DP83848HSQ National Semiconductor, DP83848HSQ Datasheet - Page 33

• Manufacturer Part Number: DP83848HSQ
• Description: IC, TRANSCEIVER, ENET PHYTER, 40LLP
• Manufacturer: National Semiconductor

Specifications of DP83848HSQ

• Data Rate: 100Mbps
• No. Of Ports: 1
• Ethernet Type: IEEE 802.3u
• Supply Current: 92mA
• Supply Voltage Range: 3V To 3.6V
• Operating Temperature Range: -40°C To +125°C
• Digital Ic Case Style: LLP
• No. Of: RoHS Compliant
• Interface Type: MII Serial, RMII
• Rohs Compliant: Yes

1. This limit is provided as a guideline for component selection and not guaranteed by production testing. Refer to
AN-1548, “PHYTER 100 Base-TX Reference Clock Jitter Tolerance,” for details on jitter performance.
5.2 ESD Protection
Typically, ESD precautions are predominantly in effect
when handling the devices or board before being installed
in a system. In those cases, strict handling procedures
need be implemented during the manufacturing process
to greatly reduce the occurrences of catastrophic ESD
events. After the system is assembled, internal compo-
nents are less sensitive from ESD events.
See Section 8.0 for ESD rating.
5.3 Clock In (X1) Recommendations
The DP83848H supports an external CMOS level oscilla-
tor source or a crystal resonator device.
Oscillator
If an external clock source is used, X1 should be tied to
the clock source and X2 should be left floating.
The CMOS oscillator specifications for MII Mode are listed
in Table 7. 25 MHz Oscillator Specification. For RMII
Mode, the CMOS oscillator specifications are listed in
Table 8. 50 MHz Oscillator Specification. For RMII mode,
it is not recommended that the system clock out, Pin 21,
be used as the reference clock to the MAC without first
verifying the interface timing. See AN-1405 for more
details.
Crystal
A 25 MHz, parallel, 20 pF load crystal resonator should be
used if a crystal source is desired. Figure 12 shows a typi-
cal connection for a crystal resonator circuit. The load
Rise / Fall Time
Parameter
Frequency
Frequency
Frequency
Tolerance
Symmetry
Stability
Jitter
Jitter
40%
Min
Table 7. 25 MHz Oscillator Specification
Typ
50
33
capacitor values will vary with the crystal vendors; check
with the vendor for the recommended loads.
The oscillator circuit is designed to drive a parallel reso-
nance AT cut crystal with a minimum drive level of 100 W
and a maximum of 500 W. If a crystal is specified for a
lower drive level, a current limiting resistor should be
placed in series between X2 and the crystal.
As a starting point for evaluating an oscillator circuit, if the
requirements for the crystal are not known, C
should be set at 33 pF, and R
Specification for 25 MHz crystal are listed in Table 8.
800
800
60%
Max
+50
+50
Figure 12. Crystal Oscillator Circuit
6
C
L1
1
1
X1
Units
nsec
psec
psec
MHz
ppm
ppm
1
should be set at 0
X2
Operational Tem-
www.national.com
1 year aging
R
C
20% - 80%
Duty Cycle
Condition
Short term
Long term
1
perature
L2
L1
and C
L2