AK2573A Datasheet, PDF (35/38 Pages) Asahi Kasei Microsystems – 125M / 156M Laser Diode Driver + APC

ASAHI KASEI
Fig 8-1 The data format of signed 9 bit register
Register (9bit 2's complement)
Sign
Body (8bit)
D8
D7
D6
D5
D4
D3
D2
D1
D0
Read Data via Digital I/F (8 bit)
(Sign + Body (MSB 7bit)
Write Data via Digital I/F (8 bit)
(Body 8bit, Negative Data can not be written)
[AK2573A]
9. Operation Mode
The AK2573A has 3 operating modes: Self-running, Adjustment and EEPROM mode.
9.1 Self-running Mode
Self-running mode is ready for normal operation after all adjustments are completed. In this mode, temperature
detection, EEPROM access and feeding current are automatically performed using the on-chip oscillator. The
AK2573A works in this mode after power-on.
9.2 Adjustment Mode
Adjustment mode is designed for training the LD characteristics. The AK2573A operates according to the register
settings set through the I²C^TM I/F. During adjustment mode, R_SFP should be 0.
9.3 EEPROM Mode
EEPROM mode is used for storing LD characteristics into EEPROM.
9.4 MODE Control
The AK2573A operation modes are changed through the I²C^TM interface. Table 9-1 shows the access limitation of
each operation mode and Table 9-2 shows the command to change operation mode.
Note: The I²C^TM interface access is prohibited for 1ms after power-on or mode transfer to self-running mode.
Table 9-1 Access limitation of each operation mode
EEPROM Access
Operation mode
Read
Write
Self-running mode
(WP=”L”)
○
×
Adjustment mode
(WP=”L”)
○
×
EEPROM mode
(WP=”L”)
○
○
WP = “H”
○
×
Self-running mode only _{(User Area Only)}
Read
○
○
○
×
Register Access
Write
×
(except mode-change command)
○
×
(except mode-change command)
×
Table 9-2 Operation mode change
Device Address R/W
1010100
W
1010100
W
1010100
W
Address
11111111
11111111
11111111
Data
10100000
10100111
10101110
Operation mode
Self-running mode
Adjustment mode
EEPROM mode
9.5 Operation Mode Protection
When set WP = “H”, only self-running mode is selected.
<MS0189-E-01>
-35-
2004/5