a
Ultraprecision Low Noise, 2.048 V/2.500 V/
3.00 V/5.00 V XFET
®
Voltage References
ADR420/ADR421/ADR423/ADR425
PIN CONFIGURATION
Surface-Mount Packages
8-Lead SOIC
8-Lead Mini_SOIC
TP
1
V
IN 2
NIC
3
8
TP
FEATURES
Low Noise (0.1 Hz to 10 Hz)
ADR420: 1.75 V p-p
ADR421: 1.75 V p-p
ADR423: 2.0 V p-p
ADR425: 3.4 V p-p
Low Temperature Coefficient: 3 ppm/ C
Long-Term Stability: 50 ppm/1000 Hours
Load Regulation: 70 ppm/mA
Line Regulation: 35 ppm/V
Low Hysteresis: 40 ppm Typical
Wide Operating Range
ADR420: 4 V to 18 V
ADR421: 4.5 V to 18 V
ADR423: 5 V to 18 V
ADR425: 7 V to 18 V
Quiescent Current: 0.5 mA Maximum
High Output Current: 10 mA
Wide Temperature Range: –40 C to +125 C
APPLICATIONS
Precision Data Acquisition Systems
High-Resolution Converters
Battery-Powered Instrumentation
Portable Medical Instruments
Industrial Process Control Systems
Precision Instruments
Optical Network Control Circuits
GENERAL DESCRIPTION
ADR42x
7
NIC
6
V
OUT
TOP VIEW
GND
4
(Not to Scale)
5
TRIM
NIC = NO INTERNAL CONNECTION
TP = TEST PIN (DO NOT CONNECT)
Table I. ADR42x Products
The ADR42x series are ultra-precision second-generation XFET
voltage references featuring low noise, high accuracy, and excel-
lent long-term stability in a SOIC and Mini_SOIC footprints.
Patented temperature drift curvature correction technique and XFET
(eXtra implanted junction FET) technology minimize nonlinearity
of the voltage change with temperature. The XFET architecture
offers superior accuracy and thermal hysteresis than the bandgap
references. It also operates at lower power and lower supply
headroom than the Buried Zener references.
The superb noise, stable, and accurate characteristics of ADR42x
make them ideal for precision conversion applications such as
optical network and medical equipment. The ADR42x trim
terminal can also be used to adjust the output voltage over a
±0.5%
range without compromising any other performance. The
ADR42x series voltage references offer two electrical grades and
are specified over the extended industrial temperature range
of –40°C to +125°C. Devices are available in 8-lead SOIC-8 or
30% smaller 8-lead Mini_SOIC-8 packages.
XFET is a registered trademark of Analog Devices, Inc.
ADR420
Products
ADR420
ADR421
ADR423
ADR425
Output
Voltage
V
O
2.048
2.50
3.00
5.00
Initial
Accuracy
mV
%
1, 3
1, 3
1.5, 4
2, 6
0.05, 0.15
0.04, 0.12
0.04, 0.12
0.04, 0.12
Tempco
ppm/
°
C
3, 10
3, 10
3, 10
3, 10
REV. A
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. No license is granted by implication or otherwise
under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 2001
ADR42x–SPECIFICATIONS
ADR420 ELECTRICAL SPECIFICATIONS
Parameter
Output Voltage
Initial Accuracy
Output Voltage
Initial Accuracy
A Grade
Symbol
V
O
V
OERR
V
O
V
OERR
TCV
O
V
IN
– V
O
∆V
O
/∆V
IN
∆V
O
/∆I
LOAD
I
IN
e
N
p-p
e
N
t
R
∆V
O
V
O_HYS
RRR
I
SC
–40°C < T
A
< +125°C
2
V
IN
= 5 V to 18 V
–40°C < T
A
< +125°C
I
LOAD
= 0 mA to 10 mA
–40°C < T
A
< +125°C
No Load
–40°C < T
A
< +125°C
0.1 Hz to 10 Hz
1 kHz
1000 Hours
f
IN
= 10 kHz
10
35
70
390
1.75
60
10
50
40
75
27
500
600
(@ V
IN
= 5.0 V to 15.0 V, T
A
= 25 C, unless otherwise noted.)
