MAX918 Maxim, MAX918 Datasheet - Page 12

• Manufacturer Part Number: MAX918
• Description: The MAX917–MAX920 nanopower comparators in space-saving SOT23 packages feature Beyond-the-Rails™ inputs and are guaranteed to operate down to +1
• Manufacturer: Maxim

SOT23, 1.8V, Nanopower, Beyond-the-Rails
Comparators With/Without Reference
6) Verify the trip voltages and hysteresis as follows:
Power-supply bypass capacitors are not typically
needed, but use 100nF bypass capacitors close to the
device’s supply pins when supply impedance is high,
supply leads are long, or excessive noise is expected
on the supply lines. Minimize signal trace lengths to
reduce stray capacitance. A ground plane and sur-
face-mount components are recommended.
Figure 4. MAX918/MAX920 Additional Hysteresis
12
=
V
IN
( ) ARE FOR MAX917/MAX918.
V
______________________________________________________________________________________
REF
V rising : V
V falling : V
IN
IN
Pin Configurations (continued)
R1
×
TOP VIEW
R1
IN- (REF)
Hysteresis = V
N.C.
⎛
⎜
⎝
R2
IN+
V
R1
EE
THR
THF
1
V
REF
Board Layout and Bypassing
1
2
4
3
+
=
=
R2
R3
1
V
REF
+
MAX917
MAX918
MAX919
MAX920
V
V
V
R3 R4
CC
EE
SO
CC
×
MAX918
MAX920
THR
1
+
R1
OUT
- V
⎞
⎟ −
⎠
⎛
⎜
⎝
6
R1
8
7
5
THF
1
R3 R4
N.C.
V
OUT
N.C.
+
CC
R1
+
R2
R4
1
+
R3
×
1
⎞
⎟
⎠
V
CC
Figure 5 shows a zero-crossing detector application.
The MAX919’s inverting input is connected to ground,
and its noninverting input is connected to a 100mV
signal source. As the signal at the noninverting input
crosses 0V, the comparator’s output changes state.
The Typical Application Circuit shows an application
that converts 5V logic to 3V logic levels. The MAX920 is
powered by the +5V supply voltage, and the pullup
resistor for the MAX920’s open-drain output is connect-
ed to the +3V supply voltage. This configuration allows
the full 5V logic swing without creating overvoltage on
the 3V logic inputs. For 3V to 5V logic-level translations,
simply connect the +3V supply voltage to V
+5V supply voltage to the pullup resistor.
Figure 5. Zero-Crossing Detector
100mV
5V (3V) LOGIC IN
100kΩ
100kΩ
P-P
Typical Application Circuit
IN-
IN+
IN+
IN-
+5V (+3V)
Zero-Crossing Detector
V
Logic-Level Translator
V
CC
EE
V
V
V
CC
CC
EE
LOGIC-LEVEL
TRANSLATOR
MAX920
MAX919
OUT
OUT
+3V (+5V)
CC
R
PULLUP
3V (5V)
LOGIC OUT
and the
P-P