02094-DSH-001-C Mindspeed Technologies™ March 2005
Mindspeed Proprietary and Confidential
M02094
3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps
Applications
• EPON FTTH modules
• Gigabit Ethernet modules
• 1G/2G Fibre Channel modules
• Digital Video
The M02094 is a highly integrated, programmable VCSEL driver intended for SFP/SFF modules to 2.0 Gbps. Using
differential PECL data inputs, the M02094 supplies the bias and modulation current required to drive a VCSEL or
edge-emitting laser. The modulation output can be AC or DC-coupled to a FP laser diode or AC coupled to a com-
mon anode or common cathode VCSEL.
Peaking adjustment is available to improve VCSEL fall time.
EPON burst mode operation is supported with no extra components.
Integrated safety circuitry detects faults and provides latched bias and modulation current shutdown.
Functional Block Diagram
V
CC3
-1.3V
Internal
3.3V reg.
Input
Buffer
Output
Buffer
Laser
Driver
Automatic Power Control
(laser bias current)
TX
Disable
Safety
Circuitry with
Latched Fault
Modulation
Control
V
CC
V
CC3
FAIL
VCC3
SEL
PEAK
AD J
SV
CC
and
IB
OUT_CC
OUT-
OUT+
GND
0
IB
OUT_CA
and
SGND
IPIN
DISDLY
DIS
MOD
SET
TC
SLOPE
MOD
MON
RESET
BIAS
MON
APC
SET
C
APC
TxPwr
MON
D
IN
-
D
IN
+
In te rnal Power Bus
GND
CC
SEL
Features
• High speed operation; suitable for SFP/SFF applications from
155Mbps to 2.0 Gbps. Typical rise/fall times < 110 ps.
• Supports Common Anode VCSEL, Common Cathode VCSEL, or FP
LASER. May be used with or without a monitor photodiode.
• Programmable temperature compensation. Modulation output and
bias output can be controlled using a few discrete resistors.
• Supports DDMI (SFF-8472) diagnostics.
• DC or AC coupled modulation drive.
• Peaking circuit to optimize VCSEL response.
• Low overshoot allows high extinction ratio with low jitter.
• Supports E-PON burst mode with no extra components
• Automatic Laser Power Control, with “Slow-Start”.
• 3.3V or 5V operation
ii Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
V
CC
DIN+
DIN-
VCC3
SEL
MOD
MON
BIAS
MON
C
APC
V
CC3
PEAK
ADJ
TC
SLOPE
FAIL
RESET
DISDLY
TXPWR
MON
APC
SET
I
PIN
GND
0
OUT+
OUT-
SV
CC
/
IBOUT
CC
CC
SEL
MOD
SET
IBOUT
CA
/
SGND
DIS
1
6
712
13
18
1924
\
GND, connect to
PCB ground
4 X 4 mm
Ordering Information
Part Number Package Operating Temperature
M02094-11 * QFN24
M02094-EVM Combination Electrical and Optical Evaluation board
* The letter “G” designator after the part number indicates that the device is RoHS-compliant. Refer to www.mindspeed.com for additionalinformation.
Revision History
Revision Level Date ASIC
Revision Description
AAdvance October 2003 xAdvance.
BPreliminary March 2004 xPreliminary release.
CReleased March 2005 xReleased. New datasheet format. Changes to Absolute Maximum Ratings, Operating
Temperature, AC and DC specifications. New section on video operation.
Pin Configuration
Typical Electrical Eye Diagram, Common Anode Mode
Typical Electrical Eye Diagram,
Common Cathode Mode with Peaking
02094-DSH-001-C Mindspeed Technologies™ 3
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1.0 Product Specification
1.1 Absolute Maximum Ratings
These are the absolute maximum ratings at or beyond which the IC can be expected to fail or be damaged. Reli-
able operation at these extremes for any length of time is not implied.
Table 1-1. Absolute Maximum Ratings
Symbol Parameter Rating Units
VCC Power supply voltage -0.4 to +6.0 V
VCC3 3.3V power supply voltage -0.4 to +4.0 V
TSTG Storage temperature -65 to +150 °C
IBIASOUTCA (MAX) Maximum bias output current for common anode
laser
75 mA
IBIASOUTCC (MAX) Maximum bias output current for common cathode
laser
30 mA
IMODCA (MAX) Maximum modulation current for common anode
laser
70 mA
IMODCC (MAX) Maximum modulation current for common cathode
laser
30 mA
DIN+/- Data inputs -0.4 to VCC3 + 0.4 V
DIS Disable input -0.4 to VCC + 0.4 V
BIASMON, MODMON Bias and modulation output current mirror
compliance voltage
-0.4 to VCC3 + 0.4 V
IPIN Photodiode anode voltage -0.4 to VCC3 + 0.4 V
IPIN Sink or Source Current 2.0 mA
FAIL Status flag -0.4 to VCC + 0.4 V
APCSET, MODSET Set inputs -0.4 to VCC3 + 0.4 V
TCSLOPE Temperature compensation slope -0.4 to VCC3 + 0.4 V
OUT+, OUT- Output -0.4 to VCC3 + 0.4 V
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M02094 Data Sheet
1.2 Recommended Operating Conditions
1.3 DC Characteristics
(VCC = +3.05V to +3.55V or 4.75V to 5.5V, TA = -40 °C to +95 °C, unless otherwise noted)
Typical values for common anode are at VCC = 3.3 V, IBOUTCA = 20 mA, IMOD = 20 mA, TA = 25 °C, unless otherwise noted.
Typical values for common cathode are at VCC = 3.3 V, IBOUTCC = 5 mA, IMOD = 5 mA, TA = 25 °C, unless otherwise noted
Table 1-2. Recommended Operating Conditions
Parameter Rating Units
Power supply (VCC-GND) 3.3 ± 7.5%
or 5.0 + 10%,-5% V
Operating ambient -40 to + 95 °C
Table 1-3. DC Characteristics
Symbol Parameter Conditions Min. Typ. Max. Units
ICC Supply current excluding
IMOD and IBIAS
PEAKADJ high (no peaking adjust)
Common anode operation(1)
Common cathode operation(1)
Additional current when PEAKADJ is used.
Additional current when operating from a 5V
supply(2)
–
–
-
-
28
35
2
48
55
15
mA
IBOUTCA Bias current adjust range,
common anode mode
V(IBIASOUT) > 0.7V 150 mA
IBOUTCC Bias current adjust range,
common cathode mode
V(IBIASOUT) < 2.5V 0.5 15 mA
IBOFF Bias current with optical
output disabled
DIS = high
V(IBOUTCA) = VCC3 for common anode
operation.
V(IBOUTCC) = 0V for common cathode
operation.
– – 150 µA
Ratio of IBIAS current to
BIASMON current
CCSEL low, common anode mode
CCSEL high, common cathode mode
–45.7
13.5
–A/A
VMD Monitor diode reverse bias
voltage
1.5 – – V
IMD Monitor diode current
adjustment range
Adjusted with RAPCSET 10 –1500 µA
Ratio of TxPwrMON current to
monitor photodiode current
1A/A
Product Specification
02094-DSH-001-C Mindspeed Technologies™ 5
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CMD_MAX Maximum monitor
photodiode capacitance for
APC loop stability. Includes
all associated parasitic
capacitances.
