LMH6672MA National Semiconductor, LMH6672MA Datasheet - Page 12

• Manufacturer Part Number: LMH6672MA
• Description: IC, OP-AMP, 90MHZ, 135V/µs, SOIC-8
• Manufacturer: National Semiconductor

Specifications of LMH6672MA

• Op Amp Type: High Speed
• No. Of Amplifiers: 2
• Bandwidth: 90MHz
• Slew Rate: 135V/µs
• Supply Voltage Range: ± 2.5V To ± 6.5V
• Amplifier Case Style: SOIC
• No. Of Pins: 8
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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Application Notes
I
A
turns ratio transformer, is
For a Gaussian signal, which the DMT ADSL signal approxi-
mates, A
346 mW.
In the SOIC package, with a θ
temperature rise of 60˚C. With an ambient temperature at
the maximum recommended 85˚C, the T
below the specified 150˚C maximum.
Even if we assume the absolute maximum I
ture of 18 mA, when we scale up the I
mA, the P
to 147˚C.
Although very few CPE applications will ever operate in an
environment as hot as 85˚C, if a lower T
LMH6672 is to be used in an application where the power
dissipation is higher, the PSOP package provides a much
lower θ
= (22.6 mA + 9.6 mA) x 12V = 386 mW and P
Q
VG
= 14.4 - 4.8 = 9.6 mA
|I
OUT
JA
VG
| for a full-rate ADSL CPE application, using a 1:2
DRIVER
of only 58.6˚C/W.
|I
OUT
| =
only goes up by 41 mW causing a 62˚C rise
JA
= 22.6 mA. Therefore, P
(Continued)
of 172˚C/W, this causes a
Q
= 28.28 mA RMS.
J
proportionally to 7
J
is at 145˚C, well
is desired or the
S
DRIVER
over tempera-
is 40 =
TOT
12
Using the same P
ture rise is only 19˚ and 21˚C, resulting in T
ambient of 104˚C and 106˚C respectively.
CIRCUIT LAYOUT CONSIDERATIONS
National Semiconductor suggests the following evaluation
boards as a guide for high frequency layout and as an aid in
device testing and characterization. Since the exposed PAD
(or DAP) of the PSOP package is internally floating, the
footprint for DAP could be connected to ground plane in PCB
for better heat dissipation.
These free evaluation boards are shipped when a device
sample request is placed with National Semiconductor.
Device
LMH6672MA
LMH6672MR
DRIVER
Package
8-Pin SOIC
8-Pin PSOP
as above, we find that the tempera-
Evaluation
Board PN
CLC730036
CLC730121
J
’s in an 85˚C