Datasheet SPF MIT3 02 Datasheet (lnfineon)

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SPF MIT3 02

Plastic Fiber Optic Transmitter including Bigfoot™ IC for MOST

Preliminary Data Sheet

Safety Hints: Applications of new chip technologies leads to increasing optical efficiency and growing and higher levels of optical performance. We therefore recommend that the current versions of the IEC 825-1 and EN 60825-1 standards are taken into account right from the outset, i.e. at the equipment development stage, and that suitable protection facilities are provided.

The data sheet of the 4-pin MOST Optical Transmitter (MIT3 02) has to be taken as preliminary. Samples which are delivered before the qualification and the production release are engineering samples.

Features Description

Excellent solution for converting high speed data from TTL to Plastic Optical Fiber (POF)

• High speed transmitter up to 50 Mbaud

• TTL Data Input (Logic to Light Function)

• 650 nm for working in a low attenuation

range of PMMA Fiber

• High coupled power in1000 micron plastic

fiber

• Low cost

The MOST BigfootTx Plastic Fiber Optic Transmitter is a highly integrated CMOS IC combined with a High speed LED designed to transmit up to 25Mbit/sec optical data which is biphase coded at up to 50Mbaud. The internal peaking circuit minimizes PWD. The current through the LED will be setup by an external resistor connected to VCC. This makes it possible to control the optical output power of the LED.

Applications

• Optical Transmitter for MOST Systems

MOST BigfootTx

Actual design status:

Bigfoot IC Revision

J CAI date code,

package type device marking Data sheet is valid

MIT3 02

4: Control

3: Vcc

1: TX_DATA

2: GND

since

15-Jan-03

MIT3 02

Preliminary Product Information Infineon AG CONFIDENTIAL 15-Jan-03 OASIS SiliconSystems AG Page 1

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Maximum Ratings

SPF MIT3 02

Parameter Symbol Min Max Unit

Storage Temperature Range T

Junction Temperature T

Soldering Temperature (>2.5 mm from case bottom t≤5s) Power Dissipation P

Power Supply Voltage V

CCMax

STG

TOT

-40 100 °C

- 235 °C

- 300 mW

-0.5 6.0 V

Recommended Operating Conditions

Parameter Symbol Min Max Unit

Supply Voltage V Operating Temperature Range

=13.5 kOhm)

ext

4.75 5.25 V

-40 85

°C

All the data in this specification refers to the operating conditions above unless otherwise stated.

Optical Signal Characteristics

(22.5 Mbit/s MOST Data, Vcc=4.75 .. 5.25 V)

Parameter Symbol Min Typ Max Unit

Peak wavelength at TA=25°C

Temperature coefficient λ

Peak

Peak wavelength at TA=-40..85°C

Spectral bandwidth (FWHM)

Average Output Power coupled into plastic fiber

=25°C, R

at T

Temperature coefficient P

=15 kOhm, see Note 1

ext

opt

Average Output Power coupled into plastic fiber

=-40..85°C, R

at T

=15 kOhm, see Note 1

ext

Average Output Power coupled into plastic fiber

=-40..85°C, R

at T

=15 kOhm, over lifetime,

ext

see Note 1 Gain in P

when using 13.5 KOhm instead of

opt

15 KOhm Optical Rise Time (20% - 80%) t Optical Fall Time (20% - 80%) t Extinction Ratio r Pulse Width Variation, see Note 2 t Average Pulse Width Distortion, see Note 2 t

Peak25

TCλ

Peak

Delta P

opt25, O

Popt

opt

opt, lifetime

PWV

APWD

640 650 660 nm

- 0.16 - nm/K

630 650 670 nm

-2030nm

-7.4

(185)

-5.2

(300)

-3.6

(435)

dBm (µW)

-- 0.4-%/K

-8.6

(140)

-9.6

(110)

-5.2

(300)

-5.2

(300)

-3.1

(490)

-2.1

(615)

dBm (µW) dBm (µW)

0.35 0.4 0.45 dB

-46ns

10 11 - dB

20.9 - 24.4 ns

-0.5 - 1.5 ns

Note 1: The output power coupled into plastic fiber P

is measured with a large area detector at the

opt

end of a short length of a fiber (about 30 cm), which is ideally coupled to the Sidelooker. This value must not be used for calculating the power budget for a fiber optic system with a long fiber because the numerical aperture of plastic fibers decreases on the first meters. Therefore the fiber seems to have a higher attenuation over the first few meters compared with the specified value. Due to the direct coupling of the fiber to the LED at the end of the short fiber UMD (uniform mode distribution) will be observed. Therefore the following section of the cable has higher losses compared with EMD (equilibrium mode distribution). Note 2: The electrical input signal fulfills t

= 22.9 ns and t

PWV(min)

PWV(max)

= 24.1 ns. For further details

see page 3.