100 pF
TTL/CMOS input high
voltage (DIS)
2.0 –5.5 V
TTL/CMOS input low voltage
(DIS)
– – 0.8 V
CMOS input high voltage
(VCC3SEL)
2.4 V
CMOS input low voltage
(VCC3SEL)
1.2 V
Logic output high voltage
(FAIL)
With external 10kΩ pull-up to VCC. VCC - 0.6 – – V
Logic output low voltage
(FAIL)
For 6.8k to 10k ohm resistor when pulled up
to 5V
For 4.7k to 10k ohm resistor when pulled up
to 3.3V
– – 0.4 V
RIN Differential input impedance Data inputs -- 6800 –Ω
VSELF Self-biased common-mode
input voltage
-- VCC3 - 1.3 -- V
VINCM Common-mode input
compliance voltage
Data inputs VCC3-1.45 – VCC3-[VIN(Diff)]/4 V
VIN(DIFF) Differential input voltage = 2 x (DIN+HIGH - DIN+LOW)200 –2400 mVpp
VCC3THL(3) 3.3V supply detection, lower
threshold
2.5 2.8 2.95 V
VCC3THH(3) 3.3V supply detection, upper
threshold
3.65 3.8 4.1 V
VCC5THL 5V supply detection, lower
threshold
3.9 4.25 4.65 V
VCC5THH 5V supply detection, upper
threshold
5.45 5.8 6.2 V
VREF1 Reference voltage for
MODSET
1.18 1.3 1.4 V
VAPCSET Reference voltage for APCSET 1.35 V
VBL Bias_OK lower voltage
threshold
0.88 1.0 1.05 V
Table 1-3. DC Characteristics
Symbol Parameter Conditions Min. Typ. Max. Units
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M02094 Data Sheet
1.4 AC Characteristics
(VCC = 3.05 V to 3.55V or 4.7V to 5.5V, TA = -40 °C to +95 °C, unless otherwise noted)
Typical values for common anode are at VCC = 3.3 V, IBOUTCA = 20 mA, IMOD = 20 mA, TA = 25 °C, unless otherwise noted.
Typical values for common cathode are at VCC = 3.3 V, IBOUTCC = 5 mA, IMOD = 5 mA, TA = 25 °C, unless otherwise noted.
VBH Bias_OK upper voltage
threshold
1.45 1.6 1.7 V
VFAULTL(4) Lower voltage threshold for
fault inputs IBOUTCA, OUT+,
CAPC, and MODSET
FAIL asserts if any of these signals fall below
this value.
300 400 mV
VFAULTH(5) Upper voltage threshold for
fault inputs IBOUTCC
FAIL asserts if any of these signals fall above
this value.
2.6 2.9 VCC3 - 0.2 V
VSELFL Self bias voltage for IBOUTCA
and OUT+
During disable state 0.5 1.65 2.0 V
VSELFH Self bias voltage for IBOUTCC During disable state 01.25 V
Notes:
1. Excludes bias and modulation currents.
2. Bias and modulation currents add directly to power supply current in 5V applications. The additional supply current noted excludes these currents.
3. VCC3 “supply OK” circuitry monitors the internally regulated 3.3V supply when VCC = 5V (VCC3SEL =low). When VCC = 3.3V, VCC3 “supply OK”
circuitry monitors VCC (VCC3SEL =high).
4. A low level at IBOUTCA does not trigger a fault condition during common cathode operation.
5. A low level at IBOUTCC does not trigger a fault condition during common anode operation.
Table 1-4. AC Characteristics
Symbol Parameter Conditions Min. Typ. Max. Units.
IMOD Modulation current adjust range Common Cathode Mode
OUT+ and OUT- AC coupled into 50Ω load.
Common Anode Mode
OUT+ and OUT- DC coupled into 25Ω load.(1)
1
3
–15
45
mA
IMOD(OFF)(2) Modulation current with output
disabled
DIS = high – – 150 µA
Ratio of modulation current to
MODMON current
CCSEL = high, RLOAD = 50Ω
CCSEL = low
–30
65
–A/A
IMOD-TC Programmable range for modulation
current temperature coefficient
Adjustable using TCSLOPE 0 – 104ppm/°C
TTCSTART Temperature at which modulation
current TC compensation enables
20 °C
Table 1-3. DC Characteristics
Symbol Parameter Conditions Min. Typ. Max. Units
Product Specification
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1.5 Safety Logic Timing
(VCC = 3.05 V to 3.55V or 4.7V to 5.5V, TA = -40 °C to +95 °C, unless otherwise noted)
Typical values for common anode are at VCC = 3.3 V, IBOUTCA = 20 mA, IMOD = 20 mA, TA = 25 °C, unless otherwise noted.
Typical values for common cathode are at VCC = 3.3 V, IBOUTCC = 5 mA, IMOD = 5 mA, TA = 25 °C, unless otherwise noted.
tr Modulation output rise time 20% to 80% into 25 Ω(3). For IMOD from 3 mA
to 30 mA. Measured using 11110000 pattern
at 2.5 Gbps
–110 140 ps
tf Modulation output fall time –110 140 ps
OSOFF Overshoot of modulation output
current in the “off” direction
into 25 Ω load -- 1 2 %
RJ Random jitter –1.2 –psrms
DJ Deterministic jitter Measured into 25Ω load, 231 - 1 PRBS at 2.0
Gbps
K28.5 pattern at 2.0 Gbps
(includes pulse width distortion)
20
20
45
45
pspp
Notes:
1. Minimum voltage at OUT+ > 0.7V.
2. The current through the laser in this state can be made negligible by adding a 1kΩ or less resistor in parallel with the laser.
3. The M02094 is designed to drive 25Ω loads. External resistance should be added in series or parallel to the Laser to create this load impedance. In
common cathode mode, 50Ω resistors internal to the M02094 are in parallel with the laser.
Table 1-5. Safety Logic Timing
Symbol Parameter Conditions Min. Typ. Max. Units.
t_off DIS assert time Rising edge of DIS to fall of output signal
below 10% of nominal(1)
10 µs
t_on DIS negate time Falling edge of DIS to rise of output signal
above 90% of nominal(1)
1ms
Table 1-4. AC Characteristics
Symbol Parameter Conditions Min. Typ. Max. Units.
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M02094 Data Sheet
t_init Time to initialize(2) Includes reset of FAIL; from power on after
Supply_OK or from negation of DIS during
reset of FAIL condition
235 ms
t_fault Laser fault time - from fault condition
to assertion of FAIL
From occurrence of fault condition or when
Supply_OK is beyond specified range
100 µs
t_reset DIS time to start reset DIS or ENA pulse width required to initialize
safety circuitry or reset a latched fault 10(3) µs
t_onBM DIS negate (turn-on) time during
burst-mode operation
Using integrated switch at SVCC (3.3V
operation) (4)
300 500 ns
t_offBM DIS assert (turn-off) time during
burst-mode operation
Using integrated switch at SVCC (3.3V
operation)(4)
200 500 ns
Notes:
1. With CAPC = 2.2nF
2. User-adjustable. Specifications reflect timing with no external RESET capacitor.
3. With < 1nF capacitor from RESET pin to ground.
4. Imod > 12mA
Figure 1-1. Safety Logic Timing Characteristics
Table 1-5. Safety Logic Timing
Symbol Parameter Conditions Min. Typ. Max. Units.
