1

2

3

4

5

6

7

8

9

10

11

12

25

28

29

30

31

32

33

34

35

36

LMX5251

NC

NC

BBP_CLOCK

TX_RX_DATA

TX_RX_SYNC

CE

CCB_CLOCK

CCB_DATA

CCB_LATCH

RESET#

NC

NC

NC

VDD_LNA

RF_PORT_RX

VDD_MIX

VDD_FILTER

VDD_IF1

RF_PORT_TX_A

VDD_PA

RF_PORT_TX_B

VDD_ANA_IN

VDD_ANA_OUT

NC

(Top View)

27

26

LMX5251

www.ti.com

SNOSCW3A – FEBRUARY 2004 – REVISED APRIL 2013

CONNECTION DIAGRAM

(TOP VIEW)

NOTE: Ground pad layout under ground slug of LMX5251 is required. These are connected by vias through all layers to

ground plane. No pins on device are ground pins so center slug must be grounded. See detail in Figure 27

"Component Placement Layer 1 Ground Pad Detail".

PIN FUNCTIONS

PIN

I/O

DESCRIPTION

NAME

NO.

NC

1, 12, 13,

–

No Connect. Place pin but do not connect to VCC or Ground.

25, 26, 35,

36, 41,

45–48

VDD_LNA

2

PWR

Power Supply for Analog Circuitry. Must be connected to the VDD_ANA_OUT pin (pin 11)

or external supply. An RF bypass capacitor should be placed as close as possible to this pin

and be connected to Ground.

RF_PORT_RX

3

I

RF Input to Receiver.

VDD_MIX

4

PWR

Power Supply for Analog Circuitry. Must be connected to the VDD_ANA_OUT pin (pin 11)

or external supply. An RF bypass capacitor should be placed as close as possible to this pin

and be connected to Ground.

VDD_FILTER

5

PWR

Power Supply for Analog Circuitry. Must be connected to the VDD_ANA_OUT pin (pin 11)

or external supply. An RF bypass capacitor should be placed as close as possible to this pin

and be connected to Ground.

VDD_IF1

6

PWR

Power Supply for Analog Circuitry. Must be connected to the VDD_ANA_OUT pin (pin 11)

or external supply. An RF bypass capacitor should be placed as close as possible to this pin

and be connected to Ground.

RF_PORT_TX_A

7

O

Transmit Positive Differential Output. Typically connected along with RF_PORT_TX_B to

a balun and fed to the antenna.

VDD_PA

8

PWR

Power Supply for Analog Circuitry. Must be connected to the VDD_ANA_OUT pin (pin 11)

or external supply. An RF bypass capacitor should be placed as close as possible to this pin

and be connected to Ground.

Copyright © 2004–2013, Texas Instruments Incorporated

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