ak2574 AKM Semiconductor, Inc., ak2574 Datasheet - Page 14

• Manufacturer Part Number: ak2574
• Description: 156m Laser Diode Driver Apc For Burst Mode
• Manufacturer: AKM Semiconductor, Inc.

when DATA (DATAP – DATAN) = 1 and sinks the current from IMODN when DATA = 0. DATA is set “ 0” when
BRST (BRSTP – BRSTN) = 0.
BRTS=1. To protect the last LD current at BRST 1$0, BIAS current turned off timing is delayed for a duty extended
when the last DATA=1.
! or more impedance respectively.
The 156M MOD driver is composed of the differential current switches, and it sinks the MOD current from IMOD pin
The BIAS driver is composed of the single-end current switch, and it sinks the BIAS current from IBIAS when
Table 2-2 shows LV PECL input characteristics. The AK2574 LVPECL input, which is biased to 0.6 * VDD with 10k
ASAHI KASEI
2. LD Driver
Fig 2-1 illustrates the block diagram of LD driver function.
The AK2574 LD driver contains a Driver part, an APC part, a LVPECL I/F part and a programmable duty
adjustment.
The driver part is composed of 156M MOD current switching controlled by DATA, and BIAS current switching
controlled by BRST.
APC part is composed of a 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).
The LVPECL I/F part is composed of LVPECL I/F for data, clock and the burst control signal (BRST).
2.1 Driver
2.2 LVPECL I/F (DATAP, DATAN, CLKP, CLKN, BRSTP, BRTSN)
The AK2574 supports direct data or latched data input (see Table 2 -1). Connect CLKP = VDD or leave open and
CLKN = VSS when SEL = “ L” .
Table 2-1 Data input
2.2.1
<MS0266-E-00>
Fig 2-1 Driver Block Diagram
DATAN
BRSTN
DATAP
BRSTP
CLKN
CLKP
LVPECL Input Characteristics
SEL (CMOS)
(LVPECL)
(LVPECL)
(LVPECL)
DATA
BRST
CLK
APC
“ H”
“ L”
TEMP_SENS
data
brst
clk
vtemp
LVPECL I/F
SEL
SEL
FF
FF
Direct data
Latched data with clock
ADC
data_ff
R_TEMP
brst_ff
AND
CLKALM
EEPEOM
DUTY_
ADJ
-14-
R_DAC2
R_DAC1
I-DAC1
I-DAC2
IMODN
Driver
Imod
Ibias
IMOD
LD
IBIAS
IBIASR1
IBIASC1
IBIASC2
[AK2574]
0.1uF
2003/12
330
0.1uF