AD584L AD [Analog Devices], AD584L Datasheet - Page 5

• Manufacturer Part Number: AD584L
• Description: Pin Programmable Precision Voltage Reference
• Manufacturer: AD [Analog Devices]

PERFORMANCE OVER TEMPERATURE
Each AD584 is tested at three temperatures over the –55 C to
+125 C range to ensure that each device falls within the Maxi-
mum Error Band (see Figure 4) specified for a particular grade
(i.e., S and T grades); three-point measurement guarantees per-
formance within the error band from 0 C to +70 C (i.e., J, K,
or L grades). The error band guaranteed for the AD584 is the
maximum deviation from the initial value at +25 C. Thus, given
the grade of the AD584, the designer can easily determine the
maximum total error from initial tolerance plus temperature
variation. For example, for the AD584T, the initial tolerance is
anteed to be 10.000 volts 25 mV from –55 C to +125 C.
OUTPUT CURRENT CHARACTERISTICS
The AD584 has the capability to either source or sink current
and provide good load regulation in either direction, although it
has better characteristics in the source mode (positive current
into the load). The circuit is protected for shorts to either posi-
tive supply or ground. The output voltage vs. output current
characteristics of the device is shown in Figure 5. Source current
is displayed as negative current in the figure; sink current is
positive. Note that the short circuit current (i.e., zero volts out-
put) is about 28 mA; when shorted to +15 volts, the sink cur-
rent goes to about 20 mA.
Figure 5. AD584 Output Voltage vs. Sink and Source
Current
DYNAMIC PERFORMANCE
Many low power instrument manufacturers are becoming in-
creasingly concerned with the turn-on characteristics of the
components being used in their systems. Fast turn-on compo-
nents often enable the end user to keep power off when not
REV. A
l0 mV and the error band is 15 mV. Hence, the unit is guar-
Figure 4. Typical Temperature Characteristic
–5–
needed, and yet respond quickly when the power is turned on
for operation. Figure 6 displays the turn-on characteristic of the
AD584. Figure 6a is generated from cold-start operation and
represents the true turn-on waveform after an extended period
with the supplies off. The figure shows both the coarse and fine
transient characteristics of the device; the total settling time to
within 10 millivolt is about 180 s, and there is no long ther-
mal tail appearing after the point.
NOISE FILTERING
The bandwidth of the output amplifier in the AD584 can be re-
duced to filter the output noise. A capacitor ranging between
0.01 F and 0.1 F connected between the Cap and V
nals will further reduce the wideband and feedthrough noise in
the output of the AD584, as shown in Figure 8. However, this
will tend to increase the turn-on settling time of the device so
ample warm-up time should be allowed.
Figure 8. Spectral Noise Density and Total rms Noise vs.
Frequency
Figure 7. Additional Noise Filtering with an External
Capacitor
Figure 6. Output Settling Characteristic
AD584
BG
termi-