ILC7526-IK Impala Linear Corporation, ILC7526-IK Datasheet - Page 5

• Manufacturer Part Number: ILC7526-IK
• Description: USB DUAL CONTROL SWITCHES
• Manufacturer: Impala Linear Corporation

Undervoltage Lockout
UVLO (undervoltage lockout) prevents the output MOS-
FET from turning on until V
In the undervoltage state, the FLAG will be low. After the
switch turns on, if the voltage drops below approximately
2.3V, UVLO shuts off the output MOSFET and signals fault
flag. Undervoltage detection functions only when at least
one switch is enabled.
Current Sensing and Limiting
The current-limit threshold is preset internally. The pre-
set level prevents damage to the output MOSFET and
external load but allows a minimum current of 0.5A
through the output MOSFET of each channel. The cur-
rent-limit circuit senses a portion of the output FET
switch current. The reaction to an overcurrent condition
varies with three scenarios:
Switch Enabled into Short Circuit
If a switch is powered on or enabled into a heavy load or
short circuit, the switch immediately goes into a constant-
current mode, reducing the output voltage. The fault flag
goes low until the load is reduced.
Short Circuit Applied to Output
When a heavy load is applied, a large transient current may
flow until the current limit circuitry will respond. Once this
occurs, the device limits current to less than the short-circuit
current limit specification.
Current-Limit Response
The ILC7526 current-limit profile exhibits a small foldback
effect of approximately 500mA.
threshold is exceeded the device enters constant-current
mode. This constant current is specified as the short circuit
current limit in the “Electrical Characteristics” table. it is
important to note that the device will deliver load current up
to the current-limit threshold which is typically 1.6A
Fault Flag
FLG is an N-channel, open-drain MOSFET output. The fault-
flag is active (low) for one or more of the following conditions:
undervoltage (while 2V < V
shutdown. The flag output MOSFET is capable of sinking a
10mA load to typically 100mV above ground. Multiple FLG
pins may be wired “NORed” to a common pull-up resistor.
ILC75267536 1.5
USB Dual Control Switches
Impala Linear Corporation
IN
IN
< 2.7), current limit, or thermal
exceeds approximately 2.5V.
Once this current-limit
[phone]
Supply Filtering
A 0.1µF to 1µF bypass capacitor from IN to GND, located at
the device, is strongly recommended to control supply tran-
sients. Without a bypass capacitor, an output short may
cause sufficient ringing on the input (from supply lead induc-
tance) to damage internal control circuitry. Input or output
transients must not exceed the absolute maximum output
supply voltage (V
Enable Input
EN must be driven logic high or logic low for a clearly
defined input.
dictable operation. EN should not be allowed to go neg-
ative with respect to GND.
Soft-Start
The ILC7526 presents a high impedance when off, and
slowly becomes a low impedance as it turns on. This
reduces in rush current and related voltage drop that
results from charging a capacitive load, satisfying the USB
voltage drop requirements for bus-powered applications.
A
www.impalalinear.com
PPLICATIONS
FLGB
FLGA
ENB
ENA
ILC7526
I
IN MAX
NFORMATION
Floating the input may cause unpre-
OUTA
OutB
GND
= 6V) even for a short duration.
IN
3.0V to 5.5V
0.1µF to 1µF
Dec 2000
Preliminary
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