AD589 Analog Devices, AD589 Datasheet - Page 4

• Manufacturer Part Number: AD589
• Description: Two-Terminal IC 1.2 V Reference
• Manufacturer: Analog Devices

AD589
APPLICATION INFORMATION
The AD589 functions as a two-terminal shunt-type regulator. It
provides a constant 1.23 V output for a wide range of input
current from 50 A to 5 mA. Figure 5 shows the simplest
configuration for an output voltage of 1.2 V or less. Note that
no frequency compensation is required. If additional filtering is
desired for ultralow noise applications, minimum recommended
capacitance is 1000 pF.
The AD589 can also be used as a building block to generate
other values of reference voltage. Figure 6 shows a circuit which
produces a buffered 10 V output. Total supply current for this
circuit is approximately 2 mA.
The low power operation of the AD589 makes it ideal for use in
battery operated portable equipment. It is especially useful as a
reference for CMOS analog-to-digital converters. Figure 7
shows the AD589 used in conjunction with two popular
integrating type CMOS A/D converters.
Figure 6. Single Supply Buffered 10 V Reference
Figure 5. Basic Configuration for 1.2 V or Less
15k
AD589
AD589
a. With 7109 12-Bit Binary A/D
2
3
+15V
AD108A
7
4
6.8k
5.6k
6.8k
0.01µF
AD589
2k
1
8
6
10k
8.2k
1k
1k
REF+
REF–
REF OUT
+V
+5V
7109
V
OUT
+5V
10V
–4–
The AD589 also is useful as a reference for CMOS multiplying
DACs such as the AD7533. These DACs require a negative
reference voltage in order to provide a positive output range.
Figure 8 shows the AD589 used to supply an equivalent –1.0 V
reference to an AD7533.
AD589
45°
0.036 (0.91)
0.046 (1.17)
Figure 8. AD589 as Reference for 10-Bit CMOS DAC
OUTLINE DIMENSIONS AND PIN DESIGNATIONS
39k
R1
Figure 7. AD589 Used as Reference for CMOS
A/D Converters
–15V
0.10 (2.54)
AD589
+15V
Dimensions shown in inches and (mm).
b. With 7107 Panel Meter A/D
5k
R2
0.028 (0.71)
0.048 (1.22)
GND
V
REF
DD
0.195 (4.95)
0.178 (4.52)
MSB
14
15
3
0.015 (0.38)
0.019 (0.48)
6.2k
10k
BIT
2
1
1k
OUT2
2
DIA
3
AD7533 SERIES
4
1
OUT1
REF HI
REF LO
COMMON
5
+V
AD542L
6
7107
0.500 (12.7)
7
MIN
+5V
16
R
0.209 (5.31)
0.230 (5.84)
8
FB
0.150 (3.81)
0.125 (3.17)
9
V
0 TO 1.00V
BIT
REV. B
10
OUT
LSB
DIA
=