Datasheet

Table Of Contents

LMH6642, LMH6643, LMH6644

SNOS966P –MAY 2001–REVISED MARCH 2013

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PRINTED CIRCUIT BOARD LAYOUT AND COMPONENT VALUES SECTION

Generally, a good high frequency layout will keep power supply and ground traces away from the inverting input

and output pins. Parasitic capacitances on these nodes to ground will cause frequency response peaking and

possible circuit oscillations (see Application Note OA-15 for more information). Texas Instruments suggests the

following evaluation boards as a guide for high frequency layout and as an aid in device testing and

characterization:

Device Package Evaluation Board PN

LMH6642MF 5-Pin SOT-23 LMH730216

LMH6642MA 8-Pin SOIC LMH730227

LMH6643MA 8-Pin SOIC LMH730036

LMH6643MM 8-Pin VSSOP LMH730123

LMH6644MA 14-Pin SOIC LMH730231

LMH6644MT 14-Pin TSSOP LMH730131

Another important parameter in working with high speed/high performance amplifiers, is the component values

selection. Choosing external resistors that are large in value will effect the closed loop behavior of the stage

because of the interaction of these resistors with parasitic capacitances. These capacitors could be inherent to

the device or a by-product of the board layout and component placement. Either way, keeping the resistor values

lower, will diminish this interaction to a large extent. On the other hand, choosing very low value resistors could

load down nodes and will contribute to higher overall power dissipation.

Product Folder Links: LMH6642 LMH6643 LMH6644