CC2531F128 Datasheet, PDF (24/35 Pages) Texas Instruments – A USB-Enabled System-On-Chip Solution for 2.4-GHz IEEE 802.15.4 and ZigBee Applications

CC2531F128, CC2531F256
SWRS086A – SEPTEMBER 2009 – REVISED JUNE 2010
APPLICATION INFORMATION
www.ti.com
Few external components are required for the operation of the CC2531. A typical application circuit is shown in
Figure 18. For a complete USB-certified reference design, see the CC2531 product page on www.ti.com. Typical
values and description of external components are shown in Table 2. The USB_P and USB_N pins need series
resistors R21 and R31 for impedance matching, and the D+ line must have a pullup resistor, R32. The series
resistors should match the 90 Ω ±15% characteristic impedance of the USB bus. Notice that the pullup resistor
and DVDD_USB must be connected to a voltage source between 3 V and 3.6 V (typically 3.3 V). The voltage
source should be derived from or controlled by the VBUS power supply provided by the USB cable. In this way,
the pullup resistor does not provide current to the D+ line when VBUS is removed. The pullup resistor may be
connected directly between VBUS and the D+ line. As an alternative, if the CC2531 firmware needs the ability to
disconnect from the USB bus, a GPIO on the CC2531 can be used to control the pullup resistor.
Optional 32-kHz Crystal
2-V–3.6-V Power Supply
3.3-V Power Supply
C401
C331
C321
R32
R31
D+
D–
R21
C31
C41
C21
1 DGND_USB
2 USB_P
3 USB_N
4 DVDD_USB
5 P1_5
6 P1_4
7 P1_3
8 P1_2
9 P1_1
10 DVDD2
CC2531
DIE ATTACH PAD
RBIAS 30
AVDD4 29
AVDD1 28
AVDD2 27
RF_N 26
RF_P 25
AVDD3 24
XOSC_Q2 23
XOSC_Q1 22
AVDD5 21
R301
L252
C251
C252
Antenna
(50 W)
C253
C261
L261
C262
C221
XTAL
C231
Power supply decoupling capacitors are not shown. Digital I / O not connected.
Figure 18. CC2531 Application Circuit
S0383-04
24
Submit Documentation Feedback
Copyright © 2009–2010, Texas Instruments Incorporated
Product Folder Link(s): CC2531F128 CC2531F256