ISL54228 Datasheet, PDF (11/17 Pages) Intersil Corporation – High-Speed USB 2.0 (480Mbps) DPST Switch with Overvoltage Protection (OVP)

ISL54228
In a typical application, V_DD will be in the range of
2.8V to 4.3V and will be connected to the battery or
LDO of the portable media device.
LOGIC CONTROL
The state of the ISL54228 device is determined by the
voltage at the OE pin, LP pin, and the signal voltage at
the COM pins. Refer to “Truth Table” on page 2.
The OE and LP pins are internally pulled low through a
4MΩ resistor to ground and can be tri-stated or left
floating.
The ISL54228 is designed to minimize I_DD current
consumption when the logic control voltage is lower than
the V_DD supply voltage. With V_DD = 3.6V and the OE
logic pin is at 1.4V, the part typically draws only 25µA.
With V_DD = 4.3V and the OE logic pin is at 2.6V, the part
typically draws only 35µA. Driving the logic pin to the
V_DD supply rail minimizes power consumption.
The OE and LP pin can be driven with a voltage higher
than the V_DD supply voltage. It can be driven up to
5.25V with a V_DD supply in the range of 2.7V to 5.25V.
TABLE 2. LOGIC CONTROL VOLTAGE LEVELS
LOGIC = “0” (LOW)
V_DD SUPPLY
RANGE
OE
LP
LOGIC = “1”
(HIGH)
OE
LP
2.7V to 3.6V
≤ 0.5V
or
floating
≤ 0.5V
or
floating
≥1.4V
≥1.4V
3.7V to 4.2V
≤ 0.7V
or
floating
≤ 0.7V
or
floating
≥1.7V
≥1.7V
4.3V to 5.25V
≤ 0.8V
or
floating
≤ 0.8V
or
floating
≥2.0V
≥2.0V
Low Power Mode
If the OE pin = Logic “0”, and the LP pin = Logic “1” the
switches will turn OFF (high impedance) and the part
will be put in a low power mode. In this mode, the part
draws only 10µA (max) of current across the operating
temperature range.
Normal Operation Mode
With a signal level in the range of 0V to 3.6V and with
the LP pin = Logic “0” the switches will be ON when the
OE pin = Logic “1” and will be OFF (high impedance)
when the OE pin = Logic “0”.
USB 2.0 V_BUS Short Requirements
The USB specification in section 7.1.1 states a USB
device must be able to withstand a V_BUS short (4.4V to
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 ISL54228 part has special power-off protection and
OVP detection circuitry to meet these short circuit
requirements. This circuitry allows the ISL54228 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_DD supply voltage is in the range
of 0V to 5.25V. In these overvoltage conditions, the part
draws < 55µA of current into the COM pins and causes
no stress/damage to the IC. In addition, all switches are
OFF and the shorted V_BUS voltage will be isolated from
getting through to the other side of the switch channels,
thereby protecting the USB transceiver.
11
FN7628.0
July 29, 2010