EL4421CN Elantec Semiconductor, Inc. (acquired by Intersil), EL4421CN Datasheet - Page 12

• Manufacturer Part Number: EL4421CN
• Description: Multiplexed-input Video Amplifier
• Manufacturer: Elantec Semiconductor, Inc. (acquired by Intersil)

Applications Information
behavior is assured In any event keeping signals
within guaranteed compliance limits will assure
freedom from overload problems
The input and output ranges are substantially
constant with temperature
Power Supplies
The mux-amps work well on any supplies from
voltages as long as the requirements of the Gnd
pin are observed (see the Switching Characteris-
tics section for a discussion) The supplies should
be bypassed close to the device with short leads
4 7 F tantalum capacitors are very good and no
smaller bypasses need be placed in parallel Ca-
pacitors as small as 0 01 F can be used if small
load currents flow
Single-polarity supplies such as
Characteristics section The inputs and outputs
will have to have their levels shifted above
ground to accommodate the lack of negative sup-
ply
The dissipation of the mux-amps increases with
power supply voltage and this must be compati-
ble with the package chosen This is a close esti-
mate for the dissipation of a circuit
For instance the EL4422 draws a maximum of
14 mA and we might require a 2V peak output
into 150
The R
supplies is 191 mW The maximum Supply volt-
age that the device can run on for a given P
the other parameter is
g
a
EL4421C 22C 41C 42C 43C 44C
Multiplexed-Input Video Amplifiers
3V to
P
V
5V can be used as described in the Switching
Where
D
S
e
max
PAR
g
2V
15V The supplies may be of different
e
and a 270
S c
is 117
I
rent
V
sumed equal)
V
R
loading the output
(P
s
S
O
PAR
I
D
max is the maximum supply cur-
s
if the output voltage
is the
a
max
V
is the parallel of all resistors
O 2
The dissipation with
a
a
(V
R
g
270
PAR
S
– V
supply voltage (as-
) 2Is
O
feedback divider
)
c
a
V
a
O
V
12V with
O
R
Contd
PAR
R
D
PAR
g
and
5V
)
12
The maximum dissipation a package support is
The most difficult case is the SO-8 package With
a maximum die temperature of 150 C and a maxi-
mum ambient temperature of 85 the 65 temper-
ature rise and package thermal resistance of
170 W gives a maximum dissipation of 382 mW
This allows a maximum supply voltage of
for the EL4422 operated in our example If the
EL4421 were driving a light load (R
it could operate on
mum ambient
The EL4441 through EL4444 can operate on
can be powered by
ages
Output Loading
The output stage of the mux-amp is very power-
ful and can source 80 mA and sink 120 mA Of
course this is too much current to sustain and
the part will eventually be destroyed by excessive
dissipation or by metal traces on the die opening
The metal traces are completely reliable while de-
livering the 30 mA continuous output given in
the Absolute Maximum Ratings table in this
data sheet or higher purely transient currents
Gain or gain accuracy degrades only 10% from
no load to 100
degrade frequency response and video distortion
only a bit becoming noticeably worse for loads
k
g
P
12V supplies in the SO package and all parts
100
Where T
D
max
ature 150 C for reliability less to re-
tain optimum electrical performance
T
70 for commercial and 85 C for indus-
trial range
R
mounted package obtained from data
sheet dissipation curves
e
D
A
TH
(T
max is the maximum die temper-
max is the ambient temperature
load Heavy resistive loading will
is the thermal resistance of the
D
g
g
max-T
15V supplies at a 70 maxi-
15V supplies in DIP pack-
A
max) R
PAR
TH
g
9 2V
% )