AMIS30585C5852RG ON Semiconductor, AMIS30585C5852RG Datasheet - Page 7

• Manufacturer Part Number: AMIS30585C5852RG
• Description: IC MODEM S-FSK HALFDUPLEX 28PLCC
• Manufacturer: ON Semiconductor

Specifications of AMIS30585C5852RG

• Baud Rates: 14.4k
• Interface: SCI
• Voltage - Supply: 3 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 28-PLCC
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Data Format: -

Pin 23: RESB
hardware reset of the AMIS−30585. This pin supports a 5 V
voltage level. The reset is active when the signal is low
(0 V).
Pin 24: TEST
mode of the chip. Normal mode is activated when TEST
signal is low (0 V). For normal operation, the TEST pin may
be left unconnected. Thank to the internal pull−down, the
signal is maintained to low (0 V). TEST pin is not 5 V safe.
Pin 27: ALC_IN
The signal is used to adjust the level of the transmitted
signal. The signal level adaptation is based on the AC
component. The DC level on the ALC_IN pin is fixed
internally to 1.65 V. Comparing the peak voltage of the AC
signal with two internal thresholds does the adaptation of the
gain. Low threshold is fixed to 0.4 V. A value under this
threshold will result in an increase of the gain. The high
threshold is fixed to 0.6 V. A value over this threshold will
result in a decrease of the gain. The pin must be decoupled
from the sensed signal by a 1 mF capacitor. An application
example is given in Figure 8. A serial capacitance is used to
filter the DC components. The level adaptation is performed
during the transmission of the first two bits of a new frame.
Eight successive adaptations are performed.
RESB is a digital input pin. It is used to perform a
TEST is a digital input pin. It is used to enable the test
ALC_IN is the automatic level control analog input pin.
Figure 8. Connection to the Line Driver
Figure 7. TX_OUT Filter
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Pin 25: TX_ENB
transmitter is activated. The signal is available to turn on the
line driver. TX_ENB is a 5 V safe with open drain output,
hence a pull−up resistance is necessary to achieve the
requested voltage level associated with a logical one. See
also Figure 4 for reference.
Pin 26: TX_OUT
provided signal is the S−FSK modulated frames. A filtering
operation must be performed to reduce the second order
harmonic distortion. For this purpose an active filter is
realized. Figure 7 gives the representation of this filter.
Pin 28: VDDA
supply is 3.3 V. A decoupling capacitor (C_DEC) must be
placed between this pin and the VSSA (see pin 1).
NOTE:
TX_ENB is a digital output pin. It is high when the
TX_OUT is the analog output pin of the transmitter. The
VDDA is the positive analog supply pin. Nominal voltage
Figure 9. Placement of Decoupling Capacitor
The user should take care about difference of ground
voltages between different boards. Should ground
voltages not be the same, the use of isolation devices is
mandatory.