isl54210 Intersil Corporation, isl54210 Datasheet - Page 9

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

Typical Application Block Diagram
Detailed Description
The ISL54210 device is a dual single pole/double throw
(SPDT) analog switch that operates from a single DC power
supply in the range of 2.7V to 3.6V. It was designed to
function as a dual 2 to 1 multiplexer to select between USB
differential data signals and audio L and R stereo signals. It
comes in tiny µTQFN and TDFN packages for use in MP3
players, PDAs, cellphones, and other personal media
players.
The part consists of two 2.5Ω audio switches and two 5.5Ω
USB switches. The audio switches can accept signals that
swing below ground. They were designed to pass audio left
and right stereo signals, that are ground referenced, with
minimal distortion. The USB switches were designed to pass
high-speed USB differential data signals with minimal edge
and phase distortion.
The ISL54210 was specifically designed for MP3 players,
personal media players and cellphone applications that need
to combine the audio headphone jack and the USB data
connector into a single shared connector, thereby saving
space and component cost. A “Typical Application Block
Diagram” of this functionality is shown on page 9.
The ISL54210 incorporates circuitry for the detection of the
USB V
audio CODEC drivers and USB transceiver of the MP3
player or cellphone. The ISL54210 contains a logic control
pin (CTRL) that when driven low while V
switches and activates the audio click and pop circuitry.
A detailed description of the two types of switches are
provided in the following sections. In a typical application,
BUS
voltage, which is used to switch between the
V
BUS
9
BUS
COM -
COM +
is low, opens all
V
BUS
4MΩ
200kΩ
200kΩ
LOGIC CONTROL
3.3V
GND
ISL54210
ISL54210
V
DD
CLICK
POP
AND
the USB transmission and audio playback are intended to be
mutually exclusive operations.
Audio Switches
The two audio switches (L, R) are 2.5Ω switches that can
pass signals that swing below ground. Crosstalk between
the audio switches is <-100dB over the audio band. These
switches have excellent off-isolation >105dB over the audio
band with a 32Ω load.
Over a signal range of
these switches have an extremely low r
variation. They can pass ground referenced audio signals
with very low distortion (<0.06% THD+N) when delivering
15.6mW into a 32Ω headphone speaker load. See Figures
16, 17, 18, and 19 THD+N in “Typical Performance Curves”.
The audio drivers should be connected at the L and R side of
the switch (pins 5 and 6 for µTQFN, pins 6 and 7 for TDFN)
and the speaker loads should be connected at the COM side
of the switch (pins 2 and 3 for µTQFN, pins 3 and 4 for
TDFN).
The audio switches have click and pop circuitry on the L and
R side that is activated when the V
0.2V or floating and the CTRL voltage
The ISL54210 should be put in this mode before powering
down or powering up of the audio CODEC drivers. In this
mode, both the audio and USB in-line switches will be OFF
and the audio click and pop circuitry will be ON. The high
off-isolation of the audio switches along with the click and
pop circuitry will isolate the transients generated during
power-up and power-down of the audio CODECs from
4MΩ
CTRL
D-
D+
R
L
±
1V (0.707V
µCONTROLLER
TRANSCEIVER
HIGH-SPEED
CODEC
AUDIO
USB
BUS
RMS
≤
ON
voltage is
) with V
to 0.5V or floating.
resistance
DD
October 3, 2008
≤
> 2.7V,
V
DD
FN6661.1
+