ATA5428-PLSW datasheet(22/100 Pages) ATMEL

22 / 100 page

4841D–WIRE–10/07

ATA5423/ATA5425/ATA5428/ATA5429

3.13

Output Power and TX Supply Current versus Supply Voltage and Temperature

Table 3-8 on page 22 shows the measurement of the output power for a typical device with

VS = VS1 = VS2 in the 433.92 MHz and 6.2 dBm case versus temperature and supply voltage

measured according to Figure 3-10 on page 21 with components according to Table 3-7. As

opposed to the receiver sensitivity, the supply voltage has here the major impact on output

power variations because of the large signal behavior of a power amplifier. Thus, a two battery

system with voltage regulator or a 5V system shows much less variation than a 2.4V to 3.6V one

battery system because the supply voltage is then well within 3.0V and 3.6V.

The reason is that the amplitude at the output RF_OUT with optimum load resistance is

AVCC – 0.4V and the power is proportional to (AVCC – 0.4V)

2 if the load impedance is not

changed. This means that the theoretical output power reduction if reducing the supply voltage

from 3.0V to 2.4V is 10 log ((3 V – 0.4 V)

2/(2.4 V – 0.4 V)2)=2.2dB. Table 3-8 shows that prin-

ciple behavior in the measurement. This is not the same case for higher voltages, since here

increasing the supply voltage from 3V to 3.6V should theoretical increase the power by 1.8 dB;

but a gain of only 0.8 dB in the measurement shows that the amplitude does not increase with

the supply voltage because the load impedance is optimized for 3V and the output amplitude

stays more constant.

Table 3-7.

Measured Output Power and Current Consumption with VS1 = VS2 = 3V, T

amb = 25°C

Frequency (MHz) TX Current (mA) Output Power (dBm)

R1 (k

Ω) VPWR_H

RLopt (Ω)L1 (nH)

QL1

C1 (pF) C3 (pF)

315

8.5

0.4

GND

2500

1.5

315

10.5

5.7

GND

920

2.2

315

16.7

10.5

AVCC

350

3.9

345

8.8

1.6

GND

2400

1.2

345

10.4

5.9

GND

900

1.8

345

16.9

10.7

AVCC

320

3.9

433.92

8.6

0.1

GND

2300

0.75

433.92

11.2

6.2

GND

890

1.5

433.92

17.8

AVCC

300

2.7

868.3

9.3

-0.3

GND

1170

1.0

3.3

868.3

11.5

5.4

GND

471

1.0

868.3

16.3

9.5

AVCC

245

1.5

915

9.6

0.1

GND

1100

0.7

915

11.8

4.9

GND

465

1.5

915

20.3

10.2

AVCC

230

1.5

Table 3-8.

Measured Output Power and Supply Current at 433.92 MHz, PWR_H = GND

VS =

2.4 V

3.0 V

3.6 V

amb = –40°C

10.19 mA

3.8 dBm

10.19 mA

5.5 dBm

10.78 mA

6.2 dBm

Tamb = +25°C

10.62 mA

4.6 dBm

11.19 mA

6.2 dBm

11.79 mA

7.1 dBm

amb = +85°C

11.4 mA

3.9 dBm

12.02 mA

5.5 dBm

12.73 mA

6.6 dBm

ATA5428-PLSW Datasheet(PDF) 22 Page - ATMEL Corporation

ATA5428-PLSW Datasheet(HTML) 22 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100

Datasheet Download

Link URL