ADA4932-1/ADA4932-2

Rev. A | Page 24 of 28

LAYOUT, GROUNDING, AND BYPASSING

As a high speed device, the ADA4932-x is sensitive to the

PCB environment in which it operates. Realizing its superior

performance requires attention to the details of high speed

PCB design.

The first requirement is a solid ground plane that covers as much

of the board area around the ADA4932-x as possible. However,

the input summing nodes (Pin 2 and Pin 3) should be cleared of

all ground and power planes (see Figure 64). Clearing the ground

and power planes minimizes any stray capacitance at these nodes

and thus minimizes peaking of the response of the amplifier at

high frequencies.

the exposed pad, soldered to a high thermal conductivity 4-layer

circuit board, as described in EIA/JESD51-7.

Bypass the power supply pins as close to the device as possible

and directly to a nearby ground plane. High frequency ceramic

chip capacitors should be used. It is recommended that two

parallel bypass capacitors (1000 pF and 0.1 μF) be used for each

supply. Place the 1000 pF capacitor closer to the device. Further

away, provide low frequency bulk bypassing using 10 μF tantalum

capacitors from each supply to ground.

Signal routing should be short and direct to avoid parasitic effects.

Wherever complementary signals exist, provide a symmetrical

layout to maximize balanced performance. When routing

differential signals over a long distance, keep PCB traces close

together, and twist any differential wiring to minimize loop

area. Doing this reduces radiated energy and makes the circuit

less susceptible to interference.

1.30

0.80

0.80

1.30

Figure 65. Recommended PCB Thermal Attach Pad Dimensions (Millimeters)

0.30

PLATED

VIA HOLE

1.30

GROUND PLANE

POWER PLANE

BOTTOM METAL

TOP METAL

Figure 66. Cross-Section of 4-Layer PCB Showing Thermal Via Connection to Buried Ground Plane (Dimensions in Millimeters)