isl54209 Intersil Corporation, isl54209 Datasheet - Page 10

• Manufacturer Part Number: isl54209
• Description: Mp3/usb 2.0 High Speed Switch With Negative Signal Handling And Low Power Shutdown
• Manufacturer: Intersil Corporation

(right) 2.5Ω audio switches are ON and the D- and D+ 5Ω
switches are OFF (high impedance).
When nothing is plugged into the common connector or a
headphone is plugged into the common connector, the
µprocessor will sense that there is no voltage at the V
pin of the connector and will drive and hold the IN control pin
of the ISL54209 low. As long as the CTRL = Logic “1,” the
ISL54209 part will be in the audio mode and the audio
drivers of the media player can drive the headphones and
play music.
USB Mode
If the IN pin = Logic “1” and CTRL pin = Logic “0” or Logic
“1”, the part will go into USB mode. In USB mode, the D- and
D+ 5Ω switches are ON and the L and R 2.5Ω audio
switches are OFF (high impedance).
When a USB cable from a computer or USB hub is
connected at the common connector, the µprocessor will
sense the presence of the 5V V
voltage high. The ISL54209 part will go into the USB mode.
In USB mode, the computer or USB hub transceiver and the
MP3 player or cell phone USB transceiver are connected
and digital data will be able to be transmitted back and forth.
When the USB cable is disconnected, the µprocessor will
sense that the 5V VBUS voltage is no longer connected and
will drive the IN pin low and put the part back into the Audio
or Low Power Mode.
Low Power Mode
If the IN pin = Logic “0” and CTRL pin = Logic “0”, the part
will be in the Low Power mode. In the Low Power mode, the
audio switches and the USB switches are OFF (high
impedance). In this state, the device draws typically 1nA of
current.
10
BUS
and drive the IN pin
BUS
ISL54209
In Low Power mode, the off-isolation and crosstalk between
switch cells is minimal for negative swinging signals. Care
should be taken to avoid negative swinging signals in this
mode of operation. In typical applications, the Low Power
state will be applied to the ISL54209 part when the portable
media player is in its sleep or hibernate mode to conserve
battery power. In the sleep mode, no audio or USB signals
are applied to the part.
USING THE COMPUTER V
“IN” PIN
External IN Pull-Down Resistor
Rather than using a micro-processor to control the IN logic
pin, one can directly drive the IN pin using the V
from the computer or USB hub.
When a headphone or nothing is connected at the common
connector, the internal 4Ω pull-down will pull the IN pin low
putting the ISL54209 in the Audio mode or Low Power
mode, depending on the condition of the CTRL pin.
When a USB cable is connected at the common connector,
the voltage at the IN pin will be driven to 5V and the part will
automatically go into the USB mode.
When the USB cable is disconnected from the common
connector, the voltage at the IN pin will be pulled low by the
pull-down resistor and return to the Audio Mode or Low
Power Mode, depending on the condition of the CTRL pin.
Note: The voltage at the IN pin can exceed the VDD voltage
by as much as 2.55V when VDD
VBUS voltage from a computer or USB hub (4.4V to 5.25V)
to drive the IN pin while the V
2.5V to 3.6V.
BUS
DD
VOLTAGE TO DRIVE THE
voltage is in the range of
≤
3.6V. This allows the
December 20, 2007
BUS
voltage
FN6627.0