AD1582/AD1583/AD1584/AD1585 Data Sheet
Rev. J | Page 10 of 16
THEORY OF OPERATION
The AD1582/AD1583/AD1584/AD1585 use the band gap
concept to produce stable, low temperature coefficient voltage
references suitable for high accuracy data acquisition compo-
nents and systems. These parts of precision references use the
underlying temperature characteristics of a silicon transistor’s
base emitter voltage in the forward-biased operating region.
Under this condition, all such transistors have a −2 mV/°C
temperature coefficient (TC) and a V
BE
that, when extrapolated
to absolute zero, 0 K (with collector current proportional to
absolute temperature), approximates the silicon band gap voltage.
By summing a voltage that has an equal and opposite tempera-
ture coefficient of 2 mV/°C with the V
BE
of a forward-biased
transistor, an almost 0 TC reference can be developed. In the
AD1582/AD1583/AD1584/AD1585 simplified circuit diagram
shown in Figure 9, such a compensating voltage, V1, is derived
by driving two transistors at different current densities and
amplifying the resultant V
BE
difference (∆V
BE
, which has a positive
TC). The sum of V
BE
and V1 (V
BG
) is then buffered and amplified
to produce stable reference voltage outputs of 2.5 V, 3 V, 4.096 V,
and 5 V.
R
4
R6
R5
GN
D
V1
+
R3
+
R
2
R
1
V
I
N
V
OU
T
V
BG
V
B
E
00701-009
Figure 9. Simplified Schematic
Data Sheet AD1582/AD1583/AD1584/AD1585
Rev. J | Page 11 of 16
APPLICATIONS INFORMATION
The AD1582/AD1583/AD1584/AD1585 are series references
that can be used for many applications. To achieve optimum
performance with these references, only two external compo-
nents are required. Figure 10 shows the AD1582/AD1583/
AD1584/AD1585 configured for operation under all loading
conditions. With a simple 4.7 µF capacitor attached to the input
and a 1 µF capacitor applied to the output, the devices can achieve
specified performance for all input voltage and output current
requirements. For best transient response, add a 0.1 µF capacitor
in parallel with the 4.7 µF capacitor. While a 1 µF output capacitor
can provide stable performance for all loading conditions, the
AD1582/AD1583/AD1584/AD1585 can operate under low
(−100 µA < I
OUT
< +100 µA) current conditions with just a
0.2 µF output capacitor. The 4.7 µF capacitor on the input can
be reduced to 1 μF in this condition.
Unlike conventional shunt reference designs, the AD1582/
AD1583/AD1584/AD1585 provide stable output voltages at
constant operating current levels. When properly decoupled,
as shown in Figure 10, these devices can be applied to any
circuit and provide superior low power solutions.
V
OUT
1
2
V
IN
3
AD1582/
AD1583/
AD1584/
AD1585
1µF
4.7µF
+
00701-010
Figure 10. Typical Connection Diagram
TEMPERATURE PERFORMANCE
The AD1582/AD1583/AD1584/AD1585 are designed for
applications where temperature performance is important.
Extensive temperature testing and characterization ensure
that device performance is maintained over the specified
temperature range.
The error band guaranteed with the AD1582/AD1583/AD1584/
AD1585 is the maximum deviation from the initial value at 25°C.
Therefore, for a given grade of the AD1582/AD1583/AD1584/
AD1585, the designer can easily determine the maximum total
error by summing initial accuracy and temperature variation. For
example, for the AD1582BRT, the initial tolerance is ±2 mV, and
the temperature error band is ±8 mV; therefore, the reference is
guaranteed to be 2.5 V ± 10 mV from −40°C to +125°C.
Figure 11 shows the typical output voltage drift for the AD1582/
AD1583/AD1584/AD1585 and illustrates the methodology. The
box in Figure 11 is bounded on the x-axis by operating tempera-
ture extremes. It is bounded on the y-axis by the maximum
and minimum output voltages observed over the operating
temperature range. The slope of the diagonal drawn from the
initial output value at 25°C to the output values at +125°C and
−40°C determines the performance grade of the device.
Duplication of these results requires a test system that is highly
accurate with stable temperature control. Evaluation of the
AD1582/AD1583/AD1584/AD1585 produces curves similar
to those in Figure 5 and Figure 11, but output readings can vary
depending on the test methods and test equipment used.
2.504
2.502
2.500
2.498
2.496
2.494
2.492
TEMPERATURE (°C)
V
OUT
(V)
–40 –20 0 20 40 60 80 100 120
2.504
2.502
2.500
2.498
2.496
2.494
2.492
TEMPERATURE (°C)
V
OUT
(V)
–40 –20 0 20 40 60 80 100 120
00701-011
Figure 11. Output Voltage vs. Temperature
VOLTAGE OUTPUT NONLINEARITY VS.
