ACS103 Semtech Corporation, ACS103 Datasheet - Page 2

• Manufacturer Part Number: ACS103
• Description: Acapella Optical Modem ic
• Manufacturer: Semtech Corporation

ACS101 Emulation mode using "SEL" input
The "SEL" input pin is normally held Low in order to
configure the device in ACS103 mode. If the "SEL"
input pin is allowed to pull High via an internal
resistor the device will be configured in ACS101
emulation mode. In ACS101 emulation mode the
device is fully compatible with the ACS101.
TxD2, TxD3 and XI3 inputs are internally disabled
with the RxD2, RxD3 and XO3 outputs forced into the
high impedance state. A full-duplex path then exists
between TxD1 and RxD1.
Transmitter and Receiver Functions
The TxD input data of the transmitting modem is
compressed, filtered, and 3B4B encoded.
receiving modem, 3B4B encoding ensures easy
extraction of the bit-clock.
filtered, decoded, then stored in an output memory.
The memory provides time expansion, de-jittering
and frequency compensation. The data is filtered
again to improve BER then directed to the RxD
output pin. Signals TxD and RxD in this specification
refer to the set of signals TxD1/2/3 and RxD1/2/3
respectively.
Transmit Current
The transmit current to the LED can be defined by the
Transmit Current pin (TRC). The current is set to the
maximum value (~100 mA) when TRC is
unconnected. The current is set to the minimum
value (~10 mA) when TRC is connected directly to
ground. To obtain current values between minimum
and maximum, TRC is connected to ground through
a resistor. The resistor value R is given by:
LED current drive (mA) = 100 * (110+R)
Data-rate Selection
ACS103 mode SEL = 0
n/a = not available
ACS103 Issue 2.03 May 1996.
DR4 DR3 DR2 DR1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
DC - 4.8
DC - 9.6
Data-rate Distance
(kbps)
n/a
n/a
n/a
n/a
19.2
38.4
19.2
38.4
48.0
56.0
64.0
(1100 + R)
The received data is
9.6
2.4
9.6
Double
Double
Double
Double
Standard
Standard
Standard
Standard
Standard
Standard
Standard
Standard
In the
The
2
The data rates given in the previous table apply to
TxD1, TxD2 and TxD3.
ACS101 mode SEL = 1
The ACS101 mode is a single channel mode
configuration - the data rates given in the previous
table apply to TxD1 only.
'Standard' mode of operation is up to 2.5 km and
'Double' mode is up to 5 km. The two asynchronous
modes are selected when DR3 = 1, DR2 = 1, DR1= 0.
The above data-rates are obtained when used in
conjunction with a crystal of 9.216 MHz.
standard data-rates may be generated by using the
appropriate crystal frequency.
generate 160 kbps data-rate in ACS101 mode, use a
crystal frequency of: (160/192) * 9.216 MHz, i.e.
7.68 MHz. Other "non-standard" data-rates may be
generated in the same way as long as the 5 - 10 MHz
crystal range is observed.
For the data-rates 9.6, 19.2, and 38.4 kbps in
ACS103 mode (9.6, 19.2, 38.4, 48 and 64 kbps in
ACS101 mode), the data-rate selection pins DR3-
DR1 are common to 'Standard' and 'Double' modes
of operation with DR4 selecting the mode.
Modem Control Signals
RSS.
The RTS/XI1, CTS/XO1, DTR/XI2, DSR/XO2, XI3
and XO3 signals may be used in either of two modes,
depending on the RSS setting:
RSS = Low; data transmission mode
RSS = High; modem handshake mode
RSS Low - Data Transmission Mode.
When configured in data transmission mode the
inputs XI1, XI2 and XI3 are sampled continuously
with the outputs appearing at XO1, XO2 and XO3
(respectively) of the far-end modem. The sample
frequency for 'Standard' mode is: (crystal freq.)/1536,
DR4 DR3 DR2 DR1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0 DC - 19.2
1
0
1
0
1
0
1
0 DC - 38.4
1
Data-rate Distance
256.0
192.0
(kbps)
19.2
38.4
48.0
64.0
19.2
38.4
48.0
56.0
64.0
9.6
2.4
9.6
For example, to
Standard
Double
Double
Double
Double
Standard
Double
Double
Standard
Standard
Standard
Standard
Standard
Standard
Standard
Standard
Non-