VRM 9.0 DC-DC Converter Design Guidelines

Minimum Vtrip should be the nominal (maximum) Vout

VRM

specified in Table 1

plus 55mV to compensate for remote sense

plus margin to prevent false trips.

Maximum Vtrip should be the maximum, non-operating voltage, V

MAX

, specified in Table 1.

No combination of input voltage sequences should falsely trigger an OVP event.

1.9.2 Fuse Protection for Power Input PROPOSED

The power input (12V) should be protected with a fuse rated not greater than 30A, which sustains

all operating and inrush conditions and which “blows” only on catastrophic failure of the

converter.

1.9.3 Overload Protection EXPECTED

The VRM should be capable of withstanding a continuous, abnormally low resistance on the

output without damage or over-stress to the unit. Output current under this condition will be

limited to no more than 150% of the maximum rated output of the VRM. Latching off or hiccup

mode is acceptable during over-current conditions. The VRM should be capable of starting into

a constant current load of 50% of maximum rated load current with maximum load capacitance,

as defined in Section 1.1.6, without tripping the OCP circuitry. For multiple-processor systems,

errors in current sharing (see Section 1.1.7) during startup should not cause OCP circuits to shut

down the converter.

1.9.4 Reset After Shutdown PROPOSED

If the VRM goes into a shutdown state due to a fault condition on its output (not an internal

failure) it should return to normal operation after the fault has been removed, or after the fault

has been removed and power has been cycled off and on.

2 Module Layout Guidelines

2.1 VRM Connector EXPECTED

The VRM interface with the system board is a 0.100” pitch, 62-pin edge connector, with an

overall 3.95” length: Tyco* 1364125-1 or equivalent. The connector uses a retention clip to hold

the VRM in place. The connector contacts have a maximum rated temperature of 90°C, based on

4-oz. copper lands on the VRM PCB and 19 pin pairs carrying 3.6A each. (Intel does not endorse

the third party products featured and/or mentioned in this document.)

Table 3 shows the VRM pin-out definitions.