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RF2051

DS140110

7628 Thorndike Road, Greensboro, NC 27409-9421 · For sales or technical

support, contact RFMD at (+1) 336-678-5570 or sales-support@rfmd.com.

Note 1: The signal should be connected to this pin such that DC current cannot flow into or out of the chip, either by using AC

coupling capacitors or by use of a transformer (see evaluation board schematic).

Note 2: DC current needs to flow from ANA_VDD into this pin, either through an RF inductor, or transformer (see evaluation

board schematic).

Note 3: Alternatively an external reference can be AC-coupled to pin 11 XTALIPN, and pin 10 XTALIPP decoupled to ground. This

may make PCB routing simpler.

Pin

Function

Description

1ENBL

digital noise.

2INDP

VCO 3 differential inductor. Normally a micro-strip inductor is used to set the VCO 3 frequency range 1200MHz

to 1600MHz.

3INDN

VCO 3 differential inductor. Normally a micro-strip inductor is used to set the VCO 3 frequency range 1200MHz

to 1600MHz.

4REXT

External bandgap bias resistor. Connect a 51k

 resistor from this pin to ground to set the bandgap reference

bias current. This could be a sensitive low frequency noise injection point.

5ANA_DEC

Analog supply decoupling capacitor. Connect to analog supply and decouple as close to the pin as possible.

6LFILT1

Phase detector output. Low-frequency noise-sensitive node.

7LFILT2

Loop filter op-amp output. Low-frequency noise-sensitive node.

8LFILT3

VCO control input. Low-frequency noise-sensitive node.

9MODE

Mode select pin. An RC low-pass filter can be used to reduce digital noise.

10

XTALIPP

Reference crystal / reference oscillator input. Should be AC-coupled if an external reference is used. See note 3.

11

XTALIPN

Reference crystal / reference oscillator input. Should be AC-coupled to ground if an external reference is used.

See note 3.

12

GND

Connect to ground.

13

RFIP1P

Differential input 1. See note 1.

14

RFIP1N

Differential input 1. See note 1.

15

NC

16

NC

17

RFOP1N

Differential output 1. See note 2.

18

RFOP1P

Differential output 1. See note 2.

19

DIG_VDD

Digital supply. Should be decoupled as close to the pin as possible.

20

NC

21

NC

22

ANA_VDD

Analog supply. Should be decoupled as close to the pin as possible.

23

RFIP2N

Differential input 2. See note 1.

24

RFIP2P

Differential input 2. See note 1.

25

NC

26

NC

27

RFOP2N

Differential output 2. See note 2.

28

RFOP2P

Differential output 2. See note 2.

29

RESETB

Chip reset (active low). Connect to DIG_VDD if external reset is not required.

30

ENX

Serial interface select (active low). An RC low-pass filter could be used to reduce digital noise.

31

SCLK

Serial interface clock. An RC low-pass filter could be used to reduce digital noise.

32

SDATA

Serial interface data. An RC low-pass filter could be used to reduce digital noise.

EP

low impedance paths.