MAX9144 Maxim, MAX9144 Datasheet - Page 8

• Manufacturer Part Number: MAX9144
• Description: The MAX9140/MAX9141 are single and the MAX9142/MAX9144 are dual/quad high-speed comparators optimized for systems powered from a 3V or 5V supply
• Manufacturer: Maxim

40ns, Low-Power, 3V/5V, Rail-to-Rail
Single-Supply Comparators
The MAX9140/MAX9141/MAX9142/MAX9144 contain a
current-driven output stage as shown in Figure 4.
During an output transition, I
or pulled to the output pin. The output source or sink
current is high during the transition, creating a rapid
slew rate. Once the output voltage reaches V
V
value, capable of maintaining the V
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
voltage output transition. This can be useful in noise-
sensitive applications where fast edges may cause
interference.
The high-gain bandwidth of the MAX9140/MAX9141/
MAX9142/MAX9144 requires design precautions to
realize the full high-speed capabilities of these com-
parators. The recommended precautions are:
8
Figure 2. MAX9141 Timing Diagram with Latch Operator
OL
1) Use a PCB with a good, unbroken, low-induc-
2) Place a decoupling capacitor (a 0.1µF ceramic
_______________________________________________________________________________________
, the source or sink current decreases to a small
tance ground plane.
capacitor is a good choice) as close to V
possible.
DIFFERENTIAL
VOLTAGE
Applications Information
INPUT
OUT
Circuit Layout and Bypassing
LE
V
V
V
V
V
OH
CC
2
2
OL
CC
CC
0
V
OS
Output Stage Circuitry
SOURCE
V
OD
t
or I
S
OH
SINK
t
H
or V
is pushed
t
PD
OL
CC
OH
static
as
or
Figure 3. Input Stage Circuitry
3) Pay close attention to the decoupling capacitor’s
4) On the inputs and outputs, keep lead lengths
5) Solder the device directly to the PCB instead of
IN–
IN+
bandwidth, keeping leads short.
short to avoid unwanted parasitic feedback
around the comparators.
using a socket.
t
LPW
4.1kΩ
4.1kΩ
t
LPD
TO INTERNAL
CIRCUITRY
TO INTERNAL
CIRCUITRY
MAX9140
MAX9141
MAX9142
MAX9144