AMIS49587C5871G ON Semiconductor, AMIS49587C5871G Datasheet - Page 23

• Manufacturer Part Number: AMIS49587C5871G
• Description: IC MODEM PLC 50/60MHZ 28PLCC
• Manufacturer: ON Semiconductor

Specifications of AMIS49587C5871G

• Baud Rates: Selectable
• 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: -

must start at it’s 0 phase position, corresponding with a 0 V
output level. When switching between f
accumulator must give a continuous phase and not restart
from phase 0.
TX_RXB goes from 1 to 0) the sine wave generator must
make sure to complete the active sine period.
TX_ENB to enable the external power amplifier. TX_ENB
is 1 when the AMIS- -49587 is in receive mode. TX_ENB is
6.2.3 DA Converter
digital word to a pulse density modulated (PDM) signal.
The PDM signal is converted to an analog signal with a first
order switched capacitor filter.
6.2.4 Low Pass Filter
path filters the quantization noise and noise generated by the
ΣΔ DA converter. The low pass filter has a circuit which
tunes the RC time constants of the filter towards the process
characteristics. The C values for the LPF filter are controlled
by the ARM micro controller.
6.2.5 Amplifier with Automatic Level Control (ALC)
transmitter output level. First a peak detection is done. The
peak value is compared to 2 thresholds levels: VTL
and VTH
control the setting of the level of TX_OUT. The level of
TX_OUT can be attenuated in 8 steps of 3 dB typical.
When AMIS- -49587 goes into receive mode (when
The control logic for the transmitter generates a signal
TX_DATA
A digital to analog ΣΔ converter converts the sine wave
A 3
The pin ALC_IN is used for level control of the
BIT_CLK
TX_OUT
TX_RXB
TX_ENB
rd
order continuous time low pass filter in the transmit
ALC_IN
. The result of the peak detection is used to
M
and f
Figure 18. TX_ENB Timing
S
the phase
ALC_IN
http://onsemi.com
23
0 when AMIS- -49587 is in transmit mode. When going from
transmit to receive mode (TX_RXB goes from 1 to 0) the
TX_ENB signal is kept active for a short period of
t
TX_DATA which corresponds to the transmitted S- -FSK
signal. When transmitting f
transmitting f
is not enabled (TX_RXB = 0) TX_DATA goes to logic 1 at
the next BIT_CLK.
(maximum attenuation) When going to reception mode
(when TX_RXB goes from 1 to 0) the level is kept in
memory so that the next transmit frame starts with the old
level. The evaluation of the level is done during 1
CHIP_CLK period.
Depending on the value of peak level on ALC_IN the
attenuation is updated:
- - Vp
- - VTL
- - Vp
The gain changes in the next CHIP_CLK period.
CHIP_CLK periods. ALC operation is enabled only during
the first 16 CHIP_CLK cycles after a hard or soft reset or
after going into transmit mode.
register R_ALC_CTRL[3] = 1. In this case the transmitter
dTX_ENB
The control logic for the transmitter generates a signal
After hard or soft reset the level is set at minimum level
An evaluation phase and a level adjustment takes 2
The automatic level control can be disabled by setting
level
ALC_IN
ALC_IN
ALC
.
≤ Vp
< VTL
> VTH
S
TX_DATA is logic 0. When the transmitter
ALC_IN
ALC
ALC
: Increase the level with 1 step
: Decrease the level with 1 step
≤ VTH
t
M
dTX_ENB
TX_DATA is logic 1. When
ALC
: Don’t change the