Conditions
Min
2.045
–3
–0.15
2.047
–1
–0.05
Typ
2.048
Max
2.051
+3
+0.15
2.049
+1
+0.05
10
3
Unit
V
mV
%
V
mV
%
ppm/°C
ppm/°C
V
ppm/V
ppm/mA
µA
µA
µV
p-p
nV/√Hz
µs
ppm
ppm
dB
mA
B Grade
2.048
Temperature Coefficient A Grade
B Grade
Supply Voltage Headroom
Line Regulation
Load Regulation
Quiescent Current
Voltage Noise
Voltage Noise Density
Turn-On Settling Time
Long-Term Stability
Output Voltage Hysteresis
Ripple Rejection Ratio
Short Circuit to GND
Specifications subject to change without notice.
2
1
ADR421 ELECTRICAL SPECIFICATIONS
Parameter
Output Voltage
Initial Accuracy
Output Voltage
Initial Accuracy
A Grade
Symbol
V
O
V
OERR
V
O
V
OERR
TCV
O
V
IN
– V
O
∆V
O
/∆V
IN
∆V
O
/∆I
LOAD
I
IN
e
N
p-p
e
N
t
R
∆V
O
V
O_HYS
RRR
I
SC
(@ V
IN
= 5.0 V to 15.0 V, T
A
= 25 C, unless otherwise noted.)
Conditions
Min
2.497
–3
–0.12
2.499
–1
–0.04
–40°C < T
A
< +125°C
2
V
IN
= 5 V to 18 V
–40°C < T
A
< +125°C
I
LOAD
= 0 mA to 10 mA
–40°C < T
A
< +125°C
No Load
–40°C < T
A
< +125°C
0.1 Hz to 10 Hz
1 kHz
1000 Hours
f
IN
= 10 kHz
10
35
70
390
1.75
80
10
50
40
75
27
500
600
Typ
2.500
Max
2.503
+3
+0.12
2.501
+1
+0.04
10
3
Unit
V
mV
%
V
mV
%
ppm/°C
ppm/°C
V
ppm/V
ppm/mA
µA
µA
µV
p-p
nV/√Hz
µs
ppm
ppm
dB
mA
B Grade
2.500
Temperature Coefficient A Grade
B Grade
Supply Voltage Headroom
Line Regulation
Load Regulation
Quiescent Current
Voltage Noise
Voltage Noise Density
Turn-On Settling Time
Long-Term Stability
Output Voltage Hysteresis
Ripple Rejection Ratio
Short Circuit to GND
Specifications subject to change without notice.
2
1
–2–
REV. A
ADR420/ADR421/ADR423/ADR425
ADR423 ELECTRICAL SPECIFICATIONS
Parameter
Output Voltage
Initial Accuracy
Output Voltage
Initial Accuracy
A Grade
Symbol
V
O
V
OERR
V
O
V
OERR
TCV
O
V
IN
−
V
O
∆V
O
/∆V
IN
∆V
O
/∆I
LOAD
I
IN
e
N
p-p
e
N
t
R
∆V
O
V
O_HYS
RRR
I
SC
–40°C < T
A
< +125°C
2
V
IN
= 5 V to 18 V
–40°C < T
A
< +125°C
I
LOAD
= 0 mA to 10 mA
–40°C < T
A
< +125°C
No Load
–40°C < T
A
< +125°C
0.1 Hz to 10 Hz
1 kHz
1000 Hours
f
IN
= 10 kHz
10
35
70
390
2
90
10
50
40
75
27
500
600
(@ V
IN
= 5.0 V to 15.0 V, T
A
= 25 C, unless otherwise noted.)
Conditions
Min
2.996
–4
–0.13
2.9985
–1.5
–0.04
Typ
3.000
Max
3.004
+4
+0.13
3.0015
+1.5
+0.04
10
3
Unit
V
mV
%
V
mV
%
ppm/°C
ppm/°C
V
ppm/V
ppm/mA
µA
µA
µV
p-p
nV/√Hz
µs
ppm
ppm
dB
mA
B Grade
3.000
Temperature Coefficient A Grade
B Grade
Supply Voltage Headroom
Line Regulation
Load Regulation
Quiescent Current
Voltage Noise
Voltage Noise Density
Turn-On Settling Time
Long-Term Stability
Output Voltage Hysteresis
Ripple Rejection Ratio
Short Circuit to GND
Specifications subject to change without notice.
2
1
ADR425 ELECTRICAL SPECIFICATIONS
(@ V
Parameter
Output Voltage
Initial Accuracy
Output Voltage
Initial Accuracy
A Grade
Symbol
V
O
V
OERR
V
O
V
OERR
TCV
O
V
IN
– V
O
∆V
O
/∆V
IN
∆V
O
/∆I
LOAD
I
IN
e
N
p-p
e
N
t
R
∆V
O
V
O_HYS
RRR
I
SC
IN
= 7.0 V to 15.0 V, T
A
= 25 C, unless otherwise noted.)
