AS3977-BQFU austriamicrosystems, AS3977-BQFU Datasheet - Page 35

• Manufacturer Part Number: AS3977-BQFU
• Description: IC RF TRANSMITTER FSK 16-QFN
• Manufacturer: austriamicrosystems

Specifications of AS3977-BQFU

• Frequency: 300MHz ~ 928MHz
• Applications: ISM
• Modulation Or Protocol: FSK
• Data Rate - Maximum: 100 kbps
• Power - Output: 10dBm
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Voltage - Supply: 2 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 16-VQFN Exposed Pad, 16-HVQFN, 16-SQFN, 16-DHVQFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Memory Size: -
• Current - Transmitting: -

AS3977
Data Sheet - A p p l i c a t i o n I n f o r m a t i o n
The value of f
current consumption
M-counter and Value of INT<9>
The value of the M-counter is given by:
The Bit INT<9> can be calculated as,
INT < 9 > = M - 4
N-counter and Value of INT<3:0>
Taken the default value of INT<8>=0 into account, the value of the INT3<..0> can be calculated by:
INT < 3:0 > = N-10
A- Counter and Value of INT<7:4>
Taken the default value of INT<8>=0 into account, the value of the INT<7:40> can be calculated by:
INT < 7:4 > = AC-1
Fractional Part and Values of FRAC<15:0>
Taken the default value of INT<8>=0 into account, multiplying the Fractional part with 2
the Fractional and synthesizer value and can be calculated by:
FRAC < 15:0 >= DR
Example:
Wanted frequency 425 MHz by 16 MHz crystal frequency.
The values of P and M can be taken from table
P=1→ Defined with the BSEL Bit’s BSEL<1:0>= Hex “2”
M=5 → INT<9>= 5-4 = 1
The Setting of DIVR<2:0> = 2 results in a reference frequency divider of 4.
The Division ratio will now be:
And can be split into the values:
As the Rest is zero, we have to set AC=M and N to decrease by one.
N=20
INT < 3:0 >= N-10 = 20-10=10 = Hex „A“
AC=5
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REF
should be in the range of 3 MHz to 5, 75 MHz to achieve an optimum on noise performance and
FRAC
N = whole numbered part of
DR
x 2
16
=
----------------- -
P f
⋅
f
RF
AC = INT < 7:4 > +1 +(INT <8> +1) x 3
REF
N = (INT < 3:0 > +INT < 8 > .6+10)
DR
=
DIVR < 2:0 > =
FRAC
433 92
--------------------
M = (INT < 9 > +4)
1.4
=
,
(
INT
R
(
---------------------------- -
<
=
DR
Revision 3.5
8
>
108 48
+
INT
M
f
----------- - 2
1
f
XTAL
REF
)
,
⎝
–
⎜
⎛
3
FRAC
–
)
=
=
DR
2
<
(
----------------------
16
108 3
15
INT
:
5
0
–
+
>
⎠
DR
⎟
⎞
)
=
FRAC
21
16
gives the register values for
(EQ 12)
(EQ 13)
(EQ 14)
(EQ 15)
(EQ 16)
(EQ 17)
(EQ 18)
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