MC2042-4WAFER - Mindspeed Technologies

02042-DSH-001-C 8/03 August 2003

Preliminary Information

MC2042-4

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel, OC3/STM-1,

IEEE1394

Data Sheet

Information provided in this Data Sheet is PRELIMINARY and is subject to change without

notice. Mindspeed™ Technologies, Inc, Proprietary and Confidential

02042-DSH-001-C 8/03 Page 2 of 13

MC2042-4

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel, OC3/STM-1, IEEE1394

Preliminary Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential

TABLE OF CONTENTS

Features ...........................................................................................................................................................3

Applications ......................................................................................................................................................3

Connections ......................................................................................................................................................3

General Description ..........................................................................................................................................3

Table 1 Ordering Information ............................................................................................................................3

Top Level Diagram ...........................................................................................................................................3

Table 2 Pin Descriptions ...................................................................................................................................4

Table 3 Absolute Maximum Ratings .................................................................................................................5

Table 4 DC Electrical Characteristics ...............................................................................................................5

Table 5 AC Electrical Characteristics ...............................................................................................................5

Typical Applications Circuit ...............................................................................................................................6

Functional Description ......................................................................................................................................6

Current Switch ..................................................................................................................................................6

LED Drive and Temperature Compensation ....................................................................................................6

Transmit Enable/Disable ..................................................................................................................................7

Pre-emphasis or ‘Peaking’ ................................................................................................................................7

LED clamping, Laser driving .............................................................................................................................7

LED drive Pulse Width Adjust (PWA) ...............................................................................................................8

Eye Diagram......................................................................................................................................................8

Evaluation Board ...............................................................................................................................................9

Bare Die ..........................................................................................................................................................10

Table 6 Bare Die Pad Coordinates ...................................................................................................................10

TSSOP20 Package Information .......................................................................................................................11

QSOP16 Package Information .........................................................................................................................12

Table 7 TSSOP20 Dimensions .........................................................................................................................12

Table 8 QSOP16 Dimensions ..........................................................................................................................12

Disclaimer .........................................................................................................................................................13

Contact Information ...........................................................................................................................................14

02042-DSH-001-C 8/03 Page 3 of 14

MC2042-4

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel, OC3/STM-1, IEEE1394

Preliminary Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential

FEATURES

Data rates to >300 Mbps, depending on LED

Single chip solution, available as die or in TSSOP20

or QSOP16 fabricated in deep sub-micron CMOS for

lowest cost & power consumption and long term

reliability

Programmable output current from 5 mA to 100 mA

RC programmable pre-emphasis or ‘peaking’ circuit

giving drive current rise and fall times <500 ps

Resistor programmable compensation for

temperature dependence of LED output power

PECL input with optional Pulse Width Adjust

Single-ended CMOS input compatible at low speeds

VREF voltage generator and output pin

Supports most LED types (e.g. 660 to 1300 nm)

Single +5 V to +3.3 V operation

APPLICATIONS

FDDI, fiber Channel

Fast Ethernet, IEEE1394

OC3/STM1

CONNECTIONS

GENERAL DESCRIPTION

The MC2042-4 is a CMOS IC designed for high-speed

LED drive in low-cost optical fiber based transmission

systems. Depending on the LED used, data rates to

>300Mbps can be achieved.

The LED drive current is set by a resistor. To improve LED

‘on’ time, a pre-emphasis circuit is included, which may be

set via a simple RC network.

To minimize the effects of temperature on LED output

power, LED drive temperature compensation can be set

by resistor over a 500 - 10,000 ppm/°C range.

Differential positive-ECL (PECL) data on the input pins

can be shaped, if desired, by the differential voltage on

the Pulse Width Adjust (PWA) pins. This adjustment is

continuous over a ±500 ps range. In addition, the VREF

output pin allows single-ended input to the MC2042 and

provides compatibility with industry-standard FO

modules.