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SPF MIT3 02

Pulse Width Variation (t

) and Average Pulse Width Distortion (t

PWV

APW D

)

The SPF MIT3 02 generates negative Puls Width Distortion. This means the optical output signal is shortened compared to the electrical input signal. Therefore the parameters t

PWV

and t

do not meet

APWD

the MOST Specification of Physical Layer Rev 1.0 (MOST SPL Rev. 1.0) either at the electrical input signal (SP1 in the MOST SPL Rev. 1.0) or at the optical output signal (SP2 in the MOST SPL Rev.

1.0). This characteristic is shown in the following table.

Parameter Symbol Min Max Min Max Unit Remarks

Pulse Width Variation Average Pulse Width Distortion

PWV

APWD

Electrical

Input Signal

22.9 24.1 20.9 24.4 nsa

1.0 1.5 -0.5 1.5 ns

Optical

Output Signal

Optical Output Signal according to MOST Specification of Physical Layer Rev.

1.0

Pulse Width Variation Average Pulse Width Distortion

PWV

APWD

21.1 23.1 19.1 23.4 nsb

-0.5 0.5 -2.0 0.5 ns

Electrical Input Signal according to MOST Specification of Physical Layer Rev. 1.0

Based on this table, the MOST System may be considered by two aspects:

a) In order to meet the MOST SPL Rev 1.0 at SP2 the t

PWV

and t

at SP1 have to be longer than

apwd

described in the MOST SPL Rev. 1.0. This can be achived e.g. by using OS8104 as MOST transceiver chip.

b) If the MOST SPL Rev. 1.0 is met regarding t

PWV

and t

at SP1, then the output signal SP2 is

apwd

systematically shortened. Within a MOST System, this characteristic can be compensated by the optical receiver which detects the signal at SP3. For this compensation, the optical receiver has to be specified in a range which is smaller than the range described in the MOST SPL Rev. 1.0. For a detailed evaluation of system behavior, see paper “OS8300 Revision J behavior on SP2 (optical output signal)” from Oasis SiliconSystems.

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DC Characteristics

Parameter Symbol Min Typ Max Unit

SPF MIT3 02

Low Level Input Voltage V High Level Input Voltage V Input Leakage Current

=5.0V, VI=0.0V or VI=5.0V)

Input Capacitance C Input Resistance R Supply Current (R

= 15 kOhm) ON state,

ext

biphase coded data, see Note 3 Supply Current (R

= 15 kOhm) OFF state,

ext

LP2

see Note 4

Note 3: The current through the LED and therefore the optical output power and overall power consumption depends on the settings of R

. The nominal value for R

ext

optical output power is about –3dB of the nominal value. Typical behaviour see Fiure below.

Important: The external resistor of R

out of this range functionality may not be given over the whole temperature range and the

ext

device lifetime. Using values below 13K for R

must be within the range of 13.5K to 33K. For values of

ext

can damage the transmitter.

ext

-0.3 - 0.8 V

2.0 - VCC + 0.3 V

--+/- 20µA

-- 7 pF

100 - - kOhm

-25 35 mA

-- 1 mA

is 15K. With R

ext

=30K the

ext

Note 4: The transmitter jumps to low power mode after TX DATA is low for max. 18µs If the transmitter is in low power mode it is switched ON 5µs (max.) after TX DATA starts toggling.

AC Electrical Characteristics

Parameter Test Conditions Symbol Min Typ Max Unit

Power Supply Rejection Ratio Power Up Time Zero à MOST Data T Power Down Time MOST Data à Zero T Input Rise Time t Input Fall Time t

25 MHz Power Supply Noise

PSRR - 30 - dB

TLH

THL

1.0 2.5 5.0 µs

- - 18.0 µs

--5ns

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Typical Output Signal

Measured with fast optical receiver (Graviton SPD-1) with 15 kOhm external resistor and 22.579 Mbit/s

SPF MIT3 02

MOST Data at T

=25°C.

Typical Dependency of Average Output Power P

(22.5 MBit MOST Data/ VCC=5 V / TA=25°C)

160

Average Optical Power [%]

140

120

100

range for R

13.5 K..33 K

ext

on external Resistor R

opt

optical power

ext

5 101520253035404550

External Resistor R

Preliminary Product Information Infineon AG CONFIDENTIAL 15-Jan-03 OASIS SiliconSystems AG Page 5

ext [KOhm]

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SPF MIT3 02

Mechanical Design MIT3 02: CAI package (cavity as interface)

Lot number, production week, component type are given on CAI backside by laser marking (for details see marking specification).

