AD8389

Rev. 0 | Page 8 of 12

The phase detector compares the delayed DX and MONITxI

DX and MONITxI. Five matched delay lines maintain the phase

relationship between DXxO, CLXxO, and ENBX(1–4)xO.

delay through the level shifter and the LCD.

The external delay of a typical system is the sum of the level

shifter delay (20 ns typical) and the LCD delay, (typically in the

range of 20 ns to 120 ns). At a 75 MHz operating clock

frequency, the maximum expected total delay of 140 ns is equal

to 10.5 clock cycles, requiring COMPEDGE = 1, SLOW = 0 for

systems using negative active edge for DX.

MONITRI

CLX

ENBX1

ENBX2

ENBX3

ENBX4

CONSTANT

CLK

DX

DXO

MONITI

CLXO

ENBX1O

ENBX2O

ENBX3O

ENBX4O

Figure 7. Typical Input Waveforms at the AD8389 and at the LCD.

COMPEDGE = HIGH.