ISL6310EVAL1Z Intersil, ISL6310EVAL1Z Datasheet - Page 4

• Manufacturer Part Number: ISL6310EVAL1Z
• Description: EVALUATION BOARD FOR ISL6310
• Manufacturer: Intersil

Specifications of ISL6310EVAL1Z

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 1.5V
• Current - Output: 60A
• Voltage - Input: 5 ~ 12V
• Regulator Topology: Buck
• Frequency - Switching: 400kHz
• Board Type: Fully Populated
• Utilized Ic / Part: ISL6310
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -

an inductor DCR sensing R-C network. This network, shown
in Figure 4, is designed not only to precisely control the load
line of the regulator, but also to thermally compensate for
any changes in DCR that may skew the load line as a result
of increases in temperature.
This sensing technique works off the principle that if the R-C
time constant of C7*R
L/DCR time constant of the inductor, the load line impedance
will be equal to R
If the load line impedance needs to be changed, all that is
required is adjusting the values of R15-R16 as explained on
page 20 of the ISL6310 data sheet. If the Inductor is
changed though, the resistance of time constant matching
network will need to be changed. The NTC resistor network
must first be adjusted so that the new L/DCR time constant
is precisely matched. Refer to page 19 and 20 of the
ISL6310 data sheet to design the entire R-C sense network
An Optional NTC resistor network consisting of 3 resistors
(R9, R10, and R14) and a single NTC thermistor (R12),
which is placed close the output inductors. This network is
designed to compensate for any change in DCR that occurs
due to temperature when the Droop option is used and a
tight load-line regulation is required, and keep the time
constant of the R-C network equal to that of the inductor
L/DCR time constant.
ISL6310
FIGURE 4. DCR SENSING CONFIGURATION WITH
PHASE1
PHASE2
ICOMP
ISUM
IREF
OPTITIONAL FOOTPRINTS FOR NTC LOAD-LINE
COMPENSATION
OPTIONAL NTC RESISTOR NETWORK
COMP
R16
10nF
C7
COMP
*DCR/R15 (R15 and R16 are equal).
R15
R14
(R
4
R
COMP
COMP
R10
0Ω
DNP
R12
= R14) is equal to the
L3
L2
DNP
* R15, R16 ARE EQUAL
R9
Application Note 1197
I
OUT
V
OUT
Overcurrent Protection Level
The ISL6310 utilizes a single resistor to set the maximum
current level for the IC’s overcurrent protection circuitry.
Please refer to page 17 of the ISL6310 data sheet, and
adjust resistor R11 accordingly to set the desired overcurrent
trip level.
Output Voltage Offset
The ISL6310 allows a designer to accurately offset the
output voltage both negatively and positively. All that is
required is a single resistor between the OFS and VCC pins,
or the OFS pin and GND. The ISL6310EVAL1Z has both of
these resistor options available on the board. To positively
offset the output voltage populate resistor R5. To negatively
offset the output voltage populate resistor R7. Please refer to
page 13 of the ISL6310 decathlete to accurately calculate
these resistor values.
Switching Frequency
The switching frequency of the ISL6310EVAL1Z board is set
to an optimal value of 400kHz giving the best efficiency and
performance for the given design with R13 = 60.4kΩ.
However, the switching frequency can be adjusted anywhere
from 80kHz to 1.5MHz per phase. In practice many factors
affect the choice of switching frequency among which are
efficiency, and gate drive losses (which depend on the
MOSFET choice and Gate Driver Voltage). Since the
ISL6310 has integrated MOSFET drivers, the driver losses
must be taken into account when the switching frequency is
chosen. To change the switching frequency refer to page 24
of the ISL6310 data sheet and adjust the value of frequency
set resistor, R13, accordingly.
MOSFET Gate Drive Voltage (PVCC)
The gate drive bias voltage of the integrated drivers in the
ISL6310 can be any voltage between +5V and +12V. This
bias voltage is set by connecting the desired voltage to the
PVCC pins of the IC. Please refer to page 2 to set the
desired gate drive voltage.
Number of Active Phases
The ISL6310 has the option of 1 or 2-phase operation. The
ISL6310EVAL1Z is designed to change the number of active
phases by simply populating or depopulating one or two
resistors, R26 and R29. Refer to Table 4 for which resistors
to populate for 1 or 2-phase operation.
TABLE 4. SETTINGS FOR NUMBER OF ACTIVE PHASES
# OF ACTIVE PHASES
2
1
OPEN
R26
0Ω
December 12, 2006
OPEN
R29
0Ω
AN1197.1