1
All data sheets are subject to change without notice
(619) 503-3300 - Fax: (619) 503-3301- www.maxwell.com
16-Bit Digital to Analog Converter
7846A
©2003 Maxwell Technologies
All rights reserved.
05.29.03 REV 5
FEATURES:
•RAD-PAK® technology-hardened against natural
space radiation
• Total dose hardness:
- > 100 krad (Si), depending upon space mission
• Excellent Single Event Effects
- SEL
TH
> 114 MeV/mg/cm
2
- SEU < 8 MeV/mg/cm
2
• Package:
-28 pin R
AD-PAK® Flat Pack
• Microprocessor compatible with readback capability
• 16-Bit monotonicity over temperature
• ±2 LSBs integral linearity error
• Unipolar or bipolar output
• Multiplying capability
• Low power (100 mW typical)
DESCRIPTION:
Maxwell Technologies’ 7846A 16-Bit DAC converter microcir-
cuit features a greater than 100 krad (Si) total dose tolerance,
depending upon space mission. The 7846A has V
REF+
and
V
REF-
reference inputs and an on-chip output amplifier which
gives the option of unipolar or bipolar output. The 7846A 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 archi-
tecture 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 accu-
racy specifications, the 7846A 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 have
readback function which allows writing to and reading from the
I/O latch.
Maxwell Technologies' patented R
AD-PAK® packaging technol-
ogy incorporates radiation shielding in the microcircuit pack-
age. It eliminates the need for box shielding while providing
the required radiation shielding for a lifetime in orbit or space
mission. In a GEO orbit, R
AD-PAK provides greater than 100
krad (Si) radiation dose tolerance. This product is available
with screening up to Class S.
16
Segment
Switch
Matrix
Control
Logic
A2
A1
A3
I/O Latch
DAC Latch
12-bit DAC
-
+
-
+
-
+
R
R
6
5
23
22
25
24
203109
8
7
21 4
V
DD
V
CC
V
REF+
V
REF-
V
SS
DB15 DB0 DGND
CLR
LDAC
R/W
CS
V
OUT
R
IN
12
12
4
R
R
R
Logic Diagram
7846A
