ISL54208 Datasheet, PDF (8/15 Pages) Intersil Corporation – Low Voltage, Dual SPDT, USB/CVBS/ Audio Switches, with Negative Signal Capability

Application Block Diagrams
ISL54208
VBUS
VDD
ISL54208
IN
LOGIC CIRCUITRY
4MΩ
COM1
CTRL
NO1
NO2
COM2
50kΩ NC1
NC2
50kΩ
μCONTROLLER
D-
USB
HIGH-SPEED
D+
TRANSCEIVER
NTSC or PAL
VIDEO
AUDIO
GND
LOGIC CONTROL VIA MICRO-PROCESSOR
VDD
VBUS
IN
22kΩ
4MΩ
COM1
ISL54208
LOGIC CIRCUITRY
4MΩ
CTRL
NO1
NO2
COM2
50kΩ NC1
NC2
50kΩ
μCONTROLLER
D-
USB
HIGH-SPEED
D+
TRANSCEIVER
NTSC or PAL
VIDEO
AUDIO
GND
LOGIC CONTROL VIA VBUS VOLTAGE FROM COMPUTER OR USB HUB
Detailed Description
The ISL54208 device is a dual single pole/double throw
(SPDT) analog switch device that can operate from a single
dc power supply in the range of 1.8V to 5.5V. It was
designed to function as a dual 2 to 1 multiplexer to select
between USB differential data signals and mono
audio/composite video baseband signals (CVBS). It comes
in tiny μTQFN and TDFN packages for use in cameras,
camcorders, video MP3 players, PDAs, cell phones, and
other personal media players.
The part consists of two 3Ω audio/video switches and two
5Ω USB switches. The audio/video switches can accept
signals that swing below ground. They were designed to
pass ground reference audio or dc restored with synch
composite video signals with minimal distortion. The USB
switches were designed to pass high-speed USB differential
data signals with minimal edge and phase distortion.
The ISL54208 was specifically designed for digital cameras,
camcorders, MP3 players, cell phones and other personal
media player applications that need to combine the
audio/video jacks and the USB data connector into a single
shared connector, thereby saving space and component
cost. Typical application block diagrams of this functionality
is shown above.
The ISL54208 logic control pins are 1.8V logic compatible
and can be driven by a standard μcontroller. It has a single
logic control pin (IN) that selects between the audio/video
switches and the USB switches. The ISL54208 also contains
a logic control pin (CTRL) that when driven Low while IN is
Low, opens all switches and puts the part into a low power
state, drawing typically 1nA of I_DD current.
A detailed description of the two types of switches is
provided in the sections below. The USB transmission and
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FN6410.0
December 18, 2006