ACS102A View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'ACS102A' PDF : 13 Pages View PDF
Advanced Communications
ACS102A Data Sheet
Single Fiber link
Link Budget Example (Rtrc set so LED launch current = 50mA peak)
Fiber type
Fiber size
Minimum Transmit Couple power to fiber (µW)
Minimum LED responsivity (A/W)
Minimum ACS102A sensitivity (nA)
Minimum input power to ACS102A amplifier (µW)
Link Budget (dB)
Average current consumption TxD = 19.2kbps (mA)
Average current consumption TxD = 64kbps (mA)
Plastic
1000 micron
1000
0.01
500
50
10
3.8
7.2
Glass
62.5micron
60
0.16
500
3.1
13
3.8
7.2
Glass
50 micron
40
0.16
500
3.1
11
3.8
7.2
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 ACS102A sensitivity (nA)
2
Minimum input power to ACS102A amplifier (µW)
Link Budget (dB)
Average current consumption TxD = 19.2kbps (mA)
Average current consumption TxD = 64kbps (mA)
Plastic
1000 micron
1000
0.1
500
5
23
7
14
Glass
62.5 micron
120
0.6
500
0.83
21
7
14
Glass
50 micron
80
0.6
500
0.83
19.8
7
7.6
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 ACS102A sensitivity (nA)
Minimum input power to ACS102A amplifier (µW)
Link Budget (dB)
Average current consumption TxD = 19.2kbps (mA)
Average current consumption TxD = 64kbps (mA)
Plastic
1000 micron
125
0.1
500
5
13.9
2.2
3.4
Glass
62.5micron
13
0.6
500
0.83
12
2.2
3.4
Glass
50 micron
6.5
0.6
500
0.83
9
2.2
3.4
Calculating average current and power consumption
Average current
Iav (mA)
=
Power
P (mW)
=
XTAL* 10 -7 (1.3 + 3*(A + U *H ) ) + Itrc (A + U * H) + Iout + Ihbt
Iav (mA) * V
Terms used in current/power calculation:
XTAL = Crystal Oscillator Frequency, Hz
H
= Handshake on
H=1 for handshakes active
H=0 for handshakes at DC level
U
= Handshake constant
U = 0.001 when HD 2/1 = 0/0
U = 0.028 when HD 2/1 = 0/1
U = 0.014 when HD 2/1 = 1/0
U = 0.007 when HD 2/1 = 1/1
A
= Active window constant
A = 0.022 when DR 3/2/1 = 0/1/1
A = 0.03 when DR 3/2/1 = 1/0/0
A = 0.045 when DR 3/2/1 = 1/0/1
A = 0.08 when DR 3/2/1 = 1/1/0
A = 0.11 when DR 3/2/1 = 1/1/1
Iout = Average current sourced
mA
from digital outputs such
as (RxD,CTS,DSR,DCD)
Ihbt = Average current sourced
mA
from HBT pin.
(see section HBT Status pin)
Itrc
= Peak Transmit current
mA
set by TRC pin.
V
= Voltage supply to the ACS102 V
Power formula is only accurate
for voltage supply = 5 Volts
Note : An application note on power extraction from the RS232 lines is available from Acapella. This shows a typical example
circuit diagram for powering the ACS102A, the optics and all related circuitry from the RS232 data lines.
8
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