AS3977BQFU austriamicrosystems, AS3977BQFU Datasheet - Page 37

• Manufacturer Part Number: AS3977BQFU
• Description: Ultra-High Frequency FSK Transmitter IC
• Manufacturer: austriamicrosystems

Specifications of AS3977BQFU

• Modulation Type: FSK
• Supply Voltage Range: 2V To 3.6V
• Module Interface: Serial
• Supply Current: 17mA
• Ic Function: Multi-Channel Narrowband FSK Transmitter
• Termination Type: SMD
• No. Of Pins: 16
• Rohs Compliant: Yes
• Operating Temperature Range: -40°C To +85°C
• Filter Terminals: SMD
• Digital Ic Case Style: QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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
Calculate the Division ratio
The A-Counter is the rest of the Division and can be calculated by:
The A-Counter is the rest of the Division and can be calculated by:
In case, the value of the A-counter is zero, the value of the A-counter has to be increased by M and the value of N has to be decreased by one
In case, the N-counter is in the range from 16 to 31 and the value of the A-counter is less than N-counter-14:
Note: In case, no solution can be found for the wanted center frequency, it may help to modify the reference frequency or INT<8>.
9.8.3 FSK Deviation Setting and Frequency Trimming
The frequency resolution Δf is determined by the reference frequency f
calculated with following equation:
9.8.3.1
The FSK deviation DF is given by the frequency resolution Δf and the setting of DF<7:0> and can be calculated with the help of:
The deviation multiplier DM is determined by the setting of DF<7:6> according to the following table:
www.austriamicrosystems.com/AS3977
1. If the fractional part is larger than 0.5
2. If the fractional part is less than 0.5
FSK Deviation Setting
DF<7:6>
0 (00)
1 (01)
2 (10)
3 (11)
DR
N= whole numbered part of
N = whole numbered part of
AC
Δf =
=
FRAC <15:0> =
DF =
----------------- -
P f
FRAC <15:0> =
AC = (DR
P
=
⋅
f
RF
( ⋅
(
REF
Δf DF
DR
INT
INT <7:4> = AC - 1
INT <3:0> = N - 16
⋅
INT
AC = AC + M
=
INT
N = N - 1
<8> +
(
DR
Revision 3.6
- 7) - N x M
–
DR
<5:0> . DM
REF
6
DR
INT
) N
FRAC
1 )
(
---------------------------- -
, the selected frequency band and the setting of INT<8> and can be
–
DR
DR
----------------------- -
FRAC
+
⋅
f
--------- -
INT
DR
2
×
INT
REF
M
+
M
16
⋅
M
1
–
FRAC
2
) 2
–
15
⋅
6
7
)
15
DM
16
1
2
4
(EQ 25)
(EQ 26)
(EQ 20)
(EQ 21)
(EQ 22)
(EQ 23)
(EQ 24)
(EQ 27)
(EQ 28)
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