Input/Output Matching

Crystal

L

parasitic

221

231

1

C

C

1

1

C

C

=

+

+

(1)

L

parasitic

321

331

1

C

C

1

1

C

C

=

+

+

(2)

On-Chip 1.8-V Voltage-Regulator Decoupling

Power-Supply Decoupling and Filtering

References

CC2530F32, CC2530F64, CC2530F128, CC2530F256

Table 2. Overview of External Components (Excluding Supply Decoupling

Capacitors) (continued)

Component

Description

Value

C401

Decoupling capacitor for the internal digital regulator

1

µF

R301

Resistor used for internal biasing

56 k

Ω

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. The recommended balun shown

consists of C262, L261, C252, and L252.

If a balanced antenna such as a folded dipole is used, the balun can be omitted.

An external 32-MHz crystal, XTAL1, with two loading capacitors (C221 and C231) is used for the 32-MHz crystal

oscillator. See the 32-MHz Crystal Oscillator section for details. The load capacitance seen by the 32-MHz

crystal is given by:

XTAL2 is an optional 32.768-kHz crystal, with two loading capacitors (C321 and C331) used for the 32.768-kHz

crystal oscillator. The 32.768-kHz crystal oscillator is used in applications where both very low sleep-current

consumption and accurate wake-up times are needed. The load capacitance seen by the 32.768-kHz crystal is

given by:

A series resistor may be used to comply with the ESR requirement.

The 1.8-V on-chip voltage regulator supplies the 1.8-V digital logic. This regulator requires a decoupling capacitor

(C401) for stable operation.

Proper power-supply decoupling must be used for optimum performance. The placement and size of the

decoupling capacitors and the power supply filtering are very important to achieve the best performance in an

application. TI provides a compact reference design that should be followed very closely.

1. IEEE Std. 802.15.4-2006: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specifications

for Low-Rate Wireless Personal Area Networks (LR-WPANs)

http://standards.ieee.org/getieee802/download/802.15.4-2006.pdf

2. CC253x User's Guide – CC253x System-on-Chip Solution for 2.4 GHz IEEE 802.15.4 and ZigBee

Applications (SWRU191)

Copyright © 2009, Texas Instruments Incorporated

Submit Documentation Feedback

23

Product Folder Link(s): CC2530F32 CC2530F64 CC2530F128 CC2530F256