12l lSI Design
Multiplexetf Character Serial BCD Output
-Support Components Required 10 (including displays)
Single +5V Power Supply Required
Balanced Differential Input
low Power Consumption (SOmWtypical)
Small Size: 16 Pin Dual-in-Line
Wide Temperature Range: Operating 0 to +7SoC
Storage -SSoC to +150oC
Extended Temperature Range Available Upon
3 DigitAID Converter
The AD2020 is a low cost 3 digit AID Converter, needing only
10 additional support components to make a complete 3 digit
DPM/DVM. The small total component count, the low cost,
and high reliability allow for a wide variation in display appli-
cations, especially those previously utilizing APM's (Analog
The technology utilized in the AD2020 is Integrated Injection
Logic (I2L), an extension of the long proven, high yield bipolar
process. This technique offers a significantly higher circuit
packing density. The input amplifier, comparator, band-gap
reference, counters, clock, control logic, multiplexer and
drivers needed to implement the dual slope conversion, are all
included on a single die.
The AD2020, although it has an internal reference, consumes
only SOmW of power and is operated from a single +5V supply,
unlike most DPM chips requiring two (2) supplies.
The DPM chip is packaged in a standard size 16 pin-dual-in-line
package. Utilizing a unique double passivation and noble-metal
interconnect scheme, this plastic package offers essentially
hermetic performance over a wide temperature range. The chip
is available in two versions with differing guaranteed operating
temperature ranges. The standard AD2020 is specified from 0
to +7SoC and because of the special packaging technique, an
extended temperature version is also available upon request.
The AD2020 measures inputs from -99mV to +999mV with
an accuracy of 0.1% of reading:1:1 digit. The balanced differen-
tial input rejects common mode voltages up to 200mV dc,
enough to eliminate most ground loop problems. Polarity de-
tection is automatic and "+" and "-" Overload conditions are
indicated through BCD coding, i.e., BCD code for "+" Over-
load is 1011 and 1010 for "-" Overload. Zero shift is :!:0.5mV .
over the full operating temperature range resulting in the same
performance as a chip with Auto-Zero.
The benefits in manufacturing labor, inventory and reliability
are self-evident. The only external components required for a
complete digital display product are: 1 capacitor, 3 transistors,
1 decoder driver, 2 potentiometers and 3 displays, all operated
from a single 5 volt supply.
WHAT IS eL?
MOS and bipolar are the two basic LSI semiconductor proc-
esses. MOS produces very dense - therefore low-cost - logic
circuits, but has difficulty achieving precision analog circuitry.
Before 12L, bipolar could offer stable high-quality devices suit-
able for precision analog circuits, but logic consumed much
expensive chip area.
Integrated Injection Logic (12L) now allows the design of sin-
gle-chip devices containing both analog and digital functions,
without calling for the compromises required in the past. 12L
has a logic density that equals or exceeds that of MOS, while
employing a bipolar process suitable for precision analog
eL eliminates the complexity of conventional bipolar logic by
using inverted transistors (collectors and emitters are inter-
changed). Figure 1 shows a conventional transistor, with its
wraparound P+ isolation region, which is needed to separate
the collectors of adjacent transistors. When the transistors
are inverted, the collectors are automatically isolated, and the
emitters are grounded, at the same time.
AID CONVERTERS 403