lm7372mrx National Semiconductor Corporation, lm7372mrx Datasheet - Page 13

• Manufacturer Part Number: lm7372mrx
• Description: High Speed, High Output Current, Dual Operational Amplifier
• Manufacturer: National Semiconductor Corporation

Application Notes
Although this application shows a single supply, conversion
to a split supply is straightforward. The half supply resistive
divider network is eliminated and the bias resistors at the
non-inverting inputs are returned to ground, see Figure 3
(the pin numbers in Figure 3 are given for the LLP and PSOP
packages, those in Figure 1 are for the SOIC package). With
a split supply, note that the ground plane and the heatsink
copper must be separate and are at different potentials, with
the heatsink (pin 4 of the LLPand PSOP, pins 6,1,8,9 &16 of
the SOIC) now at a negative potential (V
In either configuration, the area under the input pins should
be kept clear of copper (Whether ground plane copper or
heatsink copper) to avoid parasitic coupling to the inputs.
PRINTED CIRCUIT BOARD LAYOUT and EVALUATION
BOARDS
Generally, a good high-frequency layout will keep power
supply and ground traces away from the inverting input and
output pins. Parasitic capacitance on these nodes to ground
will cause frequency response peaking and possible circuit
oscillations (see Application Note OA-15 for more informa-
tion). National Semiconductor suggests the following evalu-
ation boards as a guide for high frequency layout and as an
aid in device testing and characterization:
(Continued)
−
FIGURE 3. Split Supply Application (LLP)
).
13
The LM7372 is stable with non inverting closed loop gains as
low as +2. Typical of any voltage feedback operational am-
plifier, as the closed loop gain of the LM7372 is increased,
there is a corresponding reduction in the closed loop signal
bandwidth. For low distortion performance it is recom-
mended to keep the closed loop bandwidth at least 10X the
highest signal frequency. This is because there is less loop
gain (the difference between the open loop gain and the
closed loop gain) available at higher frequencies to reduce
harmonic distortion terms.
These free evaluation boards are shipped automatically
when a device sample request is placed with National Semi-
conductor.
The DAP (die attach paddle) on the LLP-8, and the PSOP
should be tied to V
respective Evaluation Board documentation.
Device
LM7372MA
LM7372ILD
LM7372MR
−
Package
16-Pin SOIC
8-Pin LLP
8-Pin PSOP
. It should not be tied to ground. See
20004926
Evaluation
Board PN
None
CLC730114
CLC730121
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