Hot Plug (DIS Low)
VCC3
and
VCC5
status
FAIL
DIS
LASER
OUTPUT
(low)
(low)
VCC3 and VCC5
“OK”
t_on < 1ms,
(300 us typ.)
Slow Rise on Vcc=3.3V at Power-up (DIS Low)
V
CC3
FAIL
DIS
LASER
OUTPUT
(low)
(low)
3.3V
t_on < 1ms,
(300 us typ.)
V
CC
3.3V
FAIL state at power-up will
depend on pull-up voltage
Product Specification
02094-DSH-001-C Mindspeed Technologies™ 9
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Slow Rise on Vcc=5V at Power-up (DIS Low) Transmitter Enable (DIS transition Low)
V
CC3
FAIL
DIS
LASER
OUTPUT
(low)
(low)
3.3V
t_on < 1ms,
(300 us typ.)
V
CC
5V
V
CC3
and
V
CC5
status
FAIL
DIS
LASER
OUTPUT
(low)
(low)
V
CC3
and V
CC5
“OK”
t_on < 1ms,
(300 us typ.)
(high)
Fault Recovery Behaviour
Transmitter Disable (DIS transition high)
V
CC3
and
V
CC5
status
FAIL
DIS
LASER
OUTPUT
(low)
V
CC3
and V
CC5
“OK”
t_off < 10 us,
(1 us typ.)
(high)
Fault
recovery at:
MOD
SET
.
C
APC
, OUT+,
IBOUT
CA
or
IBOUT
CC
FAIL
DIS
LASER
OUTPUT
Fault
Removed
t_reset,
10 us,
min.
FAIL remains high
until reset by DIS
going high
t_on < 1ms
10 Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
Figure 1-2. Relationship Between Data Inputs and Modulation Outputs
Response to Fault
Fault at:
APC
SET
FAIL
DIS
LASER
OUTPUT
Fault Remains
t_reset,
10 us,
min.
t_init < 5ms,
(3 ms typ.)
Unsuccessful Fault Reset Attempt
Fault at:
MOD
SET
.
C
APC
, OUTP,
IBOUT
CC
or
IBOUT
CA
FAIL
DIS
LASER
OUTPUT
Fault Occurs
t_fault < 100 us,
(4 us typ.)
DIN+
D
IN
-
100 mV -
1200 mV
V
IN(DIFF)
200 mV -
2400 mV
VOUT-
> 0.7V
GND
VOUT+
02094-DSH-001-C Mindspeed Technologies™ 11
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2.0 Pin Description
2.1 Pin Definitions
Table 2-1. Pin Definitions
Pin
Number Pin Name Pin equivalent load Function
1 VCC Power supply, 5V or 3.3V.
2 DIN+
Positive data input. Self biased. Compatible with AC coupled PECL, AC coupled
CML, and DC-coupled PECL (when VCC = 3.3V).
When DIN+ is high, OUT+ will sink current.
3 DIN-See DIN+ drawing Negative data input. Self biased Compatible with AC coupled PECL, AC coupled
CML, and DC-coupled PECL (when VCC = 3.3V).
VCC3
DIN+, DIN-
VCC3-1.3V
4 k
Ω
VCC
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M02094 Data Sheet
4VCC3SEL
3.3V VCC Select.
Connect to VCC for VCC = 3.3V operation.
Connect to GND for VCC = 5V operation.
5DIS
Bias and modulation output disable (TTL/CMOS).
When high or left floating, the bias and modulation outputs are disabled. Set low
for normal operation.
6FAIL
Safety circuit fault output (TTL/CMOS). Goes high when a safety logic fault is
detected. This output will also be high when DIS is high.
Requires an external pull-up.
Table 2-1. Pin Definitions
Pin
Number Pin Name Pin equivalent load Function
72 kΩ
VCC3
SEL
190 Ω
V
CC
V
CC3
80 k
Ω
DIS
7 kΩ
V
CC3
V
CC
FAIL
VCC
Pin Description
02094-DSH-001-C Mindspeed Technologies™ 13
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7RESET
Safety circuit reset. Leave open for normal operation or add a capacitor to
ground to extend the reset time.
Connect to GND to disable window comparators at APCSET
8DISDLY
Disable delay control. Connect to ground for normal operation.
In burst mode operation add a capacitor from this pin to ground to set the
maximum disable time. Disable times greater than this maximum will engage the
“slow-start” circuitry.
9MODMON
Modulation Current Monitor. Connect to a resistor to GND.
The current through this pin is typically 1/50th of the MODULATION current to
the laser when CCSEL is low or 1/25th the MODULATION current when CCSEL is
high.
This pin may be left open if the feature is not needed and the M02094 current
consumption will be reduced by 0.5mA typically.
Table 2-1. Pin Definitions
Pin
Number Pin Name Pin equivalent load Function
RESET
190 Ω
V
CC
V
CC3
DISDLY
190 Ω
VCC
190 Ω
MOD
MON
V
CC
V
CC3
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M02094 Data Sheet
10 BIASMON See MODMON drawing
Bias Current Monitor. Connect to a resistor to GND.
The current through this pin is typically:
1/45.7th of the BIAS current to the laser when CCSEL is low
1/13.5th of the BIAS current to the laser when CCSEL is high
This pin may be left open if the feature is not needed and the M02094 current
consumption will be reduced by 0.5mA typically.
11 TxPwrMON
Transmit Power Monitor. Connect to a resistor to GND.
The current through this pin is approximately the same as the photodiode
current into IPIN. The current out of this pin is low pass filtered (no external
filtering required).
This pin may be left open if the feature is not needed and the M02094 current
consumption will be reduced by the IPIN current.
12 APCSET
Average Power Control, laser bias current adjustment. Connect to a resistor
between this pin and ground to set the bias current to the laser.
The APC loop will adjust the laser bias current to maintain a voltage at APCSET of
approximately 1.3V. The current sourced from this pin is approximately the same
as the current into IPIN.
13 IPIN
For CCSEL low - Current input from monitor photodiode anode.
The APC loop will adjust the laser bias current to maintain a voltage at APCSET of
approximately 1.3V and at this pin of approximately one VGS.
For CCSEL high - Current source for monitor photodiode cathode.
The APC loop will adjust the laser bias current to maintain a voltage at APCSET of
approximately 1.3V and at this pin of approximately one VGS below VCC3.
Table 2-1. Pin Definitions
Pin
Number Pin Name Pin equivalent load Function
33 Ω
TxPwr
MON
VCC VCC3
APC
SET
V
CC
V
CC3
33
Ω
I
PIN
V
CC
V
CC3
Pin Description
02094-DSH-001-C Mindspeed Technologies™ 15
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14
IBOUTCA
(CCSEL = low)
Laser bias current output for common anode lasers (CCSEL must be low).
