ak2573a AKM Semiconductor, Inc., ak2573a Datasheet - Page 22

• Manufacturer Part Number: ak2573a
• Description: 125m / 156m Laser Diode Driver Apc - Asahi Kasei Microsystems
• Manufacturer: AKM Semiconductor, Inc.

beyond R_TEMPALM.
R_TEMP has negative slope compared to the temperature, TEMPALM is detected when the detected temperature
ASAHI KASEI
5. Alarm
AK2573A has 5 alarm functions as shown in Table 5-1.
Table 5-1 Alarm function
Note 1: Not include delay time by RPD and CPD.
5.1 OPTALM
OPTALM level (optalm_ref) is selectable among 1/3, 1/4, 1/6 and 1/7 of APC FB reference voltage (vapc_ref) by
OPTALM is detected when vpd < optalm_ref.
APC FB keeps R_APC_FB during OPTALM detection in the “ Self running mode” .
5.2 CURRA LM
CURRALM is detected when
R_CURRA LM_DA C1 and 2 can be set every 6#.
CURRALM is clear when receiving disable request (TX_DIS1 or TX_DIS2 is set “ H” ).
5.3 TEMPALM
TEMPALM is detected when R_TEMP < R_TEMPALM.
5.4 DATAA LM
DATAALM is detected when input DATA is 0’ s or 1’ s fixed more than 4.5us (typ).
APC FB keeps R_APC_FB during DATAA LM detection in the “ Self running mode” .
DATA ALM detection is ignored when RE_DATAALM_MASK= “ 1” .
5.5 TXFAULT
TXFAULT function is shown in Table 5 -2.
Table 5-2 TXFAULT
<MS0189-E-01>
RE_OPTALM.
ALM
OPTALM
CURRALM
TEMPALM
DATA ALM
TXFAULT
RE_SFP
R_DAC1(MSB 4bit) > R_CURRA LM_DAC1 or R_DAC2(MSB 4bit) > R_CURRALM_DAC2
0
0
0
1
1
1
Shutdown request
(TXDIS 1, 2)
When monitor PD current is below the OPTALM level.
When R_DAC1 or R_DAC2 is beyond CURRALM level or
equal to full code.
When the detected temperature is beyond TEMPA LM
level.
When the detected 0s or 1s sequential data input (4.5us
typical).
When one or more alarm detected.
Detection condition
0
0
1
0
0
1
ORed ALM
X
X
0
1
0
1
TXFAULT
-22-
0 or 1 (Hold)
ORed ALM
1 (Hold)
0
1
0
Polarity
Programmable 5us (typ) (Note 1)
Programmable every 125us (typ)
Programmable every 128ms (typ)
Programmable 4.5us (typ)
Normal Operation
I-DAC output
Normal Operation
Shutdown
Normal Operation
Shutdown
Shutdown
“ H”
Detected Time
detected ALM
depends on
[AK2573A]
2004/5