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DS1862
User Manual
42 pgs547.22 Kb0

Rainbow Electronics DS1862 User Manual

General Description
The DS1862 is a closed-loop laser-driver control IC with built-in digital diagnostics designed for XFP MSA. The laser control function incorporates average power con­trol (APC) and allows extinction ratio control though a temperature indexed look-up table (LUT). The DS1862 monitors up to seven analog inputs, including tempera­ture and monitor diode (MD) current, which are used to regulate the laser bias current and extinction ratio. Warning and alarm thresholds can be programmed to generate an interrupt if monitored signals exceed toler­ance. Calibration is also provided internally using inde­pendent gain and offset scaling registers for each of the monitored analog signals. Settings such as pro­grammed calibration data are stored in password-pro­tected EEPROM memory. Programming is accomplished through an I2C*-compatible interface, which can also be used to access diagnostic functionality.
Applications
Laser Control and Monitoring 10Gbps Optical Transceiver Modules (XFP)
Laser Control and Monitoring
Digital Diagnostics in Optical Transmission
Features
♦ Implements XFP MSA Requirements for Digital
Diagnostics, Serial ID, and User Memory
♦ I2C-Compatible Serial Interface
♦ Automatic Power Control (APC)
♦ Extinction Ratio Control with Look-Up Table
♦ Seven Monitored Channels for Digital Diagnostics
(Five Basic Plus Two Auxiliary)
♦ Internal Calibration of Monitored Channels
(Temp, V
CC2/3
, Bias Current, Transmitted, and
Received Power)
♦ Programmable Quick-Trip Logic for Turning
Off Laser for Eye Safety
♦ Access to Monitoring and ID Information
♦ Programmable Alarm and Warning Thresholds
♦ Operates from 3.3V or 5V Supply
♦ 25-Pin CSBGA, 5mm x 5mm Package
♦ Internal or External Temperature Sensor
♦ -40°C to +100°C Operating Temperature Range
♦ One 8-Bit Buffered DAC
DS1862
XFP Laser Control and Digital Diagnostic IC
______________________________________________ Maxim Integrated Products 1
CSBGA (5mm x 5mm)
TOP VIEW
1
A
B
C
D
E
2345
Pin Configuration
Rev 0; 2/06
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
+Denotes lead-free package.
Ordering Information
Typical Operating Circuit appears at end of data sheet.
PART TEMP RANGE PIN-PACKAGE
DS1862B
25 CSBGA (5mm x 5mm)
DS1862B+
25 CSBGA (5mm x 5mm)
*Purchase of I2C components from Maxim Integrated Products, Inc., or one of its sublicensed Associated Companies, conveys a
license under the Philips I
2
C Patent Rights to use these components in an I2C system, provided that the system conforms to the I2C
Standard Specification as defined by Philips.
