Output Stage Circuitry

The MAX9140/MAX9141/MAX9142/MAX9144 contain a

current-driven output stage as shown in Figure 4.

or pulled to the output pin. The output source or sink

current is high during the transition, creating a rapid

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.

Applications Information

Circuit Layout and Bypassing

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:

1) Use a printed circuit board with a good, unbro-

ken, low-inductance ground plane.

2) Place a decoupling capacitor (a 0.1µF ceramic

possible.

3) Pay close attention to the decoupling capacitor’s

bandwidth, keeping leads short.

4) On the inputs and outputs, keep lead lengths

short to avoid unwanted parasitic feedback

around the comparators.

5) Solder the device directly to the printed circuit

board instead of using a socket.

40ns, Low-Power, 3V/5V, Rail-to-Rail

Single-Supply Comparators

8

_______________________________________________________________________________________

OUT

0

2

2

LE

DIFFERENTIAL

INPUT

VOLTAGE

MAX9140

MAX9141

MAX9142

MAX9144

4.1k

Ω

4.1k

Ω

TO INTERNAL

CIRCUITRY

TO INTERNAL

CIRCUITRY

IN–

IN+

Figure 3. Input Stage Circuitry

Figure 2. MAX9141 Timing Diagram with Latch Operator