ak2573a AKM Semiconductor, Inc., ak2573a Datasheet - Page 14

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

The AK2573A has two APC functions, APC FF (Feed-forward) and APC FB (Feedback).
APC FF supplies a programmed current in response to the temperature from an on-chip temperature sensor.
APC_FB provides stable a power control function using a digital feedback algorithm. The APC_FF and APC_FB is
user programmable. Fig4-1 illustrates APC block diagram.
Fig 4-1 APC Block Diagram
ASAHI KASEI
3.2 Duty Adjustment
AK2573A supplies a programmed duty adjustment in response to the temperature from an on-chip temperature
Table 3-3 Duty Adjustment characteristics
Note 1: This parameter is characterized and is not 100% tested.
Table 3-4 Pulse Extended
4. APC
<MS0189-E-01>
sensor (every 6#, Duty data is stored in E_DUTY_TC, see Table 8-3 for more information). Write same data into
E_DUTY_TC for constant duty adjustment. Table 3-3 and 3-4 show the characteristics of duty adjustment function.
Item
Maximum Pulse Extended
1 LSB Pulse Extended Step
Pulse Extended Stability
Monitor
CPD
PD
R_DUTY
RPD
30
31
0
1
2
.
.
(RE_APC_TRGT)
PDIN
PDMON
TEMPMON
APC Target
RE_TEMP_OFFSET
TEMPSN
(RE_PDGAIN)
PDGAIN
PDGAIN
S
Pulse Extended (typ) [ns]
DAC_APC
vpd
vapc_ref
Symbol
ADC
Temperature ALM
(RE_TEMPALM)
Tstep
Tsta
0.03
0.06
0.90
0.93
Td
0
.
.
COMP
APC_
R_TEMP
APC FB Initial setting
(RE_APC_INIT_SET)
apc_comp_out
(RE_APC_FF_SET)
APC Operation
ATT
(RE_OPTALM_)
min
0.5
EEPROM
OPTALM
TEMP
OPTALM Reference
ALM
Remark
(optalm_ref)
(RE_ALM_POL)
1/N
ALM Polarity
(R_DAC1_FF)
0.03
Digital Filter
typ
APC FF
-14-
APC Feedback
(R_APC_FB)
(RE_APC_FB_SET)
APC FB Operation
1/s
(R_DAC2_FF)
APC FF
max
0.2
K_DAC1
K_DAC2
_FBRT
_FBRT
(R_DAC1_FB)
+
+
I-DAC1 FB
(R_DAC2_FB)
Unit
R_DAC1
I-DAC2 FB
Over current ALM
(RE_CURRALM)
ns
ns
ns
R_DAC2
R_DAC1
R_DAC2
(RE_ALM_POL)
(RE_DAC1_GAIN)
ALMPolarity
I-DAC1
3.5V, 0.3ns Extended (Note 1)
OPTALM
Note 1
32 Steps
Ta=-40 to 85#, VDD=3.1&
Gain
(RE_DAC2_GAIN)
I-DAC2
(RE_ALM_POL)
ALM Polarity
Gain
Imod
CURR
ALM
Driver
Remarks
* 0.0095
* 0.0095
Ibias
TEMPALM
BIASMON
CURRALM
OPTALM
MODMO
[AK2573A]
IMODN
IMOD
N
IBIAS
2004/5