-40°C to +100°C
-40°C to +100°C
DS1862
XFP Laser Control and Digital Diagnostic IC
2 _____________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
RECOMMENDED OPERATING CONDITIONS
(V
CC3
= +2.9V to +5.5V, TA= -40°C to +100°C, unless otherwise noted.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Voltage on Any Open-Drain Pin
Relative to Ground.............................................-0.5V to +6.0V
Voltage on MOD-DSEL, SDA, SCL, FETG, THRSET, TX-D,
AUX1MON, AUX2MON, IBIASMON, RSSI, BIASSET, MODSET, EN1,
and EN2 ............-0.5V to (V
CC3
+ 0.5V), not to exceed +6.0V
Voltage on SC-RX-LOS, SC-RX-LOL, RX-LOS, SC-TX-LOS,
MOD-NR, EN1,
and EN2 ............-0.5V to (V
CC2
+ 0.5V), not to exceed +6.0V
Operating Temperature Range .........................-40°C to +100°C
EEPROM Programming Temperature Range .........0°C to +70°C
Storage Temperature Range .............................-55°C to +125°C
Soldering Temperature...................See J-STD-020 Specification
PARAMETER
CONDITIONS
UNITS
Main Supply Voltage V
CC3
(Note 1)
V
Secondary Supply Voltage V
CC2
V
CC2
not to exceed V
CC3
(Note 2)
V
High-Level Input Voltage (SDA, SCL)
V
IH
IIH (max) = 10µA
0.7 x
V
CC3
+
0.5
V
Low-Level Input Voltage (SDA, SCL)
V
IL
IIL (max) = -10µA
GND -
0.3
0.3 x V
High-Level Input Voltage (TX-D, MOD-DESEL, P-DOWN/RST) (Note 3)
V
IH
IIH (max) = 10µA 2
V
CC3
+
0.3
V
Low-Level Input Voltage (TX-D, MOD-DESEL, P-DOWN/RST) (Note 3)
V
IL
IIL (max) = -10µA
V
SYMBOL
MIN TYP MAX
+2.9 +5.5
+1.6 +3.6
V
CC3
V
CC3
-0.3 +0.8
DS1862
XFP Laser Control and Digital Diagnostic IC
_____________________________________________________________________ 3
DC ELECTRICAL CHARACTERISTICS
(V
CC3
= +2.9V to +5.5V, V
CC2
= +1.6V to +3.6V, TA= -40°C to +100°C, unless otherwise noted.)
PARAMETER
CONDITIONS
UNITS
Supply Current I
CC3
P-DOWN/RST = 1 3 5 mA
High-Level Output Voltage (FETG)
V
OH
IOH (max) = -2mA
V
CC3
-
0.5
V
Low-Level Output Voltage (MOD-NR, INTERRUPT, SDA, and FETG)
V
OL
IOL (max) = 3mA 0 0.4 V
Resistor (Pullup) R
PU
91215kΩ
I/O Capacitance C
I/O
(Note 4) 10 pF
Leakage Current I
L
-10
µA
Leakage Current (SCL, SDA) I
L
-10
µA
Digital Power-On Reset POD 1.0 2.2 V
Analog Power-On Reset POA 2.0 2.6 V
DC ELECTRICAL CHARACTERISTICS—INTERFACE SIGNALS TO SIGNAL CONDITIONERS
(V
CC2
= +1.6V to +3.6V, V
CC3
= +2.9V to +5.5V, TA= -40°C to +100°C, unless otherwise noted.)
PARAMETER
CONDITIONS
UNITS
High-Level Input Voltage (SC-RX-LOS, SC-RX-LOL, and SC-TX-LOS)
V
IH
IIH (max) = 100µA
0.7 x
V
CC2
+
0.1
V
Low-Level Input Voltage (SC-RX-LOS, SC-RX-LOL, and SC-TX-LOS)
V
IL
IIL (max) = -100µA 0
