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LM3S6965 Microcontroller

Figure 23-14. I2C Timing

 

I2

I6

I5

 

 

I2CSCL

 

 

 

 

 

I1

I4

I7

I8

I3

I9

I2CSDA

 

 

 

 

 

23.2.10Ethernet Controller

Table 23-17. 100BASE-TX Transmitter Characteristicsa

Parameter Name

Min Nom

Max

Unit

Peak output amplitude

950

-

1050 mVpk

Output amplitude symmetry

98

-

102

%

Output overshoot

-

-

5

%

Rise/Fall time

3

-

5

ns

Rise/Fall time imbalance

-

-

500

ps

Duty cycle distortion

-

-

-

ps

Jitter

-

-

1.4

ns

a. Measured at the line side of the transformer.

Table 23-18. 100BASE-TX Transmitter Characteristics (informative)a

Parameter Name

Min Nom Max Unit

Return loss

16

-

-

dB

Open-circuit inductance

350

-

-

µH

a. The specifications in this table are included for information only. They are mainly a function of the external transformer and termination resistors used for measurements.

Table 23-19. 100BASE-TX Receiver Characteristics

Parameter Name

Min Nom

Max

Unit

Signal detect assertion threshold

600

700

-

mVppd

Signal detect de-assertion threshold

350

425

-

mVppd

Differential input resistance

-

20

-

kΩ

Jitter tolerance (pk-pk)

4

-

-

ns

Baseline wander tracking

-75

-

+75

%

Signal detect assertion time

-

-

1000

µs

Signal detect de-assertion time

-

-

4

µs

Table 23-20. 10BASE-T Transmitter Characteristicsa

Parameter Name

Min Nom Max Unit

Peak differential output signal

2.2

-

2.8

V

Harmonic content

27

-

-

dB

Link pulse width

-

100

-

ns

November 16, 2008

581

Preliminary

Electrical Characteristics

Parameter Name

Min Nom Max Unit

Start-of-idle pulse width

- 300

- ns

 

350

 

a. TheManchester-encodeddatapulses,thelinkpulseandthestart-of-idlepulsearetestedagainstthetemplatesandusing the procedures found in Clause 14 of IEEE 802.3.

Table 23-21. 10BASE-T Transmitter Characteristics (informative)a

Parameter Name

Min

Nom Max Unit

Output return loss

15

-

-

dB

Output impedance balance

29-17log(f/10)

-

-

dB

Peak common-mode output voltage

-

-

50

mV

Common-mode rejection

-

-

100

mV

Common-mode rejection jitter

-

-

1

ns

a. The specifications in this table are included for information only. They are mainly a function of the external transformer and termination resistors used for measurements.

Table 23-22. 10BASE-T Receiver Characteristics

Parameter Name

Min Nom Max

Unit

DLL phase acquisition time

-

10

-

BT

Jitter tolerance (pk-pk)

30

-

-

ns

Input squelched threshold

500

600

700

mVppd

Input unsquelched threshold 275

350

425

mVppd

Differential input resistance

-

20

-

kΩ

Bit error ratio

-

10-10

-

-

Common-mode rejection

25

-

-

V

Table 23-23. Isolation Transformersa

Name

Value

Condition

Turns ratio

1 CT : 1 CT

+/- 5%

Open-circuit inductance

350 uH (min)

@ 10 mV, 10 kHz

Leakage inductance

0.40 uH (max)

@ 1 MHz (min)

Inter-winding capacitance

25 pF (max)

 

DC resistance

0.9 Ohm (max)

 

Insertion loss

0.4 dB (typ)

0-65 MHz

HIPOT

1500

Vrms

a. Two simple 1:1 isolation transformers are required at the line interface. Transformers with integrated common-mode chokes are recommended for exceeding FCC requirements. This table gives the recommended line transformer characteristics.

Note: The 100Base-TX amplitude specifications assume a transformer loss of 0.4 dB. For the transmit line transformer with higher insertion losses, up to 1.2 dB of insertion loss can be compensatedbyselectingtheappropriatesettingintheTransmitAmplitudeSelection(TXO) bits in the MR19 register.

582

November 16, 2008

Preliminary

LM3S6965 Microcontroller

Table 23-24. Ethernet Reference Crystala

Name

Value

Condition

Frequency

25.00000

MHz

Frequency tolerance

±50

PPM

Aging

±2

PPM/yr

Temperature stability (-40° to 85°)

±5

PPM

Temperature stability (-40° to 105°)

±5

PPM

Oscillation mode

Parallel resonance, fundamental mode

 

Parameters at 25° C ±2° C; Drive level = 0.5 mW

 

 

Drive level (typ)

50-100

µW

Shunt capacitance (max)

10

pF

Motional capacitance (min)

10

fF

Serious resistance (max)

60

Spurious response (max)

> 5 dB below main within 500 kHz

 

a. If the internal crystal oscillator is used, select a crystal with the following characteristics.

Figure 23-15. External XTLP Oscillator Characteristics

Tr

 

 

 

 

 

 

 

 

Tf

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Tclkhi Tclklo

Tclkper

Table 23-25. External XTLP Oscillator Characteristics

Parameter Name

Symbol Min Nom Max Unit

XTLN Input Low Voltage

XTLNILV

-

-

0.8

-

XTLP Frequencya

XTLPf

-

25.0

-

-

XTLP Periodb

Tclkper

-

40

-

-

XTLP Duty Cycle

XTLPDC

40

-

60

%

 

 

 

 

 

 

 

40

 

60

 

Rise/Fall Time

Tr , Tf

-

-

4.0

ns

Absolute Jitter

 

-

-

0.1

ns

a.IEEE 802.3 frequency tolerance ±50 ppm.

b.IEEE 802.3 frequency tolerance ±50 ppm.

November 16, 2008

583

Preliminary

Electrical Characteristics

23.2.11Analog Comparator

Table 23-26. Analog Comparator Characteristics

Parameter

Parameter Name

Min Nom

Max

Unit

VOS

Input offset voltage

-

±10

±25

mV

VCM

Input common mode voltage range

0

-

VDD-1.5

V

CMRR

Common mode rejection ratio

50

-

-

dB

TRT

Response time

-

-

1

µs

TMC

Comparator mode change to Output Valid

-

-

10

µs

Table 23-27. Analog Comparator Voltage Reference Characteristics

Parameter

Parameter Name

Min

Nom

Max Unit

RHR

Resolution high range

-

VDD/32

-

LSB

RLR

Resolution low range

-

VDD/24

-

LSB

AHR

Absolute accuracy high range

-

-

±1/2

LSB

ALR

Absolute accuracy low range

-

-

±1/4

LSB

584

November 16, 2008

Preliminary

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