ISL59920_09 INTERSIL [Intersil Corporation], ISL59920_09 Datasheet - Page 14

• Manufacturer Part Number: ISL59920_09
• Description: Triple Analog Video Delay Lines
• Manufacturer: INTERSIL [Intersil Corporation]

NOTE: Test Register word = 000wxyz0. wxyz fed to DAC. z is LSB
TABLE 3. DAC VOLTAGE RANGE - INPUT REFERRED
wxyz
1000
1001
1010
1011
1100
1101
0000
0001
0010
0011
0100
0101
0110
1110
1111
0111
DAC RANGE [mV]
(GAIN 1)
14
-400
-350
-300
-250
-200
-150
-100
100
150
200
250
300
350
-50
50
0
ISL59920, ISL59921, ISL59922, ISL59923
DAC RANGE [mV]
(GAIN 2)
-200
-175
-150
-125
-100
100
125
150
175
-75
-50
-25
25
50
75
0
Power Dissipation
As the delay setting increases, additional filter blocks turn on
and insert into the signal path. When the delay per channel
increments, V
does not change significantly. Under the extreme settings,
the positive supply current reaches 141mA and the negative
supply current can be 41mA. Operating at ±5V power supply,
the worst-case ISL5992x power dissipation is:
The minimum θ
the ISL5992x is calculated using Equation 2:
Where:
T
T
For a 20 Ld package on a well laid-out PCB with good
connectivity between the QFN’s pad and the PCB copper
area, 31°C/W θ
yields a much higher power dissipation of 3.54W using
Equation 2 (see Figure 32). To disperse the heat, the bottom
heat spreader must be soldered to the PCB. Heat flows
through the heat spreader to the circuit board copper then
spreads and convects to air. Thus, the PCB copper plane
becomes the heatsink (see TB389). This has proven to be a
very effective technique. A separate application note, which
details the 20 Ld QFN PCB design considerations, is
available.
PD
θ
A
J
JA
is the maximum junction temperature (+135°C)
is the maximum ambient temperature (+85°C)
=
=
5 141mA
(
T
•
J
–
T
A
SP
) PD
JA
JA
⁄
+
current increases by 0.9mA while V
required for long term reliable operation of
5 41mA
thermal resistance can be achieved. This
•
=
55°
C W
⁄
=
910mW
May 28, 2009
SM
FN6826.1
(EQ. 1)
(EQ. 2)