0.3 x V
V
OH
IOH (max) = -0.7mA
V
CC2
-
0.2
V
OH2
V
CC2
= 2.5V to 3.6V
I
OH
(max) = -2mA
V
CC2
-
0.4
High-Level Output Voltage (EN1 and EN2)
V
OH3
V
CC2
= 1.6V
I
OH
(max) = -0.7mA
V
CC2
-
0.2
V
V
OL
IOL (max) = 0.7mA
Low-Level Output Voltage (EN1, EN2, and RX-LOS)
V
OL2
V
CC2
= 2.5V to 3.6V
I
OL
(max) = 2mA
V
Leakage Current (SC-RX-LOS, SC-RX-LOL and SC-TX-LOS, RX-LOS)
I
L
-10
µA
SYMBOL
MIN TYP MAX
+10
+10
SYMBOL
MIN TYP MAX
V
CC2
V
CC2
0.20
0.40
+10
DS1862
XFP Laser Control and Digital Diagnostic IC
4 _____________________________________________________________________
I2C AC ELECTRICAL CHARACTERISTICS
(V
CC3
= +2.9V to +5.5V, TA= -40°C to +100°C, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS
UNITS
SCL Clock Frequency f
SCI
0
kHz
Clock Pulse-Width Low t
LOW
1.3 µs
Clock Pulse-Width High t
HIGH
0.6 µs
Bus Free Time between STOP and START Conditions
t
BUF
1.3 µs
Start Hold Time t
HD:SDA
0.6 µs
Start Setup Time t
SU:SDA
0.6 µs
Data in Hold Time t
HD:DAT
0 0.9 µs
Data in Setup Time t
SU:DAT
ns
Rise Time of Both SDA and SCL Signals
t
R
(Note 5)
20 +
300 ns
Fall Time of Both SDA and SCL signals
t
F
(Note 5)
20 +
300 ns
STOP Setup Time t
SU:STO
0.6 µs
MOD-SEL Setup Time
2ms
MOD-SEL Hold Time
10 µs
Aborted Sequence Bus Release
2ms
C ap aci ti ve Load for E ach Bus Li ne
C
B
(Note 5) 400 pF
EEPROM Write Time t
W
≤ 4-Byte write (Note 6) 16 ms
ANALOG OUTPUT CHARACTERISTICS
(V
CC3
= +2.9V to +5.5V, V
CC2
= +1.6V to +3.6V, TA= -40°C to +100°C, unless otherwise noted.)
PARAMETER
CONDITIONS
UNITS
I
BIASSET
mA
I
BIASSET
(Off-State Current)
Shutdown
nA
I
MODSET
mA
I
MODSET
(Off-State Current)
Shutdown
nA
V
MAX
(Note 7) 0.7 3.0 V
V
THRSET
I
MAX
= 100µA 50
mV
V
THRSET
Drift Across temperature (Note 8) -5 +5 %
V
THRSET
Capacitance load
1nF
APC Calibration Accuracy +25°C 25 µA
0.200mA to 1.5mA -5 +5 %
APC Temp Drift
50µA to 200µA 12 µA Sink, SRC_SNK_B = 0
I
BMD
DNL
Source, SRC_SNK_B = 1
LSB
Sink, SRC_SNK_B = 0
I
BMD
INL
Source, SRC_SNK_B = 1
LSB
I
BMD
Voltage Drift 1.2 %/V
I
BMD
FS Accuracy 1.5 %
MIN TYP MAX
100
0.1C
B
0.1C
B
t
H os t_sel e ct_set up
t
Host_select_hold
t
MOD-DE SEL _Ab ort
400
Voltage on I
BIASSET
and I
MODSET
SYMBOL
I
BIASSET
I
BIASSET
I
MODSET
I
MODSET
V
THRSET
C
THRSET
MIN TYP MAX
0.01 1.50 ±10 ±100
0.01 1.20 ±10 ±100
-0.9 +0.9
-0.9 +0.9
-4.0 +4.0
-4.0 +4.0
1000
DS1862
XFP Laser Control and Digital Diagnostic IC
_____________________________________________________________________ 5
AC ELECTRICAL CHARACTERISICS—XFP CONTROLLER
(V
CC3
= +2.9V to +5.5V, V
CC2
= +1.6V to +3.6V, TA= -40°C to +100°C, unless otherwise noted.)
