ICL7104-14CPL Intersil, ICL7104-14CPL Datasheet - Page 18

• Manufacturer Part Number: ICL7104-14CPL
• Description: 14 BIT A/D CONVERTER
• Manufacturer: Intersil

Specifications of ICL7104-14CPL

• Rohs Status: RoHS non-compliant
• Other names: NT5018

Power Supply Sequencing
Because of the nature of the CMOS process used to
fabricate the ICL7104, and the multiple power supplies
used, there are certain conditions of these supplies under
which a disabling and potentially damaging SCR action can
occur. All of these conditions involve the V+ supply (Norm
+5V) being more positive than the V++ supply. If there is
any possibility of this occurring during start-up, shut down,
under transient conditions during operation, or when insert-
ing a PC board into a “hot” socket, etc., a diode should be
placed between V+ and V++ to prevent it. A germanium or
Schottky rectifier diode would be best, but in most cases a
silicon rectifier is adequate.
Analog and Digital Grounds
Extreme care must be taken to avoid ground loops in the
layout of ICL7104 circuits, especially in 16-bit and high sen-
sitivity circuits. It is most important that return currents from
DIGITAL
LOGIC
V
IN
+
-
FILTER
CAP
I/P
IC L7104 - 14
IC L7104 - 16
DIG GND
AN GND
ICL7104
ICL7104
PIN 35
PIN 2
98,304 - 32,769
24,576 - 8,193
AUTOZERO
(COUNT)
C
8068 PIN 2
AZ
COMP
CONVERSION T IME (IN CONTINUOUS MODE):
FIGURE 1. GROUNDING SEQUENCE
(IF USED)
BUFF
-IN
BUFF
OUT
DEVICE PIN
(FIXED COUNT)
131,072
32,768
INTEGRATE
ICL7104
32768
8192
†
†
t
REF
VOLTAGE
t
18
O SC
O SC
V
REF
digital loads are not fed into the analog ground line. A rec-
ommended connection sequence for the ground lines is
shown in Figure 16.
Application Notes
Some application notes that may be found useful are listed
here:
(7104 - 14)
(7104 - 16)
AN016
AN017
AN018
AN030
NOTE #
+5V SUPPLY BYPASS CAPACITOR(S)
DEINTEGRATE
REFERENCE
EXTERNAL
(COUNT)
0 - 16383
0 - 65535
(IF USED)
“Selecting A/D Converters”, by Dave Fullagar
“The Integrating A/D Converter”, by Lee Evans
“Do’s and Don’ts of Applying A/D Converters,” by
Peter Bradshaw and Skip Osgood
“Building a Battery-Operated Auto Ranging DVM
with the ICL7106”
ICL7104
AN GND
PIN 35
+15V
DESCRIPTION
BOARD
-15V
EDGE
SUPPLY
RETURN