Johanson Technology, Inc. 2450BM15A0002 Impedance Matched-Balun-Low Pass Filter integrated ceramic component
For the Texas Instruments CC253X Family of ZigBee Transceivers

June 2010

 

1. Introduction

The CC253X chipset family from Texas Instruments are single-chip solutions for 2.4 GHz IEEE 802.15.4 / RF4CE / ZigBee. The chips include radio, up to 256kB FLASH and a single-cycle microcontroller. Power consumption in sleep mode can be as low as 0.4uA.

 

Johanson Technology, Inc.’s 2450BM15A0002 Balun-Low Pass Filter integrated passive component was specifically designed for use with the CC253X family. This matched balun simplifies the RF front-end by considerably reducing component count and implementation area size.

 

The 2450BM15A0002 is a six-pin device with small mechanical dimensions of only 2.0 mm x 1.25 mm x 0.7mm (EIA 0805) and an approximate footprint of 1.65 mm x 2.8 mm.

 

 

 

 

 

Figure 1. JTI Photograph Reference Design for the CC2530

 

2. Description of the Reference Design

The traditional reference design for the CC253X family has been the discrete solution shown in Figure 2. Johanson Technology has developed a solution with a chip Balun-LPF that is especially matched for the CC253X family ICs, the 2450BM15A0002. The alternate reference design is shown in Figure 3.

 

 

 

 

Figure 2. Discrete Reference Design for the CC253X

 

 

 

 

 

 

Figure 3. JTI Reference Design for the CC253X

 

Referring to Figure 3, U2 is the JTI matched balun 2450BM15A0002.

Please refer to Appendix A for the datasheet of this component.

For more updated information from the Johanson Technology web site at:

http://www.johansontechnology.com/en/integrated-passives/rohs-compliant-baluns.html

 

 

 

 

Figure 4. Component Placement

 

 

The component placement influences the RF performance. It is recommended that the reference PCB layout be copied as closely as possible. In particular, the designer should make note of all dimensions between the CC253X and 2450BM15A0002.

 

 

 

 

Figure 5. Example of CC2530 JTI Reference Design Schematic (with 2450BM15A0002)

 

3. Layout

Johanson’s 2450BM15A0002 Matched Balun-LPF enables the designer to reduce the layout area due to component cutback (to one component); furthermore, PCB sensitivity is also decreased compared to the discrete passive solution.

 

The layout greatly influences the RF performance. It is recommended to copy the reference design as closely as possible.

 

 

 

 

Figure 6. Layer 1 of the CC2530 JTI Reference Design Layout (with 2450BM15A0002)

 

In the event that the reference design can not be copied, then the routing from the RF pins RF_P and RF_N must be symmetrical to the matched balun component, U2. The length of the tracks should be kept to a minimum and preferably the same length and width that are used in the reference design. If this routing is not symmetrical, then the output power may be reduced and the harmonics may increase.

4. Measurement Results

 

All results presented in this chapter are based on measurements performed with CC2530EM JTI rev 1.0 Reference Design board with Johanson’s 2450BM15A0002. All measurement results presented are the average of each batch tested from typical devices. The output power and harmonics measurements were performed with 0xF5 settings.

Johanson’s 2450BM15A0002 Matched Balun-LPF offers improved 2nd and 3rd harmonic, it eases implementation and increases margin to FCC/ETSI compliance when compared to solution with discrete passives.

Note: all values are in dBm if not otherwise stated.

 

 

All results presented in this chapter are based on measurements performed with CC2530EM JTI rev 1.0 Reference Design board with Johanson’s 2450BM15A0002

 

5. References

 

[1] IEEE Std. 802.15.4-2006: Wireless Medium Access Control (MAC) and Physical Layer (PHY) Specification for Low-Rate Wireless Personal Area Network (LR-WPAN)

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

Appendix A

 

 

The latest specification can be downloaded from the following link:

http://www.johansontechnology.com/en/integrated-passives/rohs-compliant-baluns.html

 

 

The latest specification can be downloaded from the following link:

http://www.johansontechnology.com/en/integrated-passives/rohs-compliant-baluns.html