ASAHI KASEI
[AK2573A]
Table 6-3 Operation at shutdown release
RE_SFP TXFAULT at
RE_TEMP_ Temp Difference R_APC_FB
result
Remark
Shutdown request DET
0
0
0
1
1
1
1
X
0
1
1
0
1
1
X
X
0
1
X
0
1
Initial value
Hold data
Initial value
Initial value
Hold data
X
X
0
0
0
1
Initial value
Initial value
X
7. Power-up / down Timing
7.1 Delay Time of TXFAULT Detection with OPTALM
In correspond to the delay time caused by RPD and CPD to get the moniter PD average current, the delay time of
TXFAULT detection with OPTALM is set when RE_SFP=”1” (SFP support). AK2573A has 2 delay time when
RE_SFP=”1”: normal delay and accelerated delay. Accelerated delay may be selected when both I-DAC1 and I-DAC2
are set to APC_FF or APC_FBwithan initial value setting.
Table 7-1 shows the delay time of TXFAULT detection with OPTALM and Fig 7-1 illustrated block diagram.
Note: When accelerated delay is selected with RE_SFP=”1”, APC_FF data or initial data of APC_FB should be
suitable, otherwise AK2573A might go into shutdown by detection of OPTALM after delay time.
Fig 7-1 APC_FB Block Diagram
APC Feedback
(R_APC_FB)
PDGAIN
(R_PDGAIN)
Monitor
PD
APC_
COMP
Digital
Filter
LD
PDIN
TX_FAULT
Control
PDGAIN
vpd
CPD
RPD
OPTALM Level
(R_OPTALM)
APC Terget
(R_APC_TRGT
OPTALM
DAC_APC
ATT
OPTALM
reference
Detection and reset OPTALM
vary with the cut-off
frequency of CPD and RPD
vapc_ref
)
(opalm_ref)
Table 7-1 Delaytime of TXFAULT detection with OPTALM
RE_SFP R_TIMER_
OPTALM
R_APC_
INIT_SET FF_SET
R_APC_
Delay Time of TXFAULT Remarks
detection with OPTALM
0
X
X
X
0 ms
disable TXFAULT
detection
1
1
0
1
X
0
X
160 ms (typ)
160 ms (typ)
00
01
10
11
X
1
1
1
1
X
1
2 ms (typ)
2 ms (typ)
Acceleration
power-up
<MS0189-E-01>
-24-
2004/5
AKM [ ASAHI KASEI MICROSYSTEMS ]
