ISL54416 Datasheet, PDF (11/14 Pages) Intersil Corporation – Low Voltage, Dual SPDT, USB/CVBS/ Audio Switches with Negative Signal Capability

ISL54415, ISL54416, ISL54417
ISL54415 and ISL54416 Operation
The ISL54415 and ISL54416 function the same except the
ISL54416 does not have the V_TERM feature. The discussion
that follows pertains to both devices and will discuss using the
parts in the typical application shown in the block diagram on
page 10.
LOGIC CONTROL
The state of the ISL54415 and ISL54416 devices are
determined by the voltage at the V_BUS pin (pin 2). The V_BUS
pin is internally pulled low and can be left floating.
If V_BUS (pin 2) is floating or the V_BUS voltage ≤ V_DD + 0.2V
the part will be in the audio/video mode. In Audio/Video
mode the NC1 and NC2 1Ω audio/video switches are ON
and the NO1 and NO2 5Ω USB switches are OFF (high
impedance). In this state power to the part is provided by the
DC voltage connected at the V_DD pin (pin 1). In a typical
application V_DD will be in the range of 2.5V to 3.6V and will
be connected to the battery or LDO of the media player.
When a headphone/video receiver is plugged into the
common connector, nothing gets connected at the V_BUS pin
(its floating) and the ISL54415 and ISL54416 parts remains
in the audio/video mode and the media player audio and
video drivers can drive the headphones and video display.
If V_BUS (pin 2) voltage is greater than V_DD by 0.8V the part
will go into USB mode. In USB mode the NO1 and NO2 5Ω
USB switches are ON and the NC1 and NC2 1Ω audio/video
switches are OFF (high impedance). In this state the part will
be powered by the voltage connected at the V_BUS pin (pin
2). When a USB cable from a computer or USB hub is
connected at the common connector the V_BUS voltage is
driven to between 4.4V and 5.25V. The ISL54415 and
ISL54416 parts will go into the USB mode. In USB mode the
computer or USB hub transceiver and the media player USB
transceiver are connected and digital data will be able to be
transmit back and forth.
When the USB cable is disconnected the switch
automatically turns the NO1 and NO2 switches OFF and
turns the NC1 and NC2 audio/video switches ON.
POWER
In audio/video mode the power supply connected at V_DD
(pin 1) provides power to the ISL54415 and ISL54416 parts.
Its voltage should be kept in the range of 2.5V to 3.6V when
used in a USB application to ensure you get proper
switching when the V_BUS voltage is at its lower limit of 4.4V.
In USB mode power for the ISL54415 and ISL54416 parts is
provided from the V_BUS line from the host USB controller of
the computer or USB hub. Its voltage will be between 4.4V
and 5.25V.
V_TERM OPERATION (ISL54415 ONLY)
When a USB cable from a computer is connected to a USB
device a V_TERM voltage must be applied to a speed
indicating pull-up resistor to properly terminate the bus and
identify whether the USB device is a full-speed or low-speed
device to facilitate proper digital transmission. When the
cable is removed from the device this V_TERM voltage must
be disconnected from the speed indicating pullup resistor.
The ISL54415 device can perform this operation.
When V_DD ≥ 2.5V and V_BUS ≥ V_DD + 0.8V, the V_TERM pin
(pin 10) outputs an open circuit voltage equal to the voltage
at the V_BUS pin. Otherwise the V_TERM pin will be in a HI-Z
state.
The ISL54415 V_TERM circuitry has an internal series resistor
approximately equal to 5.3kΩ. For a full-speed USB
application it is recommended you use a 3kΩ ±5% speed
indicating pull-up resistor. When the USB bus is in the idle
state, a 3kΩ ±5% resistor will put the D+ line voltage in the
range of 2.7V to 3.6V as required by the USB specification.
For low-speed USB application it is recommend you use a
2kΩ ±5% pull-up resistor at the D- line in order to meet the
USB connect and disconnect timing requirements.
ISL54417 Operation
The ISL54417 is an audio/video and data switch. Its logic
control is typical of a standard dual SPDT switch.
The digital control for the ISL54417 are the IN pins (pin 2
and pin 10). These pins are 1.8V logic compatible when
operated with a 3.0V supply. The device has been designed
to have low I_DD current even when the logic voltage is not at
the rail. With V_DD = 5.5V and V_IN = 2.85V the ISL54417
draws only 8µA current.
When logic pin IN1 (pin 10) is LOW the NC1 audio/video
switch is ON and the NO1 USB data switch is OFF. When
logic pin IN1 (pin 10) is HIGH the NC1 audio/video switch is
OFF and the NO1 USB data switch is ON.
When logic pin IN2 (pin 2) is LOW the NC2 audio/video
switch is ON and the NO2 USB data switch is OFF. When
logic pin IN2 (pin 2) is HIGH the NC2 audio/video switch is
OFF and the NO2 USB data switch is ON.
Power for the ISL54417 device is always provided by the DC
voltage source connected at the V_DD pin (pin 1). The V_DD
power supply voltage range is from 1.8V to 5.5V.
11
FN6318.1
June 27, 2006