Connect directly to laser cathode or at higher bit rates through a ferrite or a
resistor to isolate the capacitance of this pin from the modulation drive, (~ 6pF).
Maintain a voltage at least 0.7V above GND at this pin
SGND (CCSEL
= high)
Switched ground connection for common cathode lasers (CCSEL must be high).
Provides redundant shutdown during a disable or fault condition. This switch is
disabled during common anode operation.
15 GNDO
Ground for output stage. May be connected directly to circuit board ground. At
high bit rates (>2Gb/s) an optional inductor or ferrite may be added to reduce
switching transients.
Table 2-1. Pin Definitions
Pin
Number Pin Name Pin equivalent load Function
IBOUT
CA
V
CC
SGND
V
CC
GND0
V
CC
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M02094 Data Sheet
16 OUT+
Positive modulation current output (AC or DC coupled to cathode of laser in
common anode designs). Sinks current when DIN+ is HIGH.
Maintain a voltage > 0.7V at this pin.
17 OUT- See OUT+ drawing
Negative modulation current output (AC coupled to anode of laser in common
cathode designs). Sinks current when DIN- is HIGH
Maintain a voltage > 0.7V at this pin.
18
SVCC (CCSEL =
low)
Switched VCC. Supplies laser current for common anode designs. (CCSEL must
be LOW).
Provides redundant shutdown during a disable or fault condition. This switch is
disabled during common cathode operation.
IBOUTCC
(CCSEL =
high)
Laser bias current output for common cathode laser designs (CCSEL must be
high).
Connect directly to laser anode or at higher bit rates through a ferrite or a
resistor to isolate the capacitance of this pin from the modulation drive.
Maintain a voltage of < 2.5V at this pin.
Table 2-1. Pin Definitions
Pin
Number Pin Name Pin equivalent load Function
OUT+
V
CC
GND
0
SV
CC
V
CC
V
CC3
V
CC
V
CC3
I
BOUT
CC
12 kΩ
Pin Description
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19 CCSEL
Laser select input.
When high, common cathode operation is selected; IBOUTCC and SGND are
functional and internal 50Ω output terminations are switched in at the
modulation outputs OUT+ and OUT-.
When low or floating, common anode operation is selected; IBOUTCA and SVCC
are functional and the 50Ω internal termination resistors at OUT+ and OUT- are
disconnected.
20 CAPC
Automatic power control loop dominant pole capacitor. (Connect a capacitor
between this pin and VCC3.)
A nominal capacitance of 2.2nF will give a bias current enable time of less than 1
ms.
21 VCC3
3.3V applications - Power supply input. Connect to VCC.
5V applications - Do not connect to 5V. Internally generated 3.3V power supply
output. Do not attach to non-M02094 circuitry.
Table 2-1. Pin Definitions
Pin
Number Pin Name Pin equivalent load Function
48 kΩ
CC
SEL
24 kΩ
V
CC
V
CC3
100 Ω
C
APC
V
CC
V
CC3
V
CC
V
CC
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M02094 Data Sheet
22 PEAKADJ
Peaking adjustment input. A resistor (2kΩ to 20kΩ) between this pin and ground
sets the amount of peaking current on OUT- to improve the fall time of the laser
output. The peaking current is approximately (4 * (1.3V / resistance to ground)).
Connect to VCC3 to disable peaking control.
23 MODSET
Modulation current control. Connect a resistor to ground to set the modulation
current.
24 TCSLOPE See MODSET drawing
Modulation current temperature compensation slope adjustment. Connect a
resistor to ground to set the temperature coefficient. Leave open to minimize the
temperature compensation coefficient.
CENTER
PAD GND Ground. Must be connected to ground for proper operation. This is the only
package ground connection.
Table 2-1. Pin Definitions
Pin
Number Pin Name Pin equivalent load Function
1.8 kΩ
PEAK
ADJ
V
CC
V
CC3
+
-
1.28V
190
Ω
MOD
SET
V
CC
V
CC3
+
-
1.28V
Pin Description
02094-DSH-001-C Mindspeed Technologies™ 19
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Figure 2-1. Pin Assignments for M02094 Device
VCC
DIN+
DIN-
VCC3SEL
MOD
MON
BIASMON
CAPC
VCC3
PEAKADJ
TCSLOPE
FAIL
RESET
DISDLY
TXPWRMON
APCSET
IPIN
GND
0
OUT+
OUT-
SVCC/
IBOUT
CC
CCSEL
MOD
SET
IBOUT
CA
/
SGND
DIS
1
6
712
13
18
1924
\
GND, connect to
PCB ground
4 X 4 mm
20 Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
02094-DSH-001-C Mindspeed Technologies™ 21
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3.0 Functional Description
3.1 Overview
The M02094 is a highly integrated laser driver intended for applications to 2.0 Gbps.
Many features are user-adjustable, including common anode or common cathode laser mode, the APC (automatic
power control) loop bias control (via a monitor photodiode), modulation current, temperature compensation control
of modulation current, and peaking adjustment. The part may be operated from a 3.3V or 5V supply.
For E-PON and other burst-mode applications, the part supports fast and accurate turn-on and turn-off of the laser
bias and modulation currents.
Safety circuitry is also included to provide a latched shut-down of laser bias and modulation current if a fault condi-
tion occurs. An internal VCC switch provides redundant shutdown when operating the device in common anode
configuration. An internal ground switch provides redundant shutdown when operating the device in common cath-
ode configuration.
Modulation, bias, and transmit power monitor current mirrors are provided for DDMI applications and allow moni-
toring without disturbing the analog signal path.
22 Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
Figure 3-1. M02094 Block Diagram Example
V
CC3
-1.3V
Internal
3.3V reg.
Input
Buffer
Output
Buffer
Laser
Driver
Automatic Power Control
(laser bias current)
TX
Disable
Safety
Circuitry with
Latched Fault
Modulation
Control
V
CC
V
CC3
FAIL
VCC3
SEL
PEAK
AD J
SV
CC
and
IB
OUT_CC
OUT-
OUT+
GND
0
IB
OUT_CA
and
SGND
IPIN
DISDLY
DIS
MOD
SE T
TC
SLOPE
MOD
MON
RESET
BIAS
MON
APC
SE T
C
APC
TxPwr
MON
D
IN
-
D
IN
+
Internal Power Bus
GND
CC
SEL
Functional Description
02094-DSH-001-C Mindspeed Technologies™ 23
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3.2 Features
• High speed operation; suitable for SFP/SFF applications from 155Mbps to 2.0 Gbps. Typical rise/fall times <
110 ps.
• Supports Common Anode VCSEL, Common Cathode VCSEL, or FP LASER. May be used with or without a
monitor photodiode.
• Programmable temperature compensation. Modulation output and bias output can be controlled using a few
discrete resistors.
• Supports DDMI (SFF-8472) diagnostics.
• DC or AC coupled modulation drive.
• Peaking circuit to optimize VCSEL response.
