ADCMP606/ADCMP607

Rev. A | Page 12 of 16

The hysteresis control pin appears as a 1.25 V bias voltage seen

through a series resistance of 70 kΩ ± 20% throughout the

hysteresis control range. The advantages of applying hysteresis in

this manner are improved accuracy, improved stability, reduced

component count, and maximum versatility. An external bypass

capacitor is not recommended on the LE/HYS pin because it

impairs the latch function and often degrades the jitter perform-

ance of the device. As described in the Using/Disabling the

Latch Feature section, hysteresis control need not compromise

the latch function.

CROSSOVER BIAS POINTS

In both op amps and comparators, rail-to-rail inputs of this type

have a dual front-end design. Certain devices are active near the

mined point in the common-mode range, a crossover occurs. At

this point, normally VCCI/2, the direction of the bias current

reverses and the measured offset voltages and currents change.

The ADCMP606/ADCMP607 comparators slightly elaborate

on this scheme. Crossover points are found at approximately

0.6 V and 1.6 V common mode.

MINIMUM INPUT SLEW RATE REQUIREMENT

With the rated load capacitance and normal good PCB design

practice, as discussed in the Optimizing Performance section,

these comparators should be stable at any input slew rate with

no hysteresis. Broadband noise from the input stage is observed

in place of the violent chattering seen with most other high

speed comparators. With additional capacitive loading or poor

bypassing, oscillation is observed. This oscillation is due to the

high gain bandwidth of the comparator in combination with

feedback parasitics in the package and PC board. In many

applications, chattering is not harmful.