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ZHCSCZ3A July 2014 – November 2015 CC2540T

PRODUCTION DATA.

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机械数据 (封装 | 引脚)

RHA|40
- MPQF135D

散热焊盘机械数据 (封装 | 引脚)

RHA|40
- QFND114P

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6 Applications, Implementation, and Layout

NOTE

Information in the following Applications section is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

6.1 Application Information

Few external components are required for the operation of the CC2540T. A typical application circuit is shown in Figure 6-1.

(1) 32-kHz crystal is mandatory when running the chip in low-power modes, except if the link layer is in the standby state (Vol. 6 Part B Section 1.1, see [1]).

NOTE:

Different antenna alternatives will be provided as reference designs.

Figure 6-1 CC2540T Application Circuit

Table 6-1 Overview of External Components (Excluding Supply Decoupling Capacitors)

COMPONENT	DESCRIPTION	VALUE
C221	32-MHz XTAL loading capacitor	12 pF
C231	32-MHz XTAL loading capacitor	12 pF
C251	Part of the RF matching network	18 pF
C252	Part of the RF matching network	1 pF
C253	Part of the RF matching network	1 pF
C261	Part of the RF matching network	18 pF
C262	Part of the RF matching network	1 pF
C321	32-kHz XTAL loading capacitor	15 pF
C331	32-kHz XTAL loading capacitor	15 pF
C401	Decoupling capacitor for the internal digital regulator	1 µF
L251	Part of the RF matching network	2 nH
L252	Part of the RF matching network	1 nH
L253	Part of the RF matching network	3 nH
L261	Part of the RF matching network	2 nH
R301	Resistor used for internal biasing	56 kΩ

6.2 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. The recommended balun shown consists of C262, L261, C252, and L252.

6.3 Crystal

An external 32-MHz crystal, XTAL1, with two loading capacitors (C221 and C231) is used for the 32-MHz crystal oscillator. See Section 4.10 for details. The load capacitance seen by the 32-MHz crystal is given by Equation 1:

Equation 1. CC2540T E001_WRS081.gif

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 Equation 2:

Equation 2. CC2540T E002_WRS081.gif

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

6.4 On-Chip 1.8-V Voltage Regulator Decoupling

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.

6.5 Power-Supply Decoupling and Filtering

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 (see Section 6.6).

6.6 Reference Design

Bluetooth Low Energy Light Reference Design

This reference design is an example of using the SimpleLink™ Bluetooth low energy CC2540T high temperature range, wireless microcontroller in lighting applications. The board includes RGBW LEDs controlled by the CC2540T and is USB powered. The board can be controlled out-of-the-box by the TI BLE Multitool smart phone app.