AD580
output amplifier is also low power, requiring only 2.5 mA
THE AD580 AS A LOW POWER, LOW VOLTAGE,
PRECISION REFERENCE FOR DATA CONVERTERS
quiescent current. Its laser-trimmed offset voltage preserves the
1/2 LSB linearity of the AD7542KN without user trims, and it
typically settles to 1/2 LSB in less than 3 µs. It will provide the
0 V to –2.5 V output swing from 5 V supplies.
The AD580 has a number of features that make it ideally suited
for use with A/D and D/A data converters used in complex
microprocessor-based systems. The calibrated 2.500 V output
minimizes user trim requirements and allows operation from a
single, low voltage supply. Low power consumption (1 mA
quiescent current) is commensurate with that of CMOS-type
devices, while the low cost and small package complements the
decreasing cost and size of the latest converters.
+5V
+E
E
OUT
AD580
–E
GAIN
500Ω
ADJUST
V
REF
SYSTEM
8-BIT DATA BUS
V
DD
14
200Ω
OUT1
RFB
15
22pF
D0
D1
D2
D3
16
7
6
5
4
I
1
2
ANALOG
INPUT
I
AD7542
OUT2
AD544L
Figure 12 shows the AD580 used as a reference for the AD7542
12-bit CMOS DAC with complete microprocessor interface.
The AD580 and the AD7542 are specified to operate from a
single 5 V supply, thus eliminating the need to provide a 15 V
power supply for the sole purpose of operating a reference. The
AD7542 includes three 4-bit data registers, a 12-bit DAC
register, and address decoding logic. It may thus be interfaced
directly to a 4-, 8- or 16-bit data bus. Only 8 mA of quiescent
current from the single 5 volt supply is required to operate the
AD7542 which is packaged in a small, 16-pin DIP. The AD544
3
13
10
11
9
8
12
AGND
–5V
AD7
AD0
CLR A0 A1 WR CS
FROM SYSTEM RESET
DGND
A0
FROM ADDRESS BUS
A1
FROM WR
FROM ADDRESS DECODER
Figure 12. Low Power, Low Voltage Reference for the AD7542
Microprocessor-Compatible, 12-Bit DAC
Rev. B | Page ± of 8
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