FUNCTIONAL BLOCK DIAGRAM
REV. A
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a
Microprocessor-Compatible
12-Bit D/A Converter
AD667*
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700 Fax: 617/326-8703
FEATURES
Complete 12-Bit D/A Function
Double-Buffered Latch
On Chip Output Amplifier
High Stability Buried Zener Reference
Single Chip Construction
Monotonicity Guaranteed Over Temperature
Linearity Guaranteed Over Temperature: 1/2 LSB max
Settling Time: 3 ms max to 0.01%
Guaranteed for Operation with 612 V or 615 V
Supplies
Low Power: 300 mW Including Reference
TTL/5 V CMOS Compatible Logic Inputs
Low Logic Input Currents
MIL-STD-883 Compliant Versions Available
PRODUCT DESCRIPTION
The AD667 is a complete voltage output 12-bit digital-to-analog
converter including a high stability buried Zener voltage refer-
ence and double-buffered input latch on a single chip. The
converter uses 12 precision high speed bipolar current steering
switches and a laser trimmed thin-film resistor network to pro-
vide fast settling time and high accuracy.
Microprocessor compatibility is achieved by the on-chip double-
buffered latch. The design of the input latch allows direct inter-
face to 4-, 8-, 12-, or 16-bit buses. The 12 bits of data from the
first rank of latches can then be transferred to the second rank,
avoiding generation of spurious analog output values. The latch
responds to strobe pulses as short as 100 ns, allowing use with
the fastest available microprocessors.
The functional completeness and high performance in the
AD667 results from a combination of advanced switch design,
high speed bipolar manufacturing process, and the proven laser
wafer-trimming (LWT) technology. The AD667 is trimmed at
the wafer level and is specified to ±1/4 LSB maximum linearity
error (K, B grades) at +25°C and ±1/2 LSB over the full operat-
ing temperature range.
The subsurface (buried) Zener diode on the chip provides a low
noise voltage reference which has long-term stability and tem-
perature drift characteristics comparable to the best discrete ref-
erence diodes. The laser trimming process which provides the
excellent linearity, is also used to trim the absolute value of the
reference as well as its temperature coefficient. The AD667 is
thus well suited for wide temperature range performance with
±1/2 LSB maximum linearity error and guaranteed monotonic-
ity over the full temperature range. Typical full-scale gain TC is
5 ppm/°C.
*Protected by Patent Numbers 3,803,590; 3,890,611; 3,932,863; 3,978,473;
4,020,486; and others pending.
The AD667 is available in five performance grades. The
AD667J and K are specified for use over the 0°C to +70°C tem-
perature range and are available in a 28-pin molded plastic DIP
(N) or PLCC (P) package. The AD667S grade is specified for
the –55°C to +125°C range and is available in the ceramic DIP
(D) or LCC (E) package. The AD667A and B are specified for
use over the –25°C to +85°C temperature range and are avail-
able in a 28-pin hermetically sealed ceramic DIP (D) package.
PRODUCT HIGHLIGHTS
1. The AD667 is a complete voltage output DAC with voltage
reference and digital latches on a single IC chip.
2. The double-buffered latch structure permits direct interface
to 4-, 8-, 12-, or 16-bit data buses. All logic inputs are TTL
or 5 volt CMOS compatible.
3. The internal buried Zener reference is laser-trimmed to 10.00
volts with a ±1% maximum error. The reference voltage is
also available for external application.
4. The gain setting and bipolar offset resistors are matched to
the internal ladder network to guarantee a low gain tempera-
ture coefficient and are laser-trimmed for minimum full-scale
and bipolar offset errors.
5. The precision high speed current steering switch and on-board
high speed output amplifier settle within 1/2 LSB for a 10 V
full-scale transition in 2.0 µs as when properly compensated.
6. The AD667 is available in versions compliant with MIL-
STD-883. Refer to the Analog Devices Military Products
Databook or current AD667/883B data sheet for detailed
specifications.