TEMPERATURE
When using a voltage reference with data converters, it is
important to understand the impact that temperature drift can
have on converter performance. The nonlinearity of the reference
output drift represents additional error that cannot be easily
calibrated out of the overall system. To better understand the
impact such a drift can have on a data converter, refer to Figure 12,
where the measured drift characteristic is normalized to the
endpoint average drift. The residual drift error for the AD1582/
AD1583/AD1584/AD1585 of approximately 200 ppm demon-
strates that these parts are compatible with systems that require
12-bit accurate temperature performance.
250
200
150
100
5
0
0
–50
TEMPERATURE
(°C)
–50 –2
5 0 25 50 7
5 100
ΔV
OUT
(ppm)
00701-012
Figure 12. Residual Drift Error
AD1582/AD1583/AD1584/AD1585 Data Sheet
Rev. J | Page 12 of 16
OUTPUT VOLTAGE HYSTERESIS
High performance industrial equipment manufacturers can
require the AD1582/AD1583/AD1584/AD1585 to maintain a
consistent output voltage error at 25°C after the references are
operated over the full temperature range. All references exhibit
a characteristic known as output voltage hysteresis; however, the
AD1582/AD1583/AD1584/AD1585 are designed to minimize
this characteristic. This phenomenon can be quantified by mea-
suring the change in the +25°C output voltage after temperature
excursions from +125°C to +25°C and from −40°C to +25°C.
Figure 13 displays the distribution of the AD1582/AD1583/
AD1584/AD1585 output voltage hysteresis.
80
70
60
50
–700 –450 –200 50 300 550
NUMBER OF PARTS
40
30
20
10
0
ppm
0
0701-013
Figure 13. Output Voltage Hysteresis Distribution
SUPPLY CURRENT VS. TEMPERATURE
The quiescent current for the AD1582/AD1583/AD1584/
AD1585 varies slightly over temperature and input supply range.
Figure 14 illustrates the typical performance for the
AD1582/AD1583/AD1584/AD1585 reference when varying
both temperature and supply voltage. As is evident from
Figure 14, the AD1582/AD1583/AD1584/AD1585 supply
current increases only 1.0 μA/V, making this device extremely
attractive for use in applications where there can be wide
variations in supply voltage and a need to minimize power
dissipation.
100
80
60
40
20
0
I
Q
(µA)
V
IN
(V)
34567891011
T
A
= +25°C
T
A
= +85°C
T
A
= –40°C
00701-014
Figure 14. Typical Supply Current over Temperature
SUPPLY VOLTAGE
One of the ideal features of the AD1582/AD1583/AD1584/AD1585
is low supply voltage headroom. The parts can operate at supply
voltages as low as 200 mV above V
OUT
and up to 12 V. However,
if negative voltage is inadvertently applied to V
IN
with respect to
ground, or any negative transient >5 V is coupled to V
IN
, the
device can be damaged.
AC PERFORMANCE
To apply the AD1582/AD1583/AD1584/AD1585, it is important
to understand the effects of dynamic output impedance and
power supply rejection. In Figure 15, a voltage divider
is formed by the AD1582/AD1583/AD1584/ AD1585 output
impedance and by the external source impedance. Figure 16
shows the effect of varying the load capacitor on the reference
output. Power supply rejection ratio (PSRR) should be determined
when characterizing the ac performance of a series voltage
reference. Figure 17 shows a test circuit used to measure PSRR,
and Figure 18 demonstrates the ability of the AD1582/AD1583/
AD1584/AD1585 to attenuate line voltage ripple.
5V
5µF
1µF
2×V
OUT
10k
10k
2k
10k
±2V
±100µA
×1
V
LOAD
DC
DUT
0
0701-015
Figure 15. Output Impedance Test Circuit
100
AD1585
AD1582
10
1
0.1
10
100
1k 10k 100k 1M
FREQUENCY (Hz)
OUTPUT IMPEDANCE ()
1µF CAP
0
0701-016
Figure 16. Output Impedance vs. Frequency
5V ± 100mV
0.22µF
0.22µF
10V
10k
10k
±200mV
×1
DUT
V
OUT
0
0701-017
Figure 17. Ripple Rejection Test Circuit

AD1582ARTZ-R2

Mfr. #:
Manufacturer:
Analog Devices Inc.
Description:
Voltage References 25V MICROPOWER REF IC
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
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