TABLE 1 ORDERING INFORMATION

TOP LEVEL DIAGRAM

6.5 x 4.4mm TSSOP Package

4.3 x 3.9mm QSOP Package

MC2042-4

Datecode

PWA-

REF

RESET2

RTSET

DD1

PWA-

GND

DD2

GND

IOUT

PEAK

DD2

TSSOP20

MC2042-4

Dat ecode

GND

DD2

GND

IOUT

PEAK

DD2

QSOP16

PWA-

DD1

PWA+

REF

RTSET2

RTSET

Fig.1 TOP VIEWS

Part Pin-Package

MC2042-4DIEWP Waffle pack

MC2042-4WAFER Expanded Whole Wafer on a ring

MC2042-4Q16 QSOP16

MC2042-4T20 TSSOP20

Fig. 2

Input Data Pulse Shaping

VREF Generator

GND GND RTSET RTSET2

PEAK

VDD2

VDD1

DIN

PWA

IOUT

PWA

DIN

VREF

Current Switch and Peaking

Control

Programmable

Current Sink

IOUT

02042-DSH-001-C 8/03 Page 4 of 14

MC2042-4

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel, OC3/STM-1, IEEE1394

Preliminary Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential

TABLE 2 PIN DESCRIPTIONS

TSSOP20

QSOP16

Die

Pin Name Description

1 - - NC Not connected, leave open

2113PWA

Inverse pulse width adjust input

3214PWA

Differential pulse width adjust input. Allows continuous adjustment of input data

pulse width

4315

DIN Differential data input

5416

DIN Inverse differential data input

651

VREF Reference output. Can be used with single-ended data input

762

RTSET2 Temperature compensation adjustment pin. Allows temperature dependence of

LED light output to be reduced or removed

873

RTSET Sets nominal LED drive current

984

VDD1 Power pin, connect to most positive supply

10 - - NC Not connected

11 - - NC Not connected

12 9 5 VDD2 LED shorting pin, connect to most positive supply. Speeds LED switch off

13 10 6 VDD2 LED shorting pin, connect to most positive supply. Speeds LED switch off

14 11 7 PEAK Connection for pre-emphasis or peaking circuit

15 12 8 IOUT Driver output. Connect LED between this pin and VDD

16 13 9 IOUT Driver output. Connect LED between this pin and VDD

17 14 10 IOUT

Logical inverse of pin 8. Connect resistor of approximately the same value as

LED (at the programmed drive current level) between this pin and VDD

18 15 11 GND Ground pin. Connect to the most negative supply

19 16 12 GND Ground pin. Connect to the most negative supply

20 - - NC Not connected, leave open

02042-DSH-001-C 8/03 Page 5 of 14

MC2042-4

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel, OC3/STM-1, IEEE1394

Preliminary Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential

TABLE 3 ABSOLUTE MAXIMUM RATINGS

These are the absolute maximum ratings at or beyond which the IC can be expected to fail or be damaged. Reliable

operation at these extremes for any length of time is not implied.

TABLE 4 DC ELECTRICAL CHARACTERISTICS

TABLE 5 AC ELECTRICAL CHARACTERISTICS

Symbol Parameter Rating Units

PTOT Total power dissipation (TSSOP20) 255 mW

VCC Power supply (VCC-GND) 7V

TJJunction temperature 150 °C

TAOperating ambient -40 to +85 °C

TSTG Storage temperature -65 to +50 °C

Symbol Parameter Min Typ Max Units

VCC Supply Voltage 3.0 - 5.5 V

Din Allowable voltage at data inputs Gnd - 0.3 - VCC+0.3

VREF Voltage reference VCC-1.6 VCC-1.4 VCC-1.03

ILED’ ON LED drive current 5 - 120 mA

ILED’ OFF LED off current - - 50 µA

ICOMP LED drive current temperature compensation range 0.05 - 1 %/°C

V_LED_H Minimum allowable voltage at IOUT VDD-2.0 --V

Symbol Parameter Min Typ Max Units

Vin(Diff) Differential Input Voltage, 2*(DinH - DinL) 300mV - 2*Vcc V

Common Mode Input Voltage VCC/2 -(Vcc-(Vin[Diff])/4) V

fCMaximum data rate 300 - - Mbps

TPWA Input data pulse width adjust range -500 - 500 ps

LED trLED drive rise time - 0.7 1 ns

LED tfLED drive fall time - 0.7 1 ns

IPEAK Peaking current (as % of LED drive current) 0 - 50 %

PEAK trPeaking current rise time - - 1 ns

PEAK tfPeaking current fall time - - 1 ns

PEAK tdPeaking current decay time - C1x(R4+5) - S

IDD Supply current - ILED+10 ILED+20 mA

02042-DSH-001-C 8/03 Page 6 of 14

MC2042-4

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel, OC3/STM-1, IEEE1394

Preliminary Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential

TYPICAL APPLICATIONS CIRCUIT

Current Switch

Differential Positive-ECL (PECL) data on the data input

pins controls the LED current switch. The LED current

flows either through the LED or via the dummy load so

that VDD noise is minimized. To reduce LED ‘turn-off’

time, the LED is momentarily short-circuited, via VDD2,

before the current is switched to the dummy load.

