AD1580ART View Datasheet(PDF) - Analog Devices
Part Name
Description
Manufacturer
AD1580ART Datasheet PDF : 8 Pages
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2.0V
1.8V
VIN
CL = 0.01µF
10mV/DIV
50µs/DIV
Figure 17. Transient Response with Capacitive Load
PRECISION MICROPOWER LOW DROPOUT
REFERENCE
The circuit in Figure 18 provides an ideal solution for making a
stable voltage reference with low standby power consumption,
low input/output dropout capability, and minimum noise
output. The amplifier both buffers and optionally scales up the
AD1580 output voltage, VR. Output voltages as high as 2.1 V
can supply 1 mA of load current. A one-pole filter connected
between the AD1580 and the OP193 input may be used to
achieve low output noise. The nominal quiescent power consump-
tion is a mere 200 µW.
3V
34.8kΩ
205Ω
4.7µF
AD1580
OP193
VOUT = +1.225V
OR
VOUT = +1.225 (1+R2/R3)
R3 R2
Figure 18. Micropower Buffered Reference
USING THE AD1580 WITH 3 V DATA CONVERTERS
The AD1580’s low output drift (50 ppm/°C) and compact sub-
miniature SOT-23 package makes it ideally suited for today’s
high performance converters in space critical applications.
AD1580
One family of ADCs that the AD1580 is well suited for is the
AD7714-3 and AD7715-3. The AD7714/AD7715 are charge-
balancing (sigma-delta) A/D converters with on-chip digital
filtering intended for the measurement of wide dynamic range,
low frequency signals such as those representing chemical,
physical or biological processes. Figure 19 shows the AD1580
connected to the AD7714/AD7715 for 3 V operation.
3V
34.8kΩ
AD1580
REFIN(+)
REFIN(–)
RSW
5kΩ (TYP)
CREF
(3–8pF)
AD7714/15–3
HIGH
IMPEDANCE
>1GΩ
SWITCHING
FREQUENCY DEPENDS
ON FCLKIN
Figure 19. Reference Circuit for the AD7714/AD7715–3
The AD1580 is ideal for creating the reference level to use with
12-bit multiplying DACs such as the AD7943, AD7945, and
AD7948. In the single supply bias mode (Figure 20), the
impedance seen looking into the IOUT2 terminal changes with
DAC code. If the AD1580 drives IOUT2 and AGND directly,
less than 0.2 LSBs of additional linearity error will result. The
buffer amp eliminates any linearity degradation that could result
from variations in the reference level .
+3.3V
VIN
VREF
VDD
DAC
RBF
IOUT1
IOUT2
C1
A1
VOUT
AD7943/45/48 AGND
DGND
A1: OP295
AD822
OP2283
+3.3V
41.2kΩ
A1
AD1580
SIGNAL GROUND
Figure 20. Single Supply System
REV. 0
–7–
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