3.5.4.2 Power Setting and Matching to a 50Ω Load

By setting different values for the current sources using the RF front-end register FEPAC.PACR[5:0], the current of the sources can be adjusted for output power values between -12 dBm and +14.5 dBm. The output power shown in the following table can be achieved with an optimum load transformation using L₁₅, C₅ and C₁₆ on the application board, as described in Application Board Design.

Table 3-42. Output Power with Optimized Load for VS_PA = 3V
FEPAC.PACR [5:0]	P_OUT/dBm Low-Band	P_OUT/dBm High-Band	FEPAC.PACR [5:0]	P_OUT/dBm Low-Band	P_OUT/dBm High-Band
0	-11.80	-12.90	32	4.72	4.08
1	-11.30	-12.33	33	5.09	4.51
2	-10.70	-11.76	34	5.57	5.01
3	-10.20	-11.10	35	6.00	5.42
4	-9.70	-10.60	36	6.41	5.79
5	-9.20	-10.00	37	6.77	6.27
6	-8.60	-9.50	38	7.19	6.70
7	-8.00	-9.00	39	7.55	7.11
8	-7.50	-8.50	40	7.98	7.47
9	-7.00	-7.90	41	8.40	7.89
10	-6.40	-7.30	42	8.79	8.25
11	-5.90	-6.80	43	9.11	8.68
12	-5.30	-6.30	44	9.46	9.10
13	-4.77	-5.70	45	9.82	9.49
14	-4.17	-5.20	46	10.18	9.81
15	-3.67	-4.60	47	10.60	10.16
16	-3.12	-4.07	48	10.89	10.52
17	-2.56	-3.47	49	11.30	10.88
18	-2.10	-2.97	50	11.62	11.30
19	-1.58	-2.42	51	12.06	11.59
20	-1.08	-1.86	52	12.39	12.00
21	-0.50	-1.40	53	12.82	12.32
22	0.00	-0.88	54	13.22	12.76
23	0.41	-0.38	55	13.58	13.09
24	1.00	0.20	56	13.95	13.52
25	1.42	0.70	57	14.22	13.92
26	1.83	1.11	58	14.41	14.28
27	2.42	1.70	59	14.49	14.65
28	2.88	2.12	60	14.60	14,65
29	3.38	2.53	61	14.60	14.65
30	3.81	3.12	62	14.60	14.65
31	4.31	3.58	63	14.60	14.65

The following table shows the measured transformation of the power amplifier output to a 50Ω load connected to pin Ant1 of the application board as described in Application Board Design. The parameters no. 10.20 to 11.50 in RF Transmit Characteristics are measured with these transformations on the application board.

Note: For these measurements, L₁₅ of Table 3-43 is placed on the C₁₅ spot on the application board.

Table 3-43. Matching RF_OUT to Ant1 on Application Board without Using SPDT for VS_PA = 3V
Frequency/Output Power [MHz/dBm]	FEPAC. PACR [5:0]	L₁₅	C₅	C₁₆	Inductor Toko	Q_L₁₅ at f_TX	SRF_L15
315 MHz/6 dBm	35	47nH	3.3 pF	100 pF	LL1005FHL47N	16	1.5 GHz
315 MHz/10 dBm	46	27nH	3.3 pF	100 pF	LL1005FHL27N	19	2.1 GHz
315 MHz/14 dBm	56	15nH	10 pF	100 pF	LL1005FHL15N	19	2.8 GHz
433.92 MHz/6 dBm	35	33nH	5.6 pF	100 pF	LL1005FHL33N	20	2.1 GHz
433.92 MHz/10 dBm	46	22nH	4.7 pF	100 pF	LL1005FHL22N	22	2.5 GHz
433.92 MHz/14 dBm	56	10nH	6.8 pF	100 pF	LL1005FHL10N	24	4.3 GHz
868.3 MHz/6 dBm	36	8.2nH	3.9 pF	100 pF	LL1005FHL8N2	33	4.7 GHz
868.3 MHz/10 dBm	47	5.6nH	2.7 pF	100 pF	LL1005FHL5N6	32	6.1 GHz
868.3 MHz/14 dBm	57	2.7nH	3.3 pF	100 pF	LL1005FHL2N7	30	9.6 GHz
915 MHz/6 dBm	36	5.6nH	4.7 pF	100 pF	LL1005FHL5N6	33	6.1 GHz
915 MHz/10 dBm	47	3.9nH	3.3 pF	100 pF	LL1005FHL3N9	32	7.4 GHz
915 MHz/14 dBm	57	1.2nH	3.3 pF	100 pF	LL1005FHL1N2	28	16 GHz