AD1582B AD [Analog Devices], AD1582B Datasheet - Page 12

• Manufacturer Part Number: AD1582B
• Description: 2.5 V to 5.0 V Micropower, Precision Series Mode Voltage References
• Manufacturer: AD [Analog Devices]

AD1582/AD1583/AD1584/AD1585
TURN-ON TIME
Many low power instrument manufacturers are becoming increas-
ingly concerned with the turn-on characteristics of the components
being used in their systems. Fast turn-on components often enable
the end user to save power by keeping power off when it is not
needed. Turn-on settling time is defined as the time required, after
the application of power (cold start), for the output voltage to
reach its final value within a specified error. The two major factors
affecting this are the active circuit settling time and the time
required for the thermal gradients on the chip to stabilize.
Figure 12a shows the turn-on settling and transient response test
circuit. Figure 12b shows the turn-on characteristic of the
AD1582. This characteristic is generated from cold-start operation
and represents the true turn-on waveform after power-up.
Figure 12c shows the fine settling characteristics of the AD1582.
Typically, the reference settles to within 0.1% of its final value
in about 100 µs.
The device can momentarily draw excessive supply current
when V
Power supply resistance must be low enough to ensure reliable
turn-on. Fast power supply edges minimize this effect.
Figure 12a. Turn-On/Transient Response Test Circuit
0V OR 10V
0V TO 10V
SUPPLY
Figure 12b. Turn-On Characteristics
is slightly below the minimum specified level.
100
100
10k
10k
90
0%
90
0%
10
10
Figure 12c. Turn-On Settling
5V
1V
5V
1mV
1
0.22 F
DUT
20 s
20 s
20 s
20 s
V
OUT
0.22 F
5V OR 10V
0V OR 5V
–12–
DYNAMIC PERFORMANCE
Many A/D and D/A converters present transient current loads
to the reference, and poor reference response can degrade the
converter’s performance. The AD1582/AD1583/AD1584/AD1585
family of references provides superior static and dynamic line
and load regulation. Since these series references are capable of
both sourcing and sinking large current loads, they exhibit
excellent settling characteristics.
Figure 13 displays the line transient response for the AD1582.
The circuit used to perform such a measurement is shown in
Figure 12a, where the input supply voltage is toggled from 5 V
to 10 V and the input and output capacitors are each 0.22 µF.
Figures 14 and 15 show the load transient settling characteristics
for the AD1582 when load current steps of 0 mA to +5 mA
and 0 mA to –1 mA are applied. The input supply voltage
remains constant at 5 V, the input decoupling and output load
capacitors are 4.7 µF and 1 µF, respectively, and the output current
is toggled. For both positive and negative current loads, the
reference responses settle very quickly and exhibit initial voltage
spikes less than 10 mV.
Figure 15. Load Transient Response (0 mA to –1 mA Load)
Figure 14. Load Transient Response (0 mA to 5 mA Load)
Figure 13. Line Transient Response
100
100
100
0%
90
0%
0%
90
10
10
90
10
5V
5V
5mV
200mV
5mV
5V
20 s
20 s
50 s
20 s
20 s
50 s
REV. D