AK2574 Datasheet, PDF (16/30 Pages) Asahi Kasei Microsystems – 156M Laser Diode Driver + APC for Burst Mode

ASAHI KASEI
Fig 2-5 Input timing example with CLK
BRSTP - BRSTN
CLKP- CLKN
DATAP - DATAN
2 CLK (typ)
Preamble + Delimiter
(24bit include Guard Time)
[AK2574]
ATM Cell (53byte)
2.2.3 Input Timing (SEL=”L”, in the case of direct DATA)
AK2574 operates without CLK when SEL=”L”. DATA input should be 12.8ns or more behind BRST = 0 → 1
transition. ToprotectthelastDATA,BRST1→0transitionshouldbebehindthelastDATAinput. Fig2-6illustrates
the timing example.
Fig 2-6 Input timing example without CLK
BRSTP - BRSTN
DATAP - DATAN
12.8ns (min)
Preamble + Delimiter
(24bit included Guard Time)
ATM Cell (53byte)
2.3 Duty Adjustment
AK2574 supplies a programmed duty adjustment in response to the temperature from an on-chip temperature
sensor (every 6℃, Duty data is stored in E_DUTY_TC, see Table 6-3 for more information). Write same data into
E_DUTY_TC for constant duty adjustment. Table 2-3 and 2-4 show the characteristics of duty adjustment function.
Table 2-3 Duty Adjustment characteristics
Item
Symbol min typ max
Maximum Pulse Extended Td
0.5
1 LSB Pulse Extended Step Tstep
0.03
Pulse Extended Stability
Tsta
0.2
Note 1: This parameter is characterized and is not 100% tested.
Unit
Remarks
ns Note 1
ns 32 Steps
ns Ta=-40 to 85℃, VDDDR=3.1～3.5V
0.3ns Extended (Note 1)
Table 2-4 Pulse Extended
R_DUTY Pulse Extended (typ) [ns]
0
0
1
0.03
2
0.06
.
.
.
.
30
0.90
31
0.93
Remark
<MS0266-E-00>
-16-
2003/12