el2344 Intersil Corporation, el2344 Datasheet - Page 9

• Manufacturer Part Number: el2344
• Description: Triple Low-power 60mhz Unity-gain Stable Op Amp
• Manufacturer: Intersil Corporation

an excellent choice for applications such as fast log
amplifiers.
Power Dissipation
With the wide power supply range and large output drive
capability of the EL2344, it is possible to exceed the 150°C
maximum junction temperatures under certain load and
power-supply conditions. It is therefore important to calculate
the maximum junction temperature (T
applications to determine if power supply voltages, load
conditions, or package type need to be modified for the
EL2344 to remain in the safe operating area. These
parameters are related as follows:
where PDmaxtotal is the sum of the maximum power
dissipation of each amplifier in the package (PDmax).
PDmax for each amplifier can be calculated as follows:
PDmax = (2*V
where:
• T
• T
• PD
• V
• I
• V
• R
To serve as a guide for the user, we can calculate maximum
allowable supply voltages for the example of the video cable-
driver below since we know that T
T
shown in Table 1. If we assume (for this example) that we are
driving a back-terminated video cable, then the maximum
average value (over duty-cycle) of V
R
Single-Supply Operation
The EL2344 has been designed to have a wide input and
output voltage range. This design also makes the EL2344 an
excellent choice for single-supply operation. Using a single
positive supply, the lower input voltage range is within
100mV of ground (R
range is within 300mV of ground. Upper input voltage range
reaches 4.2V, and output voltage range reaches 3.8V with a
EL2344CN
EL2344CS
MAX
L
Application
SMAX
= 150:, giving the results seen in Table 1.
JA
MAX
OUTMAX
S
L
MAX
= Load Resistance
= Supply Voltage
= Thermal Resistance of the Package
= 75°C, I
= Maximum Ambient Temperature
= Maximum Supply Current of 1 Amplifier
= Maximum Power Dissipation of 1 Amplifier
T
JMAX
= Maximum Output Voltage Swing of the
PDIP14
SO14
S
PACKAGE
SMAX
*I
SMAX
= T
L
= 7.6mA, and the package T
= 500:), and the lower output voltage
MAX
+(V
TABLE 1
70° C/W
110°C/W
S
+ (
-V
4
9
T JA*
JA
OUTMAX
JMAX
(PDmaxtotal))
OUTMAX
1.071W @ 75° C
0.682W @ 75° C
Jmax
MAX PDISS
)*(V
= 150°C ,
@ T
) for all
OUTMAX
MAX
is 1.4V, and
JA
/R
s are
±11.5V
L
±7.5V
MAX
))
V
S
EL2344
5V supply and R
swing on a single 5V supply. This wide output voltage range
also allows single-supply operation with a supply voltage as
high as 36V or as low as 2.5V. On a single 2.5V supply, the
EL2344 still has 1V of output swing.
Gain-Bandwidth Product and the -3dB Bandwidth
The EL2344 has a gain-bandwidth product of 60MHz while
using only 5.2mA of supply current per amplifier. For gains
greater than 4, their closed-loop -3dB bandwidth is
approximately equal to the gain-bandwidth product divided
by the noise gain of the circuit. For gains less than 4, higher-
order poles in the amplifiers’ transfer function contribute to
even higher closed loop bandwidths. For example, the
EL2344 has a -3dB bandwidth of 120MHz at a gain of +1,
dropping to 60MHz at a gain of +2. It is important to note that
the EL2344 has been designed so that this “extra” bandwidth
in low-gain applications does not come at the expense of
stability. As seen in the typical performance curves, the
EL2344 in a gain of +1 only exhibits 1.0dB of peaking with a
1000: load.
Video Performance
An industry-standard method of measuring the video
distortion of components such as the EL2344 is to measure
the amount of differential gain (d
(d
0.286V
offset (0IRE) at either 3.58MHz for NTSC or 4.43MHz for
PAL. A second measurement is then made at 0.714V DC
offset (100IRE). Differential gain is a measure of the change
in amplitude of the sine wave, and is measured in percent.
Differential phase is a measure of the change in phase, and
is measured in degrees.
For signal transmission and distribution, a back-terminated
cable (75: in series at the drive end, and 75: to ground at
the receiving end) is preferred since the impedance match at
both ends will absorb any reflections. However, when double
termination is used, the received signal is halved; therefore a
gain of 2 configuration is typically used to compensate for
the attenuation.
The EL2344 has been designed as an economical solution
for applications requiring low video distortion. It has been
thoroughly characterized for video performance in the
topology described above, and the results have been
included as typical d
performance curves. In a gain of +2, driving 150:, with
standard video test levels at the input, the EL2344 exhibits
d
Because d
video performance of the EL2344 has been characterized
over the entire DC offset range from -0.714V to +0.714V. For
more information, refer to the curves of d
Input Offset.
G
P
) that they introduce. To make these measurements, a
and d
PP
P
(40IRE) signal is applied to the device with 0V DC
G
of only 0.04% and 0.15° at NTSC and PAL.
and d
L
= 500:. This results in a 3.5V output
P
G
can vary with different DC offsets, the
and d
P
specifications and as typical
G
) and differential phase
G
and d
P
vs DC