ISL54226 INTERSIL [Intersil Corporation], ISL54226 Datasheet - Page 11

• Manufacturer Part Number: ISL54226
• Description: High-Speed USB 2.0 (480Mbps) DPST Switch with Overvoltage Protection (OVP) and Dedicated Charger Port Detection
• Manufacturer: INTERSIL [Intersil Corporation]

ISL54226 Operation
The following will discuss using the ISL54226 shown in
the “Application Block Diagram” on page 8.
Power
The power supply connected at the VDD pin provides the
DC bias voltage required by the ISL54226 part for proper
operation. The ISL54226 can be operated with a V
voltage in the range of 2.7V to 5.25V.
For lowest power consumption you should use the lowest
VDD supply.
A 0.01µF or 0.1µF decoupling capacitor should be
connected from the VDD pin to ground to filter out any
power supply noise from entering the part. The capacitor
should be located as close to the VDD pin as possible.
In a typical application, V
to 4.3V and will be connected to the battery or LDO of
the portable media device.
Logic Control
The state of the ISL54226 device is determined by the
voltage at the OE/ALM pin and the signal voltage at the
COM pins. Refer to “Truth Table” on page 2.
The OE/ALM pin is internally pulled low through 4MΩ
resistors to ground and can be tri-stated by a µProcessor.
The OE/ALM pin is an open drain connection. It should be
pulled high through an external 100kΩ pull-up resistor.
The OE/ALM pin can then be driven “Low” by a
µProcessor to open all switches or it can be monitored by
the µProcessor for a “Low” when the part goes into an
overvoltage condition.
The ISL54226 is designed to minimize I
consumption when the logic control voltage is lower than
the V
OE/ALM logic pin is at 1.4V the part typically draws only
25µA. With V
2.6V the part typically draws only 35µA. Driving the logic
pin to the V
The OE/ALM pin can be driven with a voltage higher than
the V
a V
DD
DD
DD
supply in the range of 2.7V to 5.25V.
supply voltage. It can be driven up to 5.25V with
supply voltage. With V
DD
DD
supply rail minimizes power consumption.
= 4.3V and the OE/ALM logic pin is at
DD
11
will be in the range of 2.8V
DD
= 3.6V and the
DD
current
DD
ISL54226
Normal Operation Mode
With a signal level in the range of 0V to 3.6V the
switches will be ON when the OE/ALM pin = Logic “1”
and will be OFF (high impedance) when the OE/ALM
pin = Logic “0”.
USB 2.0 V
The USB specification in section 7.1.1 states a USB
device must be able to withstand a V
5.25V) or a -1V short to the D+ or D- signal lines when
the device is either powered off or powered on for at
least 24 hours.
The ISL54226 part has special power-off protection and
OVP detection circuitry to meet these short circuit
requirements. This circuitry allows the ISL54226 to
provide protection to the USB down-stream transceiver
connected at its signal pins (D-, D+) to meet the USB
specification short circuit requirements.
The power-off protection and OVP circuitry allows the
COM pins (COM-, COM+) to be driven up to 5.25V or
down to -5V while the V
of 0V to 5.25V. In these overvoltage conditions with a
500Ω external VDD resistor the part draws <55
current into the COM pins and causes no stress/damage
to the IC. In addition all switches are OFF and the
shorted V
through to the other side of the switch channels, thereby
protecting the USB transceiver.
V
4.3V to 5.25V
2.7V to 3.6V
3.7V to 4.2V
DD
TABLE 2. LOGIC CONTROL VOLTAGE LEVELS
RANGE
SUPPLY
BUS
BUS
voltage will be isolated from getting
Short Requirements
LOGIC = “0”
DD
OE/ALM
(LOW)
floating
floating
floating
≤0.8V
≤0.5V
≤0.7V
supply voltage is in the range
or
or
or
BUS
LOGIC = “1”
short (4.4V to
OE/ALM
(HIGH)
≥1.4V
≥1.7V
≥2.0V
July 29, 2010
µ
A of
FN7614.0