Bypass

Capacitors

Output-matching

resistor close to

parasitic output

capacitance

Bypass

Capacitors

Ground plane

removed under

Minimize the

trace length of

the feedback

element

OPA659

SBOS342C – DECEMBER 2008 – REVISED NOVEMBER 2015

www.ti.com

Layout Guidelines (continued)

attenuation as a result of the voltage divider formed by the series output into the terminating impedance.

5. Socketing a high-speed part such as the OPA659 is not recommended. The additional lead length and

pin-to-pin capacitance introduced by the socket can create an extremely troublesome parasitic network that

can make it almost impossible to achieve a smooth, stable frequency response. Best results are obtained by

soldering the OPA659 directly onto the board.

6. The thermal slug on bottom of OPA659 DRB package must be tied to the most negative supply. The

DRB package is a thermally-enhanced package. Best results are obtained by soldering the exposed metal

tab on the bottom of the OPA659 DRB directly to a metal plane on the PCB that is connected to the most

negative supply voltage of the operational amplifier. For general layout guidelines, refer to the EVM layout in

the Schematic and PCB Layout section.

11.2 Layout Example

Figure 43. Layout Recommendation

11.3 Thermal Pad Information

The DRB package includes an exposed thermal pad for increased thermal performance. When using this

package, TI recommends to distribute the negative supply as a power plane, and tie the thermal pad to this

supply with multiple vias for proper power dissipation. For proper operation, the thermal pad must be tied to the

most negative supply voltage. TI recommends using five evenly-spaced vias under the device as shown in the

EVM layer views (see Figure 45). For more general data and detailed information about the exposed thermal

pad, go to www.ti.com/thermal.

22

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