isl54220 Intersil Corporation, isl54220 Datasheet - Page 8

• Manufacturer Part Number: isl54220
• Description: High-speed Usb 2.0 480mbps Multiplexer
• Manufacturer: Intersil Corporation

the other side of the switch. When V
2.7V to 5.5V the fault voltage will pass through to the output
of an active switch channel.
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).
ISL54220 Operation
The following will discuss using the ISL54220 shown in the
“Application Block Diagram” on page 7.
POWER
The power supply connected at the VDD pin provides the
DC bias voltage required by the ISL54220 part for proper
operation. The ISL54220 can be operated with a VDD
voltage in the range of 2.7V to 5.5V. When used in a USB
application, the VDD voltage should be kept in the range of
3.0V to 5.5V to ensure you get the proper signal levels for
good signal quality.
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
4.3V and will be connected to the battery or LDO of the
portable media device.
LOGIC CONTROL
The state of the ISL54220 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 ISL54220 logic pins are designed to minimize current
consumption when the logic control voltage is lower than the
V
the part typically draws only 6.6µA. With V
logic pins at 2.6V the part typically draws only 0.2µA. Driving
the logic pins to the V
consumption.
The logic pins must be held 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
DD
supply voltage. With V
DD
supply voltage in the range of 2.7V to 3.6V the
DD
DD
supply rail minimizes power
DD
will be in the range of 2.8V to
OE ≤
OE ≥
8
SEL ≤
SEL ≥
= 3.6V and logic pins at 1.4V
0.5V
1.4V
DD
0.5V
1.4V
is in the range of
DD
= 4.3V and
ISL54220
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 one is active, a link will be
established between the USB 1 driver section of the media
player and the computer. The device will be able to transmit
and receive data from the computer at a data rate of
480Mbps.
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 driver section of the media player and the computer. The
device will be able to transmit and receive data from the
computer at a data rate of 480Mbps.
All Switches OFF 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).
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 ISL54220 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 specification in section 7.1.1 states a USB device
must be able to withstand a V
signal lines when the device is either powered off or
powered on for at least 24 hours. The ISL54220 part has
special fault protection circuitry to meet these short circuit
requirements.
The fault protection circuitry allows the signal pins (D-, D+,
HS1D-, HS1D+, HS2D-, HS2D+) to be driven up to 5.5V
while the V
this overvoltage condition the part draws < 500µA of current
and causes no stress/damage to the IC.
DD
supply voltage in the range of 4.3V to 5.5V the
DD
BUS
supply voltage is in the range of 0V to 5.5V. In
Short Requirments
OE ≤
OE ≥
BUS
SEL ≤
SEL ≥
0.8V
short to the D+ or D-
2.0V
0.8V
2.0V
December 16, 2008
FN6819.0