AK2574VB AKM [Asahi Kasei Microsystems], AK2574VB Datasheet - Page 17

• Manufacturer Part Number: AK2574VB
• Description: 156M Laser Diode Driver + APC for Burst Mode
• Manufacturer: AKM [Asahi Kasei Microsystems]

programmable BIAS and MOD currents in response to the temperature (APC_FF), an on-chip temperature sensor,
and 2 current DACs (I-DAC1 and I-DAC2).
automatically.
+115℃ and EEPROM is prepared with 1.5℃ steps.
current DAC for BIAS current.
AK2574 provides the APC (Auto Power Control) function for the burst mode application. APC is composed of a
If the current data over temperature is set to each EEPROM address, the compensated current is supplied to the LD
To use this function, current data should be stored in EEPROM in advance. The temperature sensor covers –40℃ to
I-DAC1 is 85mA @ Full code sink type current DAC for MOD current and I-DAC2 is 54mA @ Full code sink type
Table 2-5 shows I-DAC1 characteristics and Table 2-6 shows I-DAC2 characteristics.
Table 2-5 I-DAC1 Characteristics
2.4 APC
2.4.1
Fig 2-7 illustrates the APC_FF functions. The operation is as follows:
(1) Analog to digital conversion of the voltage (7 bit) that reflects the temperature for every temperature detection
(2) Read the 8 bit current data (address is indicated by the ADC data) from EEPROM and set this value to the
Fig 2-7 APC FF function
2.4.2
AK2574 has two current output 8 bit DACs; I-DAC1 and I-DAC2.
<MS0266-E-00>
Resolution
Output Current with
Full Code
1 LSB Current Step
DNL
period (128ms typ).
I-DACs.
TEMPSENS
Temperature
APC_FF
I-DAC
TEMPSENS
charatcteristics
Item
Addressing with
R_TEMP
IMOD = VDD – 1.8V
IMOD = VDD – 1.8V
IMOD = VDD – 1.8V
(7bit)
ADC
Memory for
Memory for
I-DAC2
Condition
I-DAC1
R_TEMP
Address
EEPROM
Data
min
76
-1
-17-
R_DAC1
R_DAC2
0.333
typ
85
8
I-DAC1
I-DAC2
max
94
+1
BIAS Current
MOD Current
Unit Remark
LSB Code 20h to FFh
mA
mA
bit
Driver
Driver
MOD
BIAS
2003/12
LD