AS3977-BQFU austriamicrosystems, AS3977-BQFU Datasheet - Page 26

• 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
When the circuit is in Power Down Mode, the crystal oscillator and all the other analog/digital circuits are OFF. The
transmitter interface is the only supplied circuit and it is sensitive to SDI signals. The current consumption is limited by
the leakage current. The configuration registers do not alter as long as the minimum supply requirements are met. The
state can only be left by the rising edge of ENABLE. The state can be entered either by setting the set power down bit
(SETPD) via. SDI communication or by setting ENABLE low for more than 2
When the Power Down Mode is left (by the rising edge of ENABLE), the crystal oscillator is activated.
Software Power Down Method
Lock Transmit Bit
When the Power Down Mode is left, the lock transmit bit (LT) is set high. The power amplifier can not be switched on
as long as the bit is set to high.
Active Edge of CLK
When the Power Down Mode is left, the level of CLK at the rising edge of ENABLE determines the active edge of CLK
(CLK polarity). Once the CLK polarity is set, it stays unchanged until the next Power Down Mode is re-entered.
Active State
The Active state is entered at the rising edge of ENABLE, which as well resets the Power Down timer. Possible
previous states are Power Down Mode, Transmit state. DATAIO is set to SDI data input and the Interface expects a
command control byte to configure the state-machine. The SDI state can be left by programming another state or by
setting ENABLE low for more than 2
Transmit State
The state is entered upon command. The transmit command byte defines in combination with the configuration
registers the transmit configuration. The power amplifier (PA) will be activated on the subsequent sampling edge of
CLK after receiving the command byte only if the lock transmit bit has been reset (0) by a previous SDI command.
Here (only here) the baud rate and data generator counters are reset, i.e. if Transmit was interrupted by a SDI
communication and is re-entered again (with active PA), the baud rate generator is kept synchronized with the
previous transmitted string. DATAIO is set to TX data input. If during transmit a low power reset (LPR) occurs, the lock
transmit bit is set high and hence the power amplifier is switched off.
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Power Down Mode
Power Down Mode
Power Down Mode
All other states
All other states
State
State
Step
1
2
ENABLE
16
XTAL cycles (Power Down timer).
↑
↑
↑
ENABLE
↑
↑
Set power Down Bit =1 and put ENABLE to LOW level
Power on reset complete with next xtal cycle
Revision 3.5
CLK
Software Power Down Method
X
0
1
LT
DATAIO is sampled at the falling edge of CLK
DATAIO is sampled at the rising edge of CLK
LT
1
-1
16
XTAL cycles (Power Down Timer).
CLK behavior is unchanged
Description
LT is unchanged except the
Supply voltage drops down
below the threshold level
LT is set to High
Description
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