4-V to 5.45-V

Power Supply

R21

R11

R251

D–

D+

C41

C171

C181

C21

C11

C311

CC2544

DIE ATTACH PAD

Antenna

(50

)

W

S0383-06

1

2

3

4

5

6

7

8

17

18

19

20

21

22

23

24

Power Supply Decoupling Capacitors are Not Shown

Digital I/O Not Connected

VDD

USB_P

VDD

VDD

RF_N

RF_P

VDD

XOSC2

XOSC1

USB_N

VDD

DCPL2

VBUS

P1_0

P1_1

VDD

CC2544

www.ti.com

SWRS103D – JUNE 2011 – REVISED MAY 2012

APPLICATION INFORMATION

Few external components are required for the operation of the CC2544. A typical application circuit is shown in

Figure 19. For suggestions of component values other than those listed in Table 2, see reference design

CC2544EM. The performance stated in this data sheet is only valid for the CC2544EM reference design. To

obtain similar performance, the reference design should be copied as closely as possible.

Figure 19. CC2544 Application Circuit

Table 2. Overview of External Components (Excluding Balun, Crystal and Supply Decoupling Capacitors)

Component

Description

Value

C11

USB D+ decoupling

47 pF

C21

USB D– decoupling

47 pF

Decoupling capacitor for the internal 5V-3.3V digital voltage

C41

1 µF

regulator

Decoupling capacitor for the internal 1.8V digital voltage

C311

1 µF

regulator

R11

USB D+ series resistor

33

Ω

R21

USB D– series resistor

33

Ω

R251

Precision resistor ±1%, used for internal biasing

56 k

Ω

Input/Output Matching

When using an unbalanced antenna such as a monopole, a balun should be used to optimize performance. The

balun can be implemented using low-cost discrete inductors and capacitors. See reference design, CC2544EM,

for recommended balun.

Copyright © 2011–2012, Texas Instruments Incorporated

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