AS3977BQFU austriamicrosystems, AS3977BQFU Datasheet - Page 20

• 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
Figure 6. Operation Mode Relations
9.2 Transmitter Control Interface
The AS3977 is controlled by an external micro controller (µC) via. a bi-directional communication interface (serial digital interface, SDI). The SDI
enables data to be read from and written to internal control registers without the necessity of an internal clock signal. Analog de-bouncing of
clock and data input is implemented in order to improve the overall system reliability.
The SDI-control interface includes a state machine, which expects a command control word as first byte and in reference to this byte, the
interface is configured as write, read, or transmit operation. This method enables an effective and easy control of basic transmitter functions.
Four preset independent output frequencies and two preset independent output power levels and modulation types can be selected using the
control-command byte, thus enabling fast channel hopping and/or fast changes to the output power level and modulation type. The selection of
the active output frequency and/or power level and modulation type is done using the so-called command byte.
As an additional feature, the AS3977 provides a configurable clock signal derived from the crystal frequency. The purpose of this clock signal is
to provide a µC clock and to enable data synchronization.
A timer is included to power down (Power Down Mode) the transmitter after a certain time, which is defined as 2
oscillator- Period.
www.austriamicrosystems.com/AS3977
ENABLE to LOW for 2
Software Power Down
command via SPI
XTAL cycles
or
16
Revision 3.6
Transmit Mode
Clock Enable
Power Down
PLL Enable
Power ON
Hardware
External
Reset
Mode
Mode
Mode
ENABLE High
ENABLE is
Command
Command
Pulse
HIGH
SPI
SPI
16
multiplied with the crystal
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