EVAL-ADN2891EB AD [Analog Devices], EVAL-ADN2891EB Datasheet - Page 11

• Manufacturer Part Number: EVAL-ADN2891EB
• Description: 3.3 V, 3.2 Gbps, Limiting Amplifier
• Manufacturer: AD [Analog Devices]

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.
ADN2880
VCC
VCC
0.1μF
Figure 20. Typical Applications Circuit (Example of Using PIN PD and On-Chip RSSI Detector)
C5
C1
C2
C6
AVCC
AVEE
NIN
C12
PIN
1
2
3
4
16
5
R2
ADN2891
CONNECT
VCC
EXPOSED
15
PAD TO
6
Rev. A | Page 11 of 16
GND
C11
14
7
C9
VCC
13
8
ON HOST BOARD
R3
4.7kΩ TO 10kΩ
12
10
11
9
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.
R1
DRVCC
OUTP
OUTN
DRVEE
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
C10
C3
C4
RSSI MEASUREMENT
TO ADC
C7
TO HOST
BOARD
VCC
C8
ADN2891