el2111 Intersil Corporation, el2111 Datasheet - Page 6

• Manufacturer Part Number: el2111
• Description: Low Cost, Gain Of 2, Video Op Amp
• Manufacturer: Intersil Corporation

range requirement 25% and the output offset is shifted to
2.1V you can take a gain of 1.5 and have a standard NTSC
1V at the 75: load.
A simple transistor, capacitor and resistor sync tip clamp
may be used when the input is already AC coupled to set the
sync tip to ground. This gives the input a fixed DC level and
can be used like a direct coupled input. The clamp uses a
PNP transistor with the collector at ground and the base has
a 200k: resistor to 5V. The emitter connects to the amplifier
input and a capacitor from the video input. The clamp
functions as an inverted Beta current source for input bias
current with plus inputs and a clamp to ground for minus
inputs. The R
option (Figure 4).
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
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.
A
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
and R
+
–
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
B
Video
1V
47µF
CI
Option
For information regarding Intersil Corporation and its products, see www.intersil.com
Clamp
resistors are removed for the clamp
6
V
IN
1.4VB
PNP
2N3904
+
-
12K
R
1K
RF
AMP
FIGURE 4.
A
RC
200K
EL2111
2.1VB
Printed Circuit Layout
The EL2111 is well behaved, and easy to apply in most
applications. However, a few simple techniques will help
assure rapid, high quality results. As with any high frequency
device, good PCB layout is necessary for optimum
performance. Ground-plane construction is highly
recommended, as is good power supply bypassing. A 0.1µF
ceramic capacitor is recommended for bypassing both
supplies. Pin lengths should be as short as possible, and
bypass capacitors should be as close to the device pins as
possible. For good AC performance, parasitic capacitances
should be kept to a minimum at both inputs and at the
output. Resistor values should be kept under 5k: because
of the RC time constants associated with the parasitic
capacitance. Metal-film and carbon resistors are both
acceptable, use of wire-wound resistors is not recommended
because of their parasitic inductance. Similarly, capacitors
should be low-inductance for best performance.
+
–
5V
V1
V AMP
RO
36
47µF
CO
V
OUT
1V