ISL54222A_10 INTERSIL [Intersil Corporation], ISL54222A_10 Datasheet - Page 10

• Manufacturer Part Number: ISL54222A_10
• Description: High-Speed USB 2.0 (480Mbps) Multiplexer
• Manufacturer: INTERSIL [Intersil Corporation]

in the range of 1.8V to 3.3V, the fault voltage will pass
through to the output of an active switch channel.
During the fault condition normal operation is not
guaranteed until the fault is removed. See the following
“USB 2.0 VBUS Short Requirements” on page 10.
The HS1 channel switches are active (turned ON)
whenever the SEL voltage is logic”0”(Low) and the OE
voltage is logic”0”(Low).
The HS2 channel switches are active (turned ON)
whenever the SEL voltage is logic “1” (High) and the OE
voltage is logic “0” (Low).
ISL54222A Operation
The following will discuss using the ISL54222A shown in
the “Application Block Diagram” on page 9.
POWER
The power supply connected at the VDD pin provides the
DC bias voltage required by the ISL54222A part for
proper operation. The ISL54222A can be operated with a
V
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.
LOGIC CONTROL
The state of the ISL54222A device is determined by the
voltage at the SEL pin and the OE pin. SEL is only active
when the OE pin is logic “0” (Low). Refer to “Truth Table”
on page 2.
The ISL54222A logic pins are designed to minimize
current consumption when the logic control voltage is
lower than the V
logic pins at 1.4V, the part typically draws only 6.6µA.
With V
draws only 0.2µA. Driving the logic pins to the V
supply rail minimizes power consumption. The logic pins
must be driven High or Low and must not float.
LOGIC CONTROL VOLTAGE LEVELS
With V
logic levels are:
OE = Logic “0” (Low) when V
OE = Logic “1” (High) when V
SEL = Logic “0” (Low) when V
SEL = Logic “1” (High) when V
HSD1 USB CHANNEL
If the SEL pin = Logic “0” and the OE pin = Logic “0”,
high-speed Channel 1 will be ON. The HSD1- and HSD1+
switches are ON and the HSD2- and HSD2+ switches are
OFF (high impedance).
When a computer or USB hub is plugged into the
common USB connector and Channel 1 is active, a link
will be established between the USB 1 transceiver section
of the media player and the computer. The device
DD
voltage in the range of 1.8V to 3.3V.
DD
DD
= 1.8V and logic pins at 1.4V, the part typically
supply voltage in the range of 1.8V to 3.3V the
DD
supply voltage. With V
10
OE ≤
OE ≥
SEL ≤
SEL ≥
0.5V
1.4V
0.5V
1.4V
DD
= 3.3V and
DD
ISL54222A
transceiver 1 will be able to transmit and receive data
from the computer.
HSD2 USB Channel
If the SEL pin = Logic “1” and the OE pin = Logic “0”,
high-speed Channel 2 will be ON. The HSD2- and HSD2+
switches are ON and the HSD1- and HSD1+ switches are
OFF (high impedance).
When a USB cable from a computer or USB hub is
connected at the common USB connector and the part
has Channel 2 active, a link will be established between
the USB 2 transceiver section of the media player and
the computer. The device transceiver 2 will be able to
transmit and receive data from the computer.
ALL SWITCHES OFF/LOW POWER MODE
If the SEL pin = Logic “0” or Logic “1” and the OE
pin = Logic “1”, all of 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 1.5µA (max) of
current across the operating temperature range.
The all OFF state can be used to switch between the two
USB sections of the media player. When disconnecting
from one USB device to the other USB device, you can
momentarily put the ISL54222A switch in the “all off”
state in order to get the computer to disconnect from the
one device so it can properly connect to the other USB
device when that channel is turned ON.
USB 2.0 V
The USB 2.0 specification in chapter 7, section 7.1.1
states a USB device must be able to withstand a V
short to the D+ or D- signal lines when the device is
either powered off or powered on for at least 24 hours.
The ISL54222A part has special fault protection circuitry
to meet these short circuit requirements.
The fault protection circuitry allows the signal pins
(D-, D+, HSD1-, HSD1+, HSD2-, HSD2+) to be driven
up to 5.5V while the V
0V to 3.3V. In this overvoltage condition, the part draws
< 300µA of I
to the IC.
In addition, when V
OFF and the shorted V
other side of the switch.
When V
V
(turned ON) switch channel but not through a turned OFF
channel. Any components connected on the active
channel must be able to withstand the overvoltage
condition.
Note: During the fault condition, normal operation of the
USB channel is not guaranteed until the fault condition is
removed.
BUS
voltage will pass through to the output of an active
DD
is in the range of 1.8V to 3.3V, the shorted
BUS
DD
current and causes no stress or damage
Short Requirements
DD
DD
BUS
is at 0V (ground), all switches are
supply voltage is in the range of
voltage is isolated from the
February 4, 2010
FN6902.1
BUS