Supply Voltage Range (Typical). . . . . . . . . . . . . . . . . . 2.7V to 5.5V
CAUTION: Stresses 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 sections of this specification is not implied.
NOTES:
1.
JA
is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
2. All voltages are relative to GND, unless otherwise specified.
Electrical Specifications
PARAMETER
POWER SWITCH
ISL6118 On Resistance at 2.7V
Supply Voltages = 3.3V, T
A
= T
J
= -40 to 85°C, Unless Otherwise Specified
SYMBOL
TEST CONDITIONS
MIN
TYP
MAX
UNITS
r
DS(ON)_27
VIN = 2.7V, I
OUT
= 0.4A, T
A
= T
J
= 25°C
T
A
= T
J
= 85°C
-
-
-
-
-
-
-
-
-
-
90
115
80
115
80
115
300
8
8
4
105
130
100
130
95
130
450
-
-
-
m
m
m
m
m
m
mV
V/ms
V/ms
V/s
ISL6118 On Resistance at 3.3V
r
DS(ON)_33
VIN = 3.3V, I
OUT
= 0.4A, T
A
= T
J
= 25°C
T
A
= T
J
= 85°C
ISL6118 On Resistance at 5.0V
r
DS(ON)_50
VIN = 5V, I
OUT
= 0.4A, T
A
= T
J
= 25°C
T
A
= T
J
= 85°C
Disabled Output Voltage
OUT Rising Rate
Slow V
OUT
Turn-off Rate
Fast V
OUT
Turn-off Rate
CURRENT CONTROL
Current Limit, VIN = 3.3V - 5V
OC Regulation Settling Time
Severe OC Regulation Settling Time
Overcurrent Latch-off Time
I/O PARAMETERS
Fault Output Voltage
ENABLE High Threshold
ENABLE Low Threshold at 2.7V
ENABLE Low Threshold at 5.5V
ENABLE Input Current
BIAS PARAMETERS
Enabled VIN Current
Disabled VIN Current
Undervoltage Lockout Threshold
UV Hysteresis
Over Temperature Disable
V
OUT_DIS
t_vout_rt
t_svout_offt
t_fvout_offt
VIN = 5V, Switch Disabled, 50A Load
R
L
= 10C
L
= 0.1F, 10%-90%
R
L
= 10C
L
= 0.1F, 90%-10%
R
L
= 1C
L
= 0.1F, 90%-10%
Ilim
tsett
Ilim
tsett
Ilim_sev
t
OC_loff
V
OUT
= 0.8V
R
L
= 3C
L
= 0.1F to within 10% of CR
R
L
< 1C
L
= 0.1F to within 10% of CR
ISL6118X, T
J
= 25°C
0.45
-
-
-
0.6
2
100
12
0.75
-
-
-
A
ms
s
ms
V
FAULT
Ven_vih
Ven_vil
Ven_vil
Ien_i
Fault Output Current = 10mA
VIN = 5.5V
VIN = 2.7V
VIN = 5.5V
ENABLE = 0V to 5V, VIN = 5V, T
J
> 25°C
-
2.0
-
-
-0.5
-
-
-
-
0
0.4
-
0.6
0.8
0.5
V
V
V
V
A
I
VDD
I
VDD
V
UVLH
UV
HYS
Temp_dis
Switches Closed, OUTPUT = OPEN, T
J
> 0°C
Switches Open, OUTPUT = OPEN
VIN Rising, Switch Enabled
-
-
1.7
50
-
120
1
2.25
100
150
200
5
2.5
-
-
A
A
V
mV
°C
FN9008 Rev 2.00
March 2004
Page 3 of 10
ISL6118
Introduction
The ISL6118 is a fully independent dual channel overcurrent
(OC) fault protection IC for the +2.5V to +5.5V environment.
Each ISL6118 incorporates in a single 8-lead SOIC package two
80mW N-channel MOSFET power switches for power control.
See Figure 2 for integrated FET on resistance curves.
Independent enabling inputs and fault reporting outputs
compatible with 3V and 5V logic allow for external control and
monitoring. This device features internal current monitoring,
accurate current limiting, integrated power switches and current
limited timed delay to latch-off for system protection.
switch’s electrical condition. See Figure 10 for waveforms
illustrating independent latch-off.
