ISL54200 Datasheet, PDF (9/18 Pages) Intersil Corporation – USB 2.0 High/Full Speed Multiplexer

ISL54200
Application Block Diagram
3.3V
VBUS
D-
D+
GND
VDD
ISL54200
IN
LOGIC
COMD1
COMD2
GND
EN
4MΩ
HSD1
HSD2
FSD1
FSD2
µCONTROLLER
USB
HIGH-SPEED
TRANSCEIVER
USB
FULL-SPEED
TRANSCEIVER
PORTABLE MEDIA DEVICE
Detailed Description
The ISL54200 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 5.5V. It was
designed to function as a dual 2-to-1 multiplexer to
select between a USB high-speed transceiver and a USB
full-speed transceiver in portable battery powered
products. It is offered in a TDFN package and a small
µTQFN package for use in MP3 players, cameras, PDAs,
cellphones, and other personal media players. The device
has an enable pin to open all switches.
The part consists of two 7Ω full speed (FSx) switches and
two 4.5Ω high speed (HSx) switches. The FSx switches
can swing from 0V to V_DD. They were designed to pass
USB full speed (12Mbps) differential data signals with
minimal distortion. The HSx switches have high
bandwidth and low capacitance to pass USB high-speed
(480Mbps) differential data signals with minimal edge
and phase distortion.
The ISL54200 was designed for MP3 players, cameras,
cellphones, and other personal media player applications
that have both high-speed and full-speed transceivers
and need to multiplex between these USB sources to a
single USB host (computer). A typical application block
diagram of this functionality is shown on page 9.
A detailed description of the two types of switches are
provided in the following sections.
FSx Switches (FSD1, FSD2)
The two FSx switches (FSD1, FSD2) are bidirectional
switches that can pass rail-to-rail signals. When powered
with a 3.3V supply, these switches have a nominal r_ON
resistance of 7Ω over the signal range of 0V to 3.3V. They
were specifically designed to pass USB full-speed
(12Mbps) differential signals and meet the USB 2.0 full-
speed signal quality specifications. See Figure 8.
The FSx switches can also pass USB high speed signals
(480Mbps) but do not quite meet the USB 2.0 high speed
signal quality eye diagram compliance requirement.
The maximum signal range for the FSx switches is from
-1.5V to V_DD. The signal voltage should not be allowed to
exceed the V_DD voltage rail or go below ground by more
than -1.5V.
When operated with a 2.7V to 3.6V supply, the FSx
switches are active (turned ON) whenever the IN logic
control voltage is ≤0.5V and the EN logic voltage ≥1.4V.
HSx Switches (HSD1, HSD2)
The two HSx switches (HSD2, HSD1) are bi-directional
switches that can pass rail-to-rail signals. When powered
with a 3.3V supply, these switches have a nominal r_ON of
4.5Ω over the signal range of 0V to 400mV with a r_ON
flatness of 0.4Ω. The r_ON matching between the HSD1
and HSD2 switches over this signal range is only 0.01Ω,
ensuring minimal impact by the switches to USB high
speed signal transitions. As the signal level increases, the
r_ON switch resistance increases. At signal level of 3.3V,
the switch resistance is nominally 20Ω.
The HSx switches were specifically designed to pass USB
2.0 high-speed (480Mbps) differential signals typically in
the range of 0V to 400mV. They have low capacitance
and high bandwidth to pass the USB high-speed signals
with minimum edge and phase distortion to meet USB
2.0 high speed signal quality specifications. See Figures 9
and 10.
The HSx switches can also pass USB full-speed signals
(12Mbps) with minimal distortion and meet all the USB
9
FN6408.2
June 17, 2010