isl54210 Intersil Corporation, isl54210 Datasheet - Page 10

• Manufacturer Part Number: isl54210
• Description: Mp3/usb 2.0 High Speed Switch With Negative Signal Handling/click And Pop Suppression
• Manufacturer: Intersil Corporation

getting through to the headphones, thus eliminating click and
pop noise in the headphones.
The audio switches are active (turned ON) whenever the
V
voltage
USB Switches
The two USB switches (D+, D-) are 5.5Ω bidirectional
switches that were specifically designed to pass high-speed
USB differential signals typically in the range of 0V to
400mV. The switches have low capacitance and high
bandwidth to pass USB high-speed signals (480Mbps) with
minimum edge and phase distortion to meet USB 2.0 signal
quality specifications. See Figure 20 for high-speed eye
pattern taken with switch in the signal path.
These switches can also swing rail-to-rail and pass USB
full-speed signals (12Mbps) with minimal distortion. See
Figure 21 for full-speed eye pattern taken with switch in the
signal path.
The maximum signal range for the USB switches is from
-1.5V to V
allowed to exceed the V
by more than -1.5V.
The USB switches are active (turned ON) whenever the
V
low, so when V
ISL54210 Operation
The following discusses using the ISL54210 in the “Typical
Application Block Diagram” on page 9.
V
The DC power supply connected at V
pin 1 for TDFN) provides the required bias voltage for proper
switch operation. Its voltage should be kept in the range of
2.7V to 3.6V when used in a USB/Audio application to
ensure you get proper switching when the V
its lower limit of 4.4V.
In a typical USB/Audio application for portable battery
powered devices, the V
or an LDO and be in the range of 2.7V to 4.3V. For best
possible USB full-speed operation (12Mbps), it is
recommended that the V
a USB data signal level above 2.7V.
Before power-up and power-down of the ISL54210 part, the
V
tri-stated. This will put the switch in the mute state which
turns all switches OFF and activates the click and pop
circuitry. Which will minimize transients at the speaker loads
during power-up and power-down.
LOGIC CONTROL
The state of the ISL54210 device is determined by the
voltage at the V
and the CTRL pin (pin 9 for µTQFN, pin 10 for TDFN). The
BUS
BUS
DD
BUS
SUPPLY
voltage is
voltage is
and CTRL control pins should be driven to ground or
≥
to 1.4V.
DD
. The signal voltage at D- and D+ should not be
BUS
BUS
≤
≥
V
to V
DD
is floating the USB switches are OFF.
pin (pin 1 for µTQFN, pin 2 for TDFN)
DD
+ 0.2V or floating and the CTRL
DD
DD
DD
+ 0.8V. V
voltage will come from a battery
voltage rail or go below ground
voltage be ≥2.7V in order to get
10
BUS
DD
is internally pulled
(pin 10 for µTQFN,
BUS
voltage is at
ISL54210
part has three states or modes of operation: Audio Mode,
USB Mode and Mute Mode. Refer to the “Truth Table” on
page 2.
The V
4MΩ resistors to ground and can be left floating or tri-stated.
The CTRL control pin is only active when V
Logic Control Voltage Levels:
V
Floating.
V
CTRL = Logic “0” (Low) when
CTRL = Logic “1” (High) when
Audio Mode
If the V
will be in the Audio mode. In Audio mode, the L (left) and R
(right) 2.5Ω audio switches are ON, the D- and D+ 5.5Ω
switches are OFF (high impedance) and the audio click and
pop circuitry is OFF (high impedance).
In a typical application, V
3.6V and will be connected to the battery or LDO of the MP3
player or cellphone. When a headphone is plugged into the
common connector, nothing gets connected at the V
(its internally pulled low) and as long as the CTRL = Logic “1”
the ISL54210 part remains in the audio mode and the audio
drivers of the player can drive the headphones and play
music.
USB Mode
If the V
“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 voltage at the
V
The ISL54210 part will go into the USB mode. In USB mode,
the computer or USB hub transceiver and the MP3 player or
cellphone USB transceiver are connected and digital data
will be able to be transmitted back and forth.
When the USB cable is disconnected the ISL54210
automatically turns the D+ and D- switches OFF.
Mute Mode
If the V
will be in the Mute mode. In the Mute mode, the audio
switches and the USB switches are OFF (high impedance)
and the audio click and pop circuitry is ON.
Before powering down or powering up of the audio CODECs
drivers, the ISL54210 should be put in the Mute mode. In
Mute mode transients present at the L and R signal pins due
to the changing DC voltage of the audio drivers will not pass
to the headphones preventing clicks and pops in the
BUS
BUS
BUS
BUS
= Logic “0” (Low) when V
= Logic “1” (High) when V
pin will be driven to in the range of 4.4V and 5.25V.
BUS
BUS
BUS
pin and CTRL pin are internally pulled low through
pin = Logic “0” and CTRL pin = Logic “1”, the part
pin = Logic “1” and CTRL pin = Logic “0” or Logic
pin = Logic “0” and CTRL pin = Logic “0”, the part
DD
will be in the range of 2.7V to
≤
≥
BUS ≤
0.5V or Floating.
BUS ≥
1.4V
V
V
DD
DD
+ 0.2V or
BUS
+ 0.8V
is logic “0”.
October 3, 2008
BUS
FN6661.1
pin