ADR423 Analog Devices, ADR423 Datasheet - Page 5

• Manufacturer Part Number: ADR423
• Description: Ultraprecision Low Noise/ 2.048 V/2.500 V/ 3.00 V/5.00 V XFET Voltage References
• Manufacturer: Analog Devices

PARAMETER DEFINITIONS
Temperature Coefficient
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:
where
V
V
V
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
Typical shift of output voltage at 25°C on a sample of parts
subjected to operation life test of 1000 hours at 125°C:
where
V
V
O
O
O
O
O
(25°C) = V
(T
(T
(t
(t
0
1
1
2
) = V
) = V
) = V
) = V
TCV
O
O
O
O
at 25°C at Time 0
at 25°C after 1,000 hours operation at 125°C.
O
at Temperature 1
at Temperature 2.
O
(
∆
ppm C
at 25°C
V
O
(
/
ppm
°
∆
V
O
)
)
=
=
=
V
V t
V t
O
O
O
V T
( ) –
(
( ) –
O
25
0
V t
0
( ) –
O
°
( )
C
2
V t
0
V t
O
) (
O
( )
×
( )
V T
1
1
T
O
2
( )
×
–
10
1
T
1
6
)
×
10
6
Thermal Hysteresis
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.
where
V
V
to +125°C and back to +25°C.
Input Capacitor
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
The ADR42x does not need output capacitors for stability
under any load condition. An output capacitor, typically 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.
O
O_TC
(25°C) = V
ADR420/ADR421/ADR423/ADR425
= V
O
V
at 25°C after temperature cycle at +25°C to –40°C
O HYS
_
O
at 25°C
V
O HYS
(
ppm
_
)
=
=
V
V
O
O
(
(
25
25
V
O
°
°
C
(
C
25
) –
) –
°
V
C
V
O TC
O TC
)
_
_
×
10
6