EL5123 Intersil Corporation, EL5123 Datasheet - Page 12

• Manufacturer Part Number: EL5123
• Description: Buffer, Quad 12MHz, Rail-to-rail Input-Output, 600
• Manufacturer: Intersil Corporation

when sourcing, and
P
when sinking.
where:
If we set the two P
can solve for R
power dissipation curves provide a convenient way to see if
the device will overheat. The maximum safe power
dissipation can be found graphically, based on the package
type and the ambient temperature. By using the previous
equation, it is a simple matter to see if P
device's power derating curves.
Unused Buffers
It is recommended that any unused buffer have the input tied
to the ground plane.
Driving Capacitive Loads
The EL5123, EL5223, EL5323, and EL5423 can drive a wide
range of capacitive loads. As load capacitance increases,
however, the -3dB bandwidth of the device will decrease and
the peaking increase. The buffers drive 10pF loads in
parallel with 10kΩ with just 1.5dB of peaking, and 100pF
with 6.4dB of peaking. If less peaking is desired in these
applications, a small series resistor (usually between 5Ω and
50Ω) can be placed in series with the output. However, this
will obviously reduce the gain slightly. Another method of
reducing peaking is to add a “snubber” circuit at the output.
A snubber is a shunt load consisting of a resistor in series
with a capacitor. Values of 150Ω and 10nF are typical. The
advantage of a snubber is that it does not draw any DC load
current or reduce the gain.
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notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
DMAX
i = 1 to Total number of buffers
V
I
V
I
SMAX
LOAD
S
OUT
= Total supply voltage
=
i = Maximum output voltage of the application
i = Load current
= Maximum quiescent current per channel
Σi V
[
S
LOAD
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
×
I
SMAX
DMAX
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
i to avoid device overheat. The package
For information regarding Intersil Corporation and its products, see www.intersil.com
+
equations equal to each other, we
(
V
OUT
12
i V
–
S
- )
×
DMAX
EL5123, EL5223, EL5323, EL5423
I
LOAD
exceeds the
i
]
Power Supply Bypassing and Printed Circuit
Board Layout
As with any high frequency device, good printed circuit
board layout is necessary for optimum performance. Ground
plane construction is highly recommended, lead lengths
should be as short as possible, and the power supply pins
must be well bypassed to reduce the risk of oscillation. For
normal single supply operation, where the V
connected to ground, a 0.1µF ceramic capacitor should be
placed from V
should then be connected from V
4.7µF capacitor may be used for multiple devices. This same
capacitor combination should be placed at each supply pin
to ground if split supplies are to be used.
S
+ pin to ground. A 4.7µF tantalum capacitor
S
+ pin to ground. One
S
- pin is
November 19, 2004
FN7176.1