AK2572 Datasheet, PDF (5/50 Pages) Asahi Kasei Microsystems – APC for Burst Mode Applicable Direct Modulation Laser Diode

ASAHI KASEI
[AK2572]
Pin Description (Continued)
Pin# Pin Name
Function
I/O
Note
LD Bias current output (Current-sink type : Maximum sink current
＝85.0 mA [Typ.]). The current value is set by I-DAC2.
16 IOUT2 Please operate the device under IOUT2-pin voltage≧(VDD－1.7 V) Ao
condition. When the voltage on this pin becomes lower, a sink
current error becomes larger.
17 VSSBI Ground for I-DAC2
PWR
18 VDDBI Power supply for I-DAC2.
PWR
I-DAC1 current output (Current-source type : Maximum sourcing
current 10.2 mA [Typ.]).
When RE_MODV_SEL＝“0“, this becomes an LD modulation
19
IOUT1
current output and when RE_MODV_SEL＝“1“, it is I to V
converted and it can be used as an APD control voltage or a
Ao
reference voltage for LDD (Laser Diode Driver) etc.. Please operate
the device under IOUT1-pin voltage≦1.3 V. When the voltage on
this pin becomes higher, a sourcing current error becomes larger.
20 VDDMD Power supply for I-DAC1.
PWR
V-DAC3 voltage output pin (Maximum output voltage: 2.2 V [Typ.]).
21
VOUT3
When RE_MODV_SEL＝“0”, this voltage can be used as either an
APD control voltage or LDD reference voltage etc.. When
RE_MODV_SEL＝“1“, this outputs an LD modulation current
control voltage. Please connect an external RC filter (LPF : R＝1kΩ
Ao
Connect it to
external RC
filter
and C＝0.01μF are recommended) to this pin.
PDMON is the Normalized PDIN voltage output pin.
22
PDMON
Adjust RE_PDGAIN so that PDMON voltage is equal to 1.0 V [typ].
When APC_FB function or OPTALM function is used,
Ao
RE_PDGAIN adjustment is required.
23 TEMPMON On-chip temperature sensor voltage output.
Ao
24
BIAS
BIAS resistor connection pin.
Connect this pin to AVSS via a 12kΩ±1% resistor.
Ao
Connect it to
a resistor
Irregular external signal detect [1] input pin. A polarity of
25
EXTALM1
EXTALM1 detection can be selected by RE_EXTALM1_POL.
EXTALM1 can be set as a target TXFAULT output alarm by
Di
Should not
be left open
RE_EXTALM1_SET. When this pin is not used, connect it to DVSS.
This pin functions as MOD_CTRL input pin when both
RE_SFP_SET＝“1“ and RE_PWR_LVL1_SET＝“1“.
This pin becomes EXTALM2 input pin when either RE_SFP_SET
＝“0“ or RE_PWR_LVL1_SET＝“0“.
When MOD_CTRL-pin function (Power leveling [1] control signal
26
EXTALM2 /
MOD_CTRL
input pin) is selected, Power leveling [1] is executed by a Hardware
pin control. In this case, then, EXTALM2-related function is
automatically turned off.
Di
Should not
be left open
When EXTALM2-pin function (Irregular external signal detection
[2] input pin) is selected, EXTALM2 is set as a target TXFAULT
output alarm by RE_EXTALM2_SET, and RE_EXTALM2_POL
sets the polarity of EXTALM2 detection. When this pin is not used,
connect it to DVSS.
27 TEST4 Output pin for AKM test. Leave it open for Normal operation.
Do Open
Write protect control pin. This pin is internally pulled-up via a 20kΩ
28
WP
[Typ.] resistor. WP-pin and R_WP_CTRL set the limitation of an
accessible EEPROM space via Digital interface. Please refer to
Di_pu
Section 9.2 for details.
-5-
<MS0290-E-01>
2004/8