PARAMETER
CONDITIONS
UNITS
Time to Initialize t
INIT
V
CC3
within ±5% of nominal 30 200 ms
TX-D Assert Time t
OFF
IBIAS and IMOD below 10% of nominal 5 µs
TX-D Deassert Time t
ON
IBIAS and IMOD above 90% of nominal 1 ms
P-DOWN/RST Assert Time t
PDR-ON
IBIAS and IMOD below 10% of nominal 100 µs
P-DOWN/RST Deassert Time
IBIAS and IMOD above 90% of nominal 200 ms
MOD-DESEL Deassert Time
Time until proper response to I2C communication
2ms
INTERRUPT Assert Delay t
INT-ON
Time from fault to interrupt assertion 100 ms
INTERRUPT Deassert Delay t
INT-OFF
Time from read (clear flags) to interrupt deassertion
500 µs
MOD-NR Assert Delay
Time from fault to MOD-NR assertion 0.5 ms
MOD-NR Deassert Delay
Time from read (clear flags) to MOD-NR deassertion
0.5 ms
RX-LOS Assert Time t
LOS-ON
Time from SC-RX-LOS assertion to RX-LOS assertion
100 ns
RX-LOS Deassert Time t
LOS-OFF
Time from SC-RX-LOS deassertion to RX-LOS deassertion
100 ns
P-DOWN/RST Reset Time t
RESET
Time from P-DOWN/RST assertion to initial reset
10 µs
Shutdown Time t
FAULT
Time from fault to I
BIASSET
, I
MODSET
,
and I
BMD
below 10%
30 µs
ANALOG OUTPUT CHARACTERISTICS (continued)
(V
CC3
= +2.9V to +5.5V, V
CC2
= +1.6V to +3.6V, TA= -40°C to +100°C, unless otherwise noted.)
PARAMETER
CONDITIONS
UNITS
I
MODSET
Accuracy
+25°C I
MODSET
= 0.04mA to 1.2mA
%
75µA range 150µA range 300µA range 600µA range
I
MODSET
DNL
1200µA range
LSB
75µA range 150µA range 300µA range 600µA range
I
MODSET
INL
1200µA range
LSB
I
MODSET
Temp Drift 5%
I
MODSET
Voltage Drift 1.2 %/V
I
MODSET
FS Accuracy 1.5 %
APC Bandwidth IMD / I
APC
= 1 (Note 4) 6 10 30 kHz
SYMBOL
SYMBOL
MIN TYP MAX
-1.5 +1.5
-0.9 +0.9
-0.9 +0.9
-0.9 +0.9
-0.9 +0.9
-0.9 +0.9
-1.5 +1.5
-1.5 +1.5
-1.0 +1.0
-1.0 +1.0
-1.0 +1.0
MIN TYP MAX
t
PDR-OFF
t
MOD-DESEL
t
MOD-NR-ON
t
MOD-NR-OFF
DS1862
XFP Laser Control and Digital Diagnostic IC
6 _____________________________________________________________________
AC ELECTRICAL CHARACTERISICS—SOFT* CONTROL AND STATUS
(V
CC3
= +2.9V to +5.5V, V
CC2
= +1.6V to +3.6V, TA= -40°C to +100°C, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS
UNITS
Soft TX-D Assert Time t
OFF_Soft
IBIAS and IMOD below 10% of nominal 50 ms
Soft TX-D Deassert Time t
ON_Soft
IBIAS and IMOD above 90% of nominal 50 ms
Soft P-DOWN/RST Assert Time
IBIAS and IMOD below 10% of nominal 50 ms
IBIAS and IMOD above 90% of nominal
ms
Soft MOD-NR Assert Delay
t
MOD-NR-ON
_Soft
Time from fault to MOD-NR assertion 50 ms
Soft MOD-NR Deassert Delay
t
MOD-NR-OFF
_Soft
Time from read (clear flags) to MOD-NR deassertion
50 ms
Soft RX_LOS Assert Time
Time from SC-RX-LOS assertion to RX-LOS assertion
50 ms
Soft RX_LOS Deassert Time
Time from SC-RX-LOS deassertion to RX-LOS deassertion
50 ms
Analog Parameter data Ready (DATA-NR)
ms
*All SOFT timing specifications are measured from the falling edge of “STOP” signal during I2C communication.
ANALOG INPUT CHARACTERISTICS
(V
CC3
= +2.9V to +5.5V, TA= -40°C to +100°C, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS
UNITS
I
BMD
Configurable Source or
Sink (+/-)
mA
Source mode 2.0
I
BMD
Voltage (I
BMD
- 0µA) V
BMD
Sink mode
1.2
V
I
BMD
Input Resistance R
BMD
400 550
Ω
A/D INPUT VOLTAGE MONITORING (IBIASMON, AUX2MON, AUX1MON, RSSI, BMD)
(V
CC3
= +2.9V to +5.5V, TA= -40°C to +100°C, unless otherwise noted.)
