4
V
IN
V
OUT
GND
R
L
200
C
L
1
F
2N7002
V
15V
V
O
C
IN
0.1
F
C
OUT
0.1
F
ADR44x
V
IN
05428-041
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
O
to 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
O
to aid with capacitive
loading.
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 18 of 20
OUTLINE DIMENSIONS
0.25 (0.0098)
0.17 (0.0067)
1.27 (0.0500)
0.40 (0.0157)
0.50 (0.0196)
0.25 (0.0099)
45
8
0
1.75 (0.0688)
1.35 (0.0532)
SEATING
PLANE
0.25 (0.0098)
0.10 (0.0040)
4
1
8
5
5.00 (0.1968)
4.80 (0.1890)
4.00 (0.1574)
3.80 (0.1497)
1.27 (0.0500)
BSC
6.20 (0.2440)
5.80 (0.2284)
0.51 (0.0201)
0.31 (0.0122)
COPLANARITY
0.10
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
COMPLIANT TO JEDEC STANDARDS MS-012-AA
Figure 40. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-8)
Dimensions shown in millimeters and (inches)
0.80
0.60
0.40
8
0
4
8
1
5
4.90
BSC
PIN 1
0.65 BSC
3.00
BSC
SEATING
PLANE
0.15
0.00
0.38
0.22
1.10 MAX
3.00
BSC
COPLANARITY
0.10
0.23
0.08
COMPLIANT TO JEDEC STANDARDS MO-187-AA
Figure 41. 8-Lead Mini Small Outline Package [MSOP}
(RM-8)
Dimensions show in millimeters
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 19 of 20
ORDERING GUIDE
Output
Voltage
Initial
Accuracy
Temperature
Coefficient
Package
Model
(V
O
) V
(mV)
(%)
(ppm/C)
Package
Description
Branding
Temperature
Range (C)
Ordering
Quantity
ADR440ARZ
1
2.048
3
0.15
10
8-lead SOIC_N
40 to +125
98
ADR440ARZ-REEL7
1
2.048
3
0.15
10
8-Lead SOIC_N
40 to +125
1,000
ADR440ARMZ
1
2.048
3
0.15
10
8-Lead MSOP
R01
40 to +125
98
ADR440ARMZ-REEL7
1
2.048
3
0.15
10
8-Lead MSOP
R01
40 to +125
1,000
ADR440BRZ
1
2.048
1
0.05
3
8-lead SOIC_N
40 to +125
98
ADR440BRZ-REEL7
1
2.048
1
0.05
3
8-Lead SOIC_N
40 to +125
1,000
ADR441ARZ
1
2.500
3
0.12
10
8-Lead SOIC_N
40 to +125
98
ADR441ARZ-REEL7
1
2.500
3
0.12
10
8-Lead SOIC_N
40 to +125
1,000
ADR441ARMZ
1
2.500
3
0.12
10
8-Lead MSOP
R02
40 to +125
98
ADR441ARMZ-REEL7
1
2.500
3
0.12
10
8-Lead MSOP
R02
40 to +125
1,000
ADR441BRZ
1
2.500
1
0.04
3
8-Lead SOIC_N
40 to +125
98
ADR441BRZ-REEL7
1
2.500
1
0.04
3
8-Lead SOIC_N
40 to +125
1,000
ADR443ARZ
1
3.000
4
0.12
10
8-Lead SOIC_N
40 to +125
98
ADR443ARZ-REEL7
1
3.000
4
0.12
10
8-Lead SOIC_N
40 to +125
1,000
ADR443ARMZ
1
3.000
4
0.12
10
8-Lead MSOP
R03
40 to +125
98
ADR443ARMZ-REEL7
1
3.000
4
0.12
10
8-Lead MSOP
R03
40C to +125C
1,000
ADR443BRZ
1
3.000
1.2
0.05
3F
8-Lead SOIC_N
40 to +125
98
ADR443BRZ-REEL7
1
3.000
1.2
0.05
3
8-Lead SOIC_N
40 to +125
1,000
ADR444ARZ
1
4.096
5
0.13
10
8-Lead SOIC_N
40 to +125
98
ADR444ARZ-REEL7
1
4.096
5
0.13
10
8-Lead SOIC_N
40 to +125
1,000
ADR444ARMZ
1
4.096
5
0.13
10
8-Lead MSOP
R04
40 to +125
98
ADR444ARMZ-REEL7
1
4.096
5
0.13
10
8-Lead MSOP
R04
40 to +125
1,000
ADR444BRZ
1
4.096
1.6
0.04
3
8-Lead SOIC_N
40 to +125
98
ADR444BRZ-REEL7
1
4.096
1.6
0.04
3
8-Lead SOIC_N
40 to +125
1,000
ADR445ARZ
1
5.000
6
0.12
10
8-Lead SOIC_N
40 to +125
98
ADR445ARZ-REEL7
1
5.000
6
0.12
10
8-Lead SOIC_N
40 to +125
1,000
ADR445ARMZ
1
5.000
6
0.12
10
8-Lead MSOP
R05
40 to +125
98
ADR445ARMZ-REEL7
1
5.000
6
0.12
10
8-Lead MSOP
R05
40 to +125
1,000
ADR445BRZ
1
5.000
2
0.04
3
8-Lead SOIC_N
40 to +125
98
ADR445BRZ-REEL7
1
5.000
2
0.04
3
8-Lead SOIC_N
40 to +125
1,000
1
Z = Pb-free part.
ADR440/ADR441/ADR443/ADR444/ADR445
Rev. 0 | Page 20 of 20
NOTES
Purchase of licensed I
2
C components of Analog Devices or one of its sublicensed Associated Companies conveys a license for the purchaser under the Philips I
2
C Patent
Rights to use these components in an I
2
C system, provided that the system conforms to the I
2
C Standard Specification as defined by Philips.
2005 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05428-0-10/05(0)