• Low overshoot allows high extinction ratio with low jitter.
• Supports E-PON burst mode with no extra components
• Automatic Laser Power Control, with “Slow-Start”.
• 3.3V or 5V operation
3.3 General Description
3.3.1 Detailed Description
The M02094 laser driver consists of the following circuitry: an internal regulator, common anode/common cathode
configuration control, bias current generator and automatic power control, data inputs, peaking adjust, modulation
current control, modulator output, laser fail indication, disable control, and monitor outputs for the bias current,
modulation current, and transmitted power.
3.3.2 Internal Regulator
The M02094 contains an internal 3.3V regulator so high bit rate performance can be achieved with 5V or 3.3V
power supply.
When operating from a 5V supply (VCC is connected to +5V), an internal regulator provides a voltage of approxi-
mately 3.3V to the majority of the on-chip circuitry. The on-chip regulator is internally compensated, requiring no
external components. When a 3.3V supply is used (VCC and VCC3 connected to 3.3V) the regulator is switched off
and the internal circuitry is powered directly through the VCC3 supply pin. The decision as to whether or not the
internal regulator is required is made via the VCC3SEL pin, which also determines whether the safety circuitry
needs to monitor for proper +5V supply voltage.
SVCC is sourced from VCC3 through a switch for common anode applications (this pin becomes IBOUT_CC in com-
mon cathode applications). When a fault condition is present, FAIL will assert and the switch sourcing SVCC will
open so no current can pass through the laser. SVCC does not need any external capacitance, if capacitance to
ground is added at SVCC it should be less than or equal to 100 pF.
24 Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
VCC and VCC3 status are internally monitored by the M02094 during power-up and normal operation. During
power-up the “slow-start” circuitry requires that VCC and VCC3 each reach an acceptable level before enabling bias
or modulation current.
3.3.3 Common Cathode/Common Anode Configuration Control
When CCSEL is programmed high, the M02094 is configured for common cathode lasers. When CCSEL is low, the
M02094 is configured for common anode lasers.
The state of the CCSEL pin determines:
1. whether bias current is sourced or sunk
2. whether monitor photodiode current is sunk or sourced
3. whether internal termination resistors at OUT+ and OUT- are active
4. whether the redundant safety switch disconnects VCC or GND from the output circuitry.
The affected pins are OUT+, OUT-, SVCC/IBOUTCC, and SGND/IBOUTCA. The Table 3-2 below shows the configu-
ration of each pin for the 2 states of CCSEL.
Table 3-1. Pin Connection for 3.3V and 5V VCC
Pin Connection For:
VCC = 3.3V VCC = 5V
Pins Dependent on VCC Voltage
VCC3
(pin 21)
Connect to VCC Reference for CAPC and PEAKADJ
CAPC
(pin 20)
Capacitor between CAPC and VCC3 or VCC Capacitor between CAPC and VCC3 (not VCC)
PEAKADJ
(pin 22)
Connect to VCC3 or VCC to disable Connect to VCC3 to disable (not VCC)
VCC3SEL
(pin 4)
Connect to VCC3 or VCC Connect to GND
Functional Description
02094-DSH-001-C Mindspeed Technologies™ 25
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3.3.4 Bias Current Generator and Automatic Power Control
The M02094 can either source or sink bias current for the laser diode depending on whether it is in common anode
or common cathode mode. In common cathode mode (CCSEL high) IBOUTCC will source current. In common anode
mode (CCSEL low) IBOUTCA will sink current.
Regardless of whether the M02094 is configured for common anode or common cathode mode, the following infor-
mation applies.
To maintain constant average optical power, the M02094 incorporates a control loop to compensate for the
changes in laser threshold current over temperature and lifetime. The bias current will be determined by the value
of the external resistor RAPCSET and the transfer efficiency between the laser and monitor photodiode.
The photo current from the monitor photodiode mounted in the laser package is sunk or sourced at IPIN. This photo
current is mirrored and an equivalent current is sourced from pins TxPwrMON and APCSET. The APC loop adjusts
the laser bias current (hence the monitor diode photo current) to maintain a voltage of 1.3V at APCSET.
RAPCSET * IPIN = 1.3 V
The APC loop has a time constant determined by CAPC, RAPCSET and the transfer efficiency between the laser and
monitor photodiode. The larger the CAPC capacitor the lower the bandwidth of the loop and the larger the RAPCSET
resistor the lower the bandwidth of the loop.
In general, it is recommended that at least 2.2 nF of external capacitance be added externally between CAPC and
VCC3 to assure loop stability. With use of a 2.2 nF capacitor, the bias current can reach 90% of its final value within
1 millisecond.
Table 3-2. Pin Connection for Common Anode and Common Cathode Laser Modes
Pin Connection When:
CCSEL = High CCSEL = Low
Pins Dependent on CCSEL Setting
Pin 18
SVCC
Inactive Supply for laser and all output load
components.
IBOUTCC Laser bias source current. Inactive
Pin 14
SGND Ground for laser and all output load
components
Inactive
IBOUTCA Inactive Laser bias sink current.
Pin 13 IPIN Monitor photodiode source current Monitor photodiode sink current
Pin 22 PEAKADJ
Controls Negative going edge of OUT- Controls Negative going edge of OUT-, (do not
use)
Internal 50Ω pull-up resistors on
OUT+ and OUT-
Active Inactive
Ratio of Bias current to BIASMON
current
13.5:1 45.7:1
Ratio of Modulation current to
MODMON current
30:1 65:1
26 Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
In Common Anode mode with a 2.2nF CAPC capacitor the APC loop bandwidth is less than 30 kHz for almost all
combinations of RAPCSET and transfer efficiency., which should be adequate for bit rates of 155Mbps. (and all
higher bit rates).
In Common Cathode mode with a 2.2nF CAPC capacitor the APC loop bandwidth will be slightly higher, but should
be less than 40 kHz for almost all combinations of RAPCSET and transfer efficiency. Contact the factory with your
specific values of CAPC, RAPCSET, and transfer efficiency to determine the maximum APC loop bandwidth in your
application.
The bias generator also includes a bias current monitor mirror (BIASMON), whose output current is typically 1/
45.7th of the bias current in common anode mode (CCSEL = low) or 1/13.5th of the bias current in common cath-
ode mode (CCSEL = high). This pin can be connected through a resistor to ground. If this function is not needed
this pin can be left open.
The M02094 can be used without a monitor photodiode by connecting BIASMON to APCSET (see Figure 3-7 and
Figure 4-3). In this case the M02094 will increase the bias current (hence the BIASMON current) to the laser until
the voltage at APCSET is approximately 1.3V.
3.3.5 Data Inputs
The inputs to the data buffers are self-biased through 4 kΩ resistors to an internal voltage VTT which is approxi-
mately VCC3 - 1.3V. Both CML and PECL inputs signals can be AC coupled to the M02094, or in 3.3V applications
PECL inputs can be DC coupled to the data inputs. In most applications the data inputs are AC coupled with con-
trolled impedance pcb traces which will need to be terminated externally with a 100Ω or 150Ω resistor between the
+ and - inputs.