PARAMETER
CONDITIONS
UNITS
Input Resolution ∆V
MON
µV
Supply Resolution
1.6 mV
Input/Supply Accuracy A
CC
At factory setting
0.5
%FS
AUX1MON and AUX2MON disabled 48 52
Update Rate
All channels enabled 64 75
ms
Input/Supply Offset V
OS
(Note 4) 0 5 LSB
Full-Scale Input (I
BIASMON
and
RSSI)
At factory setting
2.5
V
Full-Scale Input (AUX1MON, AUX2MON, and V
CC2/3
)
At factory setting (Note 9)
V
BMD (Monitor) (TX-P) FS setting 1.5 mA
Soft P-DOWN/RST Deassert Time t
t
PDR-ON_Soft
PDR-OFF_Soft
t
LOS-ON_Soft
t
LOS-OFF_Soft
MIN TYP MAX
MIN TYP MAX
200
500
0.05 1.50
I
range 0 to 1.5mA
BMD
SYMBOL
MIN TYP MAX
610
∆V
CC2/3
0.25
t
FRAME1
t
FRAME2
2.4875
6.5208 6.5536 6.5864
700
2.5125
DS1862
XFP Laser Control and Digital Diagnostic IC
_____________________________________________________________________ 7
FAST ALARMS AND VCCFAULT CHARACTERISTICS
(V
CC3
= +2.9V to +5.5V, V
CC2
= +1.6V to +3.6V, TA= -40°C to +100°C, unless otherwise noted.)
PARAMETER
CONDITIONS
UNITS
HIGHBIAS and TX-P Threshold FS
(Note 10)
2.5
mA
V
CC2/3
Fault Asserted
Falling Edge Delay
↓ V
CC2/3
(Note 11)
75 ms
QT Temperature Coefficient -3 +3 %
QT Voltage Coefficient 0.5 %/V
QT FS Trim Accuracy (4.2V, +25°C)
mA
QT Accuracy (Trip) (INL) -2 0 +2 LSB
QT Voltco 0.5 %/V
QT Tempco 1.5 3 %
Note 1: All voltages are referenced to ground. Current into IC is positive, out of the IC is negative. Note 2: Secondary power supply is used to support optional variable power-supply feature of the XFP module. If V
CC2
is not used,
(i.e., signal conditioners using 3.3V supply) V
CC2
should be connected to the V
CC3
.
Note 3: Input signals (i.e., TX-D, MOD-DESEL, and P-DOWN/RST have internal pullup resistors. Note 4: Guaranteed by design. Simulated over process and 50µA < I
BMD
< 1500µA.
Note 5: C
B
—total capacitance of one bus line in picofarads.
Note 6: EEPROM write begins after a stop condition occurs. Note 7: This is the maximum and minimum voltage on the MODSET and BIASSET pins required to meet accuracy and drift specifi-
cations.
Note 8: For V
THRSET
, offset may be as much as 10mV.
Note 9: This is the uncalibrated offset provided by the factory; offset adjustment is available on this channel. Note 10: % FS refers to calibrated FS in case of internal calibration, and uncalibrated FS in the case of external calibration.
Uncalibrated FS is set in the factory and specified in this data sheet FS (factory). Calibrated FS is set by the user, allowing a change in any monitored channel scale.
Note 11: See the Monitor Channels section for more detail or V
CC2
and V
CC3
selection.
NONVOLATILE MEMORY CHARACTERISTICS
(V
CC3
= +2.9V to +5.5V, unless otherwise noted.)
