82573 Datasheet, PDF (19/39 Pages) Intel Corporation – GbE Controllers

Datasheet—82573
Table 5.
3.3.2
3.3.2.1
1.2V External Supply Voltage Ramp and Sequencing Recommendations
Parameter
Description
Rise Time
Monotonicity
Slope
Operational Range
Operational Range
Ripple
Undershoot
Overshoot
Output
Capacitance
Input Capacitance
Capacitance ESR
I_CTRL
Rise time from 10% to 90%
Voltage dip allowed in ramp
Ramp rate at any time between 10% to 90%
Minimum = (0.8 * Vmin) / (Maximum Rise Time)
Maximum = (0.8 * Vmax) / (Minimum Rise Time)
Voltage range for normal operating conditions
Voltage range for normal operating conditions
Maximum voltage ripple at a bandwidth of 50 MHz
Maximum voltage allowed will not exceed 10% of
nominal supply
Maximum voltage allowed²
Capacitance range when using a PNP circuit
Capacitance range when using a PNP circuit
Equivalent series resistance of output capacitance³
Maximum output current rating with respect to
CTRL_12
Min
1.5¹
1.14
-5
Max
120
Unit
ms
mV
1500
mV/ms
1.26
+5
60
V
%
mV_pk-pk
500
mV
4.7
25
µF
4.7
µF
10
mΩ
20
mA
1. Good design practices achieve voltage ramps to within the regulation bands in approximately 20 ms or less.
2. Excessive overshoot can affect long term reliability.
3. Tantalum capacitors must not be used.
Power Sequencing with External Regulators
The following power-on and power-off sequence should be applied when external power
supplies are in use. Designs must comply with the required power sequence to avoid
risk of either latch-up or forward biased internal diodes.
Generally, the 82573 power sequencing should power up the three power rails in the
following order: 3.3V Æ 2.5V Æ 1.2V. However, if this general guideline is not followed,
there are specific requirements that must be adhered to. These requirements are listed
in the following two subsections.
External LVR Power Up Sequencing and Tracking
Sequencing of the external supplies during power up might be necessary to ensure that
the 82573 is not electrically overstressed and does not latch-up. These requirements
are shown in Figure 2.
The 82573 core voltage (1.2V) cannot exceed the 3.3V supply by more than 0.5 V at
any time during the power up. The 82573 core voltage (1.2V) cannot exceed the 2.5V
supply by more than 0.5 V at any time during the power up. The core voltage is not
required to begin ramping before the 3.3V or the 2.5V supply.
The 82573 analog voltage (2.5V) can not exceed the 3.3V supply by more than 0.5 V at
any time during the power up. The analog voltage is not required to begin ramping
before the 3.3V supply.
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