If, after the ISL6118 has latched off, and the fault has asserted
and the enable is not deasserted but the OC condition still
exists, the ISL6118 (unlike other IC devices) does not send to
the controller a continuous string of fault pulses. The ISL6118’s
single fault signal is sent at the time of latch off.
Slow and Fast Shutdown
The ISL6118 has two shutdown modes. When disabled with a
load current less than the current regulation (CR) level the
ISL6118 shuts down in a controlled manner using a 500nA
constant current source controlled ramp. When disabled during
CR or if the timer has expired the ISL6118 quickly pulls down
the output thereby quickly removing the faulted load from the
voltage bus. See Figures 8 and 9 for illustrative waveforms of
each shutdown mode.
Key Feature Description and Operation
UV Lockout
The ISL6118 undervoltage (UVLO) lockout prevents
functionality of the device unless the correct ENABLE state
and VIN > 2.5V are present.
Over Temperature Shutdown
Although the ISL6118 has a thermal shutdown feature,
because of the 12ms timed shutdown this will only be invoked
in extremely high ambient temperatures.
Soft Start
A constant 500nA current source ramps up the switch’s gate
causing a voltage follower effect on the output voltage. This
provides a soft start turn-on and eliminates bus voltage
drooping caused by inrush current charging heavy load
capacitances. Rising and falling outputs are current limited
voltage ramps so that both the inrush current and voltage slew
rate are limited, independent of load. This reduces supply
droop due to surge and also eliminates the need for external
EMI filters necessary on other IC products. See Figure 3 for
soft start waveforms.
Active Output Pulldown
Another unique ISL6118 feature is the active pull down on the
outputs to 300mV above GND when the device is disabled.
Figure 1 illustrates the ISL6118 operational waveforms,
showing the relationships between the various I/O signals
during typical and faulted conditions. It also graphically
highlights many of the terms and modes of operation referred
to in this data sheet.
Fault Blanking on Start-Up
During initial turn-on the ISL6118 prevents nuisance faults from
being reported to the system controller by blanking the fault
signal for 12ms. This blanking eliminates the need for external
RC filters necessary for other vendors’ products.
Using the ISL6118EVAL1 Platform
General and Biasing Information
The ISL6118EVAL1 platform, Figure 14, allows evaluation of
the ISL6118 dual power supply control IC and comparison
against a suitably sized PPTC component.
The evaluation platform is biased and monitored through
numerous test points (TP#). See Table 1 for test point
assignments and descriptions.
TABLE 1. ISL6118EVAL1 TEST POINT ASSIGNMENTS
TP #
TP1
TP2
TP3
TP4
TP5
TP6
TP7
TP8
TP9
TP10
TP11
DESCRIPTION
Eval Board and IC GND
Eval Board +3.3V Bias
Enable Switch 1
Enable Switch 2
Switch 2 Fault
Switch Out 2
Switch Out 1
Switch 1 Fault
IC VIN Pin
PPTC Load Side
Invoke Overcurrent
Current Regulation
The ISL6118 has integrated current sensing on the power
MOSFETs that allows for rapid control of OC events. Once an
OC condition is detected the ISL6118 goes into its current
regulation (CR) control mode. The ISL6118 CR level is set to a
nominal 0.6A and is regulated to within ±25% over full
temperature, bias voltage range and OC magnitude. The
speed of this control is proportional to the level of OC. Thus a
hard OC is more quickly controlled than a marginal condition.
See Figures 4 through 7 for current regulation performance
curves and waveforms.
Latch-Off Time Delay
The primary function of any OC protection device is to quickly
isolate the voltage bus from a faulty load. Unlike other
manufacturers’ IC products that sense the IC thermal condition
to isolate a faulty load, the ISL6118 uses an internal 12ms
timer that starts upon OC detection. Once an OC condition is
detected, the appropriate output is current limited for 12ms to
allow transient conditions to pass before latch-off. The time to
latch-off is independent of the device’s thermal or adjacent
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