AD7846 Datasheet, PDF (1/16 Pages) Analog Devices – LC2MOS 16-Bit Voltage Output DAC

a
LC²MOS
16-Bit Voltage Output DAC
FEATURES
16-Bit Monotonicity over Temperature
؎2 LSBs Integral Linearity Error
Microprocessor Compatible with Readback Capability
Unipolar or Bipolar Output
Multiplying Capability
Low Power (100 mW Typical)
AD7846
FUNCTIONAL BLOCK DIAGRAM
V_CC
V_DD
V_{REF +}
R
A2
16
R
SEGMENT
SWITCH
MATRIX
R
A1
V_{REF –}
4
AD7846
R
R
12-BIT DAC
12
DAC LATCH
12
I/O LATCH
A3
CONTROL
LOGIC
R_IN
V_OUT
CS
R/ W
LDAC
CLR
GENERAL DESCRIPTION
The AD7846 is a 16-bit DAC constructed with Analog Devices’
LC²MOS process. It has V_REF+ and V_REF– reference inputs and
an on-chip output amplifier. These can be configured to give a
unipolar output range (0 V to +5 V, 0 V to +10 V) or bipolar
output ranges (± 5 V, ± 10 V).
The DAC uses a segmented architecture. The 4 MSBs in the
DAC latch select one of the segments in a 16-resistor string.
Both taps of the segment are buffered by amplifiers and fed to a
12-bit DAC, which provides a further 12 bits of resolution. This
architecture ensures 16-bit monotonicity. Excellent integral
linearity results from tight matching between the input offset
voltages of the two buffer amplifiers.
In addition to the excellent accuracy specifications, the AD7846
also offers a comprehensive microprocessor interface. There are
16 data I/O pins, plus control lines (CS, R/W, LDAC and CLR).
R/W and CS allow writing to and reading from the I/O latch.
This is the readback function which is useful in ATE applica-
tions. LDAC allows simultaneous updating of DACs in a multi-
DAC system and the CLR line will reset the contents of the
DAC latch to 00 . . . 000 or 10 . . . 000 depending on the state
of R/W. This means that the DAC output can be reset to 0 V in
both the unipolar and bipolar configurations.
The AD7846 is available in 28-lead plastic, ceramic, and PLCC
packages.
V_SS
DB15 DB0
DGND
PRODUCT HIGHLIGHTS
1. 16-Bit Monotonicity
The guaranteed 16-bit monotonicity over temperature makes
the AD7846 ideal for closed-loop applications.
2. Readback
The ability to read back the DAC register contents minimizes
software routines when the AD7846 is used in ATE systems.
3. Power Dissipation
Power dissipation of 100 mW makes the AD7846 the lowest
power, high accuracy DAC on the market.
REV. E
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