3.3.6 Peak Adjust
Some VCSELs do not turn off quickly without peaking the negative going edge.
In common cathode applications, peaking on this edge can be added with a resistor connected between the PEAK-
ADJ input and GND. The amount of peaking is approximately
Peaking current = 4 * (1.3V / resistance to ground).
The resistance to ground should be between 2kΩ and 20kΩ. (Which will result in a peaking currents from 2.6mA to
260µA.)
Peaking control can be disabled by connecting PEAKADJ to VCC3, resulting in no peaking current and reducing
supply current by approximately 2mA.
In common anode configuration the PEAKADJ pin should be connected to VCC3.
Note: Unlike the rest of the signal currents in the M02094, the output Peak Adjust current is unbalanced (single-
sided drive). The designer should be aware that the use of peaking may result in unwanted EMI emissions. If EMI
problems are traced to the use of peaking, high frequency decoupling (10pF capacitor or smaller) may be needed
on the VCC line.
3.3.7 Modulation Control
There are two programmable control lines for controlling the modulation current and its temperature compensation.
These inputs can be programmed simply with a resistor to ground .
The modulation current amplitude is controlled by the MODSET input pin. The modulation current is temperature
compensated by the TCSLOPE input.
Functional Description
02094-DSH-001-C Mindspeed Technologies™ 27
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If the temperature compensation at TCSLOPE is disabled, the modulation output current is simply:
IOUT = 42 x (1.3V / RMODSET) when CCSEL is low
and
IOUT = 22 x (1.3V / RMODSET) when CCSEL is high and a 50Ω VCSEL is used.
Where RMODSET is the resistance from pin MODSET to ground.
To temperature compensate the modulation current, choose RTCSLOPE to meet the following relationship:
RTCSLOPE = 19.5*(TC)-1.5, where TC is the desired slope of the modulation current from 25°C to 85°C in%/°C and
RTCSLOPE is in kΩ. If no temperature compensation is desired, leave RTCSLOPE open.
In any case, RTCSLOPE will have negligible effect at M02094 case temperatures below 10°C.
For example:
Given a common cathode VCSEL with a desired modulation current at low temperatures of 10mA and a tempera-
ture coefficient of -0.5%/°C at high temperatures (which will require a laser driver temperature coefficient of
+0.5%).
Choose RMODSET = 22 x (1.3V / 10mA) = 2.8kΩ.
Choose RTCSLOPE =19.5*(0.5)-1.5 kΩ = 55kΩ.
Figure 3-2. Selecting TCSLOPE Resistance in Common Anode Configuration
-30.00
-20.00
-10.00
0.00
10.00
20.00
30.00
40.00
50.00
60.00
-40 -20 0 20 40 60 80 100
Ambient Temperature in degrees C
% change in modulation current
RTCslope:
22k
27k
33k
39k
47k
51k
62k
75k
82k
100k
120k
150k
220k
390k
750k
open
28 Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
3.3.8 Modulator (Figure 3-4)
The output stages OUT+ and OUT- are designed to drive 25Ω output loads over a wide range of currents and cir-
cuit architectures. The VCSEL may be a common anode or common cathode device. The output can be AC, DC,
or Differentially coupled depending on the supply voltage and laser configuration.
In a common anode configuration with a VCSEL (Figure 4-1), OUT+ should be connected through a capacitor to
the VCSEL. A pull-up resistor should be added in parallel to the VCSEL from SVCC to the OUT+ output. The
dynamic impedance of the parallel combination of the VCSEL and pull-up resistor should be roughly 25 ohms. A 24
ohm pull-up resistor should also be added from SVCC to OUT- so the currents and voltage swings in the two out-
puts are balanced.
In a common anode configuration with a Fabry-Perot laser (Figure 4-4), OUT+ may be AC, DC, or Differentially
coupled to the laser cathode. A resistor should be added in series with the laser such that the dynamic impedance
of the series combination of the laser and resistor should be roughly 25 ohms. A 24 ohm pull-up resistor to SVCC is
needed on the OUT- output.
For common cathode operation with a VCSEL (Figure 4-3), internal 50 ohm terminations are switched in between
the OUT+ and OUT- outputs and VCC3. VCSELs with impedances from 25-75Ω can be simply AC coupled to the
OUT- output with no additional load matching resistors. In this case OUT+ should be AC coupled to ground through
50Ω.
The VCSEL driver output stage is separately grounded from the rest of the circuitry (through GND0). At higher data
rates (above 2Gb/s) GND0 may be connected to ground through a minimum of 2 nH of inductance to improve the
Figure 3-3. Selecting TCSLOPE Resistance in Common Cathode Configuration
-30.0
-20.0
-10.0
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
-40 -20 0 20 40 60 80 100
Ambient Temperature in degrees C
% change in modulation current
RTCslope:
27k
33k
39k
47k
51k
62k
75k
82k
100k
120k
150k
180k
220k
390k
510k
open
Functional Description
02094-DSH-001-C Mindspeed Technologies™ 29
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transient response. A ferrite can also provide the extra isolation (Murata BLM18HG471SN1 or equivalent recom-
mended).
3.3.9 Fail Output
The M02094 has a FAIL alarm output which is compatible with the TX_FAULT signalling requirements of common
pluggable module standards.
The ESD protection on this pin provides a true open collector output that can withstand significant variation in VCC
when signalling between circuit boards. Also, if the M02094 loses power the FAIL output will continue to pull up
and signal a fail condition. In a simple static protection scheme used by other ICs the protection diodes would
clamp the FAIL signal to ground when the chip loses power.
3.3.10 TX Disable and Disable Delay Control
The DIS pin is used to disable the transmit signal. When the transmit is disabled both the bias and modulation cur-
rents are off.
The DIS input is compatible with TTL levels regardless of whether VCC = 5V or VCC = 3.3V. In most module appli-
cations a pull-up resistor to VCC between 4.7 kΩ and 10 kΩ is required. Because this pin has an internal 7 kΩ
resistor to VCC, no external pull-up resistor is required.
The DISDLY pin is used in conjunction with the DIS pin to control bias current enable time. (The modulation current
enable time is always less than 600 ns). Unless the DISDLY pin is programmed for burst mode, the APC loop
enable time will be slow (less than 1 ms with a CAPC = 2.2 nF).
When a capacitor C is added to the DISDLY pin, the slow-start circuitry is disabled for typically
T = 3 * 106 (sec/F)* C (F)
following the DIS high transition. If DIS transitions low during this time, the bias current will quickly return to within
90% of its final value (within less than 500 ns). If DIS transitions low after this time the slow-start circuitry will
engage and the bias current will not return to its final value for approximately 1ms (depending on the CAPC capaci-
tor).
Figure 3-4. Modulator Output
OUT+
0.4pF
0.75 nH OUT-
GND
0
(optional
external
inductance)
*
* Denotes bond
wire internal to
MLF package
0.75 nH *
OUT+ and OUT- should not be
driven below 0.7V
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M02094 Data Sheet
3.3.11 Burst Mode Operation (Figure 3-5)
The M02094 will meet the timing requirements of EPON with the addition of a capacitor at DISDLY (see paragraph
above and Figure 3-5).
