±15kV ESD-Protected, Single/Dual/Octal,
CMOS Switch Debouncers
MAX6816/MAX6817/MAX6818
t
DP
IN1
EN
1/2
V
CC
t
EN
1/2
V
CC
OUT1–OUT8
OUT1
t
PE
OUT NORMALLY
1/2
V
CC
LOW
t
PE
t
PD
V
OL
+ 0.5V
IN2
OUT1–OUT8
t
PC
1/2
V
CC
OUT NORMALLY
HIGH
1/2
V
CC
V
OH
- 0.5V
t
PD
OUT2
CH
Figure 4. MAX6818 µP-Interface Timing Diagram
CH
+V
CC
MAX6818 ONLY
0.1µF
+V
CC
Figure 2. Input Characteristics
SW1
IN1
20V
IN
(20V/div)
0
-20V
IN8
SW8
4V
OUT
(2V/div)
0
OUT8
EN
CH
I/O
IRQ
µP
MAX6818
OUT1
D0
D7
Figure 5. MAX6818 Typical µP Interfacing Circuit
20ms/div
Figure 3. Switch Input ±25V Fault Tolerance
Robust Switch Inputs
The switch inputs on the MAX6816/MAX6817/MAX6818
have overvoltage clamping diodes to protect against
damaging fault conditions. Switch input voltages
can safely swing ±25V to ground (Figure 3). Proprietary
ESD-protection structures protect against high
ESD encountered in harsh industrial environments,
membrane keypads, and portable applications.
They are designed to withstand ±15kV per the
IEC1000-4-2 Air Gap Discharge Test and ±8kV per the
IEC1000-4-2 Contact Discharge Test.
Since there are 63kΩ (typical) pull-up resistors con-
nected to each input, driving an input to -25V will draw
approximately 0.5mA (up to 4mA for eight inputs) from
the V
CC
supply. Driving an input to +25V will cause
approximately 0.32mA of current (up to 2.6mA for eight
inputs) to flow back into the V
CC
supply. If the total sys-
tem V
CC
supply current is less than the current flowing
back into the V
CC
supply, V
CC
will rise above normal
levels. In some low-current systems, a zener diode on
V
CC
may be required.
±15kV ESD Protection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electro-
static discharges encountered during handling and
assembly. The MAX6816/MAX6817/MAX6818 have
extra protection against static electricity. Maxim's engi-
neers have developed state-of-the-art structures to pro-
tect against ESD of ±15kV at the switch inputs without
5
_______________________________________________________________________________________
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
