CC2530: cc2530 with cc2591

The PCB antennas we recommend is covered in www.ti.com/.../swra496.pdf
In the report you will find the expected performance for the different antennas including efficiency.

Why are you using CC2591 and not CC2592? The later is the recommended part for new designs.

Before you look at range and antenna types you should do conducted measurements and see if you get the expected performance in 50 ohm before looking into radiated measurements. Please look at the debug tab in the excel sheet found here: e2e.ti.com/.../375556

Dear Sir,

Shall I know what is the difference between CC2591 and CC2592 ? Any output power difference is there.?

CC2591:
Low Transmit Current Consumption
(100 mA at 3 V for 20-dBm Out, PAE = 33%)
Low-Receive Current Consumption
– 3.4 mA for High-Gain Mode
– 1.7 mA for Low-Gain Mode

CC2592:
Low-Transmit Current Consumption
– 155mAat3Vfor+22dBm,PAE=34%
Low-Receive Current Consumption
– 4.0-mA for High-Gain Mode
– 1.9-mA for Low-Gain Mode

You can refer to data sheet for details.

For CC2591 the reference design has to be followed very precisely since line inductance is used. If the inductance is different from the ref design the performance will likely degrade. A CC2591 design could easily be unstable due to this.

CC2592 is easier to design with and easier to get a stable design. Therefore it's highly recommended to use CC2592 if you are free to do so.

Thanks for the reply. 

I would like to  explain little more in detail.

We have Done three type of Devices.

Device 1: Gateway which is quite bigger in size has Zigbee CC2530 with PA CC2591 (which act as co ordinator) as shown below. Since our board size is bigger we could accommodate the antenna  given in the reference design with PA. 

Device 2: Zigbee Node with only CC2530

Device 3: Zigbee Node as shown below which also has CC2530 and CC2591 but due too the board size restriction, we have chosen the antenna from the TI antenna guide which is fitting to our board size.   Both Device 2 and 3 has same type of antenna. 

We found Device 2 Node to Node distance is very small in the mesh that is the reason we gone for Device 3 by adding PA  to increase the range between Node to Node in the mesh. But we are not seeing any difference between Node (without PA) Device 2 and (Node With PA) Device 3 

We tried to measure the RF output power in the spectrum analyser (on the antenna feed) and we are getting around 18 dBm for Device 3 With PA and 3.1 dBm for Device 2 without PA.   Device 3 (With PA ) Node to node range is 60 -70 feet. and  Device 2 (without PA) is giving better range like 80 to 100 feet. 

We found Device 2 (without PA)  node to node is far better than Device 3 (With PA).  We are using the same antenna for both the devices 2 and 3. Are we missing something. ? Or Is there is any antenna changes required for PA which can accommodate for the space of 18.76mm width ? 

We are ready to change the design but we would like to get some guidance before changing the design. 

Thank you for your support given so far.

With Regards,

Balakumar.A

6 dB different link budget should give 2x range difference. The conducted output difference based on your measurements is about 15 dB which should give at lease a 4x distance improvement.

Since you have 15 dB more output power even a slightly de-tuned antenna should give better range on the board with CC2591.

One possibility is that the load presented by the antenna is not optimal for CC2591. If you use a 2.4 GHz antenna attached to the spectrum and measure at the same distance and with the same placement/ orientation (say 10 cm from) board 2 and board 3 and compare the spectrum and the output power from the two boards and see how that looks like.