Functional Description
02061-DSH-001-F Mindspeed Technologies®32
Mindspeed Proprietary and Confidential
3.5 Fault Conditions when SCB is Low
This section describes the M02061 operating modes during fault conditions. Over voltage, under
voltage, pins shorted to VCC and pins shorted to ground are included in the fault table.
Table 3-3. Circuit Response to Single-point Fault Conditions, when SCB is Low 1 2 (1 of 2)
Pin Name Circuit Response to Over-voltage Condition
or Short to VCC
Circuit Response to Under-Voltage Condition
or Short to Ground
VCC Bias and modulation outputs are disabled once VCC rises
above the supply detection (high voltage) threshold Bias and modulation outputs are disabled on ce VCC drops below
the supply detection (low voltage) threshold
DIN+, DIN- The APC loop will attempt to compensate for the change in
output power. If the APC loop can not maintain the set
average power, a fault state occurs.(1, 2)
The APC loop will attempt to co mp ensate for the change in
output power. If the APC loop can not maintain the set average
power, a fault state occurs.(1, 2)
VCC3SEL Does not affect laser power. Does not affect laser power.
DIS Bias and modulation outputs are disabled.
3.3V operation - SVCC is opened.
5V operation - SHDWNOUT goes high.
Does not affect laser power (normal condition for circuit
operation).
FAIL Does not affect laser power. Does not affect laser power.
RESET Does not affect laser power. Does not affect laser power.
MODMON Does not affect laser power. Does not affect laser power.
BIASMON Does not affect laser power. Does not affect laser power.
TxPWRMON Does not affect laser power. Does not affect laser power.
APCSET A fault state occurs.(1) A fault state occurs.(1)
IPIN A fault state occurs.(1) A fault state occurs.(1)
IBIASOUT The laser will be turned off, then a fault state occurs.(1) A fault state occurs.(1)
OUTPLaser modulation is prevented; the AP C loop will increase the
bias current to compensate for the drop in laser power if it is
DC coupled. If the set output power can not be obtained, a
fault state occurs.(1, 2)
A fault state occurs.(1)
OUTNDoes not affect laser power. Does not affect laser power.
SVCC Does not affect laser power. Laser bias current will be shut off and a fault state occurs.(1)
CAPC Laser bias current will be shut off, then a fault state occurs.(1) A fault state occurs.(1)
VCC3 Bias and modulation outputs are disabled once VCC3 rises
above the supply detection (high voltage) threshold Bias and modulation outputs are disabled once VCC3 drops
below the supply detection (low voltage) threshold
PWA Does not affect laser power. Does not affect laser power
SHDWNOUT Does not affect laser power. if this pin is used to control an
external switch, laser current is disabled and fault state
occurs.(1)
Does not affect laser power.
MODSET The APC loop will attempt to compensate for the change in
output power. If the APC loop can not maintain the set
average power, a fault state occurs.(1, 2)
A fault state occurs.(1)
TCSLOPE Does not affect laser power. May affect laser power. If this is the case, the APC loop will
attempt to compensate for the change in output power. If the
APC loop can not maintain the set average power, a fault state
occurs.(1, 2)