AS3977-BQFT austriamicrosystems, AS3977-BQFT Datasheet - Page 36

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

Specifications of AS3977-BQFT

• 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
INT < 7:4 >= AC-1= 5-1=4 Hex „4“
FRAC < 15:0 >= DR
Optional Frequency Calculation with Overlapping Fractional Bands by Using the Bit INT<8>
Bit INT<8>
The bit INT<8> is a multiplier to the output of the ΣΔ-modulator. Set this Bit to high stretches the fractional-N region by
two and results in overlapping frequency bands with a bandwidth of 2*f
frequency modulation and/or frequency trimming independently on the required output frequency and selected crystal.
Note that setting INT<8> high increases the PLL in-band noise by approximately 3dB. Therefore it is recommended to
use this option only if the required frequency band did not fit to the crystal reference.
Steps for INT<8>=1
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:
www.austriamicrosystems.com
INT8=1
INT8=0
1. If the fractional part is larger than 0.5
2. If the fractional part is less than 0.5
FRAC
FRAC
FRAC
FRAC
INT=N-2
x 2
16
= 0,48 x 65536 = 31457 =Hex “7AE1”
N= whole numbered part of
N = whole numbered part of
FRAC
FRAC
DR
AC
FRAC <15:0> =
=
AC = (DR
FRAC <15:0> =
----------------- -
P f
=
⋅
f
INT=N-1
RF
(
REF
DR
INT
INT
=
Revision 3.5
Frequency Band
DR
- 7) - N x M
–
(
6
DR
INT
FRAC
) N
FRAC
DR
–
FRAC
(
---------------------------- -
+
DR
FRAC
DR
----------------------- -
DR
×
M
INT
+
INT
M
M
FRAC
⋅
1
REF
2
–
) 2
–
INT=N
15
⋅
6
7
and an overlap ratio of 50% in order to allow
)
15
FRAC
FRAC
Modulation on the Integer border
Modulation on the Integer border
with INT<8> = 0 not possible
with INT<8> = 1 not possible
INT=N+1
FRAC
FRAC
FRAC
(EQ 19)
(EQ 20)
(EQ 21)
(EQ 22)
(EQ 23)
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