AD8389ACPZ Analog Devices Inc, AD8389ACPZ Datasheet - Page 7

• Manufacturer Part Number: AD8389ACPZ
• Description: IC TRPL DELAY LOCK LOOP 48-LFCSP
• Manufacturer: Analog Devices Inc
• Type: Delayed, Locked Loopr

Specifications of AD8389ACPZ

• Frequency: 85MHz
• Voltage - Supply: 3 V ~ 3.6 V
• Current - Supply: 11mA
• Operating Temperature: 0°C ~ 85°C
• Package / Case: 48-LFCSP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Count: -

OPERATING PRINCIPLES
The image quality of an LCD system is dependent on the timing
relationship between the control inputs, DX, CLX, ENBX(1–4),
and the video channels.
TFT delay and switching speed variations, due to temperature
variations and LCD aging, degrade image quality if not
compensated.
An internal reference TFT connected to an internal pull-up
resistor, as shown in Figure 6, characterizes the internal S/H
TFTs of the LCD and monitors switching speed and delay
variations due to aging and temperature. When the MON
output of an LCD that includes such an internal reference TFT
is connected to the reference input of the AD8389 delay-locked
timing loop, continuously optimized timing of the LCD is
maintained automatically.
ENBX(1–4)
200pF
CLX,
DX
Figure 6. AD8389 Application in the Red Channel of an LCD Projection System
MONITRI
DXI
VCONTR
ENBX(1–4)O
AD8389
CLXRO,
DXRO
Rev. 0 | Page 7 of 12
MONITO
DXI
CLXIN,
ENBX(1–4)I
LEVEL SHIFTER SECTION
AD8384/AD8385
OPERATION
As part of a closed loop, the AD8389 maintains a constant delay
between the common input, DXI, and each independent
feedback reference, MONITxI. The block diagram of such
closed-loop system is shown in Figure 6.
A constant delay, t
control inputs, is applied to the DXI input to approximate the
nominal, initially expected total delay, t
shifters and the LCD as shown in Table 5.
Table 5
COMPEDGE
1
1
0
0
ENBX(1–4)O
MONITI
CLXO,
DXO
SLOW
0
1
0
1
7
, selected via the COMPEDGE and SLOW
RED LCD
REGISTER
H SHIFT
15/f
9/f
32/f
26/f
MON
CLK
CLK
CLK
CLK
+ t
+ t
+ t
+ t
4
4
4
4
Constant Delay
7
, through the level
DX
MONITRI
DX
MONITRI
CONSTANT
CONSTANT
AD8389