AK2572 Datasheet, PDF (11/50 Pages) Asahi Kasei Microsystems – APC for Burst Mode Applicable Direct Modulation Laser Diode

ASAHI KASEI
[AK2572]
Ⅵ．CIRCUIT DESCRIPTION
1. Operational Description Notation
In order to distinguish various pre-set parameter sources from EEPROM, Registers or Device pins, “ Identifier –
Main name “ notation is used in the AK2572 circuit description as shown in Table 1-1. For ease of operational
description, internal signals are sometimes defined which are all expressed in small letters.
Table 1-1 Definition of Terms
Identifier
Register
R_
EEPROM
E_
Either or Both Register
or/and EEPROM
RE_
BLOCK
Internal node
Main name
REGISTER name
（All Capital）
EEPROM name
（All Capital）
REGISTER name
EEPROM name
（All Capital）
BLOCK name
（All Capital）
signal name
（All small letter）
Remark
Indicating Register
Indicating EEPROM
Indicating either or both
Register or/and EEPROM
Example
R_DAC2
E_BIAS_TC
RE_DAC3_GAIN
I-DAC1
vpd
Identification words are assigned to the name of Register / EEPROM as shown in Table 1-2 so that each
function can be easily assumed by each name.
Table 1-2 Identification Word Classification
Classification Suffix
Contents
Example
Identification
suffix
_SET
_SEL
_TC
_WIN
_TRGT
Functional setting
Functional selection
Temperature compensation value
Window width setting by ALM set
Target value
RE_APC_FF_SET
E _MODV_SEL
E_MOD_TC
RE_TEMP_WIN
RE_APC_TRGT
Functional
identification
word
APC
DAC
BIAS
MOD
EXTRA
TEMP
PWR
ALM
FF
FB
APC related, common for I-DAC1, I-DAC2 and V-DAC3
I-DAC, V-DAC related
Bias current ( I-DAC2 ) related
MOD current ( I-DAC1, V-DAC3 ) related
EXTRA DAC ( DAC not set to MOD ) related
Temperature sensor related
Power leveling function related
Alarm related
FeedForward function
FeedBack function
RE_APC_FF_SET
E_DAC_SET
R_BIAS_FF
E_MOD_TC
R_EXTRA
R_TEMP
R_PWR_SEL
R_TEMPALM_SET
RE_APC_FF_SET
RE_APC_FB_SET
FBRT FB dividing
TIMER Timer related
R_MOD_FBRT
R_TIMER_OPTALM
GAIN Gain adjust
BURST Burst mode support function related
E_DAC1_GAIN
E_BURST_ALM
ST Status signals
POL Signal polarity
R_TXFLT_ST
E_EXTALM1_POL
< Note > Numeric values in the circuit description of the AK2572 are expressed in Binary, Decimal or
Hexadecimal. In order to identify the differences, setting values in Hexadecimal are expressed with a small
character “h“ suffix.
-11-
<MS0290-E-01>
2004/8