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Application Circuit:

SPF MIT3 02

*1) Place these components as close as possible to their corresponding pins of the FOT.

*2) Values can change due to different light output power of the LED.

*3) This is just a propo sal for the Rext application. There can be used also other circuits to switch Rext from 15K to 30K.

Design & Layout rules:

• The 100nF bypass capacitors of the FOTs must be located as close as possible between the pins

Vcc and GND of the FOTs. Use ceramic caps and tantalum caps with low ESR.

• Also the inductor/ferrite bead (receiver) and the -3dB - control circuit (transmitter) must be placed

as close as possible to the FOTs. We prefer ferrite beads (e.g. type 74279214 Würth Elektronik) since the d.c. resistance is very low. If other inductors are used the d.c. resistor should be less than 3Ohm.

• For EMC a ferrite bead should be connected to the power supply close to the transmitter and the

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receiver. Do not use only one ferrite bead together for receiver and transmitter!

• For the ground connection a ground plane is recommended (Y-structure). That means the ground

planes of the transmitter, the receiver and the shielding must be separated. The three ground planes should be connected together behind the bypass capacitors (refer to the PCB design below). This ground signal should be connected directly to the ground plane of the MOST controller (e.g. OS8104) and the power supply on the top layer and/or bottom layer and ground layer as it is indicated in the example below.

• If a multi layer design is used the ground layer must have the same ground separation like shown

for the top layer!

• A serial resistor in the Rx/Tx data line will also reduce EMC - problems. For Rx the resistor must be

placed near the receiver - for Tx the resistor must be placed near the MOST controller chip. The value depends from the distance between the FOTs and the MOST chip (< 5cm) and can be in the range of up to 150R. Higher values for the resistors will increase jitter and can therefore cause locking problems of the MOST PLL!

• The Rx/Tx signals should not be routed parallel over a long distance but may be embedded with

ground copper, if possible.

• The GND pin and the pin of Rext (15K - resistor) of the transmitter are used for heat dissipation.

Therefore there should be a good connection to the PCB à no isolation gaps! Both pins should dip into a copper area (see layout example below).

Layout example:

SPF MIT3 02

The reference board from OASIS Silicon Systems follows the requirements above. The schematic is very similar to the example above, but does not include the connection to the power supply, the OS8104 or the microcontroller.

The examples below for top- and bottom layer is the layout of the reference design board and shows how the layout around the optical receiver and transmitter should look like.

It is strongly recommended to follow this examples in your design to get best performance!

Note: The buffer circuit (IC1), the connectors and jumpers in the middle to the right section of the schematic are only for use of the reference board and will not be necessary for your HW - design.

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Top Layer with 180° version of the pigtail:

GND - BUS to OS8104 and Power Supply

SPF MIT3 02

Bottom Layer (seen from the top side of the PCB): Bottom Layer: Bottom side / positions

GND - BUS to OS8104 and Power Supply

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Other items:

• The shown circuit for the –3dB attenuation is just a proposal. Also any other circuit which can

SPF MIT3 02

double the value of R

is permitted.

ext

• Due to the fact that the optical average level jumps if the power control signal (/-3dB) is

toggled there can occur LOCK/coding – errors at the following device for a short time. This is

not very critical, since it does occur only in diagnosis mode. After a time of 10ms the device should lock again if the optical attenuation between the devices is not too high.

• The Rx and Tx signals can be measured by using standard probes (>1M/<10pF). However, if the

signal quality is very bad and the LOCK signal of the MOST chip is flaky connecting a passive probe to the Rx signal can cause the MOST chip to lock better or worse to the signal. This is due to the capacitance of the analog probe which is usually in the range of 8..12pF and shifts the phase and PWD of the signal. In this case an active probe with a capacitance of less than 1pF is recommended.

• The reference test board which corresponds to the layout examples above is available at the

Oasis Silicon System AG.

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History of Design and Specification Status of MOST Transmitter:

SPF MIT3 02

Data Sheet Status

Bigfoot IC Revision

device marking

02-Dec-02 J Date code

MIT3 02

15-Jan-03 J date

code, MIT3 02

comments, cause of change, important differences to last Status

New release

p. 2: Update of Note 2 p. 3: Section Pulse Width Variation (t

Width Distortion (t

APWD

) added

) and Average Pulse

PWV

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Notes:

SPF MIT3 02

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