Datasheet

MAX8215/MAX8216
±5V, ±12V (±15V) Dedicated
Microprocessor Voltage Monitors
6 _______________________________________________________________________________________
_______________Detailed Description
The MAX8215/MAX8216 contain 5 comparators (Figure
1). The comparator with its output labeled DOUT is dis-
tinguished from the others in that it can be set up to mon-
itor various voltages; each of the other 4 comparators
monitors a specific voltage. The DOUT comparator’s
noninverting input is available external to the device; its
inverting input is tied internally to the reference.
The MAX8215/MAX8216 comparators have open-drain
outputs. Thus, these devices require pull-up resistors
for proper operation. See the Typical Operating Circuit.
Open-drain outputs are useful for driving LEDs and for
situations in which the comparator outputs must be
connected together (i.e., wire-ORed).
Bypass V
DD
with 0.1µF connected to PGND.
__________Applications Information
Hysteresis
When the voltage on a typical comparator’s input is
at or near the voltage on the other input, ambient
noise generally causes the comparator output to
oscillate. The most common way to eliminate this
problem is by using hysteresis. When the two com-
parator input voltages are equal, hysteresis causes
one comparator input voltage to move quickly past
the other, thus taking the input out of the region
where oscillation occurs. Standard comparators
need external resistors for hysteresis; these resistors
are not necessary when using any of the MAX8215
and MAX8216 comparators because hysteresis is
built in.
NAME FUNCTION
1
VREF Output of the internal 1.24V reference
2 GND Ground. Connect to PGND.
3 +5V Input for monitoring +5V supply
PIN
4 -5V Input for monitoring -5V supply
5
+12V
(+15V)
MAX8215 input for monitoring +12V
(MAX8216 input for monitoring +15V)
6
-12V
(-15V)
MAX8215 input for monitoring -12V
(MAX8216 input for monitoring -15V)
7 DIN
Noninverting input of the auxiliary
comparator. Its inverting input is tied
to the internal reference.
8 PGND
9 DOUT Output of the auxiliary comparator
_____________________Pin Description
Power-supply ground. Bypass V
DD
to this pin.
Outputs of the four dedicated com-
parators
14 V
DD
10, 11,
12, 13
OUT4,
OUT3,
OUT2,
OUT1
Power-supply positive voltage input.
Bypass to PGND.
+5V
OUT1
-5V
OUT2
OUT3
+12V (+15V)
OUT4
-12V (-15V)
DOUT
DIN
1.24V REFERENCE
VREF
( ) ARE FOR
MAX8216 ONLY.
MAX8215
MAX8216
V
DD
PGND
GND
Figure 1. Block Diagram