ISL54213 Datasheet, PDF (10/15 Pages) Intersil Corporation – MP3/USB 2.0 High Speed Switch with Negative Signal Handling and Mute Function

ISL54213
of the ISL54213 low. As long as the CTRL = Logic “1,” the
ISL54213 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+ 5.5Ω 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 VBUS voltage and drive the IN
pin voltage high. The ISL54213 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 V_BUS voltage is no longer connected and
will drive the IN pin low and put the part back into the Audio
or Mute mode.
Mute Mode
If the IN pin = Logic “0” and CTRL pin = Logic “0”, the part
will be in the Mute mode. In the Mute mode, the audio
switches and the USB switches are OFF (high impedance).
In this state the switches have excellent off-isolation (112dB
over the audio band with a 32Ω load) for muting of audio
signals.
from the computer or USB hub. See the application block
diagram in Figure 9.
When a headphone or nothing is connected at the common
connector, the internal 4MΩ pull-down will pull the IN pin low
putting the ISL54213 in the Audio or Mute 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 or Mute mode,
depending on the condition of the CTRL pin.
Note: The ISL54213 contains an internal diode between the
IN pin and VDD pin. Whenever the IN voltage is greater than
the V_DD voltage by more than 0.7V, current will flow through
this diode into the V_DD power supply bus. An external series
resistor in the range of 100kΩ to 500kΩ is required at the IN
logic pin to limit the current when driving it with the V_BUS
voltage. This allows the V_BUS voltage from a computer or
USB hub (4.4V to 5.25V) to drive the IN pin while the V_DD
voltage is in the range of 2.5V to 3.6V. A 500kΩ resistor will
limit the current to 2.76µA and still allow the IN logic voltage
to go to around 3.67V which is will above the required V_INH
level of 1.4V. A smaller series resistor can be used but more
current will flow.
USING THE COMPUTER V_BUS VOLTAGE TO DRIVE THE
“IN” PIN
Rather than using a microprocessor to control the IN logic
pin, one can directly drive the IN pin using the V_BUS voltage
Typical Performance Curves T_A = +25°C, Unless Otherwise Specified.
0.11
0.10
R_LOAD = 32Ω
V_LOAD = 0.707V_RMS
0.10
R_LOAD = 32Ω
V_DD = 3V
0.08
0.09
3V_P-P
2.5V_P-P
0.08
0.07
V_DD = 2.6V
0.06
2V_P-P
0.06
0.05
V_DD = 2.7V
V_DD = 3V
V_DD = 3.6V
0.04
1V_P-P
0.04
20
200
2k
20k
FREQUENCY (Hz)
FIGURE 10. THD+N vs SUPPLY VOLTAGE vs FREQUENCY
0.02
20
200
2k
20k
FREQUENCY (Hz)
FIGURE 11. THD+N vs SIGNAL LEVELS vs FREQUENCY
10
FN6663.0
March 26, 2008