JM3851012801BGA Datasheet, PDF (10/12 Pages) Analog Devices – Pin Programmable, Precision Voltage Reference

AD584
Data Sheet
The AD584 is normally used in the −10 V mode with the AD7574
to give a 0 V to +10 V ADC range. This is shown in Figure 17.
Bipolar output applications and other operating details can be
found in the data sheets for the CMOS products.
–15V
+15V
R3
V+
AD584
1.2kΩ
COMMON ^5%
GAIN TRIM
R2 2kΩ*
8
4
–10V REF
R1
1
10.0V
0.1µF
SIGNAL ^{2kΩ 10%*}
INPUT
0V TO +10V
1 _AD7574 18
2 ^{(TOP VIEW)}
3
4
DIGITAL
SUPPLY
RETURN
5
GROUND
INTERTIE
* R1 AND R2 CAN BE OMITTED IF
GAIN TRIM IS NOT REQUIRED.
ANALOG
GROUND
Figure 17. AD584 as −10 V Reference for CMOS ADC
PRECISION DAC REFERENCE
The AD565A, like many DACs, can operate with an external
10 V reference element (see Figure 19). This 10 V reference
voltage is converted into a reference current of approximately
0.5 mA via the internal 19.95 kΩ resistor (in series with the external
100 Ω trimmer). The gain temperature coefficient of the AD565A
is primarily governed by the temperature tracking of the 19.95 kΩ
resistor and the 5 kΩ/10 kΩ span resistors; this gain temperature
coefficient is guaranteed to 3 ppm/°C. Therefore, using the AD584K
(at 5 ppm/°C) as the 10 V reference guarantees a maximum full-
scale temperature coefficient of 18 ppm/°C more than the
commercial range. The 10 V reference also supplies the normal
1 mA bipolar offset current through the 9.95 kΩ bipolar offset
resistor. The bipolar offset temperature coefficient thus depends
only on the temperature coefficient matching of the bipolar offset
resistor to the input reference resistor and is guaranteed to
3 ppm/°C. Figure 18 demonstrates the flexibility of the AD584
applied to another popular digital-to-analog configuration.
V+
V+
A1 (MSB)
A2
A3
A4
A5
A6
A7
A8 (LSB)
COMP
C
5
13 ₁₄
6
7
15
8
AD
DAC08
9
10
11
4
12
16
3
1
2
V_REF (+)
V_REF (–) R14
R15
R14 = R15
R_L
I_O
V_LC
8
10.0V
1
AD584
3
2.5V
4
COMMON
V– I_OUT
Figure 18. Current Output, 8-Bit Digital-to-Analog Configuration
BIPOLAR OFFSET
ADJUST
15T
R1
100Ω
+15V
0.1µF
+15V
REF OUT
8
AD584 ¹
4
GAIN
ADJUST REF
15T ^IN
R2
100Ω _REF
GND
10V
19.95kΩ
20kΩ
V_CC
BIPOLAR OFF
AD565A
5kΩ
0.5mA
I_REF
9.95kΩ
5kΩ
DAC
I_OUT =
4 × I_REF × CODE
I_O
8kΩ
CODE INPUT
20V SPAN
10V SPAN
+15V
DAC OUT 2
3
6
OP AMP
OUTPUT
OP1177 ^±10V
–15V
–V_EE
POWER
GND
MSB
LSB
0.1µF
–15V
Figure 19. Precision 12-Bit DAC
Rev. C | Page 10 of 12