As shown in Figure 4-4, the laser should be DC coupled to OUT+. VCC may be 3.3V or 5V.
Figure 3-5. DIS and DISLY Timing
DIS
DISDLY
OUT+
IBIASOUT
DIS
DISDLY
OUT+
IBIASOUT
EPON Burst Mode Operation
Normal Operation, (slow-start whenever part enabled)
t_onBM < 500ns for IMOD > 10mA
t_offBM < 500ns
t_off < 10µs
t_on < 1ms, depending on CAPC
Functional Description
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3.3.12 Video Operation
The M02094 can be used to transmit video optical data even in the presence of the pathological pattern. This is
done by fully DC coupling the signal from the input to the laser output.
In most data communications applications, AC coupling occurs at three points in a laser driver schematic: the data
inputs, the APC control, and coupling the modulation current to the laser. In the M02069, DC coupling can be used
at all three of these points. With DC coupling the laser output will not be a function of the data input one/zero den-
sity.
The data inputs can be DC coupled using PECL or CML levels.
The APC of the bias current is controlled by feedback from the monitor photodiode in the laser package in most
communications applications. In video applications this monitor photodiode should not be used if the pathological
pattern may occur. Instead, the APC should be controlled in an "open loop" configuration. (Open loop simply
means a monitor photodiode is not used). In the open loop configuration the APC is controlled by a resistor or a
thermistor network or a look-up table and DAC. This removes AC time constants from the bias current. In
Figure 3-6 the BIASmon pin is connected to the APCset pin. In this case the bias current is:
IBIAS = 45.7 x (1.35V / RAPCSET)
The modulation current output OUT+ can be DC coupled to the laser as shown in Figure 3-6. There are no AC
time constants in the modulation current amplitude in this configuration.
Figure 3-6. Video Application Block Diagram
3.3.13 Current Monitors
To facilitate complying with laser safety and DDMI1 requirements, output monitors are provided for transmit power
(TxPwrMON), bias (BIASMON), and modulation current (MODMON).
These outputs will source current proportional to the emitted optical power (TxPwrMON) the bias current (BIASMON)
and modulation current (MODMON).
V
CC3
V
CC
V
CC3
For V CC=3.3V, tie VCC3 to VCC.
V
CC3
-1.3V
Internal
3.3V reg.
Input
Buffer
Output
Buffer
Laser
Driver
Automatic Power Control
(laser bias current)
TX
Disable
Safety
Circui try wi th
Latched Fault
Modulation
Control
V
CC
V
CC3
FAIL
VCC3
SEL
PEAK
ADJ
SV
CC
OUT-
OUT+
GND
0
IB
OUT_CA
IPIN
DISDLY
DIS
MOD
SET
TC
SLOPE
MOD
MON
RESET
BIAS
MON
APC
SET
C
APC
TxPwr
MON
D
IN
-
D
IN
+
Internal Power
Bus
CC
SEL
Connect to V
CC
when V
CC
= 3.3V
Connect to GND
when V
CC
= 5V
V
CC3
32 Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
To use these pins they should be terminated with a resistor to ground that sets the desired full-scale voltage (not to
exceed 2.5V).
If the outputs of these monitors are not needed, TxPwrMON, BIASMON, and MODMON can all be left floating and the
chip current consumption will be reduced by the value of the monitor currents.
3.4 Laser Eye Safety
Using this laser driver in the manner described herein does not ensure that the resulting laser transmitter complies
with established standards such as IEC 825. Users must take the necessary precautions to ensure that eye safety
and other applicable standards are met. Note that determining and implementing the level of fault tolerance
required by the applications that this part is going into is the responsibility of the transmitter designer and manufac-
turer since the application of this device cannot be controlled by Mindspeed.
1 Digital Diagnostic Monitoring Interface for Optical Tranceivers, defined in SFF-8472.
Functional Description
02094-DSH-001-C Mindspeed Technologies™ 33
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3.4.1 Safety Circuitry
Safety Circuitry in the M02094 will disable the modulation and bias current and assert the FAIL output immediately
upon detecting a fault condition. In addition, the supply voltage that sources or sinks the laser current (SVCC or
SGND) will immediately go open circuit and prevent any current from passing through the laser.
Fault conditions checked by the M02094 include shorts to ground or VCC of all pins which can increase the laser
modulation or bias current.
For an initialization or power-up sequence to be successful, all the fault detection monitors must signal that the chip
is “healthy”.
When DIS goes low, pins are checked for shorts to ground or VCC and a FAIL condition is latched if there is a fault.
If the state of the pins is OK, a one-shot at the reset pin begins a countdown which will latch a FAIL condition if the
bias current has not stabilized to an acceptable level during the one-shot time. The one-shot can be extended with
an external capacitor connected from the RESET pin to ground.
The one-shot1 width is approximately
TONE-SHOT = 3 ms + (0.3 ms/pF)x(external capacitance).
1.The one-shot is actually comprised of an oscillator and 10-bit counter.
Figure 3-7. Safety Circuit Block Diagram
Vcc Pin
5v Hi/Lo Limits
Vcc3 Pi
n
3.3v Hi/Lo Limits
5v Mode:
AND
Vcc3 Pi
n
3.3v Hi/Lo Limits
3.3v Mode:
AND
‘1’
Vcc Pin
5v Hi/Lo Limits
VccOK Detection:
CrudeFaults Detection:
OutP
(2061)
Cmpc
MODset
IbiasOut
IboutCA
>
300mV
>
300mV
>
300mV
>
300mV
>
300mV
IboutCC
<
(Vcc3
–
300mV)
(2069 – Common Anode)
(2069 – Common Cathode)
Dela
y
Set
SRlatch:
Q
Rese
t
ON
E
-SHOT: Star
t
3ms + Tcap
t=0 PULSE
N
OTE: Pulse stays high
if Reset pin is GNDed.
RESET
optional cap for longer T_init
AND
Window Compare:
HI Limit
MPCse
t
LOW Limi
t
OR
Set
SRlatch:
Q
Reset
AND
AND AND
BiasOK Detection:
OUTPUT_ENABLE
VCC_OK
CrudeFaults_OK
BIAS_OK
Latch for
CrudeFaults
Latch for
Bias_OK
If chip is ‘healthy’, then Enable
the outputs and Start 3msec
Reset Pulse(one-shot)
(open-collector)
FAILout
OR
DIS
34 Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
3.5 Fault Conditions
This section describes the M02094 operating modes during fault conditions. Over voltage, under voltage, pins
shorted to VCC and pins shorted to ground are included in the fault Table 3-3.
Table 3-3. Circuit Response to Single-Point Fault Conditions
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 (see
Table 1-3)
Bias and modulation outputs are disabled once 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.(1,2,3)
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.(1,2,3)
VCC3SEL Does not affect laser power. Does not affect laser power.
DIS Bias and modulation outputs are disabled.
