ISL62883IRTZ Intersil, ISL62883IRTZ Datasheet - Page 18

• Manufacturer Part Number: ISL62883IRTZ
• Description: IC REG PWM 3PHASE BUCK 40TQFN
• Manufacturer: Intersil

Specifications of ISL62883IRTZ

• Applications: Controller, Intel IMVP-6.5™
• Voltage - Input: 5 V ~ 21 V
• Number Of Outputs: 1
• Voltage - Output: 0.0125 V ~ 1.5 V
• Operating Temperature: -40°C ~ 100°C
• Mounting Type: *
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

When the ISL62883 is in DE mode, it will actively drive
the output voltage up when the VID changes to a higher
value. It’ll resume DE mode operation after reaching the
new voltage level. If the load is light enough to warrant
DCM, it will enter DCM after the inductor current has
crossed zero for four consecutive cycles. The ISL62883
will remain in DE mode when the VID changes to a lower
value. The output voltage will decay to the new value and
the load will determine the slew rate.
During load insertion response, the Fast Clock function
increases the PWM pulse response speed. The ISL62883
monitors the VSEN pin voltage and compares it to
100ns - filtered version. When the unfiltered version is
20mV below the filtered version, the controller knows
there is a fast voltage dip due to load insertion, hence
issues an additional master clock signal to deliver a PWM
pulse immediately.
The R
forward. The output voltage is insensitive to a fast slew
rate input voltage change.
Protections
The ISL62883 provides overcurrent, current-balance,
undervoltage, overvoltage, and over-temperature
protections.
The ISL62883 determines overcurrent protection (OCP)
by comparing the average value of the droop current
I
declares OCP when I
120µs. A resistor R
programs the OCP current source threshold, as Table 3
shows. It is recommended to use the nominal R
value. The ISL62883 detects the R
beginning of start up, and sets the internal OCP
threshold accordingly. It remembers the R
until the VR_ON signal drops below the POR threshold.
The default OCP threshold is the value when R
not populated. It is recommended to scale the droop
current I
approximately the desired OCP level, then use R
fine tune the OCP level if necessary.
droop
MIN.
(kΩ)
320
210
155
104
78
62
45
3
with an internal current source threshold. It
™ modulator intrinsically has voltage feed
NOMINA
droop
TABLE 3. ISL62883 OCP THRESHOLD
R
L (kΩ)
none
comp
400
235
165
120
85
66
50
such that the default OCP threshold gives
MAX.
comp
(kΩ)
none
480
260
175
136
92
70
55
droop
from the COMP pin to GND
18
1-PHASE
is above the threshold for
MODE
22.7
20.7
22.7
20.7
20
18
20
18
OCP THRESHOLD (µA)
comp
2-PHASE
MODE
37.33
45.3
41.3
38.7
42.7
40
36
44
value at the
ISL62883, ISL62883B
comp
comp
3-PHASE
comp
value
MODE
comp
60
68
62
54
56
58
64
66
is
to
For overcurrent conditions above 2.5 times the OCP
level, the PWM outputs will immediately shut off and
PGOOD will go low to maximize protection. This
protection is also referred to as way-overcurrent
protection or fast-overcurrent protection, for short-circuit
protections.
The ISL62883 monitors the ISEN pin voltages to
determine current-balance protection. If the ISEN pin
voltage difference is greater than 9mV for 1ms, the
controller will declare a fault and latch off.
The ISL62883 will declare undervoltage (UV) fault and
latch off if the output voltage is less than the VID set
value by 300mV or more for 1ms. It’ll turn off the PWM
outputs and dessert PGOOD.
The ISL62883 has two levels of overvoltage protections.
The first level of overvoltage protection is referred to as
PGOOD overvoltage protection. If the output voltage
exceeds the VID set value by +200mV for 1ms, the
ISL62883 will declare a fault and dessert PGOOD.
The ISL62883 takes the same actions for all of the above
fault protections: desertion of PGOOD and turn-off of the
high-side and low-side power MOSFETs. Any residual
inductor current will decay through the MOSFET body
diodes. These fault conditions can be reset by bringing
VR_ON low or by bringing V
When VR_ON and V
levels, a soft-start will occur.
The second level of overvoltage protection is different. If
the output voltage exceeds 1.55V, the ISL62883 will
immediately declare an OV fault, dessert PGOOD, and
turn on the low-side power MOSFETs. The low-side power
MOSFETs remain on until the output voltage is pulled
down below 0.85V when all power MOSFETs are turned
off. If the output voltage rises above 1.55V again, the
protection process is repeated. This behavior provides
the maximum amount of protection against shorted
high-side power MOSFETs while preventing output
ringing below ground. Resetting VR_ON cannot clear the
1.55V OVP. Only resetting V
OVP is active all the time when the controller is enabled,
even if one of the other faults have been declared. This
ensures that the processor is protected against high-side
power MOSFET leakage while the MOSFETs are
commanded off.
The ISL62883 has a thermal throttling feature. If the
voltage on the NTC pin goes below the 1.18V OT
threshold, the VR_TT# pin is pulled low indicating the
need for thermal throttling to the system. No other
action is taken within the ISL62883 in response to NTC
pin voltage.
Table 4 summarizes the fault protections.
DD
return to their high operating
DD
DD
below the POR threshold.
will clear it. The 1.55V
FN6891.3