Min
4.994
–6
–0.12
4.998
–2
–0.04
Typ
5.000
Max
5.006
+6
+0.12
5.002
+2
+0.04
10
3
35
70
390
3.4
110
10
50
40
75
27
500
600
Unit
V
mV
%
V
mV
%
ppm/°C
ppm/°C
V
ppm/V
ppm/mA
µA
µA
µV
p-p
nV/√Hz
µs
ppm
ppm
dB
mA
Conditions
B Grade
5.000
Temperature Coefficient A Grade
B Grade
Supply Voltage Headroom
Line Regulation
Load Regulation
Quiescent Current
Voltage Noise
Voltage Noise Density
Turn-On Settling Time
Long-Term Stability
Output Voltage Hysteresis
Ripple Rejection Ratio
Short Circuit to GND
Specifications subject to change without notice.
–40°C < T
A
< +125°C
2
V
IN
= 7 V to 18 V
–40°C < T
A
< +125°C
I
LOAD
= 0 mA to 10 mA
–40°C < T
A
< +125°C
No Load
–40°C < T
A
< +125°C
0.1 Hz to 10 Hz
1 kHz
1000 Hours
f
IN
= 10 kHz
2
1
10
REV. A
–3–
ADR420/ADR421/ADR423/ADR425
ABSOLUTE MAXIMUM RATINGS
*
PIN FUNCTION DESCRIPTIONS
Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 V
Output Short-Circuit Duration to GND . . . . . . . . . Indefinite
Storage Temperature Range
R, RM Packages . . . . . . . . . . . . . . . . . . . . –65°C to +150°C
Operating Temperature Range
ADR42x . . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +125°C
Junction Temperature Range
R, RM Packages . . . . . . . . . . . . . . . . . . . . –65°C to +150°C
Lead Temperature Range (Soldering, 60 sec) . . . . . . . 300°C
*Absolute
maximum ratings apply at 25°C, unless otherwise noted.
Pin
1, 8
Mnemonic Description
TP
Test Pin. There are actual connections in TP
pins but they are reserved for factory testing
purposes. Users should not connect any-
thing to TP pins, otherwise the device may
not function properly.
Input Voltage
No Internal Connect. NICs have no internal
connections.
Ground Pin = 0 V
Trim Terminal. It can be used to adjust the
output voltage over a
±
0.5% range without
affecting the temperature coefficient.
Output Voltage
θ
JA
*
190
130
Unit
°C/W
°C/W
2
3, 7
4
5
V
IN
NIC
GND
TRIM
PIN CONFIGURATIONS
SOIC-8
TP
1
V
IN 2
NIC
3
GND
4
8
TP
Mini_SOIC-8
TP
1
V
IN 2
NIC
3
GND
4
8
TP
6
V
OUT
ADR42x
7
NIC
6
ADR42x
7
NIC
6
V
OUT
V
OUT
Package Type
8-Lead Mini_SOIC (RM)
8-Lead SOIC (R)
5
TRIM
5
TRIM
NIC = NO INTERNAL CONNECTION
TP = TEST PIN (DO NOT CONNECT)
NIC = NO INTERNAL CONNECTION
TP = TEST PIN (DO NOT CONNECT)
*θ
JA
is specified for the worst-case conditions, i.e.,
θ
JA
is specified for device soldered
in circuit board for surface-mount packages.