SVCC is opened when CCSEL is low or floating (or SGND is
opened when CCSEL is 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)
IBOUTCA(3) The laser will be turned off, then a fault state occurs.(1) A fault state occurs.(1)
IBOUTCC(4) A fault state occurs.(1) The laser will be turned off, then a fault state occurs.(1)
OUT+(3) Laser modulation is prevented; the APC 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)
OUT-(4) Does not affect laser power during common cathode
operation because output is AC coupled.
Does not affect laser power during common cathode operation
because output is AC coupled.
SVCC(3) 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
PEAKADJ Does not affect laser power. Does not affect laser power
CCSEL Normal operation for common cathode configuration. If the
M02094 is configured for common anode drive, a fault state
will occur.(1)
Normal operation for common anode configuration. If the
M02094 is configured for common cathode drive, a fault state
will occur.(1)
MODSET When the laser is DC coupled in common anode configuration,
the APC loop will attempt to compensate for the drop 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)
Functional Description
02094-DSH-001-C Mindspeed Technologies™ 35
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TCSLOPE Does not affect laser power. When the laser is DC coupled in common anode configuration,
the APC loop will attempt to compensate for any change in
output power. If the APC loop can not maintain the set average
power, a fault state occurs.(1,2)
DISDLY Does not affect laser power. Does not affect laser power.
Notes:
1. A fault state will assert the FAIL output, disable bias and modulation outputs and will either open the switch at SVCC (CCSEL=high) or SGND
(CCSEL=low).
2. Does not affect laser power when the output is AC coupled to the laser.
3. Does not affect laser power during common cathode operation.
4. Does not affect laser power during common anode operation.
Table 3-3. Circuit Response to Single-Point Fault Conditions
Pin Name Circuit Response to Over-voltage Condition or Short
to VCC
Circuit Response to Under-Voltage Condition or Short
to Ground
36 Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
02094-DSH-001-C Mindspeed Technologies™ 37
Mindspeed Proprietary and Confidential
4.0 Applications
4.1 Applications
• EPON FTTH modules
• Gigabit Ethernet modules
• 1G/2G Fibre Channel modules
• Digital Video
Figure 4-1. Application Diagram, Common Anode VCSEL
V
CC3
V
CC
V
CC3
For V
CC
=3.3V, tie V
CC3
to V
CC
.
V
CC3
-1.3V
Internal
3.3V reg.
Input
Buffer
Output
Buffer
Laser
Driver
Auto mati c Power Control
(laser bias current)
TX
Disable
Safety
Circuitry wi th
Latched Fault
Modulation
Control
V
CC
V
CC3
FAIL
VCC3
SEL
PEAK
ADJ
SV
CC
OUT-
OUT+
GND
0
IB OUT_CA
IPIN
DISDLY
DIS
MOD
SET
TC
SLOPE
MOD
MON
RESET
BIAS
MON
APC
SET
C
APC
TxPwr
MON
D
IN
-
D
IN
+
Internal Power
Bus
CCSEL
Connect to V
CC
when V
CC
= 3.3V
Connect to GND
when V
CC
= 5V
V
CC3
V
CC3
(may be DC coupled, but extra bias current will be required for the pull-up resistor on OUT+)
38 Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
Figure 4-2. Application Diagram, Common Cathode VCSEL
V
CC3
-1.3V
Internal
3.3V reg.
Input
Buffer
Output
Buffer
Laser
Driver
Auto mati c Power Control
(laser bias current)
TX
Disable
Safety
Circuitry wi th
Latched Fault
Modulation
Control
V
CC
V
CC3
FAIL
VCC3
SEL
PEAK
ADJ
OUT-
OUT+
GND
0
IB
OUT_CC
IPIN
DIS
MOD
SET
TC
SLOPE
MOD
MON
RESET
BIAS
MON
APC
SET
C
APC
TxPwr
MON
D
IN
-
D
IN
+
Internal Power Bus
V
CC3
V
CC
V
CC3
SGND
CC
SEL
DISDLY
V
CC
For V
CC
=3.3V, tie V
CC3
to V
CC
.
Connect to V
CC
when V
CC
= 3.3V
Connect to GND
when V
CC
= 5V
Applications
02094-DSH-001-C Mindspeed Technologies™ 39
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Figure 4-3. Application Diagram, Common Cathode VCSEL w/o Monitor Diode
VCC3 -1.3V
Internal
3.3V reg.
Input
Buf f er
Output
Buf f er
Laser
Driv er
Automatic Power Control
(laser bias current)
TX
Disable
Saf ety
Circuitry with
Latched Fault
Modulation
Control
VCC
VCC3
FAIL
VCC3
SEL
PEAKADJ
OUT-
OUT+
GND0
IBOUT_CC
IPIN
DIS
MODSET
TCSLOPE
MODMON
RESET
BIASMON
APC
SET
CAPC
TxPwrMON
DIN-
D
IN+
Internal Power
Bus
VCC3
VCC VCC3
SGND
CCSEL
DISDLY
VCC3
For V CC=3.3V, tie VCC3 to VCC.
Connect to V CC
when V CC
= 3.3V
C onnect to GND
when V CC
= 5V
40 Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
Figure 4-4. Application Diagram, Common Anode FP Laser, DC Coupling
V
CC3
V
CC
V
CC3
For V
CC
=3.3V, tie V
CC3
to V
CC
.
For EPON operation, add a
capacitor to GND at DISDLY.
V
CC3
-1.3V
Internal
3.3V reg.
Input
Buffer
Output
Buffer
Laser
Driver
Autom ati c P owe r Control
(laser bias current)
TX
Disabl e
Safety
Circuitry wi th
Latched Faul t
Modulation
Control
V
CC
V
CC3
FAIL
VCC3
SEL
PEAK
ADJ
SV
CC
OUT-
OUT+
GND
0
IB
OUT_CA
IPIN
DISDLY
DIS
MOD
SET
TC
SLOPE
MOD
MON
RESET
BIAS
MON
APC
SET
C
APC
TxPwr
MON
D
IN
-
D
IN
+
Inte rn al Power
Bus
CC
SEL
Connect to V
CC
when V
CC
= 3.3V
Connect to GND
when V
CC
= 5V
V
CC3
02094-DSH-001-C Mindspeed Technologies™ 41
Mindspeed Proprietary and Confidential
5.0 Packaging Specification
5.1 Package Specification
Figure 5-1. QFN24 Package Information
Note: View is for a 20 pin package. All dimensions in the
tables apply for the 24 pin package
42 Mindspeed Technologies™ 02094-DSH-001-C
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M02094 Data Sheet
02094-DSH-001-C Mindspeed Technologies™ 43
Mindspeed Proprietary and Confidential
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Information in this document is provided in connection with Mindspeed TechnologiesTM ("MindspeedTM") products.
These materials are provided by Mindspeed as a service to its customers and may be used for informational pur-
poses only. Except as provided in Mindspeed’s Terms and Conditions of Sale for such products or in any sepa-
rate agreement related to this document, Mindspeed assumes no liability whatsoever. Mindspeed assumes no
responsibility for errors or omissions in these materials. Mindspeed may make changes to specifications and prod-
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indemnify Mindspeed for any damages resulting from such improper use or sale.
M02094 Data Sheet
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