Datasheet

Output Stage Circuitry
The MAX941/MAX942/MAX944 contain a current-driven
output stage as shown in Figure 4. During an output transi-
tion, I
SOURCE
or I
SINK
is pushed or pulled to the output pin.
The output source or sink current is high during the transi-
tion, creating a rapid slew rate. Once the output voltage
reaches V
OH
or V
OL
, the source or sink current decreases
to a small value, capable of maintaining the V
OH
or V
OL
static condition. This significant decrease in current con-
serves power after an output transition has occurred.
One consequence of a current-driven output stage is a
linear dependence between the slew rate and the load
capacitance. A heavy capacitive load will slow down a volt-
age output transition. This can be useful in noisesensitive
applications where fast edges may cause interference.
Applications Information
Circuit Layout and Bypassing
The high gain bandwidth of the MAX941/MAX942/
MAX944 requires design precautions to realize the com-
parators’ full high-speed capability. The recommended
precautions are:
1) Use a printed circuit board with a good, unbroken, low-
inductance ground plane.
2) Place a decoupling capacitor (a 0.1μF ceramic capaci-
tor is a good choice) as close to V+ as possible.
3) Pay close attention to the decoupling capacitor’s band-
width, keeping leads short.
4) On the inputs and outputs, keep lead lengths short to
avoid unwanted parasitic feedback around the com-
parators.
5) Solder the device directly to the printed circuit board
instead of using a socket.
Figure 2. MAX941 Timing Diagram with Latch Operator
V
OH
t
LPW
OUT
t
LPD
t
PD
V+
0V
V+
0V
V+
2
V+
2
V
OL
LATCH
DIFFERENTIAL
INPUT
VOLTAGE
V
OS
t
H
t
S
MAX941/MAX942/
MAX944
High-Speed, Low-Power, 3V/5V, Rail-to-Rail,
Single-Supply Comparators
www.maximintegrated.com
Maxim Integrated │ 8