LED Drive and Temperature

Compensation

The two resistors R1 and R2 set the LED drive current

and temperature compensation. The simplified

application diagram (Fig. 3) shows R1 connected

between RTSET and GND, and R2 between RTSET and

the RTSET2 pin.

The current flowing out of the RTSET pin determines the

LED drive current.

The temperature independent component of the LED

drive current is set primarily by R1. The temperature

dependent component is set primarily by R2. However,

R1 and R2 are not independent.

The RTSET2 pin connects to an internal diode in the IC,

which exhibits standard diode behaviour with

temperature. As temperature rises, the voltage on the

diode drops, the current flowing through R2 increases and

the LED drive current increases.

The LED ‘on’ current is controlled to ±5%.

If the operating temperature of the MC2042 is not

representative of the LED temperature, an external diode

may be used in place of the temperature compensating

diode internal to the MC2042. Figure 4 illustrates a circuit

using an external diode for temperature compensation.

A Microsoft Excel file is available from Mindspeed which

will calculate appropriate values for RTset resistors R1

and R2 given your LED current, forward voltage, and LED

temperature coefficient. The file may be obtained from a

Mindspeed Field Applications Engineer and is named

'MC2042-4 resistor selection.xls'.

Input Data Pulse Shaping Current Switch and Peaking

Control

VREF Generator Programmable

Current Sink

GND GND2 RTSET RTSET2

IOUT PEAK

VDD2

VDD1

DIN

PWA

IOUT

PWA

DIN

R4 C1

LED

Dummy

LED Load

VCC

VREF

Optional Peaking

Fig. 3

FUNCTIONAL DESCRIPTION

02042-DSH-001-C 8/03 Page 7 of 14

MC2042-4

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel, OC3/STM-1, IEEE1394

Preliminary Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential

FUNCTIONAL DESCRIPTION

Transmit Enable/Disable

There is no dedicated pin on the MC2042 to disable the

LED drive current. However, the LED drive current can

be disabled by disabling the current out of pin RTSET.

The LED current is approximately 100x the current out of

pin RTSET, so if the current out of this pin is 0, the LED

drive current is 0. However, if peaking is used the peaking

current will not be disabled.

Figure 5 illustrates how the current out of RTSET can be

disabled by adding a MOSFET (Q1) at the RTSET node

of the R1/R2 temperature compensation network. The

voltage on the gate of Q1 then controls transmit enable/

disable. When selecting Q1, a MOSFET should be

chosen with an Rds(on) which is negligible compared to

R1 and R2.

Pre-Emphasis Or ‘Peaking’

To improve LED ‘turn on’ time an optional pre-emphasis

function is included on the MC2042-4. If this is not

required, then the PEAK pin should be left floating.

Two external components (R4, C1) are required as shown

in Fig. 3 to implement peaking.

When the LED is turned on, the voltage on PEAK is pulled

LOW very rapidly. This voltage transient is coupled

through R4 and C1 and exerts a transient current on the

LED.

When the LED is turned off, the voltage on PEAK is pulled

HIGH rapidly. This voltage transient is coupled through

R4 and C1 and exerts a transient current in the opposite

direction on the LED.

The transient current amplitude and RC decay are given

approximately by:

Peak current (Amps): 4/(R4 + 5)

Decay (seconds): C1 x (R4 + 5)

The above approximations assume an ideal LED model

with 0 Ohms resistance. Real LEDs will slightly alter the

peaking effect. Typical values for R4 and C1 are:

R4 = 50 Ω

C1 = 20 pF

LED Clamping, Laser Driving

Since most LEDs exhibit a longer ‘turn off’ time than ‘turn

on’ time, a clamping function is included on the MC2042

in order to reduce the ‘turn off’ time. Clamping is enabled

via the two VDD2 connections.

The disadvantage of clamping is that the LED’s internal

capacitance has to be fully charged again before the LED

starts to emit light. This delayed ‘turn on’ effect becomes

noticeable when the nominal LED drive current is low.

Use of the peaking circuit helps solve this problem. Thus,

the combination of peaking and clamping results in very

fast ‘turn on’ and ‘turn off’ times for the LED.

