Data Sheet

ADN2891

Rev. B | Page 11 of 16

APPLICATIONS

PCB DESIGN GUIDELINES

Proper RF PCB design techniques must be used to ensure

optimal performance.

Output Buffer Power Supply and Ground Planes

Pin 9 (DRVEE) and Pin 12 (DRVCC) are the power supply and

ground pins that provide current to the differential output

buffer. To reduce possible series inductance, Pin 9, which is the

ground return of the output buffer, should connect to ground

directly. If the ground plane is an internal plane and

connections to the ground plane are vias, multiple vias in

parallel to ground can reduce series inductance.

Similarly, to reduce the possible series inductance, Pin 12,

which supplies power to the high speed differential

OUTP/OUTN output buffer, should connect to the power plane

directly. If the power plane is an internal plane and connections

to the power plane are vias, multiple vias in parallel can reduce

the series inductance, especially on Pin 12. See Figure 20 for the

recommended connections.

The exposed pad should connect to the GND plane using filled

vias so that solder does not leak through the vias during reflow.

Using filled vias in parallel under the package greatly reduces

the thermal resistance and enhances the reliability of the

connectivity of the exposed pad to the GND plane during

reflow.

To reduce power noise, a 10 μF electrolytic decoupling capacitor

between power and ground should be close to where the 3.3 V

supply enters the PCB. The other 0.1 μF and 1 nF ceramic chip

decoupling capacitors should be close to the VCC and VEE pins

to provide better decouple filtering and a shorter current return

loop.

CONNECT

EXPOSED

PAD TO

GND

AVCC

1

5

6

7

8

16

15

14

13

PIN

2

NIN

3

AVEE

4

DRVCC

12

OUTN

10

DRVEE

9

OUTP

C4

C3

11

C2

C1

TO HOST

BOARD

C7

C8

VCC

C5

C6

VCC

C11

C12

R2

VCC

R3

4.7kΩ TO 10kΩ

ON HOST BOARD

VCC

ADN2880

0.1µF

VCC

C9

RSSI MEASUREMENT

TO ADC

R1

C10

C1–C4, C11: 0.01µF X5R/X7R DIELECTRIC, 0201 CASE

C5, C7, C9, C10, C12: 0.1µF X5R/X7R DIELECTRIC, 0402 CASE

C6, C8: 1nF X5R/X7R DIELECTRIC, 0201 CASE

ADN2891

Figure 20. Typical Applications Circuit (Example of Using PIN PD and On-Chip RSSI Detector)