HIP6302EVAL1 Intersil, HIP6302EVAL1 Datasheet - Page 2

• Manufacturer Part Number: HIP6302EVAL1
• Description: EVALUATION BOARD HIP6302
• Manufacturer: Intersil

Specifications of HIP6302EVAL1

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 1.7V
• Current - Output: 35A
• Voltage - Input: 5V, 12V
• Regulator Topology: Buck
• Board Type: Fully Populated
• Utilized Ic / Part: HIP6302
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -
• Frequency - Switching: -

The HIP6302EVAL1 evaluation board incorporates a
reference design intended to meet the core-voltage
requirements for AMD Athlon microprocessors up to 35A.
Additional circuitry is provided to facilitate circuit evaluation
including input and output power connectors, VID jumpers,
numerous probe points, an LED power-good indicator, and a
load-transient generator.
Powering the HIP6302EVAL1
For convenience, the HIP6302EVAL1 provides two methods
of making input power connections. The 20-pin header, J1,
interfaces with a standard ATX power supply and may be the
most convenient method of powering the board.
J2, J3, and J4 are standard banana-jack connectors that can
be used to supply power using bench-top power supplies.
These inputs provide greater versatility in testing and design
validation by allowing the 12V and 5V power-input voltage
levels to be varied independently. In this way power-on level
and power-sequencing issues can be easily examined.
To start the evaluation board, insert the 20-pin connector
from an ATX supply into J1. If using bench-top supplies,
connect a 12V supply to J2 and a 5V supply to J3. Connect
the grounds from both supplies to J4.
Important
There are two things to consider when using bench-top
supplies. If the 5V supply is applied prior to the 12V supply,
the HIP6302 will begin operating before the HIP6601As. This
allows the HIP6302 to complete its soft-start cycle before the
drivers are capable of switching power to the output. When
the 12V power input is then applied, there is a large transient
as the controller tries to instantly bring the output to its full-
voltage level. This can result in an overcurrent protection
cycle and an abnormal start-up waveform. It can be avoided
by applying 5V supply after or at the same time as the 12V
supply or by using an ATX power supply.
The second problem can occur when operating the transient
load generator. Not all bench-top and ATX power supplies
are capable of responding to load transients, and they may
allow a momentary voltage dip on VCC5. This can activate
the power-on-reset function in the HIP6302 and cause the
output power to cycle. It can be remedied by connecting a
5600 µ F or larger capacitor between VCC5 and ground. The
capacitor, if necessary, simulates the distributed capacitance
that exists on the computer motherboard.
2
Application Note AN9888
Start Up
The waveforms in Figure 3 demonstrate the normal start-up
sequence with the HIP6302EVAL1 connected to a 55m Ω
load. After FS/EN is released, VCORE exhibits a linear ramp
until reaching its 1.7V set point. The gradual increase of
VCORE over approximately 5ms limits the current required
from the input supply, ICC5, to a level that does not strain the
supply. The HIP6302 asserts PGOOD once VCORE is within
regulation limits.
Transient Response
The HIP6302EVAL1 is equipped with a load-transient
generator that applies a 0–36A transient load current with
rise and fall rates of approximately 35A/ µs. The duration of
the transient is between 100 µs and 200 µs, and the repetition
rate is kept low in order to limit power dissipation in the load
MOSFETs and resistors. Removal of the HI/LO jumper (JP2)
causes the current to decrease from about 36A to about
31A. The load-transient generator operates when the
HIP6302EVAL1 is properly connected to a 12V power
source and SW1 is in the ON position. Operation ceases
when SW1 is moved into the OFF position or 12V is
removed from the board.
The HIP6302EVAL1 achieves the specified transient
performance while maintaining a favorable balance between
low cost, high efficiency and small profile. When the duty
cycle changes rapidly in response to a transient load current,
the inductor current immediately begins to change in order to
meet the demand. During the time the inductor current is
increasing, the output-filter capacitors are supplying the
load. It follows that the amount of required capacitance
decreases as the capability of the inductors to rapidly
assume the load current increases.
0A
0V
0V
0V
FIGURE 3. HIP6302EVAL1 START-UP WAVEFORMS
Athlon™ is a trademark of Advanced Micro Devices, Inc.
FS/EN, 5V/DIV
1ms/DIV
PGOOD, 5V/DIV
ICC5, 10A/DIV
VCORE, 1V/DIV