AK2573A Datasheet, PDF (18/38 Pages) Asahi Kasei Microsystems – 125M / 156M Laser Diode Driver + APC

ASAHI KASEI
[AK2573A]
Fig 4-7 APC example-4 (MOD=FF+FB, BIAS=FF)
R_APC_FB
R_DAC1_FF
RE_DAC1_GAIN
R_DAC1_FB
I-DAC1
1
=
R_APC_FB
R_DAC1
+
85/255
G_DAC1
Imod
I-DAC2
R_DAC2_FB
=0
R_DAC2
0
+
54/255
G_DAC2
Ibias
Fig 4-8 APC example-5 (MOD=FF, BIAS=FF+FB)
R_APC_FB
R_DAC1_FF
RE_DAC1_GAIN
I-DAC1
R_DAC1_FB
=0
R_DAC1
0
+
85/255
G_DAC1
Imod
I-DAC2
R_DAC2_FB
= R_APC_FB
R_DAC2
1
+
54/255
G_DAC2
Ibias
R_DAC1_FB = R_APC_FB
R_DAC1 = R_DAC1_FF + R_DAC1_FB
R_DAC2 = R_DAC2_FF
R_DAC2_FF
RE_DAC2_GAIN
G_DAC1/G_DAC2 = 1 or 0.5
R_DAC2_FB = R_APC_FB
R_DAC1 = R_DAC1_FF
R_DAC2 = R_DAC2_FF + R_DAC2_FB
R_DAC2_FF
RE_DAC2_GAIN
G_DAC1/G_DAC2 = 1 or 0.5
Fig 4-9 APC example-6 (MOD=FF+FB, BIAS=FB)
R_DAC1_FBRT
(E_DAC_FBRT_FIX)
R_DAC1_FF
I-DAC1
R_APC_FB
K_DAC1_
FBRT
R_DAC1_FB
R_DAC1
+
85/255
RE_DAC1_GAIN
G_DAC1
Imod
I-DAC2
R_DAC2_FB
= R_APC_FB
R_DAC2
1
+
54/255
G_DAC2
Ibias
R_DAC1_FB = K_DAC1_FBRT * R_APC_FB R_DAC2_FF = 0
R_DAC1 = R_DAC1_FF + R_DAC1_FB
R_DAC2 = R_DAC2_FB = R_APC_FB
RE_DAC2_GAIN
G_DAC1/G_DAC2 = 1 or 0.5
Fig 4-10 APC example-7 (MOD=FB, BIAS=FF+FB)
R_APC_FB
R_DAC1_FF =
0
R_DAC1_FB
I-DAC1
RE_DAC1_GAIN
1
=
R_APC_FB
R_DAC1
+
85/255
G_DAC1
Imod
R_DAC2_FBRT
(E_DAC_FBRT_FIX)
K_DAC2_ ^R_DAC2_FB
FBRT
R_DAC2
+
I-DAC2
54/255
G_DAC2
Ibias
R_DAC2_FB = K_DAC2_FBRT * R_APC_FB
R_DAC1 = R_DAC1_FB = R_APC_FB
R_DAC2 = R_DAC2_FF + R_DAC2_FB
R_DAC2_FF
RE_DAC2_GAIN
G_DAC1/G_DAC2 = 1 or 0.5
Table 4-5 EEPROM Assignments for typical operation
RE_APC_ RE_APC_ RE_APC_ E_DAC2_TC
E_DAC1_TC
FF_SET FB_SET INIT_SET
01
10
0
-
E_DAC1_FF_TC
1
E_APC_INIT_TC E_DAC1_FF_TC
10
01
0
E_DAC2_FF_TC
-
1
E_DAC2_FF_TC E_APC_INIT_TC
11
00
x
E_DAC2_FF_TC E_DAC1_FF_TC
11
01
x
E_DAC2_FF_TC E_DAC1_FF_TC
11
10
x
E_DAC2_FF_TC E_DAC1_FF_TC
01
11
0
-
E_DAC1_FF_TC
01
11
1
E_APC_INIT_TC E_DAC1_FF_TC
10
11
0
E_DAC2_FF_TC
-
10
11
1
E_DAC2_FF_TC E_APC_INIT_TC
00
11
x
Prohibit
11
11
x
E_DAC1_FF_TC: I-DAC1 current data (temperature compensated)
E_DAC2_FF_TC: I-DAC2 current data (temperature compensated)
E_APC_INIT_TC: R_APC_FB initial data (temperature compensated)
I-DAC2
(BIAS)
FB
FB
FF
FF
FF
FF
FF+FB
FB
FB
FF+FB
FF+FB
I-DAC1
(MOD)
FF
FF
FB
FB
FF
FF+FB
FF
FF+FB
FF+FB
FB
FB
Table 4-6 APC FB Operation
RE_APC_ RE_APC_
FB_SET FF_SET
K_DAC1_FBRT
00
XX
0
01
XX
1
10
XX
0
11
00
-
01
R_DAC1_FBRT*1.25/64/G_DAC1
10
1
11
-
K_DAC2_FBRT
0
0
1
-
1
R_DAC2_FBRT/32/G_DAC2
-
Remark
No FB
FB for MOD
FB for BIAS
Prohibit
R_DAC1_FBRT=E_DAC_FBRT
R_DAC2_FBRT=E_DAC_FBRT
Prohibit
<MS0189-E-01>
-18-
2004/5