ORDERING GUIDE
Model
ADR420AR
ADR420AR-Reel7
ADR420BR
ADR420BR-Reel7
ADR420ARM-Reel7
ADR421AR
ADR421AR-Reel7
ADT421BR
ADT421BR-Reel7
ADR421ARM-Reel7
ADR423AR
ADR423AR-Reel7
ADT423BR
ADT423BR-Reel7
ADR423ARM-Reel7
ADR425AR
ADR425AR-Reel7
ADT425BR
ADT425BR-Reel7
ADR425ARM-Reel7
Output
Voltage
V
O
2.048
2.048
2.048
2.048
2.048
2.50
2.50
2.50
2.50
2.50
3.00
3.00
3.00
3.00
3.00
5.00
5.00
5.00
5.00
5.00
Initial
Accuracy
Temp
Package
mV% ppm/°C Coefficient Description
3
3
1
1
3
3
3
1
1
3
4
4
1.5
1.5
4
6
6
2
2
6
0.15%
0.15%
0.05%
0.05%
0.15%
0.12%
0.12%
0.04%
0.04%
0.12%
0.13%
0.13%
0.04%
0.04%
0.13%
0.12%
0.12%
0.04%
0.04%
0.12%
10
10
3
3
10
10
10
3
3
10
10
10
3
3
10
10
10
3
3
10
SOIC
SOIC
SOIC
SOIC
Mini_SOIC
SOIC
SOIC
SOIC
SOIC
Mini_SOIC
SOIC
SOIC
SOIC
SOIC
Mini_SOIC
SOIC
SOIC
SOIC
SOIC
Mini_SOIC
Package
Option
SO-8
SO-8
SO-8
SO-8
RM-8
SO-8
SO-8
SO-8
SO-8
RM-8
SO-8
SO-8
SO-8
SO-8
RM-8
SO-8
SO-8
SO-8
SO-8
RM-8
Top
Mark
Number of
Parts per
Reel
98
3,000
98
3,000
1,000
98
3,000
98
3,000
1,000
98
3,000
98
3,000
1,000
98
3,000
98
3,000
1,000
Temp
Range
°C
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
–40 to +125
R4A
R5A
TBD
TBD
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
the AD42x 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.
WARNING!
ESD SENSITIVE DEVICE
–4–
REV. A
ADR420/ADR421/ADR423/ADR425
PARAMETER DEFINITIONS
Temperature Coefficient
Thermal Hysteresis
The change of output voltage over the operating temperature
range and normalized by the output voltage at 25°C, expressed
in ppm/°C. The equation follows:
Thermal Hysteresis is defined as the change of output voltage
after the device is cycled through temperature from +25°C to
–40°C to +125°C and back to +25°C. This is a typical value
from a sample of parts put through such a cycle.
V
O
_
HYS
=
V
O
(25
°
C
) –
V
O
_
TC
V
O
_
HYS
(
ppm
)
=
V
O
(25
°
C
) –
V
O
_
TC
V
O
(25
°
C
)
×
10
6
TCV
O
(
ppm
/
°
C
)
=
where
V
O
(25°C) = V
O
at 25°C
V
O
(
T
2
) –
V
O
(
T
1
)
×
10
6
V
O
(25
°
C
)
×
(
T
2
–
T
1
)
where
V
O
(25°C) = V
O
at 25°C
V
O_TC
= V
O
at 25°C after temperature cycle at +25°C to –40°C
to +125°C and back to +25°C.
Input Capacitor
V
O
(T
1
) = V
O
at Temperature 1
V
O
(T
2
) = V
O
at Temperature 2.
Line Regulation
The change in output voltage due to a specified change in input
voltage. It includes the effects of self-heating. Line regulation is
expressed in either percent per volt, parts-per-million per volt,
or microvolts per volt change in input voltage
Load Regulation
The change in output voltage due to a specified change in load
current. It includes the effects of self-heating. Load Regulation
is expressed in either microvolts per milliampere, parts-per-
million per milliampere, or ohms of dc output resistance.
Long-Term Stability
Input capacitors are not required on the ADR42x. There is no
limit for the value of the capacitor used on the input, but a 1
µF
to
10
µF
capacitor on the input will improve transient response in
applications where the supply suddenly changes. An additional
0.1
µF
in parallel will also help to reduce noise from the supply.
Output Capacitor
Typical shift of output voltage at 25°C on a sample of parts
subjected to operation life test of 1000 hours at 125°C:
∆
V
O
=
V
O
(
t
0
) –
V
O
(
t
1
)
∆
V
O
(
ppm
)
=
where
V
O
(t
0
) = V
O
at 25°C at Time 0
V
O
(t
1
) = V
O
at 25°C after 1000 hours operation at 125°C.
V
O
(
t
0
) –
V
O
(
t
1
)
×
10
6
V
O
(
t
0
)
The ADR42x does not need output capacitors for stability
under any load condition. An output capacitor, typical 0.1
µF,
will filter out any low-level noise voltage and will not affect
the operation of the part. On the other hand, the load transient
response can be improved with an additional 1
µF
to 10
µF
output capacitor in parallel. A capacitor here will act as a source
of stored energy for sudden increase in load current. The only
parameter that will degrade, by adding an output capacitor,
is turn-on time and it depends on the size of the capacitor chosen.
REV. A
–5–
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