ATAB5423-3-WB Atmel, ATAB5423-3-WB Datasheet - Page 21

• Manufacturer Part Number: ATAB5423-3-WB
• Description: KIT DEMO 315MHZ BLACKBIRD
• Manufacturer: Atmel
• Type: Transceiver, UHFr

Specifications of ATAB5423-3-WB

• Frequency: 315MHz
• Product: RF Modules
• For Use With/related Products: ATA5423
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ATAB-5423-3-WB

4841D–WIRE–10/07
Example:
According to
11 dBm the overall current consumption is typically 17.8 mA; hence, the PA needs
17.8 mA - 6.95 mA = 10.85 mA in this mode, which corresponds to an overall power amplifier
efficiency of the PA of (10
Using a higher resistor in this example of R
rent in the PA of 10.85 mA/1.091 = 9.95 mA and 10
using a new load resistance of 300
1 1 d B m – 0 . 3 8 d B = 1 0 . 6 d B m
6.95 mA + 9.95 mA = 16.9 mA.
The values of
quality factors Q according to
with the quality factor of Q
r e s i s ta n c e o f t h e i n d u c to r R
10 log (1 + R
the PA efficiency is then 42% instead of 38.6%.
Be aware that the high power mode (PWR_H = AVCC) can only be used with a supply voltage
higher than 2.7V, whereas the low power mode (PWR_H = GND) can be used down to 2.4V as
can be seen in the
The supply blocking capacitor C
because of the RF current flowing through it.
Figure 3-10. Power Setting and Output Matching
Lopt
Table 3-7 on page 22
Table 3-7 on page
/R
loss
“Electrical Characteristics: General” on page
) which is equal to 0.32 dB losses in this inductor. Taking this into account,
ATA5423/ATA5425/ATA5428/ATA5429
(11dBm/10)
L1
= 43 the loss in this inductor is estimated with the parallel equivalent
RF
Table 3-7 on page
OUT
C
l o s s
3
2
22, with a frequency of 433.92 MHz and output power of
were measured with standard multi-layer chip inductors with
(10 nF) has to be placed close to the matching network
VPWR_H
1 mW)/(3 V 10.85 mA)
= 2
a n d
AVCC
C
1
R
1.091 = 327 . The resulting output power is then
L
1
1
1
= 1.091
t h e
10
f
8
9
22. Looking to the 433.92 MHz/11 dBm case
C
2
o v e r a l l
ATA5423/ATA5425/
ATA5428/ATA5429
RF_OUT
R_PWR
PWR_H
L
log(1.091) = 0.38 dB less output power if
22 k = 24 k results in 9.1% less cur-
Q
L 1
c u r r e n t
a n d t h e m a tc h i n g l o s s w i t h
100% = 38.6% in this case.
67.
c o n s u m p t i o n
i s
21