LM3S8971 Datasheet, PDF (542/577 Pages) List of Unclassifed Manufacturers – Microcontroller

Electrical Characteristics
Name
Value
Condition
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
compensated by selecting the appropriate setting in the Transmit Amplitude Selection (TXO)
bits in the MR19 register.
Table 23-19. Ethernet Reference Crystal^a
Name
Value
Condition
Frequency
Load capacitance^b
25.00000
4^c
MHz
pF
Frequency tolerance
±50
PPM
Aging
±2
PPM/yr
Temperature stability (0° to 70°)
±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
Ω
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.
b. Equivalent differential capacitance across XTLP/XTLN.
c. If crystal with a larger load is used, external shunt capacitors to ground should be added to make up the equivalent
capacitance difference.
Figure 23-2. External XTLP Oscillator Characteristics
T_r
T_f
T_clkhi
T_clkper
T_clklo
542
October 01, 2007
Preliminary