CAUTION: Stress above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational section of this specification is not implied.
NOTE:
1.
θ
JA
is measured with the component mounted on a high effective thermal conductivity test board in free air. (See Tech Brief TB379 for details.)
Electrical Specifications
Parameter
INPUT SUPPLY POWER
Input Supply Current
Operating Conditions: V
CC
= 5V, T
A
= 0
o
C to 70
o
C, Unless Otherwise Specified
Test Conditions
Min
Typ
Max
Units
RT = 100k
Ω
, EN = 5V
RT = 100k
Ω
, EN = 0V
5
4.25
3.75
1.206
1.106
60
EN = 3V
10.5
9.2
4.38
3.86
1.230
1.15
15
mA
mA
Power-On Reset Threshold
VCC Rising
VCC Falling
4.5
4.0
1.254
1.194
100
50
V
V
V
V
mV
nA
Enable Threshold
EN Rising
EN Falling
Enable Hysteresis
Enable Current
SYSTEM ACCURACY
System Accuracy ISL6557
VID Pull Up
VID Input Low Level
VID Input High Level (Note 3)
OSCILLATOR
Accuracy
Frequency
Adjustment Range
Sawtooth Amplitude
Duty-Cycle Range
ERROR AMPLIFIER
Open-Loop Gain
Open-Loop Bandwidth
Slew Rate
Maximum Output Voltage
REMOTE-SENSE AMPLIFIER
Input Impedance
Slew Rate
Bandwidth
RL = 10k
Ω
to ground
CL=100pF, RL = 10k
Ω
to ground
CL=100pF, RL = 10k
Ω
to ground
RL = 10k
Ω
to ground
RT = 110k
Ω
(±1%)
(Note 2)
-0.8
-40
-20
0.8
-10
0.8
%VID
µ
A
V
V
2.0
-20
250
80
1.33
0
20
%
kHz
1500
kHz
V
75
%
72
18
5
3.6
4.1
dB
MHz
V/
µs
V
80
6
10
k
Ω
V/
µs
MHz
4
ISL6557
Electrical Specifications
Parameter
ISEN
Overcurrent Trip Level
PROTECTION and MONITOR
Overvoltage Threshold
VSEN Rising
VSEN Falling
Undervoltage Threshold
VSEN Rising
VSEN Falling
PGOOD Low Voltage
NOTES:
2. These parts are designed and adjusted for accuracy within the system tolerance given in the Electrical Specifications. The system tolerance
accounts for offsets in the differential and error amplifiers; reference-voltage inaccuracies; temperature drift; and the full DAC adjustment range.
3. VID input levels above 2.9V may produce an reference-voltage offset inaccuracy.
IPGOOD = 4mA
0.810
0.835
0.18
2.04
2.09
VID
0.990
0.925
0.4
2.13
V
V
V
V
mV
-90
-75
-60
µ
A
Operating Conditions: V
CC
= 5V, T
A
= 0
o
C to 70
o
C, Unless Otherwise Specified
(Continued)
Test Conditions
Min
Typ
Max
Units
Functional Pin Descriptions
VID4 1
VID3 2
VID2 3
VID1 4
VID0 5
COMP 6
FB 7
IOUT 8
VDIFF 9
VSEN 10
RGND 11
GND 12
24 VCC
23 EN
22 FS
21 PGOOD
20 PWM4
19 ISEN4
18 ISEN1
17 PWM1
16 PWM2
15 ISEN2
14 ISEN3
13 PWM3
input to the external regulation circuitry and the internal
protection circuitry. Connect VSEN and RGND to the sense
pins of the remote load.
GND (Pin 12)
Return for VCC and signal ground for the IC.
PWM3, PWM2, PWM1, PWM4 (Pins 13, 16, 17, 20)
Pulse-width modulation outputs. These logic outputs tell the
driver IC(s) when to turn the MOSFETs on and off.
ISEN3, ISEN2, ISEN1, ISEN4 (PINS 14, 15, 18, 19)
Current sense inputs. A resistor connected between these
pins and the respective phase nodes has a current
proportional to the current in the lower MOSFET during its
conduction interval. The current is used as a reference for
channel balancing, load sharing, protection, and load-line
regulation.
VID4, VID3, VID2, VID1, VID0 (Pins 1, 2, 3, 4, 5)
These are the inputs to the internal DAC that provides the
reference voltage for output regulation. Connect these pins
to either open-drain or active-pull-up type outputs. Pulling
these pins above 2.9V can cause a reference offset
inaccuracy.
PGOOD (Pin 21)
PGOOD is an open-drain logic output that changes to a logic
low when the differential output voltage at VDIFF swings
below 0.9V or above 2.1V.
FB (Pin 7) and COMP (Pin 6)
The internal error amplifier’s inverting input and output
respectively. These pins are connected to an external R-C
network to compensate the regulator.
FS (Pin 22)
This pin has two functions. A resistor placed from FS to
ground sets the switching frequency. There is an inverse
relationship between the value of the resistor and the
switching frequency. This pin can also be used to disable the
controller. To disable the controller, pull this pin below 1V.
IOUT (Pin 8)
The current out of this pin is proportional to output current
and is used for load-line regulation and load sharing. The
scale factor is set by the ratio of the ISEN resistors
(connected to pins 14, 15, 18, and 19) to the lower
MOSFET
r
DS(ON)
.
EN (Pin 23)
This is the threshold-sensitive enable input for the controller.
To enable the controller, pull this pin above 1.23V.
VDIFF (Pin 9), VSEN (Pin 10), RGND (Pin 11)
VSEN and RGND are the inputs to the differential remote-
sense amplifier. VDIFF is the output and it serves as the
5
VCC (Pin 24)
Bias supply voltage for the controller. Connect this pin to a
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