When driving lasers, it will often be helpful to disable this

clamping. This can be achieved by leaving the VDD2

connections floating. VDD1 must still be connected.

RTSET

RTSET2

(unused)

External Diode

for Temp. Comp.

Fig. 4

RTSET RTSET2

Transmit Enable

Fig. 5

02042-DSH-001-C 8/03 Page 8 of 14

MC2042-4

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel, OC3/STM-1, IEEE1394

Preliminary Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential

LED Drive Pulse Width Adjust (PWA)

The input pulse width can be adjusted prior to application

to the LED switch. The differential voltage on the PWA

(Pulse Width Adjust) pins shapes the input pulse linearly

over a nominal -500 to +500 ps range, according to the

formula:

Delta PW (ps) = K x VPWA

Where:

K = 500 ± 100

and

VPWA = (VPWA+) - (VPWA-)

The maximum range for VPWA is ±1V. The input

impedance is 3.6 kΩ. VPWA+ and VPWA- will settle at a

nominal voltage equal to (0.6 * VDD) if left floating. It is

recommended that adjustment be implemented by pull

down resistors on PWA+ or PWA-. However, it is

common for one or other pin to be tied to ground as a

zero-cost, ‘gross’ adjustment.

If pulse width adjustment is not required PWA+ and PWA-

should be tied to ground.

Eye Diagram

The eye diagram below is typical of the electrical output of

the MC2042-4. The crossover point can be moved up and

down using the PWA pin. The overshoot can be increased

by using the PEAK pin.

FUNCTIONAL DESCRIPTION

Fig. 6

02042-DSH-001-C 8/03 Page 9 of 14

MC2042-4

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel, OC3/STM-1, IEEE1394

Preliminary Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential

1 2 34

321

MICROCOSM COMMUNICATIONS LTD

UNIVERSITY GATE

PARK ROW

BRISTOL.

MC2042-4 EVALUATION BOARD

MC2042

1SHEET

OF 1

DOC_NO

REV

TITLE

N/C 20

GND 19

GND 18

IOUTB 17

IOUT 16

IOUT 15

PEAK 14

VDD2 13

RTSET

RTSET2

VBB

DIN-

DIN+

PWA+

PWA-

N/C

VDD1

N/C

VDD2 12

N/C 11

IC1

MICROCOSM MC2042-4

VCC1

10NF

VCC2

10NF

R2 N/C

R3 N/C

R4 22R

18PF

C5 100NF

10NF

SK1

SK2

CATHODE

ANODE

VCC2

VBB

50R

100NF

SK4

SK5

DATA INPUTS

LED INTERFACE

N/C

VCC1

SK6

DATA_CMOS

DATA_IN

DATA_INB

R11

N/C

R12

N/C

VCC1

R13

N/C

R14

N/C

R10

R17

50K

R18

50K

10K

R19

50K

100NF

CAN_GND

SK3

R15

N/C

R16

N/C

C11

10NF

C12

10NF LED PULSE WIDTH

ADJUST

SET LED

TEMP COMP

SET NOMINAL LED

DRIVE CURRENT

HD1

VCC1

3.3V

+C10

10UF

POWER

EXCCL3216U

100NF

VCC2

100NF

General

-------------

The board allows the user full flexibility for determining the

resistor valuesrequired for the pulse width adjust, LED current

and LED temperature compensation functions.

Controls

--------------

Pulse width adjust - R17/R18

These pots can be altered to give a total of +/- 500 pS

Pulse width adjustment. No adjustment occurs if PWA +

& PWA- are tied to gnd. Maximum adjustment in either direction

is obtained by connecting PWA+ to VCC and PWA- to gnd ,

or viceversa.

This board is provided for evaluation of the MC2042-4

LED drive current & temp compensation - R19 & R7

The drive current and temperature compensation

is determined by two potentiometers , R19 & R7

respectively .LED turn-on time can be improved by

proper selection of R2, R3 & C4. Refer to Microcosm

documentation for selection of these values.

Inputs

-----------

SK4 & SK5 are provided for the connection of

differential PECL input signals. Alternatively a CMOS

input may be connected to SK6.If using SK6, remove

R6, C5 & C6 and fit R8 & R9 with 1K resistors.

Evaluation Board

An electrical evaluation board is available for the

MC2042-4. Its schematic is shown below.

