Dynamic Range: 88.5 dB
Resolution: 0.375 dB
On-Chip Data Latches
+5 V Operation
AD7111A Pin Compatible with AD7524
Digitally Controlled AGC System
Logarithmic D/A Converter
FUNCTIONAL BLOCK DIAGRAMS
The LOGDAC® AD7111/AD7111A are monolithic multiplying
D/A converters featuring wide dynamic range in a small pack-
age. Both DACs can attenuate an analog input signal over the
range 0 dB to 88.5 dB in 0.375 dB steps. They are available in
16-pin DIPs and SOIC packages. The AD7111 is also available
in a 20-terminal LCCC package.
The degree of attenuation across the DAC is determined by an
8-bit word applied to the onboard decode logic. This 8-bit word
is decoded into a 17-bit word which is then applied to a 17-bit
R-2R ladder. The very fine step resolution, which is available
over the entire dynamic range, is due to the use of this 17-bit
The AD7111/AD7111A are easily interfaced to a standard 8-bit
MPU bus via an 8-bit data port and standard microprocessor
control lines. The AD7111 WR input is edge triggered and re-
quires a rising edge to load new data to the DAC. The AD7111A
WR is level triggered to allow transparent operation of the
latches, if required. It should also be noted that the AD7111A is
exactly pin and function-compatible with the AD7524, an in-
dustry standard 8-bit multiplying DAC. This allows an easy up-
grading of existing AD7524 designs which would benefit both
from the wider dynamic range and the finer step resolution of-
fered by the AD7111A.
The AD7111/AD7111A are fabricated in Linear Compatible
CMOS (LC2MOS), an advanced, mixed technology process that
combines precision bipolar circuits with low power CMOS logic.
LOGDAC is a registered trademark of Analog Devices, Inc.
D0 – D7
D0 – D7
1. Wide Dynamic Range: 0 dB to 88.5 dB attenuation range in
0.375 dB steps.
2. Small Package: The AD7111/AD7111A are available in
16-pin DIPs and SOIC packages.
3. Transparent Latch Operation: By tying the CS and WR in-
puts low, the DAC latches in the AD7111A can be made
4. Fast Microprocessor Interface: Data setup times of 25 ns and
write pulse width of 57 ns make the AD7111A compatible
with modern microprocessors.
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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