PARAMETER
CONDITIONS
UNITS
Endurance (Write Cycle) +70°C
Cycles
Endurance (Write Cycle) +25°C
Cycles
SYMBOL
SYMBOL
MIN TYP MAX
2.48
2.480 2.500 2.520
MIN TYP MAX
50k
200k
2.52
DS1862
XFP Laser Control and Digital Diagnostic IC
8 _____________________________________________________________________
Timing Diagrams
VCC > V
POA
TX-D
I
BIASSET
I
MODSET
t
INIT
P-DOWN/RST
INTERRUPT
RESET-DONE
RESET-DONE
READ-FLAGS
t
INIT ON
t
PDR-OFF
t
INIT OFF
t
INIT
READ-FLAGS
Figure 1. Power-On Initialization with P-DOWN/RST Asserted and TX-D/SOFT-TX-D Not Asserted
Figure 2. Power-On Initialization with P-DOWN/RST Not Asserted and TX-D/SOFT-TX-D Not Asserted (Normal Operation)
VCC > V
POA
TX-D
I
BIASSET
I
MODSET
t
INIT
P-DOWN/RST
INTERRUPT
t
INIT ON
t
INIT OFF
READ-FLAGS
RESET-DONE
DS1862
XFP Laser Control and Digital Diagnostic IC
_____________________________________________________________________ 9
Timing Diagrams (continued)
TX-D
TX-F
I
BIASSET
I
MODSET
t
OFF
t
ON
Figure 3. TX-D Timing During Normal Operation
Figure 4. Detection of Safety Fault Condition
TX-D
FETG
OCCURRENCE
OF FAULT
I
BIASSET
I
MODSET
t
FAULT
DS1862
XFP Laser Control and Digital Diagnostic IC
10 ____________________________________________________________________
FETG
P-DOWN/RST
OCCURRENCE
OF FAULT
I
BIASSET
I
MODSET
t
RESET
t
INIT
RESET-DONE
Figure 5. Successful Recovery from Transient Safety Fault Condition Using P-DOWN/RST
Figure 6. Unsuccessful Recovery from Transient Safety Fault Condition
FETG
(FETG_POL = 1)
P-DOWN/RST
OCCURRENCE
OF FAULT
I
BIASSET
I
MODSET
t
RESET
t
FAULT
t
FAULT
RESET-DONE
Timing Diagrams (continued)
DS1862
XFP Laser Control and Digital Diagnostic IC
____________________________________________________________________ 11
READ FLAGS
OCCURRENCE
OF MONITOR
CHANNEL FAULT
t
INIT_ON
t
INIT_OFF
INTERRUPT
Figure 7. Monitor Channel Fault Timing
Timing Diagrams (continued)
DS1862
XFP Laser Control and Digital Diagnostic IC
12 ____________________________________________________________________
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
DS1862 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
5.34.83.3 3.8 4.3
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
2.0
2.8
SRC_SINK_B = 1
SRC_SINK_B = 0
I
BMD
= 499.479µA
SUPPLY CURRENT vs. TEMPERATURE
DS1862 toc02
TEMPERATURE (°C)
SUPPLY CURRENT (mA)
8560-15 10 35
3.0
3.5
4.0
4.5
5.0
5.5
6.0
-40
SRC_SINK_B = 1
SRC_SINK_B = 0
I
BMD
= 499.479µA
V
CC3
= 5.5V, V
CC2
= 1.6V
I
BMD
DRIFT vs. TEMPERATURE
DS1862 toc03
TEMPERATURE (°C)
I
BMD
DRIFT (%)
8560-15 10 35
-2.5
-1.5
-2.0
-1.0
-0.5
0
0.5
1.0
-40
SRC_SINK_B = 1
SRC_SINK_B = 0
I
BMD
= 499.479µA
V
CC3
= 5.5V, V
CC2
= 1.6V
I
BMD
DRIFT vs. SUPPLY VOLTAGE
DS1862 toc04
SUPPLY VOLTAGE (V)
I
BMD
DRIFT (%)
5.23.6 4.4
-1.0
0
-0.2
0.2
-0.6
-0.8
-0.4
0.4
0.6
0.8
1.0
2.8
SRC_SINK_B = 1
SRC_SINK_B = 0
I
BMD
= 499.479µA
I
MODSET
DRIFT vs. TEMPERATURE
DS1862 toc05
TEMPERATURE (°C)
I
MODSET
DRIFT (%)
85-15 10 35 60
-2.0
