M02094-12 Datasheet, PDF(28/46 Page) M/A-COM Technology Solutions, Inc.

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M02094-12 Datasheet, PDF (28/46 Pages) M/A-COM Technology Solutions, Inc. – EPON FTTH modules

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M02094-12

3.3 or 5 Volt VCSEL/FP Laser Driver IC for Applications to 2 Gbps

Rev V5

Table 3-2.

Pin Connection for Common Anode and Common Cathode Laser Modes

Pin Connection When:

Pin 18

Pin 14

Pin 13

Pin 22

SVCC

IBOUTCC

SGND

IBOUTCA

IPIN

PEAKADJ

Inactive

CCSEL = High

Laser bias source current.

Ground for laser and all output load components

Inactive

Monitor photodiode source current

Controls Negative going edge of OUT-

Internal 50Î© pull-up resistors on OUT+ Active

and OUT-

CCSEL = Low

Supply for laser and all output load components.

Inactive

Laser bias sink current.

Monitor photodiode sink current

Controls Negative going edge of OUT-, (do not

use)

Inactive

Ratio of Bias current to BIASMON

current

13.5:1

45.7:1

Ratio of Modulation current to

30:1

65:1

MODMON current

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.

M/A-COM Technology Solutions Inc. (MACOM) and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice.

Visit www.macom.com for additional data sheets and product information.

For further information and support please visit:

http://www.macom.com/support

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