Fig. 7

02042-DSH-001-C 8/03 Page 10 of 14

MC2042-4

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel, OC3/STM-1, IEEE1394

Preliminary Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential

BARE DIE

TABLE 6 BARE DIE PAD COORDINATES

Pad Description X Y Pad Description X Y

1VREF -73 394.5 9 IOUT 73 -394.5

2RTSET2 -219 394.5 10 IOUT 219 -394.5

3RTSET -397 214.7 11 GND 397 -223.3

4VDD1 -397 68.7 12 GND 397 -77.3

5VDD2 -397 -77.3 13 PWA 397 68.7

6VDD2 -397 -223.3 14 PWA 397 214.7

7 PEAK -219 -394.5 15 DIN 219 394.5

8IOUT -73 -394.5 16 DIN 73 394.5

RTSET

VDD1

PEAK

IOUT

GND

PWA

DIN

VREF

VDD2

IOUT

GND

PWA

DIN

RTSET2

789

Fig. 8

Die size: 1.0 x 1.0 mm

Pad openings: 95 um square

02042-DSH-001-C 8/03 Page 11 of 14

MC2042-4

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel, OC3/STM-1, IEEE1394

Preliminary Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential

TSSOP20 PACKAGE INFORMATION

Note:

Package dimensions on page 12.

Fig. 9

02042-DSH-001-C 8/03 Page 12 of 14

MC2042-4

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel, OC3/STM-1, IEEE1394

Preliminary Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential

QSOP16 PACKAGE INFORMATION

TABLE 7 TSSOP20 DIMENSIONS TABLE 8 QSOP16 DIMENSIONS

Fig. 10

Dims. Tols/leads TSSOP20L

A MAX 1.20

A1 0.5MIN/.10MAX.

A2 NOM .90

D ±.05 6.50

E ±.10 6.40

E1 ±.10 4.40

L +.15/-.10 .60

L1 REF. 1.00

Zp REF. .325

e BASIC .65

b±.05 .22

c .13MIN/.20MAX

e ±4° 4°

aaa MAX. .10

bbb MAX. .10

ccc MAX .05

ddd MAX. .20

Dims. Tols/N QSOP16

A MAX. 1.60

A1 ±.05 0.1

A2 ±.10 1.40

D ±.10 4.9

E ±.20 6.00

E1 ±.10 3.90

L ±.05 0.6

ccc MAX. 0.10

ddd MAX. 0.10

e BASIC 0.65

b ±.05 0.25

c±.05.2 Min.

.24 Max.

R ±.05 0.20

R1 Min. 0.20

MC2042-4

02042-DSH-001-C 8/03 Page 13 of 14

LED/Laser Driver for FDDI, Fast Ethernet, Fibre Channel OC3/STM-1

Preliminary Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential

DISCLAIMER

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 purposes only.

Except as provided in Mindspeed’s Terms and Conditions of Sale for such products or in any separate 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 product descriptions at any time, without

notice. Mindspeed makes no commitment to update the information and shall have no responsibility whatsoever for

conflicts or incompatibilities arising from future changes to its specifications and product descriptions. No license, express

or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document.

THESE MATERIALS ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED,

RELATING TO SALE AND/OR USE OF MINDSPEED PRODUCTS INCLUDING LIABILITY OR WARRANTIES

RELATING TO FITNESS FOR A PARTICULAR PURPOSE, CONSEQUENTIAL OR INCIDENTAL DAMAGES,

MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY

RIGHT. MINDSPEED FURTHER DOES NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE

INFORMATION, TEXT, GRAPHICS OR OTHER ITEMS CONTAINED WITHIN THESE MATERIALS. MINDSPEED

SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING

WITHOUT LIMITATION, LOST REVENUES OR LOST PROFITS, WHICH MAY RESULT FROM THE USE OF THESE

MATERIALS.

Mindspeed products are not intended for use in medical, lifesaving or life sustaining applications. Mindspeed customers

using or selling Mindspeed products for use in such applications do so at their own risk and agree to fully indemnify

Mindspeed for any damages resulting from such improper use or sale.

02042-DSH-001-C 8/03 Page 14 of 14

Headquarters

Newport Beach

Mindspeed Technologies

4000 MacArthur Boulevard, East Tower

Newport Beach, CA 92660

Phone: (949) 579-3000

Fax: (949) 579-3020

www.mindspeed.com

Contact Information

Information provided in this Data Sheet is PRELIMINARY and is subject to change without notice.

Mindspeed™ Technologies, Proprietary and Confidential