-1.5
-1.0
-0.5
0
0.5
1.0
-40
I
BMD
= 499.479µAV
CC3
= 5.5V, V
CC2
= 1.6V
INTEGRAL NONLINEARITY
OF QUICK TRIPS
DS1862 toc06
CODE (0–255)
ERROR (LSB)
256128
-0.8
-0.2
0
-0.6
-0.4
0.2
0.4
0.6
0.8
0
DIFFERENTIAL NONLINEARITY
OF I
MODSET
DS1862 toc07
CODE (0–255)
ERROR (LSB)
256128
-0.20
-0.05
0
-0.15
-0.10
0.05
0.10
0.15
0.20
0
FSR = 75µA
V
CC3
= 4.2V, V
CC2
= 1.6V
INTEGRAL NONLINEARITY
OF I
MODSET
DS1862 toc08
CODE (0–255)
ERROR (LSB)
256128
-0.20
-0.05
0
-0.15
-0.10
0.05
0.10
0.15
0.20
0
FSR = 75µAV
CC3
= 4.2V, V
CC2
= 1.6V
DS1862
XFP Laser Control and Digital Diagnostic IC
____________________________________________________________________ 13
Pin Description
NAME
DESCRIPTION
Power-Down/Reset Input. This multifunction pin is pulled high internally. See the Power-Down/Reset Pin
section for additional information.
Signal Conditioner Receiver Loss-of-Signal Input. This pin is an active-high input with LVCMOS/LVTTL voltage levels.
Signal Conditioner Receiver Loss-of-Lock Input. This pin is an active-high input with LVCMOS/LVTTL voltage levels.
THRSET
Threshold Set Output. This pin is a programmable voltage source that can be used for Rx signal conditioner.
V
CC2
1.8V Power-Supply Input
RX-LOS
Receiver Loss-of-Signal. This open-drain output indicates when there is insufficient optical power.
SCL
I2C Serial-Clock Input
FETG
FET Gate Output. This pin can drive an external FET gate associated with safety fault disconnect.
RSSI
Received Power Signal Input
MODSET
Modulation Current Output. This pin is only capable of sinking current.
TX-D
Transmit Disable Input. This pin has an internal pullup resistor.
SDA
I2C Serial-Data Input/Output
EN1
Enable 1 Output. Functional control for signal conditioners.
EN2
Enable 2 Output. Functional control for signal conditioners.
BIASSET
Bias Current Output. This pin is only capable of sinking current. Interrupt. This open-drain output pin indicates a possible operational fault or critical status condition to the
host.
MOD-NR
Indicating Module Operational Fault. Open-drain output. This pin indicates the status of the MOD-NR flag.
Aux1 Monitor Input. This pin can be used to measure any voltage quantity.
Aux2 Monitor Input. This pin can be used to measure any voltage quantity or external temperature sensor.
BMD
Monitor Diode Current Input. This pin is capable of sourcing or sinking current.
GND
Ground
Module Deselect Input. This pin must be pulled low to enable I2C communication. This pin is pulled high
internally.
IBIASMON
Bias Monitor Input. This pin can be used to monitor the voltage across the laser.
Signal Conditioner Transmitter Loss-of-Signal. This pin is an active-high input with LVCMOS/LVTTL
voltage levels.
V
CC3
3.3V or 5V Power-Supply Input
PIN
P-DOWN/RST A1
SC-RX-LOS A2
SC-RX-LOL A3
A4
A5
B1
B2
B3
B4
B5
C1
C2
C3
C4
C5
INTERRUPT D1
MOD-DESEL E2
SC-TX-LOS E4
D2
AUX1MON D3
AUX2MON D4
D5
E1
E3
E5
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