EL1516 INTERSIL [Intersil Corporation], EL1516 Datasheet - Page 14

• Manufacturer Part Number: EL1516
• Description: Dual Ultra Low Noise Amplifier
• Manufacturer: INTERSIL [Intersil Corporation]

Applications Information
Product Description
The EL1516 is a dual voltage feedback operational amplifier
designed especially for DMT ADSL and other applications
requiring very low voltage and current noise. It also features
low distortion while drawing moderately low supply current.
The EL1516 uses a classical voltage-feedback topology
which allows it to be used in a variety of applications where
current-feedback amplifiers are not appropriate because of
restrictions placed upon the feedback element used with the
amplifier. The conventional topology of the EL1516 allows,
for example, a capacitor to be placed in the feedback path,
making it an excellent choice for applications such as active
filters, sample-and-holds, or integrators.
ADSL CPE Applications
The low noise EL1516 amplifier is specifically designed for
the dual differential receiver amplifier function with ADSL
transceiver hybrids as well as other low-noise amplifier
applications. A typical ADSL CPE line interface circuit is
shown in Figure 44. The EL1516 is used in receiving DMT
down stream signal. With careful transceiver hybrid design
and the EL1516 1.4nV/√Hz voltage noise and 1.5pA/√Hz
current noise performance, -140dBm/Hz system background
noise performance can be easily achieved.
Power Dissipation
With the wide power supply range and large output drive
capability of the EL1516, 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
RECEIVE
RECEIVE
DRIVER
INPUT
OUT +
OUT -
FIGURE 44. TYPICAL LINE INTERFACE CONNECTION
AMPLIFIERS
RECEIVE
R
G
+
+
-
-
R
R
R
R
+
+
+
-
-
-
F
F
F
F
R
R
R
R
14
IN
IN
R
R
OUT
JMAX
OUT
) for all
LINE +
LINE -
EL1516, EL1516A
Z
LINE
EL1516 to remain in the safe operating area. These
parameters are related as follows:
where:
• PD
• PD
where:
• T
• θ
• 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
75°C, I
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
giving the results seen in Table 1.
Single-Supply Operation
The EL1516 has been designed to have a wide input and
output voltage range. This design also makes the EL1516 an
excellent choice for single-supply operation. Using a single
positive supply, the lower input voltage range is within 1.2V
of ground (R
within 875mV of ground. Upper input voltage range reaches
3.6V, and output voltage range reaches 3.8V with a 5V
supply and R
on a single 5V supply. This wide output voltage range also
PD
T
EL1516IS
EL1516IY
EL1516AIY
JMAX
dissipation of each amplifier in the package (PD
application
MAX
MAX
JA
PART
MAX
S
OUTMAX
L
MAXTOTAL
MAX
MAX
= Load resistance
= Supply voltage
= Thermal resistance of the package
SMAX
=
= Maximum supply current of 1 amplifier
=
= Maximum ambient temperature
T
for each amplifier can be calculated as follows:
2
= Maximum power dissipation of 1 amplifier
MAX
×
L
= Maximum output voltage swing of the
L
PACKAGE
= 7.7mA, and the package θ
V
MSOP10
= 500Ω), and the lower output voltage range is
MSOP8
= 500Ω. This results in a 2.625V output swing
S
+
SO8
×
is the sum of the maximum power
(
θ
I
SMAX
JA
×
PD
+
TABLE 1.
(
110°C/W
115°C/W
115°C/W
MAXTOTAL
OUTMAX
V
S
θ
JA
–
V
OUTMAX
JMAX
is 1.4V, and R
)
MAX P
0.406W @
0.400W @
0.400W @
@ T
= 150°C, T
85°C
85°C
85°C
JA
)
MAX
×
DISS
s are shown in
V
--------------------------- -
OUTMAX
R
L
MAX
L
MAX V
MAX
May 4, 2005
= 150Ω,
FN7328.0
)
=
S