ACS104A Semtech Corporation, ACS104A Datasheet - Page 6

• Manufacturer Part Number: ACS104A
• Description: Acs104a Fiber Modem
• Manufacturer: Semtech Corporation

Dual Fiber link optimised for performance
Link Budget Example (Rtrc set so LED launch current = 100mA peak)
Fiber type
Fiber size
Minimum Transmit Couple power to fiber (µW)
Minimum PIN responsivity (A/W)
Minimum ACS104A sensitivity (nA)
Minimum input power to ACS104A amplifier (µW)
Link Budget (dB)
Average current consumption TxD = 19.2kbps (mA)
Average current consumption TxD = 64kbps (mA)
Dual Fiber link optimised for low power & low cost optical components
Link Budget Example (Rtrc set so LED launch current = 12.5mA peak)
Fiber type
Fiber size
Minimum Transmit Couple power to fiber (µW)
Minimum PIN responsivity (A/W)
Minimum ACS104A sensitivity (nA)
Minimum input power to ACS104A amplifier (µW)
Link Budget (dB)
Average current consumption TxD = 19.2kbps (mA)
Average current consumption TxD = 64kbps (mA)
Calculating average current and power consumption
Average current
I
Power
P (mW)
Terms used in current/power calculation:
XTAL
H
U
A
Note :
av
(mA)
Advanced Communications
=
=
=
=
An application note on power extraction from the RS232 lines is available from Acapella. This shows a typical example
circuit diagram for powering the ACS104A, the optics and all related circuitry from the RS232 data lines.
Crystal Oscillator Frequency, Hz
Handshake on
H=1 for handshakes active
H=0 for handshakes at DC level
Handshake constant
U = 0.001
U = 0.028
U = 0.014
U = 0.007
Active window constant
A = 0.022
A = 0.03
A = 0.045
A = 0.08
A = 0.11
=
=
XTAL* 10
I
av
(mA) * V
when HD 2/1 = 0/0
when HD 2/1 = 0/1
when HD 2/1 = 1/0
when HD 2/1 = 1/1
when DR 3/2/1 = 0/1/1
when DR 3/2/1 = 1/0/0
when DR 3/2/1 = 1/0/1
when DR 3/2/1 = 1/1/0
when DR 3/2/1 = 1/1/1
-7
(1.3 + 3*(A + U *H ) ) + I
trc
(A + U * H) + I
I
I
I
V
6
out
hbt
trc
Plastic
1000 micron
1000
0.1
500
5
23
7
14
Plastic
1000 micron
125
0.1
500
5
13.9
2.2
3.4
=
=
=
=
out
Average current sourced
from digital outputs such
as (RxD,CTS,DSR,DCD)
Average current sourced
from HBT pin.
(see section HBT Status pin)
Peak Transmit current
set by TRC pin.
Voltage supply to the ACS104 V
Power formula is only accurate
for voltage supply = 5 Volts
+ I
hbt
Glass
62.5 micron
120
0.6
500
0.83
21
7
14
Glass
62.5micron
13
0.6
500
0.83
12
2.2
3.4
ACS104A Data Sheet
mA
mA
mA
50 micron
Glass
50 micron
80
0.6
500
0.83
19.8
7
7.6
Glass
6.5
0.6
500
0.83
9
2.2
3.4