ISL6263CRZ Intersil, ISL6263CRZ Datasheet - Page 12

• Manufacturer Part Number: ISL6263CRZ
• Description: IC VREG CORE 5BIT 1PHASE 32-QFN
• Manufacturer: Intersil

Specifications of ISL6263CRZ

• Applications: Converter, Intel IMVP-6
• Voltage - Input: 5 ~ 25 V
• Number Of Outputs: 1
• Voltage - Output: 0.41 ~ 1.29 V
• Operating Temperature: -10°C ~ 100°C
• Mounting Type: Surface Mount
• Package / Case: 32-VQFN Exposed Pad, 32-HVQFN, 32-SQFN, 32-DHVQFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

frequency further improves efficiency by reducing switching
losses. The converter will automatically enter DEM after
eight consecutive PWM pulses where the PHASE pin has
detected positive voltage shortly after the LGATE pin has
gone high. The converter will return to CCM on the following
cycle after the PHASE pin detects negative voltage shortly
after the LGATE pin has gone high, indicating that the body
diode of the low-side MOSFET is conducting positive
inductor current. The converter inhibits the automatic 33%
change of V
Smooth mode transitions are facilitated by the R
which correctly maintains the internally synthesized ripple
current information throughout mode transitions.
Protection
The ISL6263 provides overcurrent protection (OCP),
overvoltage protection (OVP), and undervoltage protection
(UVP) as shown in Table 3.
Overcurrent protection is tied to the voltage droop, which is
determined by the resistors selected in the Static Droop
Design Using DCR Sensing section. After the load line is set,
the OCSET resistor can be selected. The OCP threshold
detector is checked every 15µs and will increment a counter
if the OCP threshold is exceeded, conversely the counter will
be decremented if the load current is below the OCP
threshold. The counter will latch an OCP fault when the
counter reaches eight. The fastest OCP response for
overcurrent events occurring above the OCP threshold but
below twice the OCP threshold is 120µs, which is eight
counts at 15µs each. The ISL6263 will latch an OCP fault
within 2µs for an overcurrent exceeding twice the OCP
threshold to maximize protection against hard shorts. The
value of R
For example: The desired overcurrent trip level, I
R
Undervoltage protection is independent of the overcurrent
protection. If the output voltage measured on the VO pin is
less than +300mV below the voltage on the SOFT pin for
longer than 1ms, the controller will latch a UVP fault. If the
output voltage measured on the VO pin is greater than
+200mV above the voltage on the SOFT pin for longer than
1ms, the controller will latch an OVP fault. Keep in mind that
V
states only after the soft-start capacitor C
the VID DAC output voltage. The UVP and OVP detection
circuits act on static and dynamic V
When an OCP, OVP, or UVP fault has been latched, PGOOD
becomes a low impedance and the gate driver outputs
UGATE and LGATE are pulled low. The energy stored in the
inductor is dissipated as current flows through the low-side
R
droop
SOFT
OCSET
load-line is 8mΩ, Equation 1 gives R
will equal the voltage level commanded by the VID
=
OCSET
I
--------------------------------- -
OC
W
whenever the audio filter is enabled.
10μA
⋅
R
is calculated as Equation 1:
droop
12
SOFT
SOFT
voltage.
OCSET
has slewed to
3
oc
modulator
, is 30A,
= 24kΩ.
(EQ. 1)
ISL6263
MOSFET body diode. The controller will remain latched in
the fault state until the VR_ON pin has been pulled below the
falling VR_ON threshold voltage V
gone below the falling POR threshold voltage
A severe-overvoltage protection fault occurs immediately
after the voltage between the VO and VSS pins exceed the
rising severe-overvoltage threshold V
the same reference voltage used by the VID DAC. The
ISL6263 will latch UGATE and PGOOD low but unlike other
protective faults, LGATE remains high until the voltage
between VO and VSS falls below approximately 0.77V, at
which time LGATE is pulled low. The LGATE pin will continue
to switch high and low at 1.545V and 0.77V until VDD has
gone below the falling POR threshold voltage
This provides maximum protection against a shorted high-
side MOSFET while preventing the output voltage from
ringing below ground. The severe-overvoltage fault circuit
can be triggered after another fault has already been
latched.
Gate-Driver Outputs LGATE and UGATE
The ISL6263 has internal high-side and low-side N-Channel
MOSFET gate-drivers. The LGATE driver is optimized for
low duty-cycle applications where the low-side MOSFET
conduction losses are dominant. The LGATE pull-down
resistance is very low in order to clamp the gate-source
voltage of the MOSFET below the V
current transient through the low-side gate at turnoff can be
considerable due to the characteristic large switching charge
of a low r
Overcurrent
Short Circuit
Overvoltage
(+200mV)
between VO pin
and SOFT pin
Severe
Overvoltage
(+1.55V)
between VO pin
and VSS pin
Undervoltage
(-300mV)
between VO pin
and SOFT pin
FAULT TYPE
TABLE 3. FAULT PROTECTION SUMMARY OF ISL6263
DS(on)
PROTECTION
MOSFET.
Immediately UGATE, and
DURATION
PRIOR TO
FAULT
120µs
<2µs
1ms
1ms
LGATE, UGATE, and
PGOOD latched low
LGATE, UGATE, and
PGOOD latched low
LGATE, UGATE, and
PGOOD latched low
PGOOD latched low,
LGATE toggles ON
when VO>1.55V
OFF when
VO <0.77V
until fault reset
LGATE, UGATE, and
PGOOD latched low
PROTECTION
VR_ONL
ACTIONS
GS(th)
OVPS
at turnoff. The
or until VDD has
which is 1.545V,
V
V
VDD_THF
VDD_THF.
June 10, 2010
Cycle
VR_ON or
VDD
Cycle
VR_ON or
VDD
Cycle
VR_ON or
VDD
Cycle
VDD only
Cycle
VR_ON or
VDD
RESET
FAULT
FN9213.2
.